text: /**
   * pugihtml parser - version 0.1
   * --------------------------------------------------------
   * Copyright (c) 2012 Adgooroo, LLC (kgantchev [AT] adgooroo [DOT] com)
   *
   * This library is distributed under the MIT License. See notice in license.txt
   *
   * This work is based on the pugxml parser, which is: 
   * Copyright (C) 2006-2010, by Arseny Kapoulkine (arseny [DOT] kapoulkine [AT] gmail [DOT] com)
   */
  
  #include "pugihtml.hpp"
  #include "pugiutil.hpp"
  #include "memory.hpp"
  #include <stdlib.h>
  #include <stdio.h>
  #include <string.h>
  #include <assert.h>
  #include <setjmp.h>
  #include <wchar.h>
  #include <set>
  
  #ifndef PUGIHTML_NO_XPATH
  #	include <math.h>
  #	include <float.h>
  #endif
  
  #ifndef PUGIHTML_NO_STL
  #	include <istream>
  #	include <ostream>
  #	include <string>
  #   include <algorithm>
  #endif
  
  // For placement new
  #include <new>
  
  #ifdef _MSC_VER
  #	pragma warning(disable: 4127) // conditional expression is constant
  #	pragma warning(disable: 4324) // structure was padded due to __declspec(align())
  #	pragma warning(disable: 4611) // interaction between '_setjmp' and C++ object destruction is non-portable
  #	pragma warning(disable: 4702) // unreachable code
  #	pragma warning(disable: 4996) // this function or variable may be unsafe
  #endif
  
  #ifdef __INTEL_COMPILER
  #	pragma warning(disable: 177) // function was declared but never referenced 
  #	pragma warning(disable: 1478 1786) // function was declared "deprecated"
  #endif
  
  #ifdef __BORLANDC__
  #	pragma warn -8008 // condition is always false
  #	pragma warn -8066 // unreachable code
  #endif
  
  #ifdef __SNC__
  #	pragma diag_suppress=178 // function was declared but never referenced
  #	pragma diag_suppress=237 // controlling expression is constant
  #endif
  
  // uintptr_t
  #if !defined(_MSC_VER) || _MSC_VER >= 1600
  #	include <stdint.h>
  #else
  #	if _MSC_VER < 1300
  // No native uintptr_t in MSVC6
  typedef size_t uintptr_t;
  #	endif
  typedef unsigned __int8 uint8_t;
  typedef unsigned __int16 uint16_t;
  typedef unsigned __int32 uint32_t;
  typedef __int32 int32_t;
  #endif
  
  // Inlining controls
  #if defined(_MSC_VER) && _MSC_VER >= 1300
  #	define PUGIHTML_NO_INLINE __declspec(noinline)
  #elif defined(__GNUC__)
  #	define PUGIHTML_NO_INLINE __attribute__((noinline))
  #else
  #	define PUGIHTML_NO_INLINE 
  #endif
  
  // Simple static assertion
  #define STATIC_ASSERT(cond) { static const char condition_failed[(cond) ? 1 : -1] = {0}; (void)condition_failed[0]; }
  
  // Digital Mars C++ bug workaround for passing char loaded from memory via stack
  #ifdef __DMC__
  #	define DMC_VOLATILE volatile
  #else
  #	define DMC_VOLATILE
  #endif
  
  using namespace pugihtml;
  // String utilities
  namespace
  {
  	// Get string length
  	size_t strlength(const char_t* s)
  	{
  		assert(s);
  
  	#ifdef PUGIHTML_WCHAR_MODE
  		return wcslen(s);
  	#else
  		return strlen(s);
  	#endif
  	}
  
  	// Compare two strings
  	bool strequal(const char_t* src, const char_t* dst)
  	{
  		assert(src && dst);
  
  	#ifdef PUGIHTML_WCHAR_MODE
  		return wcscmp(src, dst) == 0;
  	#else
  		return strcmp(src, dst) == 0;
  	#endif
  	}
  
  	// Compare lhs with [rhs_begin, rhs_end)
  	bool strequalrange(const char_t* lhs, const char_t* rhs, size_t count)
  	{
  		for (size_t i = 0; i < count; ++i)
  			if (lhs[i] != rhs[i])
  				return false;
  	
  		return lhs[count] == 0;
  	}
  #ifdef PUGIHTML_NO_STL
      char_t* find_first_of(char_t* first1,char_t* last1,char_t* first2,char_t* last2){
          for ( ; first1 != last1; ++first1 )
              for (char_t* it=first2; it!=last2; ++it)
                  if (*it==*first1)          // or: if (comp(*it,*first)) for the pred version
                      return first1;
          return last1;
      }
  #else
  #define find_first_of std::find_first_of
  #endif
  	
  #ifdef PUGIHTML_WCHAR_MODE
  	// Convert string to wide string, assuming all symbols are ASCII
  	void widen_ascii(wchar_t* dest, const char* source)
  	{
  		for (const char* i = source; *i; ++i) *dest++ = *i;
  		*dest = 0;
  	}
  #endif
  }
  
  #if !defined(PUGIHTML_NO_STL) || !defined(PUGIHTML_NO_XPATH)
  // auto_ptr-like buffer holder for exception recovery
  namespace
  {
  	struct buffer_holder
  	{
  		void* data;
  		void (*deleter)(void*);
  
  		buffer_holder(void* data, void (*deleter)(void*)): data(data), deleter(deleter)
  		{
  		}
  
  		~buffer_holder()
  		{
  			if (data) deleter(data);
  		}
  
  		void* release()
  		{
  			void* result = data;
  			data = 0;
  			return result;
  		}
  	};
  }
  #endif
  
  namespace pugihtml
  {
  	/// A 'name=value' HTML attribute structure.
  	struct html_attribute_struct
  	{
  		/// Default ctor
  		html_attribute_struct(html_memory_page* page): header(reinterpret_cast<uintptr_t>(page)), name(0), value(0), prev_attribute_c(0), next_attribute(0)
  		{
  		}
  
  		uintptr_t header;
  
  		char_t* name;	///< Pointer to attribute name.
  		char_t*	value;	///< Pointer to attribute value.
  
  		html_attribute_struct* prev_attribute_c;	///< Previous attribute (cyclic list)
  		html_attribute_struct* next_attribute;	///< Next attribute
  	};
  
  	/// An HTML document tree node.
  	struct html_node_struct
  	{
  		/// Default ctor
  		/// \param type - node type
  		html_node_struct(html_memory_page* page, html_node_type type): header(reinterpret_cast<uintptr_t>(page) | (type - 1)), parent(0), name(0), value(0), first_child(0), prev_sibling_c(0), next_sibling(0), first_attribute(0)
  		{
  		}
  
  		uintptr_t header;
  
  		html_node_struct*		parent;					///< Pointer to parent
  
  		char_t*					name;					///< Pointer to element name.
  		char_t*					value;					///< Pointer to any associated string data.
  
  		html_node_struct*		first_child;			///< First child
  		
  		html_node_struct*		prev_sibling_c;			///< Left brother (cyclic list)
  		html_node_struct*		next_sibling;			///< Right brother
  		
  		html_attribute_struct*	first_attribute;		///< First attribute
  	};
  }
  
  namespace
  {
  	struct html_document_struct: public html_node_struct, public html_allocator
  	{
  		html_document_struct(html_memory_page* page): html_node_struct(page, node_document), html_allocator(page), buffer(0)
  		{
  		}
  
  		const char_t* buffer;
  	};
  
  	static inline html_allocator& get_allocator(const html_node_struct* node)
  	{
  		assert(node);
  
  		return *reinterpret_cast<html_memory_page*>(node->header & html_memory_page_pointer_mask)->allocator;
  	}
  }
  
  // Low-level DOM operations
  namespace
  {
  	inline html_attribute_struct* allocate_attribute(html_allocator& alloc)
  	{
  		html_memory_page* page;
  		void* memory = alloc.allocate_memory(sizeof(html_attribute_struct), page);
  
  		return new (memory) html_attribute_struct(page);
  	}
  
  	inline html_node_struct* allocate_node(html_allocator& alloc, html_node_type type)
  	{
  		html_memory_page* page;
  		void* memory = alloc.allocate_memory(sizeof(html_node_struct), page);
  
  		return new (memory) html_node_struct(page, type);
  	}
  
  	inline void destroy_attribute(html_attribute_struct* a, html_allocator& alloc)
  	{
  		uintptr_t header = a->header;
  
  		if (header & html_memory_page_name_allocated_mask) alloc.deallocate_string(a->name);
  		if (header & html_memory_page_value_allocated_mask) alloc.deallocate_string(a->value);
  
  		alloc.deallocate_memory(a, sizeof(html_attribute_struct), reinterpret_cast<html_memory_page*>(header & html_memory_page_pointer_mask));
  	}
  
  	inline void destroy_node(html_node_struct* n, html_allocator& alloc)
  	{
  		uintptr_t header = n->header;
  
  		if (header & html_memory_page_name_allocated_mask) alloc.deallocate_string(n->name);
  		if (header & html_memory_page_value_allocated_mask) alloc.deallocate_string(n->value);
  
  		for (html_attribute_struct* attr = n->first_attribute; attr; )
  		{
  			html_attribute_struct* next = attr->next_attribute;
  
  			destroy_attribute(attr, alloc);
  
  			attr = next;
  		}
  
  		for (html_node_struct* child = n->first_child; child; )
  		{
  			html_node_struct* next = child->next_sibling;
  
  			destroy_node(child, alloc);
  
  			child = next;
  		}
  
  		alloc.deallocate_memory(n, sizeof(html_node_struct), reinterpret_cast<html_memory_page*>(header & html_memory_page_pointer_mask));
  	}
  
  	PUGIHTML_NO_INLINE html_node_struct* append_node(html_node_struct* node, html_allocator& alloc, html_node_type type = node_element)
  	{
  		html_node_struct* child = allocate_node(alloc, type);
  		if (!child) return 0;
  
  		child->parent = node;
  
  		html_node_struct* first_child = node->first_child;
  			
  		if (first_child)
  		{
  			html_node_struct* last_child = first_child->prev_sibling_c;
  
  			last_child->next_sibling = child;
  			child->prev_sibling_c = last_child;
  			first_child->prev_sibling_c = child;
  		}
  		else
  		{
  			node->first_child = child;
  			child->prev_sibling_c = child;
  		}
  			
  		return child;
  	}
  
  	PUGIHTML_NO_INLINE html_attribute_struct* append_attribute_ll(html_node_struct* node, html_allocator& alloc)
  	{
  		html_attribute_struct* a = allocate_attribute(alloc);
  		if (!a) return 0;
  
  		html_attribute_struct* first_attribute = node->first_attribute;
  
  		if (first_attribute)
  		{
  			html_attribute_struct* last_attribute = first_attribute->prev_attribute_c;
  
  			last_attribute->next_attribute = a;
  			a->prev_attribute_c = last_attribute;
  			first_attribute->prev_attribute_c = a;
  		}
  		else
  		{
  			node->first_attribute = a;
  			a->prev_attribute_c = a;
  		}
  			
  		return a;
  	}
  }
  
  // Helper classes for code generation
  namespace
  {
  	struct opt_false
  	{
  		enum { value = 0 };
  	};
  
  	struct opt_true
  	{
  		enum { value = 1 };
  	};
  }
  
  // Unicode utilities
  namespace
  {
  	inline uint16_t endian_swap(uint16_t value)
  	{
  		return static_cast<uint16_t>(((value & 0xff) << 8) | (value >> 8));
  	}
  
  	inline uint32_t endian_swap(uint32_t value)
  	{
  		return ((value & 0xff) << 24) | ((value & 0xff00) << 8) | ((value & 0xff0000) >> 8) | (value >> 24);
  	}
  
  	struct utf8_counter
  	{
  		typedef size_t value_type;
  
  		static value_type low(value_type result, uint32_t ch)
  		{
  			// U+0000..U+007F
  			if (ch < 0x80) return result + 1;
  			// U+0080..U+07FF
  			else if (ch < 0x800) return result + 2;
  			// U+0800..U+FFFF
  			else return result + 3;
  		}
  
  		static value_type high(value_type result, uint32_t)
  		{
  			// U+10000..U+10FFFF
  			return result + 4;
  		}
  	};
  
  	struct utf8_writer
  	{
  		typedef uint8_t* value_type;
  
  		static value_type low(value_type result, uint32_t ch)
  		{
  			// U+0000..U+007F
  			if (ch < 0x80)
  			{
  				*result = static_cast<uint8_t>(ch);
  				return result + 1;
  			}
  			// U+0080..U+07FF
  			else if (ch < 0x800)
  			{
  				result[0] = static_cast<uint8_t>(0xC0 | (ch >> 6));
  				result[1] = static_cast<uint8_t>(0x80 | (ch & 0x3F));
  				return result + 2;
  			}
  			// U+0800..U+FFFF
  			else
  			{
  				result[0] = static_cast<uint8_t>(0xE0 | (ch >> 12));
  				result[1] = static_cast<uint8_t>(0x80 | ((ch >> 6) & 0x3F));
  				result[2] = static_cast<uint8_t>(0x80 | (ch & 0x3F));
  				return result + 3;
  			}
  		}
  
  		static value_type high(value_type result, uint32_t ch)
  		{
  			// U+10000..U+10FFFF
  			result[0] = static_cast<uint8_t>(0xF0 | (ch >> 18));
  			result[1] = static_cast<uint8_t>(0x80 | ((ch >> 12) & 0x3F));
  			result[2] = static_cast<uint8_t>(0x80 | ((ch >> 6) & 0x3F));
  			result[3] = static_cast<uint8_t>(0x80 | (ch & 0x3F));
  			return result + 4;
  		}
  
  		static value_type any(value_type result, uint32_t ch)
  		{
  			return (ch < 0x10000) ? low(result, ch) : high(result, ch);
  		}
  	};
  
  	struct utf16_counter
  	{
  		typedef size_t value_type;
  
  		static value_type low(value_type result, uint32_t)
  		{
  			return result + 1;
  		}
  
  		static value_type high(value_type result, uint32_t)
  		{
  			return result + 2;
  		}
  	};
  
  	struct utf16_writer
  	{
  		typedef uint16_t* value_type;
  
  		static value_type low(value_type result, uint32_t ch)
  		{
  			*result = static_cast<uint16_t>(ch);
  
  			return result + 1;
  		}
  
  		static value_type high(value_type result, uint32_t ch)
  		{
  			uint32_t msh = (uint32_t)(ch - 0x10000) >> 10;
  			uint32_t lsh = (uint32_t)(ch - 0x10000) & 0x3ff;
  
  			result[0] = static_cast<uint16_t>(0xD800 + msh);
  			result[1] = static_cast<uint16_t>(0xDC00 + lsh);
  
  			return result + 2;
  		}
  
  		static value_type any(value_type result, uint32_t ch)
  		{
  			return (ch < 0x10000) ? low(result, ch) : high(result, ch);
  		}
  	};
  
  	struct utf32_counter
  	{
  		typedef size_t value_type;
  
  		static value_type low(value_type result, uint32_t)
  		{
  			return result + 1;
  		}
  
  		static value_type high(value_type result, uint32_t)
  		{
  			return result + 1;
  		}
  	};
  
  	struct utf32_writer
  	{
  		typedef uint32_t* value_type;
  
  		static value_type low(value_type result, uint32_t ch)
  		{
  			*result = ch;
  
  			return result + 1;
  		}
  
  		static value_type high(value_type result, uint32_t ch)
  		{
  			*result = ch;
  
  			return result + 1;
  		}
  
  		static value_type any(value_type result, uint32_t ch)
  		{
  			*result = ch;
  
  			return result + 1;
  		}
  	};
  
  	template <size_t size> struct wchar_selector;
  
  	template <> struct wchar_selector<2>
  	{
  		typedef uint16_t type;
  		typedef utf16_counter counter;
  		typedef utf16_writer writer;
  	};
  
  	template <> struct wchar_selector<4>
  	{
  		typedef uint32_t type;
  		typedef utf32_counter counter;
  		typedef utf32_writer writer;
  	};
  
  	typedef wchar_selector<sizeof(wchar_t)>::counter wchar_counter;
  	typedef wchar_selector<sizeof(wchar_t)>::writer wchar_writer;
  
  	template <typename Traits, typename opt_swap = opt_false> struct utf_decoder
  	{
  		static inline typename Traits::value_type decode_utf8_block(const uint8_t* data, size_t size, typename Traits::value_type result)
  		{
  			const uint8_t utf8_byte_mask = 0x3f;
  
  			while (size)
  			{
  				uint8_t lead = *data;
  
  				// 0xxxxxxx -> U+0000..U+007F
  				if (lead < 0x80)
  				{
  					result = Traits::low(result, lead);
  					data += 1;
  					size -= 1;
  
  					// process aligned single-byte (ascii) blocks
  					if ((reinterpret_cast<uintptr_t>(data) & 3) == 0)
  					{
  						while (size >= 4 && (*reinterpret_cast<const uint32_t*>(data) & 0x80808080) == 0)
  						{
  							result = Traits::low(result, data[0]);
  							result = Traits::low(result, data[1]);
  							result = Traits::low(result, data[2]);
  							result = Traits::low(result, data[3]);
  							data += 4;
  							size -= 4;
  						}
  					}
  				}
  				// 110xxxxx -> U+0080..U+07FF
  				else if ((unsigned)(lead - 0xC0) < 0x20 && size >= 2 && (data[1] & 0xc0) == 0x80)
  				{
  					result = Traits::low(result, ((lead & ~0xC0) << 6) | (data[1] & utf8_byte_mask));
  					data += 2;
  					size -= 2;
  				}
  				// 1110xxxx -> U+0800-U+FFFF
  				else if ((unsigned)(lead - 0xE0) < 0x10 && size >= 3 && (data[1] & 0xc0) == 0x80 && (data[2] & 0xc0) == 0x80)
  				{
  					result = Traits::low(result, ((lead & ~0xE0) << 12) | ((data[1] & utf8_byte_mask) << 6) | (data[2] & utf8_byte_mask));
  					data += 3;
  					size -= 3;
  				}
  				// 11110xxx -> U+10000..U+10FFFF
  				else if ((unsigned)(lead - 0xF0) < 0x08 && size >= 4 && (data[1] & 0xc0) == 0x80 && (data[2] & 0xc0) == 0x80 && (data[3] & 0xc0) == 0x80)
  				{
  					result = Traits::high(result, ((lead & ~0xF0) << 18) | ((data[1] & utf8_byte_mask) << 12) | ((data[2] & utf8_byte_mask) << 6) | (data[3] & utf8_byte_mask));
  					data += 4;
  					size -= 4;
  				}
  				// 10xxxxxx or 11111xxx -> invalid
  				else
  				{
  					data += 1;
  					size -= 1;
  				}
  			}
  
  			return result;
  		}
  
  		static inline typename Traits::value_type decode_utf16_block(const uint16_t* data, size_t size, typename Traits::value_type result)
  		{
  			const uint16_t* end = data + size;
  
  			while (data < end)
  			{
  				uint16_t lead = opt_swap::value ? endian_swap(*data) : *data;
  
  				// U+0000..U+D7FF
  				if (lead < 0xD800)
  				{
  					result = Traits::low(result, lead);
  					data += 1;
  				}
  				// U+E000..U+FFFF
  				else if ((unsigned)(lead - 0xE000) < 0x2000)
  				{
  					result = Traits::low(result, lead);
  					data += 1;
  				}
  				// surrogate pair lead
  				else if ((unsigned)(lead - 0xD800) < 0x400 && data + 1 < end)
  				{
  					uint16_t next = opt_swap::value ? endian_swap(data[1]) : data[1];
  
  					if ((unsigned)(next - 0xDC00) < 0x400)
  					{
  						result = Traits::high(result, 0x10000 + ((lead & 0x3ff) << 10) + (next & 0x3ff));
  						data += 2;
  					}
  					else
  					{
  						data += 1;
  					}
  				}
  				else
  				{
  					data += 1;
  				}
  			}
  
  			return result;
  		}
  
  		static inline typename Traits::value_type decode_utf32_block(const uint32_t* data, size_t size, typename Traits::value_type result)
  		{
  			const uint32_t* end = data + size;
  
  			while (data < end)
  			{
  				uint32_t lead = opt_swap::value ? endian_swap(*data) : *data;
  
  				// U+0000..U+FFFF
  				if (lead < 0x10000)
  				{
  					result = Traits::low(result, lead);
  					data += 1;
  				}
  				// U+10000..U+10FFFF
  				else
  				{
  					result = Traits::high(result, lead);
  					data += 1;
  				}
  			}
  
  			return result;
  		}
  	};
  
  	template <typename T> inline void convert_utf_endian_swap(T* result, const T* data, size_t length)
  	{
  		for (size_t i = 0; i < length; ++i) result[i] = endian_swap(data[i]);
  	}
  
  	inline void convert_wchar_endian_swap(wchar_t* result, const wchar_t* data, size_t length)
  	{
  		for (size_t i = 0; i < length; ++i) result[i] = static_cast<wchar_t>(endian_swap(static_cast<wchar_selector<sizeof(wchar_t)>::type>(data[i])));
  	}
  }
  
  namespace
  {	
  	enum chartype_t
  	{
  		ct_parse_pcdata = 1,	// \0, &, \r, <
  		ct_parse_attr = 2,		// \0, &, \r, ', "
  		ct_parse_attr_ws = 4,	// \0, &, \r, ', ", \n, tab
  		ct_space = 8,			// \r, \n, space, tab
  		ct_parse_cdata = 16,	// \0, ], >, \r
  		ct_parse_comment = 32,	// \0, -, >, \r
  		ct_symbol = 64,			// Any symbol > 127, a-z, A-Z, 0-9, _, :, -, .
  		ct_start_symbol = 128	// Any symbol > 127, a-z, A-Z, _, :
  	};
  
  	const unsigned char chartype_table[256] =
  	{
  		55,  0,   0,   0,   0,   0,   0,   0,      0,   12,  12,  0,   0,   63,  0,   0,   // 0-15
  		0,   0,   0,   0,   0,   0,   0,   0,      0,   0,   0,   0,   0,   0,   0,   0,   // 16-31
  		8,   0,   6,   0,   0,   0,   7,   6,      0,   0,   0,   0,   0,   96,  64,  0,   // 32-47
  		64,  64,  64,  64,  64,  64,  64,  64,     64,  64,  192, 0,   1,   0,   48,  0,   // 48-63
  		0,   192, 192, 192, 192, 192, 192, 192,    192, 192, 192, 192, 192, 192, 192, 192, // 64-79
  		192, 192, 192, 192, 192, 192, 192, 192,    192, 192, 192, 0,   0,   16,  0,   192, // 80-95
  		0,   192, 192, 192, 192, 192, 192, 192,    192, 192, 192, 192, 192, 192, 192, 192, // 96-111
  		192, 192, 192, 192, 192, 192, 192, 192,    192, 192, 192, 0, 0, 0, 0, 0,           // 112-127
  
  		192, 192, 192, 192, 192, 192, 192, 192,    192, 192, 192, 192, 192, 192, 192, 192, // 128+
  		192, 192, 192, 192, 192, 192, 192, 192,    192, 192, 192, 192, 192, 192, 192, 192,
  		192, 192, 192, 192, 192, 192, 192, 192,    192, 192, 192, 192, 192, 192, 192, 192,
  		192, 192, 192, 192, 192, 192, 192, 192,    192, 192, 192, 192, 192, 192, 192, 192,
  		192, 192, 192, 192, 192, 192, 192, 192,    192, 192, 192, 192, 192, 192, 192, 192,
  		192, 192, 192, 192, 192, 192, 192, 192,    192, 192, 192, 192, 192, 192, 192, 192,
  		192, 192, 192, 192, 192, 192, 192, 192,    192, 192, 192, 192, 192, 192, 192, 192,
  		192, 192, 192, 192, 192, 192, 192, 192,    192, 192, 192, 192, 192, 192, 192, 192
  	};
  
  	enum chartypex_t
  	{
  		ctx_special_pcdata = 1,   // Any symbol >= 0 and < 32 (except \t, \r, \n), &, <, >
  		ctx_special_attr = 2,     // Any symbol >= 0 and < 32 (except \t), &, <, >, "
  		ctx_start_symbol = 4,	  // Any symbol > 127, a-z, A-Z, _
  		ctx_digit = 8,			  // 0-9
  		ctx_symbol = 16			  // Any symbol > 127, a-z, A-Z, 0-9, _, -, .
  	};
  	
  	const unsigned char chartypex_table[256] =
  	{
  		3,  3,  3,  3,  3,  3,  3,  3,     3,  0,  2,  3,  3,  2,  3,  3,     // 0-15
  		3,  3,  3,  3,  3,  3,  3,  3,     3,  3,  3,  3,  3,  3,  3,  3,     // 16-31
  		0,  0,  2,  0,  0,  0,  3,  0,     0,  0,  0,  0,  0, 16, 16,  0,     // 32-47
  		24, 24, 24, 24, 24, 24, 24, 24,    24, 24, 0,  0,  3,  0,  3,  0,     // 48-63
  
  		0,  20, 20, 20, 20, 20, 20, 20,    20, 20, 20, 20, 20, 20, 20, 20,    // 64-79
  		20, 20, 20, 20, 20, 20, 20, 20,    20, 20, 20, 0,  0,  0,  0,  20,    // 80-95
  		0,  20, 20, 20, 20, 20, 20, 20,    20, 20, 20, 20, 20, 20, 20, 20,    // 96-111
  		20, 20, 20, 20, 20, 20, 20, 20,    20, 20, 20, 0,  0,  0,  0,  0,     // 112-127
  
  		20, 20, 20, 20, 20, 20, 20, 20,    20, 20, 20, 20, 20, 20, 20, 20,    // 128+
  		20, 20, 20, 20, 20, 20, 20, 20,    20, 20, 20, 20, 20, 20, 20, 20,
  		20, 20, 20, 20, 20, 20, 20, 20,    20, 20, 20, 20, 20, 20, 20, 20,
  		20, 20, 20, 20, 20, 20, 20, 20,    20, 20, 20, 20, 20, 20, 20, 20,
  		20, 20, 20, 20, 20, 20, 20, 20,    20, 20, 20, 20, 20, 20, 20, 20,
  		20, 20, 20, 20, 20, 20, 20, 20,    20, 20, 20, 20, 20, 20, 20, 20,
  		20, 20, 20, 20, 20, 20, 20, 20,    20, 20, 20, 20, 20, 20, 20, 20,
  		20, 20, 20, 20, 20, 20, 20, 20,    20, 20, 20, 20, 20, 20, 20, 20
  	};
  	
  #ifdef PUGIHTML_WCHAR_MODE
  	#define IS_CHARTYPE_IMPL(c, ct, table) ((static_cast<unsigned int>(c) < 128 ? table[static_cast<unsigned int>(c)] : table[128]) & (ct))
  #else
  	#define IS_CHARTYPE_IMPL(c, ct, table) (table[static_cast<unsigned char>(c)] & (ct))
  #endif
  
  	#define IS_CHARTYPE(c, ct) IS_CHARTYPE_IMPL(c, ct, chartype_table)
  	#define IS_CHARTYPEX(c, ct) IS_CHARTYPE_IMPL(c, ct, chartypex_table)
  
  	bool is_little_endian()
  	{
  		unsigned int ui = 1;
  
  		return *reinterpret_cast<unsigned char*>(&ui) == 1;
  	}
  
  	html_encoding get_wchar_encoding()
  	{
  		STATIC_ASSERT(sizeof(wchar_t) == 2 || sizeof(wchar_t) == 4);
  
  		if (sizeof(wchar_t) == 2)
  			return is_little_endian() ? encoding_utf16_le : encoding_utf16_be;
  		else 
  			return is_little_endian() ? encoding_utf32_le : encoding_utf32_be;
  	}
  
  	html_encoding guess_buffer_encoding(uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3)
  	{
  		// look for BOM in first few bytes
  		if (d0 == 0 && d1 == 0 && d2 == 0xfe && d3 == 0xff) return encoding_utf32_be;
  		if (d0 == 0xff && d1 == 0xfe && d2 == 0 && d3 == 0) return encoding_utf32_le;
  		if (d0 == 0xfe && d1 == 0xff) return encoding_utf16_be;
  		if (d0 == 0xff && d1 == 0xfe) return encoding_utf16_le;
  		if (d0 == 0xef && d1 == 0xbb && d2 == 0xbf) return encoding_utf8;
  
  		// look for <, <? or <?xm in various encodings
  		if (d0 == 0 && d1 == 0 && d2 == 0 && d3 == 0x3c) return encoding_utf32_be;
  		if (d0 == 0x3c && d1 == 0 && d2 == 0 && d3 == 0) return encoding_utf32_le;
  		if (d0 == 0 && d1 == 0x3c && d2 == 0 && d3 == 0x3f) return encoding_utf16_be;
  		if (d0 == 0x3c && d1 == 0 && d2 == 0x3f && d3 == 0) return encoding_utf16_le;
  		if (d0 == 0x3c && d1 == 0x3f && d2 == 0x78 && d3 == 0x6d) return encoding_utf8;
  
  		// look for utf16 < followed by node name (this may fail, but is better than utf8 since it's zero terminated so early)
  		if (d0 == 0 && d1 == 0x3c) return encoding_utf16_be;
  		if (d0 == 0x3c && d1 == 0) return encoding_utf16_le;
  
  		// no known BOM detected, assume utf8
  		return encoding_utf8;
  	}
  
  	html_encoding get_buffer_encoding(html_encoding encoding, const void* contents, size_t size)
  	{
  		// replace wchar encoding with utf implementation
  		if (encoding == encoding_wchar) return get_wchar_encoding();
  
  		// replace utf16 encoding with utf16 with specific endianness
  		if (encoding == encoding_utf16) return is_little_endian() ? encoding_utf16_le : encoding_utf16_be;
  
  		// replace utf32 encoding with utf32 with specific endianness
  		if (encoding == encoding_utf32) return is_little_endian() ? encoding_utf32_le : encoding_utf32_be;
  
  		// only do autodetection if no explicit encoding is requested
  		if (encoding != encoding_auto) return encoding;
  
  		// skip encoding autodetection if input buffer is too small
  		if (size < 4) return encoding_utf8;
  
  		// try to guess encoding (based on HTML specification, Appendix F.1)
  		const uint8_t* data = static_cast<const uint8_t*>(contents);
  
  		DMC_VOLATILE uint8_t d0 = data[0], d1 = data[1], d2 = data[2], d3 = data[3];
  
  		return guess_buffer_encoding(d0, d1, d2, d3);
  	}
  
  	bool get_mutable_buffer(char_t*& out_buffer, size_t& out_length, const void* contents, size_t size, bool is_mutable)
  	{
  		if (is_mutable)
  		{
  			out_buffer = static_cast<char_t*>(const_cast<void*>(contents));
  		}
  		else
  		{
  			void* buffer = global_allocate(size > 0 ? size : 1);
  			if (!buffer) return false;
  
  			memcpy(buffer, contents, size);
  
  			out_buffer = static_cast<char_t*>(buffer);
  		}
  
  		out_length = size / sizeof(char_t);
  
  		return true;
  	}
  
  #ifdef PUGIHTML_WCHAR_MODE
  	inline bool need_endian_swap_utf(html_encoding le, html_encoding re)
  	{
  		return (le == encoding_utf16_be && re == encoding_utf16_le) || (le == encoding_utf16_le && re == encoding_utf16_be) ||
  		       (le == encoding_utf32_be && re == encoding_utf32_le) || (le == encoding_utf32_le && re == encoding_utf32_be);
  	}
  
  	bool convert_buffer_endian_swap(char_t*& out_buffer, size_t& out_length, const void* contents, size_t size, bool is_mutable)
  	{
  		const char_t* data = static_cast<const char_t*>(contents);
  	
  		if (is_mutable)
  		{
  			out_buffer = const_cast<char_t*>(data);
  		}
  		else
  		{
  			out_buffer = static_cast<char_t*>(global_allocate(size > 0 ? size : 1));
  			if (!out_buffer) return false;
  		}
  
  		out_length = size / sizeof(char_t);
  
  		convert_wchar_endian_swap(out_buffer, data, out_length);
  
  		return true;
  	}
  
  	bool convert_buffer_utf8(char_t*& out_buffer, size_t& out_length, const void* contents, size_t size)
  	{
  		const uint8_t* data = static_cast<const uint8_t*>(contents);
  
  		// first pass: get length in wchar_t units
  		out_length = utf_decoder<wchar_counter>::decode_utf8_block(data, size, 0);
  
  		// allocate buffer of suitable length
  		out_buffer = static_cast<char_t*>(global_allocate((out_length > 0 ? out_length : 1) * sizeof(char_t)));
  		if (!out_buffer) return false;
  
  		// second pass: convert utf8 input to wchar_t
  		wchar_writer::value_type out_begin = reinterpret_cast<wchar_writer::value_type>(out_buffer);
  		wchar_writer::value_type out_end = utf_decoder<wchar_writer>::decode_utf8_block(data, size, out_begin);
  
  		assert(out_end == out_begin + out_length);
  		(void)!out_end;
  
  		return true;
  	}
  
  	template <typename opt_swap> bool convert_buffer_utf16(char_t*& out_buffer, size_t& out_length, const void* contents, size_t size, opt_swap)
  	{
  		const uint16_t* data = static_cast<const uint16_t*>(contents);
  		size_t length = size / sizeof(uint16_t);
  
  		// first pass: get length in wchar_t units
  		out_length = utf_decoder<wchar_counter, opt_swap>::decode_utf16_block(data, length, 0);
  
  		// allocate buffer of suitable length
  		out_buffer = static_cast<char_t*>(global_allocate((out_length > 0 ? out_length : 1) * sizeof(char_t)));
  		if (!out_buffer) return false;
  
  		// second pass: convert utf16 input to wchar_t
  		wchar_writer::value_type out_begin = reinterpret_cast<wchar_writer::value_type>(out_buffer);
  		wchar_writer::value_type out_end = utf_decoder<wchar_writer, opt_swap>::decode_utf16_block(data, length, out_begin);
  
  		assert(out_end == out_begin + out_length);
  		(void)!out_end;
  
  		return true;
  	}
  
  	template <typename opt_swap> bool convert_buffer_utf32(char_t*& out_buffer, size_t& out_length, const void* contents, size_t size, opt_swap)
  	{
  		const uint32_t* data = static_cast<const uint32_t*>(contents);
  		size_t length = size / sizeof(uint32_t);
  
  		// first pass: get length in wchar_t units
  		out_length = utf_decoder<wchar_counter, opt_swap>::decode_utf32_block(data, length, 0);
  
  		// allocate buffer of suitable length
  		out_buffer = static_cast<char_t*>(global_allocate((out_length > 0 ? out_length : 1) * sizeof(char_t)));
  		if (!out_buffer) return false;
  
  		// second pass: convert utf32 input to wchar_t
  		wchar_writer::value_type out_begin = reinterpret_cast<wchar_writer::value_type>(out_buffer);
  		wchar_writer::value_type out_end = utf_decoder<wchar_writer, opt_swap>::decode_utf32_block(data, length, out_begin);
  
  		assert(out_end == out_begin + out_length);
  		(void)!out_end;
  
  		return true;
  	}
  
  	bool convert_buffer(char_t*& out_buffer, size_t& out_length, html_encoding encoding, const void* contents, size_t size, bool is_mutable)
  	{
  		// get native encoding
  		html_encoding wchar_encoding = get_wchar_encoding();
  
  		// fast path: no conversion required
  		if (encoding == wchar_encoding) return get_mutable_buffer(out_buffer, out_length, contents, size, is_mutable);
  
  		// only endian-swapping is required
  		if (need_endian_swap_utf(encoding, wchar_encoding)) return convert_buffer_endian_swap(out_buffer, out_length, contents, size, is_mutable);
  
  		// source encoding is utf8
  		if (encoding == encoding_utf8) return convert_buffer_utf8(out_buffer, out_length, contents, size);
  
  		// source encoding is utf16
  		if (encoding == encoding_utf16_be || encoding == encoding_utf16_le)
  		{
  			html_encoding native_encoding = is_little_endian() ? encoding_utf16_le : encoding_utf16_be;
  
  			return (native_encoding == encoding) ?
  				convert_buffer_utf16(out_buffer, out_length, contents, size, opt_false()) :
  				convert_buffer_utf16(out_buffer, out_length, contents, size, opt_true());
  		}
  
  		// source encoding is utf32
  		if (encoding == encoding_utf32_be || encoding == encoding_utf32_le)
  		{
  			html_encoding native_encoding = is_little_endian() ? encoding_utf32_le : encoding_utf32_be;
  
  			return (native_encoding == encoding) ?
  				convert_buffer_utf32(out_buffer, out_length, contents, size, opt_false()) :
  				convert_buffer_utf32(out_buffer, out_length, contents, size, opt_true());
  		}
  
  		assert(!"Invalid encoding");
  		return false;
  	}
  #else
  	template <typename opt_swap> bool convert_buffer_utf16(char_t*& out_buffer, size_t& out_length, const void* contents, size_t size, opt_swap)
  	{
  		const uint16_t* data = static_cast<const uint16_t*>(contents);
  		size_t length = size / sizeof(uint16_t);
  
  		// first pass: get length in utf8 units
  		out_length = utf_decoder<utf8_counter, opt_swap>::decode_utf16_block(data, length, 0);
  
  		// allocate buffer of suitable length
  		out_buffer = static_cast<char_t*>(global_allocate((out_length > 0 ? out_length : 1) * sizeof(char_t)));
  		if (!out_buffer) return false;
  
  		// second pass: convert utf16 input to utf8
  		uint8_t* out_begin = reinterpret_cast<uint8_t*>(out_buffer);
  		uint8_t* out_end = utf_decoder<utf8_writer, opt_swap>::decode_utf16_block(data, length, out_begin);
  
  		assert(out_end == out_begin + out_length);
  		(void)!out_end;
  
  		return true;
  	}
  
  	template <typename opt_swap> bool convert_buffer_utf32(char_t*& out_buffer, size_t& out_length, const void* contents, size_t size, opt_swap)
  	{
  		const uint32_t* data = static_cast<const uint32_t*>(contents);
  		size_t length = size / sizeof(uint32_t);
  
  		// first pass: get length in utf8 units
  		out_length = utf_decoder<utf8_counter, opt_swap>::decode_utf32_block(data, length, 0);
  
  		// allocate buffer of suitable length
  		out_buffer = static_cast<char_t*>(global_allocate((out_length > 0 ? out_length : 1) * sizeof(char_t)));
  		if (!out_buffer) return false;
  
  		// second pass: convert utf32 input to utf8
  		uint8_t* out_begin = reinterpret_cast<uint8_t*>(out_buffer);
  		uint8_t* out_end = utf_decoder<utf8_writer, opt_swap>::decode_utf32_block(data, length, out_begin);
  
  		assert(out_end == out_begin + out_length);
  		(void)!out_end;
  
  		return true;
  	}
  
  	bool convert_buffer(char_t*& out_buffer, size_t& out_length, html_encoding encoding, const void* contents, size_t size, bool is_mutable)
  	{
  		// fast path: no conversion required
  		if (encoding == encoding_utf8) return get_mutable_buffer(out_buffer, out_length, contents, size, is_mutable);
  
  		// source encoding is utf16
  		if (encoding == encoding_utf16_be || encoding == encoding_utf16_le)
  		{
  			html_encoding native_encoding = is_little_endian() ? encoding_utf16_le : encoding_utf16_be;
  
  			return (native_encoding == encoding) ?
  				convert_buffer_utf16(out_buffer, out_length, contents, size, opt_false()) :
  				convert_buffer_utf16(out_buffer, out_length, contents, size, opt_true());
  		}
  
  		// source encoding is utf32
  		if (encoding == encoding_utf32_be || encoding == encoding_utf32_le)
  		{
  			html_encoding native_encoding = is_little_endian() ? encoding_utf32_le : encoding_utf32_be;
  
  			return (native_encoding == encoding) ?
  				convert_buffer_utf32(out_buffer, out_length, contents, size, opt_false()) :
  				convert_buffer_utf32(out_buffer, out_length, contents, size, opt_true());
  		}
  
  		assert(!"Invalid encoding");
  		return false;
  	}
  #endif
  
  	size_t as_utf8_begin(const wchar_t* str, size_t length)
  	{
  		STATIC_ASSERT(sizeof(wchar_t) == 2 || sizeof(wchar_t) == 4);
  
  		// get length in utf8 characters
  		return sizeof(wchar_t) == 2 ?
  			utf_decoder<utf8_counter>::decode_utf16_block(reinterpret_cast<const uint16_t*>(str), length, 0) :
  			utf_decoder<utf8_counter>::decode_utf32_block(reinterpret_cast<const uint32_t*>(str), length, 0);
      }
  
      void as_utf8_end(char* buffer, size_t size, const wchar_t* str, size_t length)
      {
  		STATIC_ASSERT(sizeof(wchar_t) == 2 || sizeof(wchar_t) == 4);
  
          // convert to utf8
          uint8_t* begin = reinterpret_cast<uint8_t*>(buffer);
          uint8_t* end = sizeof(wchar_t) == 2 ?
              utf_decoder<utf8_writer>::decode_utf16_block(reinterpret_cast<const uint16_t*>(str), length, begin) :
              utf_decoder<utf8_writer>::decode_utf32_block(reinterpret_cast<const uint32_t*>(str), length, begin);
      
          assert(begin + size == end);
          (void)!end;
  
  		// zero-terminate
  		buffer[size] = 0;
  	}
      
  #ifndef PUGIHTML_NO_STL
      std::string as_utf8_impl(const wchar_t* str, size_t length)
      {
  		// first pass: get length in utf8 characters
          size_t size = as_utf8_begin(str, length);
  
  		// allocate resulting string
  		std::string result;
  		result.resize(size);
  
  		// second pass: convert to utf8
  		if (size > 0) as_utf8_end(&result[0], size, str, length);
  
  	  	return result;
      }
  
  	std::wstring as_wide_impl(const char* str, size_t size)
  	{
  		const uint8_t* data = reinterpret_cast<const uint8_t*>(str);
  
  		// first pass: get length in wchar_t units
  		size_t length = utf_decoder<wchar_counter>::decode_utf8_block(data, size, 0);
  
  		// allocate resulting string
  		std::wstring result;
  		result.resize(length);
  
  		// second pass: convert to wchar_t
  		if (length > 0)
  		{
  			wchar_writer::value_type begin = reinterpret_cast<wchar_writer::value_type>(&result[0]);
  			wchar_writer::value_type end = utf_decoder<wchar_writer>::decode_utf8_block(data, size, begin);
  
  			assert(begin + length == end);
  			(void)!end;
  		}
  
  		return result;
  	}
  #endif
  
  	inline bool strcpy_insitu_allow(size_t length, uintptr_t allocated, char_t* target)
  	{
  		assert(target);
  		size_t target_length = strlength(target);
  
  		// always reuse document buffer memory if possible
  		if (!allocated) return target_length >= length;
  
  		// reuse heap memory if waste is not too great
  		const size_t reuse_threshold = 32;
  
  		return target_length >= length && (target_length < reuse_threshold || target_length - length < target_length / 2);
  	}
  
  	bool strcpy_insitu(char_t*& dest, uintptr_t& header, uintptr_t header_mask, const char_t* source)
  	{
  		size_t source_length = strlength(source);
  
  		if (source_length == 0)
  		{
  			// empty string and null pointer are equivalent, so just deallocate old memory
  			html_allocator* alloc = reinterpret_cast<html_memory_page*>(header & html_memory_page_pointer_mask)->allocator;
  
  			if (header & header_mask) alloc->deallocate_string(dest);
  			
  			// mark the string as not allocated
  			dest = 0;
  			header &= ~header_mask;
  
  			return true;
  		}
  		else if (dest && strcpy_insitu_allow(source_length, header & header_mask, dest))
  		{
  			// we can reuse old buffer, so just copy the new data (including zero terminator)
  			memcpy(dest, source, (source_length + 1) * sizeof(char_t));
  			
  			return true;
  		}
  		else
  		{
  			html_allocator* alloc = reinterpret_cast<html_memory_page*>(header & html_memory_page_pointer_mask)->allocator;
  
  			// allocate new buffer
  			char_t* buf = alloc->allocate_string(source_length + 1);
  			if (!buf) return false;
  
  			// copy the string (including zero terminator)
  			memcpy(buf, source, (source_length + 1) * sizeof(char_t));
  
  			// deallocate old buffer (*after* the above to protect against overlapping memory and/or allocation failures)
  			if (header & header_mask) alloc->deallocate_string(dest);
  			
  			// the string is now allocated, so set the flag
  			dest = buf;
  			header |= header_mask;
  
  			return true;
  		}
  	}
  
  	struct gap
  	{
  		char_t* end;
  		size_t size;
  			
  		gap(): end(0), size(0)
  		{
  		}
  			
  		// Push new gap, move s count bytes further (skipping the gap).
  		// Collapse previous gap.
  		void push(char_t*& s, size_t count)
  		{
  			if (end) // there was a gap already; collapse it
  			{
  				// Move [old_gap_end, new_gap_start) to [old_gap_start, ...)
  				assert(s >= end);
  				memmove(end - size, end, reinterpret_cast<char*>(s) - reinterpret_cast<char*>(end));
  			}
  				
  			s += count; // end of current gap
  				
  			// "merge" two gaps
  			end = s;
  			size += count;
  		}
  			
  		// Collapse all gaps, return past-the-end pointer
  		char_t* flush(char_t* s)
  		{
  			if (end)
  			{
  				// Move [old_gap_end, current_pos) to [old_gap_start, ...)
  				assert(s >= end);
  				memmove(end - size, end, reinterpret_cast<char*>(s) - reinterpret_cast<char*>(end));
  
  				return s - size;
  			}
  			else return s;
  		}
  	};
  	
  	char_t* strconv_escape(char_t* s, gap& g)
  	{
  		char_t* stre = s + 1;
  
  		switch (*stre)
  		{
  			case '#':	// &#...
  			{
  				unsigned int ucsc = 0;
  
  				if (stre[1] == 'x') // &#x... (hex code)
  				{
  					stre += 2;
  
  					char_t ch = *stre;
  
  					if (ch == ';') return stre;
  
  					for (;;)
  					{
  						if (static_cast<unsigned int>(ch - '0') <= 9)
  							ucsc = 16 * ucsc + (ch - '0');
  						else if (static_cast<unsigned int>((ch | ' ') - 'a') <= 5)
  							ucsc = 16 * ucsc + ((ch | ' ') - 'a' + 10);
  						else if (ch == ';')
  							break;
  						else // cancel
  							return stre;
  
  						ch = *++stre;
  					}
  					
  					++stre;
  				}
  				else	// &#... (dec code)
  				{
  					char_t ch = *++stre;
  
  					if (ch == ';') return stre;
  
  					for (;;)
  					{
  						if (static_cast<unsigned int>(ch - '0') <= 9)
  							ucsc = 10 * ucsc + (ch - '0');
  						else if (ch == ';')
  							break;
  						else // cancel
  							return stre;
  
  						ch = *++stre;
  					}
  					
  					++stre;
  				}
  
  			#ifdef PUGIHTML_WCHAR_MODE
  				s = reinterpret_cast<char_t*>(wchar_writer::any(reinterpret_cast<wchar_writer::value_type>(s), ucsc));
  			#else
  				s = reinterpret_cast<char_t*>(utf8_writer::any(reinterpret_cast<uint8_t*>(s), ucsc));
  			#endif
  					
  				g.push(s, stre - s);
  				return stre;
  			}
  			case 'a':	// &a
  			{
  				++stre;
  
  				if (*stre == 'm') // &am
  				{
  					if (*++stre == 'p' && *++stre == ';') // &amp;
  					{
  						*s++ = '&';
  						++stre;
  							
  						g.push(s, stre - s);
  						return stre;
  					}
  				}
  				else if (*stre == 'p') // &ap
  				{
  					if (*++stre == 'o' && *++stre == 's' && *++stre == ';') // &apos;
  					{
  						*s++ = '\'';
  						++stre;
  
  						g.push(s, stre - s);
  						return stre;
  					}
  				}
  				break;
  			}
  			case 'g': // &g
  			{
  				if (*++stre == 't' && *++stre == ';') // &gt;
  				{
  					*s++ = '>';
  					++stre;
  					
  					g.push(s, stre - s);
  					return stre;
  				}
  				break;
  			}
  			case 'l': // &l
  			{
  				if (*++stre == 't' && *++stre == ';') // &lt;
  				{
  					*s++ = '<';
  					++stre;
  						
  					g.push(s, stre - s);
  					return stre;
  				}
  				break;
  			}
  			case 'q': // &q
  			{
  				if (*++stre == 'u' && *++stre == 'o' && *++stre == 't' && *++stre == ';') // &quot;
  				{
  					*s++ = '"';
  					++stre;
  					
  					g.push(s, stre - s);
  					return stre;
  				}
  				break;
  			}
  		}
  		
  		return stre;
  	}
  
  	// Utility macro for last character handling
  	#define ENDSWITH(c, e) ((c) == (e) || ((c) == 0 && endch == (e)))
  
  	char_t* strconv_comment(char_t* s, char_t endch)
  	{
  		gap g;
  		
  		while (true)
  		{
  			while (!IS_CHARTYPE(*s, ct_parse_comment)) ++s;
  		
  			if (*s == '\r') // Either a single 0x0d or 0x0d 0x0a pair
  			{
  				*s++ = '\n'; // replace first one with 0x0a
  				
  				if (*s == '\n') g.push(s, 1);
  			}
  			else if (s[0] == '-' && s[1] == '-' && ENDSWITH(s[2], '>')) // comment ends here
  			{
  				*g.flush(s) = 0;
  				
  				return s + (s[2] == '>' ? 3 : 2);
  			}
  			else if (*s == 0)
  			{
  				return 0;
  			}
  			else ++s;
  		}
  	}
  
  	char_t* strconv_cdata(char_t* s, char_t endch)
  	{
  		gap g;
  			
  		while (true)
  		{
  			while (!IS_CHARTYPE(*s, ct_parse_cdata)) ++s;
  			
  			if (*s == '\r') // Either a single 0x0d or 0x0d 0x0a pair
  			{
  				*s++ = '\n'; // replace first one with 0x0a
  				
  				if (*s == '\n') g.push(s, 1);
  			}
  			else if (s[0] == ']' && s[1] == ']' && ENDSWITH(s[2], '>')) // CDATA ends here
  			{
  				*g.flush(s) = 0;
  				
  				return s + 1;
  			}
  			else if (*s == 0)
  			{
  				return 0;
  			}
  			else ++s;
  		}
  	}
  	
  	typedef char_t* (*strconv_pcdata_t)(char_t*);
  		
  	template <typename opt_eol, typename opt_escape> struct strconv_pcdata_impl
  	{
  		static char_t* parse(char_t* s)
  		{
  			gap g;
  			
  			while (true)
  			{
  				while (!IS_CHARTYPE(*s, ct_parse_pcdata)) ++s;
  					
  				if (*s == '<') // PCDATA ends here
  				{
  					*g.flush(s) = 0;
  					
  					return s + 1;
  				}
  				else if (opt_eol::value && *s == '\r') // Either a single 0x0d or 0x0d 0x0a pair
  				{
  					*s++ = '\n'; // replace first one with 0x0a
  					
  					if (*s == '\n') g.push(s, 1);
  				}
  				else if (opt_escape::value && *s == '&')
  				{
  					s = strconv_escape(s, g);
  				}
  				else if (*s == 0)
  				{
  					return s;
  				}
  				else ++s;
  			}
  		}
  	};
  	
  	strconv_pcdata_t get_strconv_pcdata(unsigned int optmask)
  	{
  		STATIC_ASSERT(parse_escapes == 0x10 && parse_eol == 0x20);
  
  		switch ((optmask >> 4) & 3) // get bitmask for flags (eol escapes)
  		{
  		case 0: return strconv_pcdata_impl<opt_false, opt_false>::parse;
  		case 1: return strconv_pcdata_impl<opt_false, opt_true>::parse;
  		case 2: return strconv_pcdata_impl<opt_true, opt_false>::parse;
  		case 3: return strconv_pcdata_impl<opt_true, opt_true>::parse;
  		default: return 0; // should not get here
  		}
  	}
  
  	typedef char_t* (*strconv_attribute_t)(char_t*, char_t);
  	
  	template <typename opt_escape> struct strconv_attribute_impl
  	{
  		static char_t* parse_wnorm(char_t* s, char_t end_quote)
  		{
  			gap g;
  
  			// trim leading whitespaces
  			if (IS_CHARTYPE(*s, ct_space))
  			{
  				char_t* str = s;
  				
  				do ++str;
  				while (IS_CHARTYPE(*str, ct_space));
  				
  				g.push(s, str - s);
  			}
  
  			while (true)
  			{
  				while (!IS_CHARTYPE(*s, ct_parse_attr_ws | ct_space)) ++s;
  				
  				if (*s == end_quote)
  				{
  					char_t* str = g.flush(s);
  					
  					do *str-- = 0;
  					while (IS_CHARTYPE(*str, ct_space));
  				
  					return s + 1;
  				}
  				else if (IS_CHARTYPE(*s, ct_space))
  				{
  					*s++ = ' ';
  		
  					if (IS_CHARTYPE(*s, ct_space))
  					{
  						char_t* str = s + 1;
  						while (IS_CHARTYPE(*str, ct_space)) ++str;
  						
  						g.push(s, str - s);
  					}
  				}
  				else if (opt_escape::value && *s == '&')
  				{
  					s = strconv_escape(s, g);
  				}
  				else if (!*s)
  				{
  					return 0;
  				}
  				else ++s;
  			}
  		}
  
  		static char_t* parse_wconv(char_t* s, char_t end_quote)
  		{
  			gap g;
  
  			while (true)
  			{
  				while (!IS_CHARTYPE(*s, ct_parse_attr_ws)) ++s;
  				
  				if (*s == end_quote)
  				{
  					*g.flush(s) = 0;
  				
  					return s + 1;
  				}
  				else if (IS_CHARTYPE(*s, ct_space))
  				{
  					if (*s == '\r')
  					{
  						*s++ = ' ';
  				
  						if (*s == '\n') g.push(s, 1);
  					}
  					else *s++ = ' ';
  				}
  				else if (opt_escape::value && *s == '&')
  				{
  					s = strconv_escape(s, g);
  				}
  				else if (!*s)
  				{
  					return 0;
  				}
  				else ++s;
  			}
  		}
  
  		static char_t* parse_eol(char_t* s, char_t end_quote)
  		{
  			gap g;
  
  			while (true)
  			{
  				while (!IS_CHARTYPE(*s, ct_parse_attr)) ++s;
  				
  				if (*s == end_quote)
  				{
  					*g.flush(s) = 0;
  				
  					return s + 1;
  				}
  				else if (*s == '\r')
  				{
  					*s++ = '\n';
  					
  					if (*s == '\n') g.push(s, 1);
  				}
  				else if (opt_escape::value && *s == '&')
  				{
  					s = strconv_escape(s, g);
  				}
  				else if (!*s)
  				{
  					return 0;
  				}
  				else ++s;
  			}
  		}
  
  		static char_t* parse_simple(char_t* s, char_t end_quote)
  		{
  			gap g;
  
  			while (true)
  			{
  				while (!IS_CHARTYPE(*s, ct_parse_attr)) ++s;
  				
  				if (*s == end_quote)
  				{
  					*g.flush(s) = 0;
  				
  					return s + 1;
  				}
  				else if (opt_escape::value && *s == '&')
  				{
  					s = strconv_escape(s, g);
  				}
  				else if (!*s)
  				{
  					return 0;
  				}
  				else ++s;
  			}
  		}
  	};
  
  	strconv_attribute_t get_strconv_attribute(unsigned int optmask)
  	{
  		STATIC_ASSERT(parse_escapes == 0x10 && parse_eol == 0x20 && parse_wconv_attribute == 0x40 && parse_wnorm_attribute == 0x80);
  		
  		switch ((optmask >> 4) & 15) // get bitmask for flags (wconv wnorm eol escapes)
  		{
  		case 0:  return strconv_attribute_impl<opt_false>::parse_simple;
  		case 1:  return strconv_attribute_impl<opt_true>::parse_simple;
  		case 2:  return strconv_attribute_impl<opt_false>::parse_eol;
  		case 3:  return strconv_attribute_impl<opt_true>::parse_eol;
  		case 4:  return strconv_attribute_impl<opt_false>::parse_wconv;
  		case 5:  return strconv_attribute_impl<opt_true>::parse_wconv;
  		case 6:  return strconv_attribute_impl<opt_false>::parse_wconv;
  		case 7:  return strconv_attribute_impl<opt_true>::parse_wconv;
  		case 8:  return strconv_attribute_impl<opt_false>::parse_wnorm;
  		case 9:  return strconv_attribute_impl<opt_true>::parse_wnorm;
  		case 10: return strconv_attribute_impl<opt_false>::parse_wnorm;
  		case 11: return strconv_attribute_impl<opt_true>::parse_wnorm;
  		case 12: return strconv_attribute_impl<opt_false>::parse_wnorm;
  		case 13: return strconv_attribute_impl<opt_true>::parse_wnorm;
  		case 14: return strconv_attribute_impl<opt_false>::parse_wnorm;
  		case 15: return strconv_attribute_impl<opt_true>::parse_wnorm;
  		default: return 0; // should not get here
  		}
  	}
  
  	inline html_parse_result make_parse_result(html_parse_status status, ptrdiff_t offset = 0)
  	{
  		html_parse_result result;
  		result.status = status;
  		result.offset = offset;
  
  		return result;
  	}
      
  	struct html_parser
  	{
  		html_allocator alloc;
  		char_t* error_offset;
  		jmp_buf error_handler;
  		
  		// Parser utilities.
  		#define SKIPWS()			{ while (IS_CHARTYPE(*s, ct_space)) ++s; }
  		#define OPTSET(OPT)			( optmsk & OPT )
  		#define PUSHNODE(TYPE)		{ cursor = append_node(cursor, alloc, TYPE); if (!cursor) THROW_ERROR(status_out_of_memory, s); }
  		#define POPNODE()			{ cursor = cursor->parent; }
  		#define SCANFOR(X)			{ while (*s != 0 && !(X)) ++s; }
  		#define SCANWHILE(X)		{ while ((X)) ++s; }
  		#define ENDSEG()			{ ch = *s; *s = 0; ++s; }
  		#define THROW_ERROR(err, m)	error_offset = m, longjmp(error_handler, err)
  		#define CHECK_ERROR(err, m)	{ if (*s == 0) THROW_ERROR(err, m); }
  		
  		html_parser(const html_allocator& alloc): alloc(alloc), error_offset(0)
  		{
  		}
  
  		// DOCTYPE consists of nested sections of the following possible types:
  		// <!-- ... -->, <? ... ?>, "...", '...'
  		// <![...]]>
  		// <!...>
  		// First group can not contain nested groups
  		// Second group can contain nested groups of the same type
  		// Third group can contain all other groups
  		char_t* parse_doctype_primitive(char_t* s)
  		{
  			if (*s == '"' || *s == '\'')
  			{
  				// quoted string
  				char_t ch = *s++;
  				SCANFOR(*s == ch);
  				if (!*s) THROW_ERROR(status_bad_doctype, s);
  
  				s++;
  			}
  			else if (s[0] == '<' && s[1] == '?')
  			{
  				// <? ... ?>
  				s += 2;
  				SCANFOR(s[0] == '?' && s[1] == '>'); // no need for ENDSWITH because ?> can't terminate proper doctype
  				if (!*s) THROW_ERROR(status_bad_doctype, s);
  
  				s += 2;
  			}
  			else if (s[0] == '<' && s[1] == '!' && s[2] == '-' && s[3] == '-')
  			{
  				s += 4;
  				SCANFOR(s[0] == '-' && s[1] == '-' && s[2] == '>'); // no need for ENDSWITH because --> can't terminate proper doctype
  				if (!*s) THROW_ERROR(status_bad_doctype, s);
  
  				s += 4;
  			}
  			else THROW_ERROR(status_bad_doctype, s);
  
  			return s;
  		}
  
  		char_t* parse_doctype_ignore(char_t* s)
  		{
  			assert(s[0] == '<' && s[1] == '!' && s[2] == '[');
  			s++;
  
  			while (*s)
  			{
  				if (s[0] == '<' && s[1] == '!' && s[2] == '[')
  				{
  					// nested ignore section
  					s = parse_doctype_ignore(s);
  				}
  				else if (s[0] == ']' && s[1] == ']' && s[2] == '>')
  				{
  					// ignore section end
  					s += 3;
  
  					return s;
  				}
  				else s++;
  			}
  
  			THROW_ERROR(status_bad_doctype, s);
  
  			return s;
  		}
  
  		char_t* parse_doctype_group(char_t* s, char_t endch, bool toplevel)
  		{
  			assert(s[0] == '<' && s[1] == '!');
  			s++;
  
  			while (*s)
  			{
  				if (s[0] == '<' && s[1] == '!' && s[2] != '-')
  				{
  					if (s[2] == '[')
  					{
  						// ignore
  						s = parse_doctype_ignore(s);
  					}
  					else
  					{
  						// some control group
  						s = parse_doctype_group(s, endch, false);
  					}
  				}
  				else if (s[0] == '<' || s[0] == '"' || s[0] == '\'')
  				{
  					// unknown tag (forbidden), or some primitive group
  					s = parse_doctype_primitive(s);
  				}
  				else if (*s == '>')
  				{
  					s++;
  
  					return s;
  				}
  				else s++;
  			}
  
  			if (!toplevel || endch != '>') THROW_ERROR(status_bad_doctype, s);
  
  			return s;
  		}
  
  		char_t* parse_exclamation(char_t* s, html_node_struct* cursor, unsigned int optmsk, char_t endch)
  		{
  			// parse node contents, starting with exclamation mark
  			++s;
  
  			if (*s == '-') // '<!-...'
  			{
  				++s;
  
  				if (*s == '-') // '<!--...'
  				{
  					++s;
  
  					if (OPTSET(parse_comments))
  					{
  						PUSHNODE(node_comment); // Append a new node on the tree.
  						cursor->value = s; // Save the offset.
  					}
  
  					if (OPTSET(parse_eol) && OPTSET(parse_comments))
  					{
  						s = strconv_comment(s, endch);
  
  						if (!s) THROW_ERROR(status_bad_comment, cursor->value);
  					}
  					else
  					{
  						// Scan for terminating '-->'.
  						SCANFOR(s[0] == '-' && s[1] == '-' && ENDSWITH(s[2], '>'));
  						CHECK_ERROR(status_bad_comment, s);
  
  						if (OPTSET(parse_comments))
  							*s = 0; // Zero-terminate this segment at the first terminating '-'.
  
  						s += (s[2] == '>' ? 3 : 2); // Step over the '\0->'.
  					}
  				}
  				else THROW_ERROR(status_bad_comment, s);
  			}
  			else if (*s == '[')
  			{
  				// '<![CDATA[...'
  				if (*++s=='C' && *++s=='D' && *++s=='A' && *++s=='T' && *++s=='A' && *++s == '[')
  				{
  					++s;
  
  					if (OPTSET(parse_cdata))
  					{
  						PUSHNODE(node_cdata); // Append a new node on the tree.
  						cursor->value = s; // Save the offset.
  
  						if (OPTSET(parse_eol))
  						{
  							s = strconv_cdata(s, endch);
  
  							if (!s) THROW_ERROR(status_bad_cdata, cursor->value);
  						}
  						else
  						{
  							// Scan for terminating ']]>'.
  							SCANFOR(s[0] == ']' && s[1] == ']' && ENDSWITH(s[2], '>'));
  							CHECK_ERROR(status_bad_cdata, s);
  
  							*s++ = 0; // Zero-terminate this segment.
  						}
  					}
  					else // Flagged for discard, but we still have to scan for the terminator.
  					{
  						// Scan for terminating ']]>'.
  						SCANFOR(s[0] == ']' && s[1] == ']' && ENDSWITH(s[2], '>'));
  						CHECK_ERROR(status_bad_cdata, s);
  
  						++s;
  					}
  
  					s += (s[1] == '>' ? 2 : 1); // Step over the last ']>'.
  				}
  				else THROW_ERROR(status_bad_cdata, s);
  			}
  			else if (s[0] == 'D' && s[1] == 'O' && s[2] == 'C' && s[3] == 'T' && s[4] == 'Y' && s[5] == 'P' && ENDSWITH(s[6], 'E'))
  			{
  				s -= 2;
  
                  if (cursor->parent) THROW_ERROR(status_bad_doctype, s);
  
                  char_t* mark = s + 9;
  
  				s = parse_doctype_group(s, endch, true);
  
                  if (OPTSET(parse_doctype))
                  {
                      while (IS_CHARTYPE(*mark, ct_space)) ++mark;
  
                      PUSHNODE(node_doctype);
  
                      cursor->value = mark;
  
                      assert((s[0] == 0 && endch == '>') || s[-1] == '>');
                      s[*s == 0 ? 0 : -1] = 0;
  
                      POPNODE();
                  }
  			}
  			else if (*s == 0 && endch == '-') THROW_ERROR(status_bad_comment, s);
  			else if (*s == 0 && endch == '[') THROW_ERROR(status_bad_cdata, s);
  			else THROW_ERROR(status_unrecognized_tag, s);
  
  			return s;
  		}
  
  		char_t* parse_question(char_t* s, html_node_struct*& ref_cursor, unsigned int optmsk, char_t endch)
  		{
  			// load into registers
  			html_node_struct* cursor = ref_cursor;
  			char_t ch = 0;
  
  			// parse node contents, starting with question mark
  			++s;
  
  			// read PI target
  			char_t* target = s;
  
  			if (!IS_CHARTYPE(*s, ct_start_symbol)) THROW_ERROR(status_bad_pi, s);
  
  			SCANWHILE(IS_CHARTYPE(*s, ct_symbol));
  			CHECK_ERROR(status_bad_pi, s);
  
  			// determine node type; stricmp / strcasecmp is not portable
  			bool declaration = (target[0] | ' ') == 'x' && (target[1] | ' ') == 'm' && (target[2] | ' ') == 'l' && target + 3 == s;
  
  			if (declaration ? OPTSET(parse_declaration) : OPTSET(parse_pi))
  			{
  				if (declaration)
  				{
  					// disallow non top-level declarations
  					if (cursor->parent) THROW_ERROR(status_bad_pi, s);
  
  					PUSHNODE(node_declaration);
  				}
  				else
  				{
  					PUSHNODE(node_pi);
  				}
  
  				cursor->name = target;
  
  				ENDSEG();
  
  				// parse value/attributes
  				if (ch == '?')
  				{
  					// empty node
  					if (!ENDSWITH(*s, '>')) THROW_ERROR(status_bad_pi, s);
  					s += (*s == '>');
  
                      if(cursor->parent)
                      {
  						POPNODE(); // Pop.
                      }
                      else
                      {
                          // We have reached the root node so do not 
                          // attempt to pop anymore nodes
                          return s;
                      }
  				}
  				else if (IS_CHARTYPE(ch, ct_space))
  				{
  					SKIPWS();
  
  					// scan for tag end
  					char_t* value = s;
  
  					SCANFOR(s[0] == '?' && ENDSWITH(s[1], '>'));
  					CHECK_ERROR(status_bad_pi, s);
  
  					if (declaration)
  					{
  						// replace ending ? with / so that 'element' terminates properly
  						*s = '/';
  
  						// we exit from this function with cursor at node_declaration, which is a signal to parse() to go to LOC_ATTRIBUTES
  						s = value;
  					}
  					else
  					{
  						// store value and step over >
  						cursor->value = value;
  						
                          if(cursor->parent)
                          {
  						    POPNODE(); // Pop.
                          }
                          else
                          {
                              // We have reached the root node so do not 
                              // attempt to pop anymore nodes
                              return s;
                          }
  						ENDSEG();
  
  						s += (*s == '>');
  					}
  				}
  				else THROW_ERROR(status_bad_pi, s);
  			}
  			else
  			{
  				// scan for tag end
  				SCANFOR(s[0] == '?' && ENDSWITH(s[1], '>'));
  				CHECK_ERROR(status_bad_pi, s);
  
  				s += (s[1] == '>' ? 2 : 1);
  			}
  
  			// store from registers
  			ref_cursor = cursor;
  
  			return s;
  		}
  
  		void parse(char_t* s, html_node_struct* htmldoc, unsigned int optmsk, char_t endch)
  		{
  			strconv_attribute_t strconv_attribute = get_strconv_attribute(optmsk);
  			strconv_pcdata_t strconv_pcdata = get_strconv_pcdata(optmsk);
  			
  			char_t ch = 0;
  
              // Point the cursor to the html document node
  			html_node_struct* cursor = htmldoc;
  
              // Set the marker
  			char_t* mark = s;
  
              // It's necessary to keep another mark when we have to roll
              // back the name and the mark at the same time.
              char_t* sMark = s;
              char_t* nameMark = s;
  
              // Parse while the current character is not '\0'
  			while (*s != 0)
  			{
                  // Check if the current character is the start tag character
  				if (*s == '<')
  				{
                      // Move to the next character
  					++s;
  
                      // Check if the current character is a start symbol
                  LOC_TAG:
  					if (IS_CHARTYPE(*s, ct_start_symbol)) // '<#...'
  					{
                          // Append a new node to the tree.
  						PUSHNODE(node_element); 
  
                          // Set the current element's name
  						cursor->name = s;
                          
                          // Scan while the current character is a symbol belonging
                          // to the set of symbols acceptable within a tag. In other
                          // words, scan until the termination symbol is discovered.
  						SCANWHILE(IS_CHARTYPE(*s, ct_symbol)); 
  						
                          // Save char in 'ch', terminate & step over.
                          ENDSEG();
  
                          // Capitalize the tag name
                          to_upper(cursor->name);
  
  						if (ch == '>')
  						{
  							// end of tag
  						}
  						else if (IS_CHARTYPE(ch, ct_space))
  						{
  						LOC_ATTRIBUTES:
  						    while (true)
  						    {
  								SKIPWS(); // Eat any whitespace.
  						
  								if (IS_CHARTYPE(*s, ct_start_symbol)) // <... #...
  								{
  									html_attribute_struct* a = append_attribute_ll(cursor, alloc); // Make space for this attribute.
  									if (!a) THROW_ERROR(status_out_of_memory, s);
  
  									a->name = s; // Save the offset.
  
  									SCANWHILE(IS_CHARTYPE(*s, ct_symbol)); // Scan for a terminator.
  									CHECK_ERROR(status_bad_attribute, s); //$ redundant, left for performance
  
  									ENDSEG(); // Save char in 'ch', terminate & step over.
                                      
                                      // Capitalize the attribute name
                                      to_upper(a->name);
                                      
                                      //$ redundant, left for performance
  									CHECK_ERROR(status_bad_attribute, s); 
  
  									if (IS_CHARTYPE(ch, ct_space))
  									{
  										SKIPWS(); // Eat any whitespace.
  										CHECK_ERROR(status_bad_attribute, s); //$ redundant, left for performance
  
  										ch = *s;
  										++s;
  									}
  									
  									if (ch == '=') // '<... #=...'
  									{
  										SKIPWS(); // Eat any whitespace.
  
  										if (*s == '"' || *s == '\'') // '<... #="...'
  										{
  											ch = *s; // Save quote char to avoid breaking on "''" -or- '""'.
  											++s; // Step over the quote.
  											a->value = s; // Save the offset.
  
  											s = strconv_attribute(s, ch);
  										
  											if (!s) THROW_ERROR(status_bad_attribute, a->value);
  
  											// After this line the loop continues from the start;
  											// Whitespaces, / and > are ok, symbols and EOF are wrong,
  											// everything else will be detected
  											if (IS_CHARTYPE(*s, ct_start_symbol)) THROW_ERROR(status_bad_attribute, s);
  										}
  										else THROW_ERROR(status_bad_attribute, s);
  									}
                                      else {//hot fix:try to fix that attribute=value situation;
                                          ch='"';
                                          a->value=s;
                                          char_t* dp=s;
                                          char_t temp;
                                          const char *sch="> /";
                                          //find the end of attribute,200 length is enough,it must return a position;
                                          temp=*dp;//backup the former char
                                          *dp='"';//hack at the end position;
                                          s=strconv_attribute(s,ch);
                                          *dp=temp;//restore it;
                                          s--;// back it because we come to the " but it is > indeed;
                                          if (IS_CHARTYPE(*s, ct_start_symbol)) THROW_ERROR(status_bad_attribute, s);
  
                                      }
                                      //THROW_ERROR(status_bad_attribute, s);
  								}
  								else if (*s == '/')
  								{
  									++s;
  									
  									if (*s == '>')
  									{
  										if(cursor->parent)
                                          {
  						                    POPNODE(); // Pop.
                                          }
                                          else
                                          {
                                              // We have reached the root node so do not 
                                              // attempt to pop anymore nodes
                                              break;
                                          }
  										s++;
  										break;
  									}
  									else if (*s == 0 && endch == '>')
  									{
  										if(cursor->parent)
                                          {
  						                    POPNODE(); // Pop.
                                          }
                                          else
                                          {
                                              // We have reached the root node so do not 
                                              // attempt to pop anymore nodes
                                              break;
                                          }
  										break;
  									}
  									else THROW_ERROR(status_bad_start_element, s);
  								}
  								else if (*s == '>')
  								{
  									++s;
  
  									break;
  								}
  								else if (*s == 0 && endch == '>')
  								{
  									break;
  								}
  								else THROW_ERROR(status_bad_start_element, s);
  							}// while
  
  							// !!!
  						}
  						else if (ch == '/') // '<#.../'
  						{
  							if (!ENDSWITH(*s, '>')) THROW_ERROR(status_bad_start_element, s);
  
                              if(cursor->parent)
                              {
  							    POPNODE(); // Pop.
                              }
                              else
                              {
                                  // We have reached the root node so do not 
                                  // attempt to pop anymore nodes
                                  break;
                              }
  
  							s += (*s == '>');
  						}
  						else if (ch == 0)
  						{
  							// we stepped over null terminator, backtrack & handle closing tag
  							--s;
  							
  							if (endch != '>') THROW_ERROR(status_bad_start_element, s);
  						}
  						else THROW_ERROR(status_bad_start_element, s);
  					}
  					else if (*s == '/')
  					{
  						++s;
  
  						char_t* name = cursor->name;
  						if (!name)
                          {
                              // TODO ignore exception
                              //THROW_ERROR(status_end_element_mismatch, s);
                          }
                          else
                          {
                              sMark = s;
                              nameMark = name;
                              // Read the name while the character is a symbol
  						    while (IS_CHARTYPE(*s, ct_symbol))
  						    {
                                  // Check if we're closing the correct tag name:
                                  // if the cursor tag does not match the current
                                  // closing tag then throw an exception.
  							    if (*s++ != *name++)
                                  {
                                      // TODO POPNODE or ignore exception
                                      //THROW_ERROR(status_end_element_mismatch, s);
  
                                      // Return to the last position where we started
                                      // reading the expected closing tag name.
                                      s = sMark;
                                      name = nameMark;
                                      break;
                                  }
  						    }
                              // Check if the end element is valid
  						    if (*name)
  						    {
  							    if (*s == 0 && name[0] == endch && name[1] == 0)
                                  {
                                      THROW_ERROR(status_bad_end_element, s);
                                  }
  							    else 
                                  {
                                      // TODO POPNODE or ignore exception
                                      //THROW_ERROR(status_end_element_mismatch, s);
                                  }
  						    }
                          }
  						
                          // The tag was closed so we have to pop the
                          // node off the "stack".
  						if(cursor->parent)
                          {
  							POPNODE(); // Pop.
                          }
                          else
                          {
                              // We have reached the root node so do not 
                              // attempt to pop anymore nodes
                              break;
                          }
  
  						SKIPWS();
  
                          // If there end of the string is reached.
  						if (*s == 0)
  						{
                              // Check if the end character specified is the
                              // same as the closing tag.
  							if (endch != '>') 
                              {
                                  THROW_ERROR(status_bad_end_element, s);
                              }
  						}
  						else
  						{
                              // Skip the end character becaue the tag
                              // was closed and the node was popped off
                              // the "stack".
  							if (*s != '>') 
                              {
                                  // Continue parsing
                                  continue;
                                  // TODO ignore the exception
                                  // THROW_ERROR(status_bad_end_element, s);
                              }
  							++s;
  						}
  					}
  					else if (*s == '?') // '<?...'
  					{
  						s = parse_question(s, cursor, optmsk, endch);
  
  						assert(cursor);
  						if ((cursor->header & html_memory_page_type_mask) + 1 == node_declaration) 
                          {
                              goto LOC_ATTRIBUTES;
                          }
  					}
  					else if (*s == '!') // '<!...'
  					{
  						s = parse_exclamation(s, cursor, optmsk, endch);
  					}
  					else if (*s == 0 && endch == '?')
                      {
                          THROW_ERROR(status_bad_pi, s);
                      }
  					else 
                      {
                          THROW_ERROR(status_unrecognized_tag, s);
                      }
  				}
  				else
  				{
  					mark = s; // Save this offset while searching for a terminator.
  
  					SKIPWS(); // Eat whitespace if no genuine PCDATA here.
  
  					if ((!OPTSET(parse_ws_pcdata) || mark == s) && (*s == '<' || !*s))
  					{
  						continue;
  					}
  
  					s = mark;
  							
  					if (cursor->parent)
  					{
  						PUSHNODE(node_pcdata); // Append a new node on the tree.
  						cursor->value = s; // Save the offset.
  
  						s = strconv_pcdata(s);
  
  						POPNODE(); // Pop since this is a standalone.
  						
  						if (!*s) break;
  					}
  					else
  					{
  						SCANFOR(*s == '<'); // '...<'
  						if (!*s) break;
  						
  						++s;
  					}
  
  					// We're after '<'
  					goto LOC_TAG;
  				}
  			}
  
  			// Check that last tag is closed
  			if (cursor != htmldoc)
              {
                  // TODO POPNODE or ignore exception
                  // THROW_ERROR(status_end_element_mismatch, s);
                  cursor = htmldoc;
              }
  		}
  
  		static html_parse_result parse(char_t* buffer, size_t length, html_node_struct* root, unsigned int optmsk)
  		{
  			html_document_struct* htmldoc = static_cast<html_document_struct*>(root);
  
  			// store buffer for offset_debug
  			htmldoc->buffer = buffer;
  
  			// early-out for empty documents
  			if (length == 0) return make_parse_result(status_ok);
  
  			// create parser on stack
  			html_parser parser(*htmldoc);
  
  			// save last character and make buffer zero-terminated (speeds up parsing)
  			char_t endch = buffer[length - 1];
  			buffer[length - 1] = 0;
  			
  			// perform actual parsing
  			int error = setjmp(parser.error_handler);
  
  			if (error == 0)
  			{
  				parser.parse(buffer, htmldoc, optmsk, endch);
  			}
  
  			html_parse_result result = make_parse_result(static_cast<html_parse_status>(error), parser.error_offset ? parser.error_offset - buffer : 0);
  			assert(result.offset >= 0 && static_cast<size_t>(result.offset) <= length);
  
  			// update allocator state
  			*static_cast<html_allocator*>(htmldoc) = parser.alloc;
  
  			// since we removed last character, we have to handle the only possible false positive
  			if (result && endch == '<')
  			{
  				// there's no possible well-formed document with < at the end
  				return make_parse_result(status_unrecognized_tag, length);
  			}
  
  			return result;
  		}
  	};
  
  	// Output facilities
  	html_encoding get_write_native_encoding()
  	{
  	#ifdef PUGIHTML_WCHAR_MODE
  		return get_wchar_encoding();
  	#else
  		return encoding_utf8;
  	#endif
  	}
  
  	html_encoding get_write_encoding(html_encoding encoding)
  	{
  		// replace wchar encoding with utf implementation
  		if (encoding == encoding_wchar) return get_wchar_encoding();
  
  		// replace utf16 encoding with utf16 with specific endianness
  		if (encoding == encoding_utf16) return is_little_endian() ? encoding_utf16_le : encoding_utf16_be;
  
  		// replace utf32 encoding with utf32 with specific endianness
  		if (encoding == encoding_utf32) return is_little_endian() ? encoding_utf32_le : encoding_utf32_be;
  
  		// only do autodetection if no explicit encoding is requested
  		if (encoding != encoding_auto) return encoding;
  
  		// assume utf8 encoding
  		return encoding_utf8;
  	}
  
  #ifdef PUGIHTML_WCHAR_MODE
  	size_t get_valid_length(const char_t* data, size_t length)
  	{
  		assert(length > 0);
  
  		// discard last character if it's the lead of a surrogate pair 
  		return (sizeof(wchar_t) == 2 && (unsigned)(static_cast<uint16_t>(data[length - 1]) - 0xD800) < 0x400) ? length - 1 : length;
  	}
  
  	size_t convert_buffer(char* result, const char_t* data, size_t length, html_encoding encoding)
  	{
  		// only endian-swapping is required
  		if (need_endian_swap_utf(encoding, get_wchar_encoding()))
  		{
  			convert_wchar_endian_swap(reinterpret_cast<char_t*>(result), data, length);
  
  			return length * sizeof(char_t);
  		}
  	
  		// convert to utf8
  		if (encoding == encoding_utf8)
  		{
  			uint8_t* dest = reinterpret_cast<uint8_t*>(result);
  
  			uint8_t* end = sizeof(wchar_t) == 2 ?
  				utf_decoder<utf8_writer>::decode_utf16_block(reinterpret_cast<const uint16_t*>(data), length, dest) :
  				utf_decoder<utf8_writer>::decode_utf32_block(reinterpret_cast<const uint32_t*>(data), length, dest);
  
  			return static_cast<size_t>(end - dest);
  		}
  
  		// convert to utf16
  		if (encoding == encoding_utf16_be || encoding == encoding_utf16_le)
  		{
  			uint16_t* dest = reinterpret_cast<uint16_t*>(result);
  
  			// convert to native utf16
  			uint16_t* end = utf_decoder<utf16_writer>::decode_utf32_block(reinterpret_cast<const uint32_t*>(data), length, dest);
  
  			// swap if necessary
  			html_encoding native_encoding = is_little_endian() ? encoding_utf16_le : encoding_utf16_be;
  
  			if (native_encoding != encoding) convert_utf_endian_swap(dest, dest, static_cast<size_t>(end - dest));
  
  			return static_cast<size_t>(end - dest) * sizeof(uint16_t);
  		}
  
  		// convert to utf32
  		if (encoding == encoding_utf32_be || encoding == encoding_utf32_le)
  		{
  			uint32_t* dest = reinterpret_cast<uint32_t*>(result);
  
  			// convert to native utf32
  			uint32_t* end = utf_decoder<utf32_writer>::decode_utf16_block(reinterpret_cast<const uint16_t*>(data), length, dest);
  
  			// swap if necessary
  			html_encoding native_encoding = is_little_endian() ? encoding_utf32_le : encoding_utf32_be;
  
  			if (native_encoding != encoding) convert_utf_endian_swap(dest, dest, static_cast<size_t>(end - dest));
  
  			return static_cast<size_t>(end - dest) * sizeof(uint32_t);
  		}
  
  		assert(!"Invalid encoding");
  		return 0;
  	}
  #else
  	size_t get_valid_length(const char_t* data, size_t length)
  	{
  		assert(length > 4);
  
  		for (size_t i = 1; i <= 4; ++i)
  		{
  			uint8_t ch = static_cast<uint8_t>(data[length - i]);
  
  			// either a standalone character or a leading one
  			if ((ch & 0xc0) != 0x80) return length - i;
  		}
  
  		// there are four non-leading characters at the end, sequence tail is broken so might as well process the whole chunk
  		return length;
  	}
  
  	size_t convert_buffer(char* result, const char_t* data, size_t length, html_encoding encoding)
  	{
  		if (encoding == encoding_utf16_be || encoding == encoding_utf16_le)
  		{
  			uint16_t* dest = reinterpret_cast<uint16_t*>(result);
  
  			// convert to native utf16
  			uint16_t* end = utf_decoder<utf16_writer>::decode_utf8_block(reinterpret_cast<const uint8_t*>(data), length, dest);
  
  			// swap if necessary
  			html_encoding native_encoding = is_little_endian() ? encoding_utf16_le : encoding_utf16_be;
  
  			if (native_encoding != encoding) convert_utf_endian_swap(dest, dest, static_cast<size_t>(end - dest));
  
  			return static_cast<size_t>(end - dest) * sizeof(uint16_t);
  		}
  
  		if (encoding == encoding_utf32_be || encoding == encoding_utf32_le)
  		{
  			uint32_t* dest = reinterpret_cast<uint32_t*>(result);
  
  			// convert to native utf32
  			uint32_t* end = utf_decoder<utf32_writer>::decode_utf8_block(reinterpret_cast<const uint8_t*>(data), length, dest);
  
  			// swap if necessary
  			html_encoding native_encoding = is_little_endian() ? encoding_utf32_le : encoding_utf32_be;
  
  			if (native_encoding != encoding) convert_utf_endian_swap(dest, dest, static_cast<size_t>(end - dest));
  
  			return static_cast<size_t>(end - dest) * sizeof(uint32_t);
  		}
  
  		assert(!"Invalid encoding");
  		return 0;
  	}
  #endif
  
  	class html_buffered_writer
  	{
  		html_buffered_writer(const html_buffered_writer&);
  		html_buffered_writer& operator=(const html_buffered_writer&);
  
  	public:
  		html_buffered_writer(html_writer& writer, html_encoding user_encoding): writer(writer), bufsize(0), encoding(get_write_encoding(user_encoding))
  		{
  		}
  
  		~html_buffered_writer()
  		{
  			flush();
  		}
  
  		void flush()
  		{
  			flush(buffer, bufsize);
  			bufsize = 0;
  		}
  
  		void flush(const char_t* data, size_t size)
  		{
  			if (size == 0) return;
  
  			// fast path, just write data
  			if (encoding == get_write_native_encoding())
  				writer.write(data, size * sizeof(char_t));
  			else
  			{
  				// convert chunk
  				size_t result = convert_buffer(scratch, data, size, encoding);
  				assert(result <= sizeof(scratch));
  
  				// write data
  				writer.write(scratch, result);
  			}
  		}
  
  		void write(const char_t* data, size_t length)
  		{
  			if (bufsize + length > bufcapacity)
  			{
  				// flush the remaining buffer contents
  				flush();
  
  				// handle large chunks
  				if (length > bufcapacity)
  				{
  					if (encoding == get_write_native_encoding())
  					{
  						// fast path, can just write data chunk
  						writer.write(data, length * sizeof(char_t));
  						return;
  					}
  
  					// need to convert in suitable chunks
  					while (length > bufcapacity)
  					{
  						// get chunk size by selecting such number of characters that are guaranteed to fit into scratch buffer
  						// and form a complete codepoint sequence (i.e. discard start of last codepoint if necessary)
  						size_t chunk_size = get_valid_length(data, bufcapacity);
  
  						// convert chunk and write
  						flush(data, chunk_size);
  
  						// iterate
  						data += chunk_size;
  						length -= chunk_size;
  					}
  
  					// small tail is copied below
  					bufsize = 0;
  				}
  			}
  
  			memcpy(buffer + bufsize, data, length * sizeof(char_t));
  			bufsize += length;
  		}
  
  		void write(const char_t* data)
  		{
  			write(data, strlength(data));
  		}
  
  		void write(char_t d0)
  		{
  			if (bufsize + 1 > bufcapacity) flush();
  
  			buffer[bufsize + 0] = d0;
  			bufsize += 1;
  		}
  
  		void write(char_t d0, char_t d1)
  		{
  			if (bufsize + 2 > bufcapacity) flush();
  
  			buffer[bufsize + 0] = d0;
  			buffer[bufsize + 1] = d1;
  			bufsize += 2;
  		}
  
  		void write(char_t d0, char_t d1, char_t d2)
  		{
  			if (bufsize + 3 > bufcapacity) flush();
  
  			buffer[bufsize + 0] = d0;
  			buffer[bufsize + 1] = d1;
  			buffer[bufsize + 2] = d2;
  			bufsize += 3;
  		}
  
  		void write(char_t d0, char_t d1, char_t d2, char_t d3)
  		{
  			if (bufsize + 4 > bufcapacity) flush();
  
  			buffer[bufsize + 0] = d0;
  			buffer[bufsize + 1] = d1;
  			buffer[bufsize + 2] = d2;
  			buffer[bufsize + 3] = d3;
  			bufsize += 4;
  		}
  
  		void write(char_t d0, char_t d1, char_t d2, char_t d3, char_t d4)
  		{
  			if (bufsize + 5 > bufcapacity) flush();
  
  			buffer[bufsize + 0] = d0;
  			buffer[bufsize + 1] = d1;
  			buffer[bufsize + 2] = d2;
  			buffer[bufsize + 3] = d3;
  			buffer[bufsize + 4] = d4;
  			bufsize += 5;
  		}
  
  		void write(char_t d0, char_t d1, char_t d2, char_t d3, char_t d4, char_t d5)
  		{
  			if (bufsize + 6 > bufcapacity) flush();
  
  			buffer[bufsize + 0] = d0;
  			buffer[bufsize + 1] = d1;
  			buffer[bufsize + 2] = d2;
  			buffer[bufsize + 3] = d3;
  			buffer[bufsize + 4] = d4;
  			buffer[bufsize + 5] = d5;
  			bufsize += 6;
  		}
  
  		// utf8 maximum expansion: x4 (-> utf32)
  		// utf16 maximum expansion: x2 (-> utf32)
  		// utf32 maximum expansion: x1
  		enum { bufcapacity = 2048 };
  
  		char_t buffer[bufcapacity];
  		char scratch[4 * bufcapacity];
  
  		html_writer& writer;
  		size_t bufsize;
  		html_encoding encoding;
  	};
  
  	void write_bom(html_writer& writer, html_encoding encoding)
  	{
  		switch (encoding)
  		{
  		case encoding_utf8:
  			writer.write("\xef\xbb\xbf", 3);
  			break;
  
  		case encoding_utf16_be:
  			writer.write("\xfe\xff", 2);
  			break;
  
  		case encoding_utf16_le:
  			writer.write("\xff\xfe", 2);
  			break;
  
  		case encoding_utf32_be:
  			writer.write("\x00\x00\xfe\xff", 4);
  			break;
  
  		case encoding_utf32_le:
  			writer.write("\xff\xfe\x00\x00", 4);
  			break;
  
  		default:
  			assert(!"Invalid encoding");
  		}
  	}
  
  	void text_output_escaped(html_buffered_writer& writer, const char_t* s, chartypex_t type)
  	{
  		while (*s)
  		{
  			const char_t* prev = s;
  			
  			// While *s is a usual symbol
  			while (!IS_CHARTYPEX(*s, type)) ++s;
  		
  			writer.write(prev, static_cast<size_t>(s - prev));
  
  			switch (*s)
  			{
  				case 0: break;
  				case '&':
  					writer.write('&', 'a', 'm', 'p', ';');
  					++s;
  					break;
  				case '<':
  					writer.write('&', 'l', 't', ';');
  					++s;
  					break;
  				case '>':
  					writer.write('&', 'g', 't', ';');
  					++s;
  					break;
  				case '"':
  					writer.write('&', 'q', 'u', 'o', 't', ';');
  					++s;
  					break;
  				default: // s is not a usual symbol
  				{
  					unsigned int ch = static_cast<unsigned int>(*s++);
  					assert(ch < 32);
  
  					writer.write('&', '#', static_cast<char_t>((ch / 10) + '0'), static_cast<char_t>((ch % 10) + '0'), ';');
  				}
  			}
  		}
  	}
  
  	void text_output_cdata(html_buffered_writer& writer, const char_t* s)
  	{
  		do
  		{
  			writer.write('<', '!', '[', 'C', 'D');
  			writer.write('A', 'T', 'A', '[');
  
  			const char_t* prev = s;
  
  			// look for ]]> sequence - we can't output it as is since it terminates CDATA
  			while (*s && !(s[0] == ']' && s[1] == ']' && s[2] == '>')) ++s;
  
  			// skip ]] if we stopped at ]]>, > will go to the next CDATA section
  			if (*s) s += 2;
  
  			writer.write(prev, static_cast<size_t>(s - prev));
  
  			writer.write(']', ']', '>');
  		}
  		while (*s);
  	}
  
  	void node_output_attributes(html_buffered_writer& writer, const html_node& node)
  	{
  		const char_t* default_name = PUGIHTML_TEXT(":anonymous");
  
  		for (html_attribute a = node.first_attribute(); a; a = a.next_attribute())
  		{
  			writer.write(' ');
  			writer.write(a.name()[0] ? a.name() : default_name);
  			writer.write('=', '"');
  
  			text_output_escaped(writer, a.value(), ctx_special_attr);
  
  			writer.write('"');
  		}
  	}
  
  	void node_output(html_buffered_writer& writer, const html_node& node, const char_t* indent, unsigned int flags, unsigned int depth)
  	{
  		const char_t* default_name = PUGIHTML_TEXT(":anonymous");
  
  		if ((flags & format_indent) != 0 && (flags & format_raw) == 0)
  			for (unsigned int i = 0; i < depth; ++i) writer.write(indent);
  
  		switch (node.type())
  		{
  		case node_document:
  		{
  			for (html_node n = node.first_child(); n; n = n.next_sibling())
  				node_output(writer, n, indent, flags, depth);
  			break;
  		}
  			
  		case node_element:
  		{
  			const char_t* name = node.name()[0] ? node.name() : default_name;
  
  			writer.write('<');
  			writer.write(name);
  
  			node_output_attributes(writer, node);
  
  			if (flags & format_raw)
  			{
  				if (!node.first_child())
  					writer.write(' ', '/', '>');
  				else
  				{
  					writer.write('>');
  
  					for (html_node n = node.first_child(); n; n = n.next_sibling())
  						node_output(writer, n, indent, flags, depth + 1);
  
  					writer.write('<', '/');
  					writer.write(name);
  					writer.write('>');
  				}
  			}
  			else if (!node.first_child())
  				writer.write(' ', '/', '>', '\n');
  			else if (node.first_child() == node.last_child() && (node.first_child().type() == node_pcdata || node.first_child().type() == node_cdata))
  			{
  				writer.write('>');
  
                  if (node.first_child().type() == node_pcdata)
                      text_output_escaped(writer, node.first_child().value(), ctx_special_pcdata);
                  else
                      text_output_cdata(writer, node.first_child().value());
  
  				writer.write('<', '/');
  				writer.write(name);
  				writer.write('>', '\n');
  			}
  			else
  			{
  				writer.write('>', '\n');
  				
  				for (html_node n = node.first_child(); n; n = n.next_sibling())
  					node_output(writer, n, indent, flags, depth + 1);
  
  				if ((flags & format_indent) != 0 && (flags & format_raw) == 0)
  					for (unsigned int i = 0; i < depth; ++i) writer.write(indent);
  				
  				writer.write('<', '/');
  				writer.write(name);
  				writer.write('>', '\n');
  			}
  
  			break;
  		}
  		
  		case node_pcdata:
  			text_output_escaped(writer, node.value(), ctx_special_pcdata);
  			if ((flags & format_raw) == 0) writer.write('\n');
  			break;
  
  		case node_cdata:
  			text_output_cdata(writer, node.value());
  			if ((flags & format_raw) == 0) writer.write('\n');
  			break;
  
  		case node_comment:
  			writer.write('<', '!', '-', '-');
  			writer.write(node.value());
  			writer.write('-', '-', '>');
  			if ((flags & format_raw) == 0) writer.write('\n');
  			break;
  
  		case node_pi:
  		case node_declaration:
  			writer.write('<', '?');
  			writer.write(node.name()[0] ? node.name() : default_name);
  
  			if (node.type() == node_declaration)
  			{
  				node_output_attributes(writer, node);
  			}
  			else if (node.value()[0])
  			{
  				writer.write(' ');
  				writer.write(node.value());
  			}
  
  			writer.write('?', '>');
  			if ((flags & format_raw) == 0) writer.write('\n');
  			break;
  
  		case node_doctype:
  			writer.write('<', '!', 'D', 'O', 'C');
  			writer.write('T', 'Y', 'P', 'E');
  
              if (node.value()[0])
              {
                  writer.write(' ');
                  writer.write(node.value());
              }
  
              writer.write('>');
  			if ((flags & format_raw) == 0) writer.write('\n');
  			break;
  
  		default:
  			assert(!"Invalid node type");
  		}
  	}
  
  	inline bool has_declaration(const html_node& node)
  	{
  		for (html_node child = node.first_child(); child; child = child.next_sibling())
  		{
  			html_node_type type = child.type();
  
  			if (type == node_declaration) return true;
  			if (type == node_element) return false;
  		}
  
  		return false;
  	}
  
  	inline bool allow_insert_child(html_node_type parent, html_node_type child)
  	{
  		if (parent != node_document && parent != node_element) return false;
  		if (child == node_document || child == node_null) return false;
  		if (parent != node_document && (child == node_declaration || child == node_doctype)) return false;
  
  		return true;
  	}
  
  	void recursive_copy_skip(html_node& dest, const html_node& source, const html_node& skip)
  	{
  		assert(dest.type() == source.type());
  
  		switch (source.type())
  		{
  		case node_element:
  		{
  			dest.set_name(source.name());
  
  			for (html_attribute a = source.first_attribute(); a; a = a.next_attribute())
  				dest.append_attribute(a.name()).set_value(a.value());
  
  			for (html_node c = source.first_child(); c; c = c.next_sibling())
  			{
  				if (c == skip) continue;
  
  				html_node cc = dest.append_child(c.type());
  				assert(cc);
  
  				recursive_copy_skip(cc, c, skip);
  			}
  
  			break;
  		}
  
  		case node_pcdata:
  		case node_cdata:
  		case node_comment:
          case node_doctype:
  			dest.set_value(source.value());
  			break;
  
  		case node_pi:
  			dest.set_name(source.name());
  			dest.set_value(source.value());
  			break;
  
  		case node_declaration:
  		{
  			dest.set_name(source.name());
  
  			for (html_attribute a = source.first_attribute(); a; a = a.next_attribute())
  				dest.append_attribute(a.name()).set_value(a.value());
  
  			break;
  		}
  
  		default:
  			assert(!"Invalid node type");
  		}
  	}
  
  	// we need to get length of entire file to load it in memory; the only (relatively) sane way to do it is via seek/tell trick
  	html_parse_status get_file_size(FILE* file, size_t& out_result)
  	{
  	#if defined(_MSC_VER) && _MSC_VER >= 1400
  		// there are 64-bit versions of fseek/ftell, let's use them
  		typedef __int64 length_type;
  
  		_fseeki64(file, 0, SEEK_END);
  		length_type length = _ftelli64(file);
  		_fseeki64(file, 0, SEEK_SET);
  	#elif defined(__MINGW32__) && !defined(__NO_MINGW_LFS) && !defined(__STRICT_ANSI__)
  		// there are 64-bit versions of fseek/ftell, let's use them
  		typedef off64_t length_type;
  
  		fseeko64(file, 0, SEEK_END);
  		length_type length = ftello64(file);
  		fseeko64(file, 0, SEEK_SET);
  	#else
  		// if this is a 32-bit OS, long is enough; if this is a unix system, long is 64-bit, which is enough; otherwise we can't do anything anyway.
  		typedef long length_type;
  
  		fseek(file, 0, SEEK_END);
  		length_type length = ftell(file);
  		fseek(file, 0, SEEK_SET);
  	#endif
  
  		// check for I/O errors
  		if (length < 0) return status_io_error;
  		
  		// check for overflow
  		size_t result = static_cast<size_t>(length);
  
  		if (static_cast<length_type>(result) != length) return status_out_of_memory;
  
  		// finalize
  		out_result = result;
  
  		return status_ok;
  	}
  
  	html_parse_result load_file_impl(html_document& doc, FILE* file, unsigned int options, html_encoding encoding)
  	{
  		if (!file) return make_parse_result(status_file_not_found);
  
  		// get file size (can result in I/O errors)
  		size_t size = 0;
  		html_parse_status size_status = get_file_size(file, size);
  
  		if (size_status != status_ok)
  		{
  			fclose(file);
  			return make_parse_result(size_status);
  		}
  		
  		// allocate buffer for the whole file
  		char* contents = static_cast<char*>(global_allocate(size > 0 ? size : 1));
  
  		if (!contents)
  		{
  			fclose(file);
  			return make_parse_result(status_out_of_memory);
  		}
  
  		// read file in memory
  		size_t read_size = fread(contents, 1, size, file);
  		fclose(file);
  
  		if (read_size != size)
  		{
  			global_deallocate(contents);
  			return make_parse_result(status_io_error);
  		}
  		
  		return doc.load_buffer_inplace_own(contents, size, options, encoding);
  	}
  
  #ifndef PUGIHTML_NO_STL
  	template <typename T> html_parse_result load_stream_impl(html_document& doc, std::basic_istream<T>& stream, unsigned int options, html_encoding encoding)
  	{
  		// get length of remaining data in stream
  		typename std::basic_istream<T>::pos_type pos = stream.tellg();
  		stream.seekg(0, std::ios::end);
  		std::streamoff length = stream.tellg() - pos;
  		stream.seekg(pos);
  
  		if (stream.fail() || pos < 0) return make_parse_result(status_io_error);
  
  		// guard against huge files
  		size_t read_length = static_cast<size_t>(length);
  
  		if (static_cast<std::streamsize>(read_length) != length || length < 0) return make_parse_result(status_out_of_memory);
  
  		// read stream data into memory (guard against stream exceptions with buffer holder)
  		buffer_holder buffer(global_allocate((read_length > 0 ? read_length : 1) * sizeof(T)), global_deallocate);
  		if (!buffer.data) return make_parse_result(status_out_of_memory);
  
  		stream.read(static_cast<T*>(buffer.data), static_cast<std::streamsize>(read_length));
  
  		// read may set failbit | eofbit in case gcount() is less than read_length (i.e. line ending conversion), so check for other I/O errors
  		if (stream.bad()) return make_parse_result(status_io_error);
  
  		// load data from buffer
  		size_t actual_length = static_cast<size_t>(stream.gcount());
  		assert(actual_length <= read_length);
  
  		return doc.load_buffer_inplace_own(buffer.release(), actual_length * sizeof(T), options, encoding);
  	}
  #endif
  
  #if defined(_MSC_VER) || defined(__BORLANDC__) || defined(__MINGW32__)
  	FILE* open_file_wide(const wchar_t* path, const wchar_t* mode)
  	{
  		return _wfopen(path, mode);
  	}
  #else
  	char* convert_path_heap(const wchar_t* str)
  	{
  		assert(str);
  
  		// first pass: get length in utf8 characters
  		size_t length = wcslen(str);
          size_t size = as_utf8_begin(str, length);
  
  		// allocate resulting string
  		char* result = static_cast<char*>(global_allocate(size + 1));
  		if (!result) return 0;
  
  		// second pass: convert to utf8
          as_utf8_end(result, size, str, length);
  
  	  	return result;
  	}
  
  	FILE* open_file_wide(const wchar_t* path, const wchar_t* mode)
  	{
  		// there is no standard function to open wide paths, so our best bet is to try utf8 path
  		char* path_utf8 = convert_path_heap(path);
  		if (!path_utf8) return 0;
  
  		// convert mode to ASCII (we mirror _wfopen interface)
  		char mode_ascii[4] = {0};
  		for (size_t i = 0; mode[i]; ++i) mode_ascii[i] = static_cast<char>(mode[i]);
  
  		// try to open the utf8 path
  		FILE* result = fopen(path_utf8, mode_ascii);
  
  		// free dummy buffer
  		global_deallocate(path_utf8);
  
  		return result;
  	}
  #endif
  }
  
  namespace pugihtml
  {
  	html_writer_file::html_writer_file(void* file): file(file)
  	{
  	}
  
  	void html_writer_file::write(const void* data, size_t size)
  	{
  		fwrite(data, size, 1, static_cast<FILE*>(file));
  	}
  
  #ifndef PUGIHTML_NO_STL
  	html_writer_stream::html_writer_stream(std::basic_ostream<char, std::char_traits<char> >& stream): narrow_stream(&stream), wide_stream(0)
  	{
  	}
  
  	html_writer_stream::html_writer_stream(std::basic_ostream<wchar_t, std::char_traits<wchar_t> >& stream): narrow_stream(0), wide_stream(&stream)
  	{
  	}
  
  	void html_writer_stream::write(const void* data, size_t size)
  	{
  		if (narrow_stream)
  		{
  			assert(!wide_stream);
  			narrow_stream->write(reinterpret_cast<const char*>(data), static_cast<std::streamsize>(size));
  		}
  		else
  		{
  			assert(wide_stream);
  			assert(size % sizeof(wchar_t) == 0);
  
  			wide_stream->write(reinterpret_cast<const wchar_t*>(data), static_cast<std::streamsize>(size / sizeof(wchar_t)));
  		}
  	}
  #endif
  
  	html_tree_walker::html_tree_walker(): _depth(0)
  	{
  	}
  	
  	html_tree_walker::~html_tree_walker()
  	{
  	}
  
  	int html_tree_walker::depth() const
  	{
  		return _depth;
  	}
  
  	bool html_tree_walker::begin(html_node&)
  	{
  		return true;
  	}
  
  	bool html_tree_walker::end(html_node&)
  	{
  		return true;
  	}
  
  	html_attribute::html_attribute(): _attr(0)
  	{
  	}
  
  	html_attribute::html_attribute(html_attribute_struct* attr): _attr(attr)
  	{
  	}
  
  	html_attribute::operator html_attribute::unspecified_bool_type() const
  	{
        	return _attr ? &html_attribute::_attr : 0;
     	}
  
     	bool html_attribute::operator!() const
     	{
     		return !_attr;
     	}
  
  	bool html_attribute::operator==(const html_attribute& r) const
  	{
  		return (_attr == r._attr);
  	}
  	
  	bool html_attribute::operator!=(const html_attribute& r) const
  	{
  		return (_attr != r._attr);
  	}
  
  	bool html_attribute::operator<(const html_attribute& r) const
  	{
  		return (_attr < r._attr);
  	}
  	
  	bool html_attribute::operator>(const html_attribute& r) const
  	{
  		return (_attr > r._attr);
  	}
  	
  	bool html_attribute::operator<=(const html_attribute& r) const
  	{
  		return (_attr <= r._attr);
  	}
  	
  	bool html_attribute::operator>=(const html_attribute& r) const
  	{
  		return (_attr >= r._attr);
  	}
  
     	html_attribute html_attribute::next_attribute() const
     	{
      	return _attr ? html_attribute(_attr->next_attribute) : html_attribute();
     	}
  
      html_attribute html_attribute::previous_attribute() const
      {
      	return _attr && _attr->prev_attribute_c->next_attribute ? html_attribute(_attr->prev_attribute_c) : html_attribute();
      }
  
  	int html_attribute::as_int() const
  	{
  		if (!_attr || !_attr->value) return 0;
  
  	#ifdef PUGIHTML_WCHAR_MODE
  		return (int)wcstol(_attr->value, 0, 10);
  	#else
  		return (int)strtol(_attr->value, 0, 10);
  	#endif
  	}
  
  	unsigned int html_attribute::as_uint() const
  	{
  		if (!_attr || !_attr->value) return 0;
  
  	#ifdef PUGIHTML_WCHAR_MODE
  		return (unsigned int)wcstoul(_attr->value, 0, 10);
  	#else
  		return (unsigned int)strtoul(_attr->value, 0, 10);
  	#endif
  	}
  
  	double html_attribute::as_double() const
  	{
  		if (!_attr || !_attr->value) return 0;
  
  	#ifdef PUGIHTML_WCHAR_MODE
  		return wcstod(_attr->value, 0);
  	#else
  		return strtod(_attr->value, 0);
  	#endif
  	}
  
  	float html_attribute::as_float() const
  	{
  		if (!_attr || !_attr->value) return 0;
  
  	#ifdef PUGIHTML_WCHAR_MODE
  		return (float)wcstod(_attr->value, 0);
  	#else
  		return (float)strtod(_attr->value, 0);
  	#endif
  	}
  
  	bool html_attribute::as_bool() const
  	{
  		if (!_attr || !_attr->value) return false;
  
  		// only look at first char
  		char_t first = *_attr->value;
  
  		// 1*, t* (true), T* (True), y* (yes), Y* (YES)
  		return (first == '1' || first == 't' || first == 'T' || first == 'y' || first == 'Y');
  	}
  
  	bool html_attribute::empty() const
  	{
  		return !_attr;
  	}
  
  	const char_t* html_attribute::name() const
  	{
  		return (_attr && _attr->name) ? _attr->name : PUGIHTML_TEXT("");
  	}
  
  	const char_t* html_attribute::value() const
  	{
  		return (_attr && _attr->value) ? _attr->value : PUGIHTML_TEXT("");
  	}
  
      size_t html_attribute::hash_value() const
      {
          return static_cast<size_t>(reinterpret_cast<uintptr_t>(_attr) / sizeof(html_attribute_struct));
      }
  
  	html_attribute_struct* html_attribute::internal_object() const
  	{
          return _attr;
  	}
  
  	html_attribute& html_attribute::operator=(const char_t* rhs)
  	{
  		set_value(rhs);
  		return *this;
  	}
  	
  	html_attribute& html_attribute::operator=(int rhs)
  	{
  		set_value(rhs);
  		return *this;
  	}
  
  	html_attribute& html_attribute::operator=(unsigned int rhs)
  	{
  		set_value(rhs);
  		return *this;
  	}
  
  	html_attribute& html_attribute::operator=(double rhs)
  	{
  		set_value(rhs);
  		return *this;
  	}
  	
  	html_attribute& html_attribute::operator=(bool rhs)
  	{
  		set_value(rhs);
  		return *this;
  	}
  
  	bool html_attribute::set_name(const char_t* rhs)
  	{
  		if (!_attr) return false;
  		
  		return strcpy_insitu(_attr->name, _attr->header, html_memory_page_name_allocated_mask, rhs);
  	}
  		
  	bool html_attribute::set_value(const char_t* rhs)
  	{
  		if (!_attr) return false;
  
  		return strcpy_insitu(_attr->value, _attr->header, html_memory_page_value_allocated_mask, rhs);
  	}
  
  	bool html_attribute::set_value(int rhs)
  	{
  		char buf[128];
  		sprintf(buf, "%d", rhs);
  	
  	#ifdef PUGIHTML_WCHAR_MODE
  		char_t wbuf[128];
  		widen_ascii(wbuf, buf);
  
  		return set_value(wbuf);
  	#else
  		return set_value(buf);
  	#endif
  	}
  
  	bool html_attribute::set_value(unsigned int rhs)
  	{
  		char buf[128];
  		sprintf(buf, "%u", rhs);
  
  	#ifdef PUGIHTML_WCHAR_MODE
  		char_t wbuf[128];
  		widen_ascii(wbuf, buf);
  
  		return set_value(wbuf);
  	#else
  		return set_value(buf);
  	#endif
  	}
  
  	bool html_attribute::set_value(double rhs)
  	{
  		char buf[128];
  		sprintf(buf, "%g", rhs);
  
  	#ifdef PUGIHTML_WCHAR_MODE
  		char_t wbuf[128];
  		widen_ascii(wbuf, buf);
  
  		return set_value(wbuf);
  	#else
  		return set_value(buf);
  	#endif
  	}
  	
  	bool html_attribute::set_value(bool rhs)
  	{
  		return set_value(rhs ? PUGIHTML_TEXT("true") : PUGIHTML_TEXT("false"));
  	}
  
  #ifdef __BORLANDC__
  	bool operator&&(const html_attribute& lhs, bool rhs)
  	{
  		return (bool)lhs && rhs;
  	}
  
  	bool operator||(const html_attribute& lhs, bool rhs)
  	{
  		return (bool)lhs || rhs;
  	}
  #endif
  
  	html_node::html_node(): _root(0)
  	{
  	}
  
  	html_node::html_node(html_node_struct* p): _root(p)
  	{
  	}
  	
  	html_node::operator html_node::unspecified_bool_type() const
  	{
        	return _root ? &html_node::_root : 0;
     	}
  
     	bool html_node::operator!() const
     	{
     		return !_root;
     	}
  
  	html_node::iterator html_node::begin() const
  	{
  		return iterator(_root ? _root->first_child : 0, _root);
  	}
  
  	html_node::iterator html_node::end() const
  	{
  		return iterator(0, _root);
  	}
  	
  	html_node::attribute_iterator html_node::attributes_begin() const
  	{
  		return attribute_iterator(_root ? _root->first_attribute : 0, _root);
  	}
  
  	html_node::attribute_iterator html_node::attributes_end() const
  	{
  		return attribute_iterator(0, _root);
  	}
  
  	bool html_node::operator==(const html_node& r) const
  	{
  		return (_root == r._root);
  	}
  
  	bool html_node::operator!=(const html_node& r) const
  	{
  		return (_root != r._root);
  	}
  
  	bool html_node::operator<(const html_node& r) const
  	{
  		return (_root < r._root);
  	}
  	
  	bool html_node::operator>(const html_node& r) const
  	{
  		return (_root > r._root);
  	}
  	
  	bool html_node::operator<=(const html_node& r) const
  	{
  		return (_root <= r._root);
  	}
  	
  	bool html_node::operator>=(const html_node& r) const
  	{
  		return (_root >= r._root);
  	}
  
  	bool html_node::empty() const
  	{
  		return !_root;
  	}
  	
  	const char_t* html_node::name() const
  	{
  		return (_root && _root->name) ? _root->name : PUGIHTML_TEXT("");
  	}
  
  	html_node_type html_node::type() const
  	{
  		return _root ? static_cast<html_node_type>((_root->header & html_memory_page_type_mask) + 1) : node_null;
  	}
  	
  	const char_t* html_node::value() const
  	{
  		return (_root && _root->value) ? _root->value : PUGIHTML_TEXT("");
  	}
  	
  	html_node html_node::child(const char_t* name) const
  	{
  		if (!_root) return html_node();
  
  		for (html_node_struct* i = _root->first_child; i; i = i->next_sibling)
  			if (i->name && strequal(name, i->name)) return html_node(i);
  
  		return html_node();
  	}
  
  	html_attribute html_node::attribute(const char_t* name) const
  	{
  		if (!_root) return html_attribute();
  
  		for (html_attribute_struct* i = _root->first_attribute; i; i = i->next_attribute)
  			if (i->name && strequal(name, i->name))
  				return html_attribute(i);
  		
  		return html_attribute();
  	}
  	
  	html_node html_node::next_sibling(const char_t* name) const
  	{
  		if (!_root) return html_node();
  		
  		for (html_node_struct* i = _root->next_sibling; i; i = i->next_sibling)
  			if (i->name && strequal(name, i->name)) return html_node(i);
  
  		return html_node();
  	}
  
  	html_node html_node::next_sibling() const
  	{
  		if (!_root) return html_node();
  		
  		if (_root->next_sibling) return html_node(_root->next_sibling);
  		else return html_node();
  	}
  
  	html_node html_node::previous_sibling(const char_t* name) const
  	{
  		if (!_root) return html_node();
  		
  		for (html_node_struct* i = _root->prev_sibling_c; i->next_sibling; i = i->prev_sibling_c)
  			if (i->name && strequal(name, i->name)) return html_node(i);
  
  		return html_node();
  	}
  
  	html_node html_node::previous_sibling() const
  	{
  		if (!_root) return html_node();
  		
  		if (_root->prev_sibling_c->next_sibling) return html_node(_root->prev_sibling_c);
  		else return html_node();
  	}
  
  	html_node html_node::parent() const
  	{
  		return _root ? html_node(_root->parent) : html_node();
  	}
  
  	html_node html_node::root() const
  	{
  		if (!_root) return html_node();
  
  		html_memory_page* page = reinterpret_cast<html_memory_page*>(_root->header & html_memory_page_pointer_mask);
  
  		return html_node(static_cast<html_document_struct*>(page->allocator));
  	}
  
  	const char_t* html_node::child_value() const
  	{
  		if (!_root) return PUGIHTML_TEXT("");
  		
  		for (html_node_struct* i = _root->first_child; i; i = i->next_sibling)
  		{
  			html_node_type type = static_cast<html_node_type>((i->header & html_memory_page_type_mask) + 1);
  
  			if (i->value && (type == node_pcdata || type == node_cdata))
  				return i->value;
  		}
  
  		return PUGIHTML_TEXT("");
  	}
  
  	const char_t* html_node::child_value(const char_t* name) const
  	{
  		return child(name).child_value();
  	}
  
  	html_attribute html_node::first_attribute() const
  	{
  		return _root ? html_attribute(_root->first_attribute) : html_attribute();
  	}
  
  	html_attribute html_node::last_attribute() const
  	{
  		return _root && _root->first_attribute ? html_attribute(_root->first_attribute->prev_attribute_c) : html_attribute();
  	}
  
  	html_node html_node::first_child() const
  	{
  		return _root ? html_node(_root->first_child) : html_node();
  	}
  
  	html_node html_node::last_child() const
  	{
  		return _root && _root->first_child ? html_node(_root->first_child->prev_sibling_c) : html_node();
  	}
  
  	bool html_node::set_name(const char_t* rhs)
  	{
  		switch (type())
  		{
  		case node_pi:
  		case node_declaration:
  		case node_element:
  			return strcpy_insitu(_root->name, _root->header, html_memory_page_name_allocated_mask, rhs);
  
  		default:
  			return false;
  		}
  	}
  		
  	bool html_node::set_value(const char_t* rhs)
  	{
  		switch (type())
  		{
  		case node_pi:
  		case node_cdata:
  		case node_pcdata:
  		case node_comment:
          case node_doctype:
  			return strcpy_insitu(_root->value, _root->header, html_memory_page_value_allocated_mask, rhs);
  
  		default:
  			return false;
  		}
  	}
  
  	html_attribute html_node::append_attribute(const char_t* name)
  	{
  		if (type() != node_element && type() != node_declaration) return html_attribute();
  		
  		html_attribute a(append_attribute_ll(_root, get_allocator(_root)));
  		a.set_name(name);
  		
  		return a;
  	}
  
  	html_attribute html_node::prepend_attribute(const char_t* name)
  	{
  		if (type() != node_element && type() != node_declaration) return html_attribute();
  		
  		html_attribute a(allocate_attribute(get_allocator(_root)));
  		if (!a) return html_attribute();
  
  		a.set_name(name);
  		
          html_attribute_struct* head = _root->first_attribute;
  
  		if (head)
          {
              a._attr->prev_attribute_c = head->prev_attribute_c;
              head->prev_attribute_c = a._attr;
          }
          else
              a._attr->prev_attribute_c = a._attr;
  		
  		a._attr->next_attribute = head;
          _root->first_attribute = a._attr;
  				
  		return a;
  	}
  
  	html_attribute html_node::insert_attribute_before(const char_t* name, const html_attribute& attr)
  	{
  		if ((type() != node_element && type() != node_declaration) || attr.empty()) return html_attribute();
  		
  		// check that attribute belongs to *this
  		html_attribute_struct* cur = attr._attr;
  
  		while (cur->prev_attribute_c->next_attribute) cur = cur->prev_attribute_c;
  
  		if (cur != _root->first_attribute) return html_attribute();
  
  		html_attribute a(allocate_attribute(get_allocator(_root)));
  		if (!a) return html_attribute();
  
  		a.set_name(name);
  
  		if (attr._attr->prev_attribute_c->next_attribute)
  			attr._attr->prev_attribute_c->next_attribute = a._attr;
  		else
  			_root->first_attribute = a._attr;
  		
  		a._attr->prev_attribute_c = attr._attr->prev_attribute_c;
  		a._attr->next_attribute = attr._attr;
  		attr._attr->prev_attribute_c = a._attr;
  				
  		return a;
  	}
  
  	html_attribute html_node::insert_attribute_after(const char_t* name, const html_attribute& attr)
  	{
  		if ((type() != node_element && type() != node_declaration) || attr.empty()) return html_attribute();
  		
  		// check that attribute belongs to *this
  		html_attribute_struct* cur = attr._attr;
  
  		while (cur->prev_attribute_c->next_attribute) cur = cur->prev_attribute_c;
  
  		if (cur != _root->first_attribute) return html_attribute();
  
  		html_attribute a(allocate_attribute(get_allocator(_root)));
  		if (!a) return html_attribute();
  
  		a.set_name(name);
  
  		if (attr._attr->next_attribute)
  			attr._attr->next_attribute->prev_attribute_c = a._attr;
  		else
  			_root->first_attribute->prev_attribute_c = a._attr;
  		
  		a._attr->next_attribute = attr._attr->next_attribute;
  		a._attr->prev_attribute_c = attr._attr;
  		attr._attr->next_attribute = a._attr;
  
  		return a;
  	}
  
  	html_attribute html_node::append_copy(const html_attribute& proto)
  	{
  		if (!proto) return html_attribute();
  
  		html_attribute result = append_attribute(proto.name());
  		result.set_value(proto.value());
  
  		return result;
  	}
  
  	html_attribute html_node::prepend_copy(const html_attribute& proto)
  	{
  		if (!proto) return html_attribute();
  
  		html_attribute result = prepend_attribute(proto.name());
  		result.set_value(proto.value());
  
  		return result;
  	}
  
  	html_attribute html_node::insert_copy_after(const html_attribute& proto, const html_attribute& attr)
  	{
  		if (!proto) return html_attribute();
  
  		html_attribute result = insert_attribute_after(proto.name(), attr);
  		result.set_value(proto.value());
  
  		return result;
  	}
  
  	html_attribute html_node::insert_copy_before(const html_attribute& proto, const html_attribute& attr)
  	{
  		if (!proto) return html_attribute();
  
  		html_attribute result = insert_attribute_before(proto.name(), attr);
  		result.set_value(proto.value());
  
  		return result;
  	}
  
  	html_node html_node::append_child(html_node_type type)
  	{
  		if (!allow_insert_child(this->type(), type)) return html_node();
  		
  		html_node n(append_node(_root, get_allocator(_root), type));
  
  		if (type == node_declaration) n.set_name(PUGIHTML_TEXT("html"));
  
  		return n;
  	}
  
  	html_node html_node::prepend_child(html_node_type type)
  	{
  		if (!allow_insert_child(this->type(), type)) return html_node();
  		
  		html_node n(allocate_node(get_allocator(_root), type));
  		if (!n) return html_node();
  
          n._root->parent = _root;
  
          html_node_struct* head = _root->first_child;
  
  		if (head)
          {
              n._root->prev_sibling_c = head->prev_sibling_c;
              head->prev_sibling_c = n._root;
          }
          else
              n._root->prev_sibling_c = n._root;
  		
  		n._root->next_sibling = head;
          _root->first_child = n._root;
  				
  		if (type == node_declaration) n.set_name(PUGIHTML_TEXT("html"));
  
  		return n;
  	}
  
  	html_node html_node::insert_child_before(html_node_type type, const html_node& node)
  	{
  		if (!allow_insert_child(this->type(), type)) return html_node();
  		if (!node._root || node._root->parent != _root) return html_node();
  	
  		html_node n(allocate_node(get_allocator(_root), type));
  		if (!n) return html_node();
  
  		n._root->parent = _root;
  		
  		if (node._root->prev_sibling_c->next_sibling)
  			node._root->prev_sibling_c->next_sibling = n._root;
  		else
  			_root->first_child = n._root;
  		
  		n._root->prev_sibling_c = node._root->prev_sibling_c;
  		n._root->next_sibling = node._root;
  		node._root->prev_sibling_c = n._root;
  
  		if (type == node_declaration) n.set_name(PUGIHTML_TEXT("html"));
  
  		return n;
  	}
  
  	html_node html_node::insert_child_after(html_node_type type, const html_node& node)
  	{
  		if (!allow_insert_child(this->type(), type)) return html_node();
  		if (!node._root || node._root->parent != _root) return html_node();
  	
  		html_node n(allocate_node(get_allocator(_root), type));
  		if (!n) return html_node();
  
  		n._root->parent = _root;
  	
  		if (node._root->next_sibling)
  			node._root->next_sibling->prev_sibling_c = n._root;
  		else
  			_root->first_child->prev_sibling_c = n._root;
  		
  		n._root->next_sibling = node._root->next_sibling;
  		n._root->prev_sibling_c = node._root;
  		node._root->next_sibling = n._root;
  
  		if (type == node_declaration) n.set_name(PUGIHTML_TEXT("html"));
  
  		return n;
  	}
  
      html_node html_node::append_child(const char_t* name)
      {
          html_node result = append_child(node_element);
  
          result.set_name(name);
  
          return result;
      }
  
      html_node html_node::prepend_child(const char_t* name)
      {
          html_node result = prepend_child(node_element);
  
          result.set_name(name);
  
          return result;
      }
  
      html_node html_node::insert_child_after(const char_t* name, const html_node& node)
      {
          html_node result = insert_child_after(node_element, node);
  
          result.set_name(name);
  
          return result;
      }
  
      html_node html_node::insert_child_before(const char_t* name, const html_node& node)
      {
          html_node result = insert_child_before(node_element, node);
  
          result.set_name(name);
  
          return result;
      }
  
  	html_node html_node::append_copy(const html_node& proto)
  	{
  		html_node result = append_child(proto.type());
  
  		if (result) recursive_copy_skip(result, proto, result);
  
  		return result;
  	}
  
  	html_node html_node::prepend_copy(const html_node& proto)
  	{
  		html_node result = prepend_child(proto.type());
  
  		if (result) recursive_copy_skip(result, proto, result);
  
  		return result;
  	}
  
  	html_node html_node::insert_copy_after(const html_node& proto, const html_node& node)
  	{
  		html_node result = insert_child_after(proto.type(), node);
  
  		if (result) recursive_copy_skip(result, proto, result);
  
  		return result;
  	}
  
  	html_node html_node::insert_copy_before(const html_node& proto, const html_node& node)
  	{
  		html_node result = insert_child_before(proto.type(), node);
  
  		if (result) recursive_copy_skip(result, proto, result);
  
  		return result;
  	}
  
  	bool html_node::remove_attribute(const char_t* name)
  	{
  		return remove_attribute(attribute(name));
  	}
  
  	bool html_node::remove_attribute(const html_attribute& a)
  	{
  		if (!_root || !a._attr) return false;
  
  		// check that attribute belongs to *this
  		html_attribute_struct* attr = a._attr;
  
  		while (attr->prev_attribute_c->next_attribute) attr = attr->prev_attribute_c;
  
  		if (attr != _root->first_attribute) return false;
  
  		if (a._attr->next_attribute) a._attr->next_attribute->prev_attribute_c = a._attr->prev_attribute_c;
  		else if (_root->first_attribute) _root->first_attribute->prev_attribute_c = a._attr->prev_attribute_c;
  		
  		if (a._attr->prev_attribute_c->next_attribute) a._attr->prev_attribute_c->next_attribute = a._attr->next_attribute;
  		else _root->first_attribute = a._attr->next_attribute;
  
  		destroy_attribute(a._attr, get_allocator(_root));
  
  		return true;
  	}
  
  	bool html_node::remove_child(const char_t* name)
  	{
  		return remove_child(child(name));
  	}
  
  	bool html_node::remove_child(const html_node& n)
  	{
  		if (!_root || !n._root || n._root->parent != _root) return false;
  
  		if (n._root->next_sibling) n._root->next_sibling->prev_sibling_c = n._root->prev_sibling_c;
  		else if (_root->first_child) _root->first_child->prev_sibling_c = n._root->prev_sibling_c;
  		
  		if (n._root->prev_sibling_c->next_sibling) n._root->prev_sibling_c->next_sibling = n._root->next_sibling;
  		else _root->first_child = n._root->next_sibling;
          
          destroy_node(n._root, get_allocator(_root));
  
  		return true;
  	}
  
  	html_node html_node::find_child_by_attribute(const char_t* name, const char_t* attr_name, const char_t* attr_value) const
  	{
  		if (!_root) return html_node();
  		
  		for (html_node_struct* i = _root->first_child; i; i = i->next_sibling)
  			if (i->name && strequal(name, i->name))
  			{
  				for (html_attribute_struct* a = i->first_attribute; a; a = a->next_attribute)
  					if (strequal(attr_name, a->name) && strequal(attr_value, a->value))
  						return html_node(i);
  			}
  
  		return html_node();
  	}
  
  	html_node html_node::find_child_by_attribute(const char_t* attr_name, const char_t* attr_value) const
  	{
  		if (!_root) return html_node();
  		
  		for (html_node_struct* i = _root->first_child; i; i = i->next_sibling)
  			for (html_attribute_struct* a = i->first_attribute; a; a = a->next_attribute)
  				if (strequal(attr_name, a->name) && strequal(attr_value, a->value))
  					return html_node(i);
  
  		return html_node();
  	}
  
  #ifndef PUGIHTML_NO_STL
  	string_t html_node::path(char_t delimiter) const
  	{
  		string_t path;
  
  		html_node cursor = *this; // Make a copy.
  		
  		path = cursor.name();
  
  		while (cursor.parent())
  		{
  			cursor = cursor.parent();
  			
  			string_t temp = cursor.name();
  			temp += delimiter;
  			temp += path;
  			path.swap(temp);
  		}
  
  		return path;
  	}
  #endif
  
  	html_node html_node::first_element_by_path(const char_t* path, char_t delimiter) const
  	{
  		html_node found = *this; // Current search context.
  
  		if (!_root || !path || !path[0]) return found;
  
  		if (path[0] == delimiter)
  		{
  			// Absolute path; e.g. '/foo/bar'
  			found = found.root();
  			++path;
  		}
  
  		const char_t* path_segment = path;
  
  		while (*path_segment == delimiter) ++path_segment;
  
  		const char_t* path_segment_end = path_segment;
  
  		while (*path_segment_end && *path_segment_end != delimiter) ++path_segment_end;
  
  		if (path_segment == path_segment_end) return found;
  
  		const char_t* next_segment = path_segment_end;
  
  		while (*next_segment == delimiter) ++next_segment;
  
  		if (*path_segment == '.' && path_segment + 1 == path_segment_end)
  			return found.first_element_by_path(next_segment, delimiter);
  		else if (*path_segment == '.' && *(path_segment+1) == '.' && path_segment + 2 == path_segment_end)
  			return found.parent().first_element_by_path(next_segment, delimiter);
  		else
  		{
  			for (html_node_struct* j = found._root->first_child; j; j = j->next_sibling)
  			{
  				if (j->name && strequalrange(j->name, path_segment, static_cast<size_t>(path_segment_end - path_segment)))
  				{
  					html_node subsearch = html_node(j).first_element_by_path(next_segment, delimiter);
  
  					if (subsearch) return subsearch;
  				}
  			}
  
  			return html_node();
  		}
  	}
  
  	bool html_node::traverse(html_tree_walker& walker)
  	{
  		walker._depth = -1;
  		
  		html_node arg_begin = *this;
  		if (!walker.begin(arg_begin)) return false;
  
  		html_node cur = first_child();
  				
  		if (cur)
  		{
  			++walker._depth;
  
  			do 
  			{
  				html_node arg_for_each = cur;
  				if (!walker.for_each(arg_for_each))
  					return false;
  						
  				if (cur.first_child())
  				{
  					++walker._depth;
  					cur = cur.first_child();
  				}
  				else if (cur.next_sibling())
  					cur = cur.next_sibling();
  				else
  				{
  					// Borland C++ workaround
  					while (!cur.next_sibling() && cur != *this && (bool)cur.parent())
  					{
  						--walker._depth;
  						cur = cur.parent();
  					}
  						
  					if (cur != *this)
  						cur = cur.next_sibling();
  				}
  			}
  			while (cur && cur != *this);
  		}
  
  		assert(walker._depth == -1);
  
  		html_node arg_end = *this;
  		return walker.end(arg_end);
  	}
  
      size_t html_node::hash_value() const
      {
          return static_cast<size_t>(reinterpret_cast<uintptr_t>(_root) / sizeof(html_node_struct));
      }
  
  	html_node_struct* html_node::internal_object() const
  	{
          return _root;
  	}
  
  	void html_node::print(html_writer& writer, const char_t* indent, unsigned int flags, html_encoding encoding, unsigned int depth) const
  	{
  		if (!_root) return;
  
  		html_buffered_writer buffered_writer(writer, encoding);
  
  		node_output(buffered_writer, *this, indent, flags, depth);
  	}
  
  #ifndef PUGIHTML_NO_STL
  	void html_node::print(std::basic_ostream<char, std::char_traits<char> >& stream, const char_t* indent, unsigned int flags, html_encoding encoding, unsigned int depth) const
  	{
  		html_writer_stream writer(stream);
  
  		print(writer, indent, flags, encoding, depth);
  	}
  
  	void html_node::print(std::basic_ostream<wchar_t, std::char_traits<wchar_t> >& stream, const char_t* indent, unsigned int flags, unsigned int depth) const
  	{
  		html_writer_stream writer(stream);
  
  		print(writer, indent, flags, encoding_wchar, depth);
  	}
  #endif
  
  	ptrdiff_t html_node::offset_debug() const
  	{
  		html_node_struct* r = root()._root;
  
  		if (!r) return -1;
  
  		const char_t* buffer = static_cast<html_document_struct*>(r)->buffer;
  
  		if (!buffer) return -1;
  
  		switch (type())
  		{
  		case node_document:
  			return 0;
  
  		case node_element:
  		case node_declaration:
  		case node_pi:
  			return (_root->header & html_memory_page_name_allocated_mask) ? -1 : _root->name - buffer;
  
  		case node_pcdata:
  		case node_cdata:
  		case node_comment:
  		case node_doctype:
  			return (_root->header & html_memory_page_value_allocated_mask) ? -1 : _root->value - buffer;
  
  		default:
  			return -1;
  		}
  	}
  
  #ifdef __BORLANDC__
  	bool operator&&(const html_node& lhs, bool rhs)
  	{
  		return (bool)lhs && rhs;
  	}
  
  	bool operator||(const html_node& lhs, bool rhs)
  	{
  		return (bool)lhs || rhs;
  	}
  #endif
  
  	html_node_iterator::html_node_iterator()
  	{
  	}
  
  	html_node_iterator::html_node_iterator(const html_node& node): _wrap(node), _parent(node.parent())
  	{
  	}
  
  	html_node_iterator::html_node_iterator(html_node_struct* ref, html_node_struct* parent): _wrap(ref), _parent(parent)
  	{
  	}
  
  	bool html_node_iterator::operator==(const html_node_iterator& rhs) const
  	{
  		return _wrap._root == rhs._wrap._root && _parent._root == rhs._parent._root;
  	}
  	
  	bool html_node_iterator::operator!=(const html_node_iterator& rhs) const
  	{
  		return _wrap._root != rhs._wrap._root || _parent._root != rhs._parent._root;
  	}
  
  	html_node& html_node_iterator::operator*()
  	{
  		assert(_wrap._root);
  		return _wrap;
  	}
  
  	html_node* html_node_iterator::operator->()
  	{
  		assert(_wrap._root);
  		return &_wrap;
  	}
  
  	const html_node_iterator& html_node_iterator::operator++()
  	{
  		assert(_wrap._root);
  		_wrap._root = _wrap._root->next_sibling;
  		return *this;
  	}
  
  	html_node_iterator html_node_iterator::operator++(int)
  	{
  		html_node_iterator temp = *this;
  		++*this;
  		return temp;
  	}
  
  	const html_node_iterator& html_node_iterator::operator--()
  	{
  		_wrap = _wrap._root ? _wrap.previous_sibling() : _parent.last_child();
  		return *this;
  	}
  
  	html_node_iterator html_node_iterator::operator--(int)
  	{
  		html_node_iterator temp = *this;
  		--*this;
  		return temp;
  	}
  
  	html_attribute_iterator::html_attribute_iterator()
  	{
  	}
  
  	html_attribute_iterator::html_attribute_iterator(const html_attribute& attr, const html_node& parent): _wrap(attr), _parent(parent)
  	{
  	}
  
  	html_attribute_iterator::html_attribute_iterator(html_attribute_struct* ref, html_node_struct* parent): _wrap(ref), _parent(parent)
  	{
  	}
  
  	bool html_attribute_iterator::operator==(const html_attribute_iterator& rhs) const
  	{
  		return _wrap._attr == rhs._wrap._attr && _parent._root == rhs._parent._root;
  	}
  	
  	bool html_attribute_iterator::operator!=(const html_attribute_iterator& rhs) const
  	{
  		return _wrap._attr != rhs._wrap._attr || _parent._root != rhs._parent._root;
  	}
  
  	html_attribute& html_attribute_iterator::operator*()
  	{
  		assert(_wrap._attr);
  		return _wrap;
  	}
  
  	html_attribute* html_attribute_iterator::operator->()
  	{
  		assert(_wrap._attr);
  		return &_wrap;
  	}
  
  	const html_attribute_iterator& html_attribute_iterator::operator++()
  	{
  		assert(_wrap._attr);
  		_wrap._attr = _wrap._attr->next_attribute;
  		return *this;
  	}
  
  	html_attribute_iterator html_attribute_iterator::operator++(int)
  	{
  		html_attribute_iterator temp = *this;
  		++*this;
  		return temp;
  	}
  
  	const html_attribute_iterator& html_attribute_iterator::operator--()
  	{
  		_wrap = _wrap._attr ? _wrap.previous_attribute() : _parent.last_attribute();
  		return *this;
  	}
  
  	html_attribute_iterator html_attribute_iterator::operator--(int)
  	{
  		html_attribute_iterator temp = *this;
  		--*this;
  		return temp;
  	}
  
      html_parse_result::html_parse_result(): status(status_internal_error), offset(0), encoding(encoding_auto)
      {
      }
  
      html_parse_result::operator bool() const
      {
          return status == status_ok;
      }
  
  	const char* html_parse_result::description() const
  	{
  		switch (status)
  		{
  		case status_ok: return "No error";
  
  		case status_file_not_found: return "File was not found";
  		case status_io_error: return "Error reading from file/stream";
  		case status_out_of_memory: return "Could not allocate memory";
  		case status_internal_error: return "Internal error occurred";
  
  		case status_unrecognized_tag: return "Could not determine tag type";
  
  		case status_bad_pi: return "Error parsing document declaration/processing instruction";
  		case status_bad_comment: return "Error parsing comment";
  		case status_bad_cdata: return "Error parsing CDATA section";
  		case status_bad_doctype: return "Error parsing document type declaration";
  		case status_bad_pcdata: return "Error parsing PCDATA section";
  		case status_bad_start_element: return "Error parsing start element tag";
  		case status_bad_attribute: return "Error parsing element attribute";
  		case status_bad_end_element: return "Error parsing end element tag";
  		case status_end_element_mismatch: return "Start-end tags mismatch";
  
  		default: return "Unknown error";
  		}
  	}
  
  	html_document::html_document(): _buffer(0)
  	{
  		create();
  	}
  
  	html_document::~html_document()
  	{
  		destroy();
  	}
  
  	void html_document::reset()
  	{
  		destroy();
  		create();
  	}
  
      void html_document::reset(const html_document& proto)
      {
          reset();
  
          for (html_node cur = proto.first_child(); cur; cur = cur.next_sibling())
              append_copy(cur);
      }
  
  	void html_document::create()
  	{
  		// initialize sentinel page
  		STATIC_ASSERT(offsetof(html_memory_page, data) + sizeof(html_document_struct) + html_memory_page_alignment <= sizeof(_memory));
  
  		// align upwards to page boundary
  		void* page_memory = reinterpret_cast<void*>((reinterpret_cast<uintptr_t>(_memory) + (html_memory_page_alignment - 1)) & ~(html_memory_page_alignment - 1));
  
  		// prepare page structure
  		html_memory_page* page = html_memory_page::construct(page_memory);
  
  		page->busy_size = html_memory_page_size;
  
  		// allocate new root
  		_root = new (page->data) html_document_struct(page);
  		_root->prev_sibling_c = _root;
  
  		// setup sentinel page
  		page->allocator = static_cast<html_document_struct*>(_root);
  	}
  
  	void html_document::destroy()
  	{
  		// destroy static storage
  		if (_buffer)
  		{
  			global_deallocate(_buffer);
  			_buffer = 0;
  		}
  
  		// destroy dynamic storage, leave sentinel page (it's in static memory)
  		if (_root)
  		{
  			html_memory_page* root_page = reinterpret_cast<html_memory_page*>(_root->header & html_memory_page_pointer_mask);
  			assert(root_page && !root_page->prev && !root_page->memory);
  
  			// destroy all pages
  			for (html_memory_page* page = root_page->next; page; )
  			{
  				html_memory_page* next = page->next;
  
  				html_allocator::deallocate_page(page);
  
  				page = next;
  			}
  
  			// cleanup root page
  			root_page->allocator = 0;
  			root_page->next = 0;
  			root_page->busy_size = root_page->freed_size = 0;
  
  			_root = 0;
  		}
  	}
  
  #ifndef PUGIHTML_NO_STL
  	html_parse_result html_document::load(std::basic_istream<char, std::char_traits<char> >& stream, unsigned int options, html_encoding encoding)
  	{
  		reset();
  
  		return load_stream_impl(*this, stream, options, encoding);
  	}
  
  	html_parse_result html_document::load(std::basic_istream<wchar_t, std::char_traits<wchar_t> >& stream, unsigned int options)
  	{
  		reset();
  
  		return load_stream_impl(*this, stream, options, encoding_wchar);
  	}
  #endif
  
  	html_parse_result html_document::load(const char_t* contents, unsigned int options)
  	{
  		// Force native encoding (skip autodetection)
  	#ifdef PUGIHTML_WCHAR_MODE
  		html_encoding encoding = encoding_wchar;
  	#else
  		html_encoding encoding = encoding_utf8;
  	#endif
  
  		return load_buffer(contents, strlength(contents) * sizeof(char_t), options, encoding);
  	}
  
  	html_parse_result html_document::load_file(const char* path, unsigned int options, html_encoding encoding)
  	{
  		reset();
  
  		FILE* file = fopen(path, "rb");
  
  		return load_file_impl(*this, file, options, encoding);
  	}
  
  	html_parse_result html_document::load_file(const wchar_t* path, unsigned int options, html_encoding encoding)
  	{
  		reset();
  
  		FILE* file = open_file_wide(path, L"rb");
  
  		return load_file_impl(*this, file, options, encoding);
  	}
  
  	html_parse_result html_document::load_buffer_impl(void* contents, size_t size, unsigned int options, html_encoding encoding, bool is_mutable, bool own)
  	{
  		reset();
  
  		// check input buffer
  		assert(contents || size == 0);
  
  		// get actual encoding
  		html_encoding buffer_encoding = get_buffer_encoding(encoding, contents, size);
  
  		// get private buffer
  		char_t* buffer = 0;
  		size_t length = 0;
  
  		if (!convert_buffer(buffer, length, buffer_encoding, contents, size, is_mutable)) return make_parse_result(status_out_of_memory);
  		
  		// delete original buffer if we performed a conversion
  		if (own && buffer != contents && contents) global_deallocate(contents);
  
  		// parse
  		html_parse_result res = html_parser::parse(buffer, length, _root, options);
  
  		// remember encoding
  		res.encoding = buffer_encoding;
  
  		// grab onto buffer if it's our buffer, user is responsible for deallocating contens himself
  		if (own || buffer != contents) _buffer = buffer;
  
  		return res;
  	}
  
  	html_parse_result html_document::load_buffer(const void* contents, size_t size, unsigned int options, html_encoding encoding)
  	{
  		return load_buffer_impl(const_cast<void*>(contents), size, options, encoding, false, false);
  	}
  
  	html_parse_result html_document::load_buffer_inplace(void* contents, size_t size, unsigned int options, html_encoding encoding)
  	{
  		return load_buffer_impl(contents, size, options, encoding, true, false);
  	}
  		
  	html_parse_result html_document::load_buffer_inplace_own(void* contents, size_t size, unsigned int options, html_encoding encoding)
  	{
  		return load_buffer_impl(contents, size, options, encoding, true, true);
  	}
  
  	void html_document::save(html_writer& writer, const char_t* indent, unsigned int flags, html_encoding encoding) const
  	{
  		if (flags & format_write_bom) write_bom(writer, get_write_encoding(encoding));
  
  		html_buffered_writer buffered_writer(writer, encoding);
  
  		if (!(flags & format_no_declaration) && !has_declaration(*this))
  		{
  			buffered_writer.write(PUGIHTML_TEXT("<?html version=\"1.0\"?>"));
  			if (!(flags & format_raw)) buffered_writer.write('\n');
  		}
  
  		node_output(buffered_writer, *this, indent, flags, 0);
  	}
  
  #ifndef PUGIHTML_NO_STL
  	void html_document::save(std::basic_ostream<char, std::char_traits<char> >& stream, const char_t* indent, unsigned int flags, html_encoding encoding) const
  	{
  		html_writer_stream writer(stream);
  
  		save(writer, indent, flags, encoding);
  	}
  
  	void html_document::save(std::basic_ostream<wchar_t, std::char_traits<wchar_t> >& stream, const char_t* indent, unsigned int flags) const
  	{
  		html_writer_stream writer(stream);
  
  		save(writer, indent, flags, encoding_wchar);
  	}
  #endif
  
  	bool html_document::save_file(const char* path, const char_t* indent, unsigned int flags, html_encoding encoding) const
  	{
  		FILE* file = fopen(path, "wb");
  		if (!file) return false;
  
  		html_writer_file writer(file);
  		save(writer, indent, flags, encoding);
  
  		fclose(file);
  
  		return true;
  	}
  
  	bool html_document::save_file(const wchar_t* path, const char_t* indent, unsigned int flags, html_encoding encoding) const
  	{
  		FILE* file = open_file_wide(path, L"wb");
  		if (!file) return false;
  
  		html_writer_file writer(file);
  		save(writer, indent, flags, encoding);
  
  		fclose(file);
  
  		return true;
  	}
  
      html_node html_document::document_element() const
      {
  		for (html_node_struct* i = _root->first_child; i; i = i->next_sibling)
  			if ((i->header & html_memory_page_type_mask) + 1 == node_element)
                  return html_node(i);
  
          return html_node();
      }
  
  #ifndef PUGIHTML_NO_STL
  	std::string PUGIHTML_FUNCTION as_utf8(const wchar_t* str)
  	{
  		assert(str);
  
          return as_utf8_impl(str, wcslen(str));
  	}
  
  	std::string PUGIHTML_FUNCTION as_utf8(const std::wstring& str)
  	{
          return as_utf8_impl(str.c_str(), str.size());
  	}
  	
  	std::wstring PUGIHTML_FUNCTION as_wide(const char* str)
  	{
  		assert(str);
  
          return as_wide_impl(str, strlen(str));
  	}
  	
  	std::wstring PUGIHTML_FUNCTION as_wide(const std::string& str)
  	{
          return as_wide_impl(str.c_str(), str.size());
  	}
  #endif
  
      void PUGIHTML_FUNCTION set_memory_management_functions(allocation_function allocate, deallocation_function deallocate)
      {
      	global_allocate = allocate;
      	global_deallocate = deallocate;
      }
  
      allocation_function PUGIHTML_FUNCTION get_memory_allocation_function()
      {
      	return global_allocate;
      }
  
      deallocation_function PUGIHTML_FUNCTION get_memory_deallocation_function()
      {
      	return global_deallocate;
      }
  }
  
  #if !defined(PUGIHTML_NO_STL) && (defined(_MSC_VER) || defined(__ICC))
  namespace std
  {
  	// Workarounds for (non-standard) iterator category detection for older versions (MSVC7/IC8 and earlier)
  	std::bidirectional_iterator_tag _Iter_cat(const html_node_iterator&)
  	{
  		return std::bidirectional_iterator_tag();
  	}
  
  	std::bidirectional_iterator_tag _Iter_cat(const html_attribute_iterator&)
  	{
  		return std::bidirectional_iterator_tag();
  	}
  }
  #endif
  
  #if !defined(PUGIHTML_NO_STL) && defined(__SUNPRO_CC)
  namespace std
  {
  	// Workarounds for (non-standard) iterator category detection
  	std::bidirectional_iterator_tag __iterator_category(const html_node_iterator&)
  	{
  		return std::bidirectional_iterator_tag();
  	}
  
  	std::bidirectional_iterator_tag __iterator_category(const html_attribute_iterator&)
  	{
  		return std::bidirectional_iterator_tag();
  	}
  }
  #endif
  
  #ifndef PUGIHTML_NO_XPATH
  
  // STL replacements
  namespace
  {
  	struct equal_to
  	{
  		template <typename T> bool operator()(const T& lhs, const T& rhs) const
  		{
  			return lhs == rhs;
  		}
  	};
  
  	struct not_equal_to
  	{
  		template <typename T> bool operator()(const T& lhs, const T& rhs) const
  		{
  			return lhs != rhs;
  		}
  	};
  
  	struct less
  	{
  		template <typename T> bool operator()(const T& lhs, const T& rhs) const
  		{
  			return lhs < rhs;
  		}
  	};
  
  	struct less_equal
  	{
  		template <typename T> bool operator()(const T& lhs, const T& rhs) const
  		{
  			return lhs <= rhs;
  		}
  	};
  
  	template <typename T> void swap(T& lhs, T& rhs)
  	{
  		T temp = lhs;
  		lhs = rhs;
  		rhs = temp;
  	}
  
  	template <typename I, typename Pred> I min_element(I begin, I end, const Pred& pred)
  	{
  		I result = begin;
  
  		for (I it = begin + 1; it != end; ++it)
  			if (pred(*it, *result))
  				result = it;
  
  		return result;
  	}
  
  	template <typename I> void reverse(I begin, I end)
  	{
  		while (begin + 1 < end) swap(*begin++, *--end);
  	}
  
  	template <typename I> I unique(I begin, I end)
  	{
  		// fast skip head
  		while (begin + 1 < end && *begin != *(begin + 1)) begin++;
  
  		if (begin == end) return begin;
  
  		// last written element
  		I write = begin++; 
  
  		// merge unique elements
  		while (begin != end)
  		{
  			if (*begin != *write)
  				*++write = *begin++;
  			else
  				begin++;
  		}
  
  		// past-the-end (write points to live element)
  		return write + 1;
  	}
  
  	template <typename I> void copy_backwards(I begin, I end, I target)
  	{
  		while (begin != end) *--target = *--end;
  	}
  
  	template <typename I, typename Pred, typename T> void insertion_sort(I begin, I end, const Pred& pred, T*)
  	{
  		assert(begin != end);
  
  		for (I it = begin + 1; it != end; ++it)
  		{
  			T val = *it;
  
  			if (pred(val, *begin))
  			{
  				// move to front
  				copy_backwards(begin, it, it + 1);
  				*begin = val;
  			}
  			else
  			{
  				I hole = it;
  
  				// move hole backwards
  				while (pred(val, *(hole - 1)))
  				{
  					*hole = *(hole - 1);
  					hole--;
  				}
  
  				// fill hole with element
  				*hole = val;
  			}
  		}
  	}
  
  	// std variant for elements with ==
  	template <typename I, typename Pred> void partition(I begin, I middle, I end, const Pred& pred, I* out_eqbeg, I* out_eqend)
  	{
  		I eqbeg = middle, eqend = middle + 1;
  
  		// expand equal range
  		while (eqbeg != begin && *(eqbeg - 1) == *eqbeg) --eqbeg;
  		while (eqend != end && *eqend == *eqbeg) ++eqend;
  
  		// process outer elements
  		I ltend = eqbeg, gtbeg = eqend;
  
  		for (;;)
  		{
  			// find the element from the right side that belongs to the left one
  			for (; gtbeg != end; ++gtbeg)
  				if (!pred(*eqbeg, *gtbeg))
  				{
  					if (*gtbeg == *eqbeg) swap(*gtbeg, *eqend++);
  					else break;
  				}
  
  			// find the element from the left side that belongs to the right one
  			for (; ltend != begin; --ltend)
  				if (!pred(*(ltend - 1), *eqbeg))
  				{
  					if (*eqbeg == *(ltend - 1)) swap(*(ltend - 1), *--eqbeg);
  					else break;
  				}
  
  			// scanned all elements
  			if (gtbeg == end && ltend == begin)
  			{
  				*out_eqbeg = eqbeg;
  				*out_eqend = eqend;
  				return;
  			}
  
  			// make room for elements by moving equal area
  			if (gtbeg == end)
  			{
  				if (--ltend != --eqbeg) swap(*ltend, *eqbeg);
  				swap(*eqbeg, *--eqend);
  			}
  			else if (ltend == begin)
  			{
  				if (eqend != gtbeg) swap(*eqbeg, *eqend);
  				++eqend;
  				swap(*gtbeg++, *eqbeg++);
  			}
  			else swap(*gtbeg++, *--ltend);
  		}
  	}
  
  	template <typename I, typename Pred> void median3(I first, I middle, I last, const Pred& pred)
  	{
  		if (pred(*middle, *first)) swap(*middle, *first);
  		if (pred(*last, *middle)) swap(*last, *middle);
  		if (pred(*middle, *first)) swap(*middle, *first);
  	}
  
  	template <typename I, typename Pred> void median(I first, I middle, I last, const Pred& pred)
  	{
  		if (last - first <= 40)
  		{
  			// median of three for small chunks
  			median3(first, middle, last, pred);
  		}
  		else
  		{
  			// median of nine
  			size_t step = (last - first + 1) / 8;
  
  			median3(first, first + step, first + 2 * step, pred);
  			median3(middle - step, middle, middle + step, pred);
  			median3(last - 2 * step, last - step, last, pred);
  			median3(first + step, middle, last - step, pred);
  		}
  	}
  
  	template <typename I, typename Pred> void sort(I begin, I end, const Pred& pred)
  	{
  		// sort large chunks
  		while (end - begin > 32)
  		{
  			// find median element
  			I middle = begin + (end - begin) / 2;
  			median(begin, middle, end - 1, pred);
  
  			// partition in three chunks (< = >)
  			I eqbeg, eqend;
  			partition(begin, middle, end, pred, &eqbeg, &eqend);
  
  			// loop on larger half
  			if (eqbeg - begin > end - eqend)
  			{
  				sort(eqend, end, pred);
  				end = eqbeg;
  			}
  			else
  			{
  				sort(begin, eqbeg, pred);
  				begin = eqend;
  			}
  		}
  
  		// insertion sort small chunk
  		if (begin != end) insertion_sort(begin, end, pred, &*begin);
  	}
  }
  
  // Allocator used for AST and evaluation stacks
  namespace
  {
  	struct xpath_memory_block
  	{	
  		xpath_memory_block* next;
  
  		char data[4096];
  	};
  		
  	class xpath_allocator
  	{
  		xpath_memory_block* _root;
  		size_t _root_size;
  
  	public:
  	#ifdef PUGIHTML_NO_EXCEPTIONS
  		jmp_buf* error_handler;
  	#endif
  
  		xpath_allocator(xpath_memory_block* root, size_t root_size = 0): _root(root), _root_size(root_size)
  		{
  		#ifdef PUGIHTML_NO_EXCEPTIONS
  			error_handler = 0;
  		#endif
  		}
  		
  		void* allocate_nothrow(size_t size)
  		{
  			const size_t block_capacity = sizeof(_root->data);
  
  			// align size so that we're able to store pointers in subsequent blocks
  			size = (size + sizeof(void*) - 1) & ~(sizeof(void*) - 1);
  
  			if (_root_size + size <= block_capacity)
  			{
  				void* buf = _root->data + _root_size;
  				_root_size += size;
  				return buf;
  			}
  			else
  			{
  				size_t block_data_size = (size > block_capacity) ? size : block_capacity;
  				size_t block_size = block_data_size + offsetof(xpath_memory_block, data);
  
  				xpath_memory_block* block = static_cast<xpath_memory_block*>(global_allocate(block_size));
  				if (!block) return 0;
  				
  				block->next = _root;
  				
  				_root = block;
  				_root_size = size;
  				
  				return block->data;
  			}
  		}
  
  		void* allocate(size_t size)
  		{
  			void* result = allocate_nothrow(size);
  
  			if (!result)
  			{
  			#ifdef PUGIHTML_NO_EXCEPTIONS
  				assert(error_handler);
  				longjmp(*error_handler, 1);
  			#else
  				throw std::bad_alloc();
  			#endif
  			}
  
  			return result;
  		}
  
  		void* reallocate(void* ptr, size_t old_size, size_t new_size)
  		{
  			// align size so that we're able to store pointers in subsequent blocks
  			old_size = (old_size + sizeof(void*) - 1) & ~(sizeof(void*) - 1);
  			new_size = (new_size + sizeof(void*) - 1) & ~(sizeof(void*) - 1);
  
  			// we can only reallocate the last object
  			assert(ptr == 0 || static_cast<char*>(ptr) + old_size == _root->data + _root_size);
  
  			// adjust root size so that we have not allocated the object at all
  			bool only_object = (_root_size == old_size);
  
  			if (ptr) _root_size -= old_size;
  
  			// allocate a new version (this will obviously reuse the memory if possible)
  			void* result = allocate(new_size);
  			assert(result);
  
  			// we have a new block
  			if (result != ptr && ptr)
  			{
  				// copy old data
  				assert(new_size > old_size);
  				memcpy(result, ptr, old_size);
  
  				// free the previous page if it had no other objects
  				if (only_object)
  				{
  					assert(_root->data == result);
  					assert(_root->next);
  
  					xpath_memory_block* next = _root->next->next;
  
  					if (next)
  					{
  						// deallocate the whole page, unless it was the first one
  						global_deallocate(_root->next);
  						_root->next = next;
  					}
  				}
  			}
  
  			return result;
  		}
  
  		void revert(const xpath_allocator& state)
  		{
  			// free all new pages
  			xpath_memory_block* cur = _root;
  
  			while (cur != state._root)
  			{
  				xpath_memory_block* next = cur->next;
  
  				global_deallocate(cur);
  
  				cur = next;
  			}
  
  			// restore state
  			_root = state._root;
  			_root_size = state._root_size;
  		}
  
  		void release()
  		{
  			xpath_memory_block* cur = _root;
  			assert(cur);
  
  			while (cur->next)
  			{
  				xpath_memory_block* next = cur->next;
  
  				global_deallocate(cur);
  
  				cur = next;
  			}
  		}
  	};
  
  	struct xpath_allocator_capture
  	{
  		xpath_allocator_capture(xpath_allocator* alloc): _target(alloc), _state(*alloc)
  		{
  		}
  
  		~xpath_allocator_capture()
  		{
  			_target->revert(_state);
  		}
  
  		xpath_allocator* _target;
  		xpath_allocator _state;
  	};
  
  	struct xpath_stack
  	{
  		xpath_allocator* result;
  		xpath_allocator* temp;
  	};
  
  	struct xpath_stack_data
  	{
  		xpath_memory_block blocks[2];
  		xpath_allocator result;
  		xpath_allocator temp;
  		xpath_stack stack;
  
  	#ifdef PUGIHTML_NO_EXCEPTIONS
  		jmp_buf error_handler;
  	#endif
  
  		xpath_stack_data(): result(blocks + 0), temp(blocks + 1)
  		{
  			blocks[0].next = blocks[1].next = 0;
  
  			stack.result = &result;
  			stack.temp = &temp;
  
  		#ifdef PUGIHTML_NO_EXCEPTIONS
  			result.error_handler = temp.error_handler = &error_handler;
  		#endif
  		}
  
  		~xpath_stack_data()
  		{
  			result.release();
  			temp.release();
  		}
  	};
  }
  
  // String class
  namespace
  {
  	class xpath_string
  	{
  		const char_t* _buffer;
  		bool _uses_heap;
  
  		static char_t* duplicate_string(const char_t* string, size_t length, xpath_allocator* alloc)
  		{
  			char_t* result = static_cast<char_t*>(alloc->allocate((length + 1) * sizeof(char_t)));
  			assert(result);
  
  			memcpy(result, string, length * sizeof(char_t));
  			result[length] = 0;
  
  			return result;
  		}
  
  		static char_t* duplicate_string(const char_t* string, xpath_allocator* alloc)
  		{
  			return duplicate_string(string, strlength(string), alloc);
  		}
  
  	public:
  		xpath_string(): _buffer(PUGIHTML_TEXT("")), _uses_heap(false)
  		{
  		}
  
  		explicit xpath_string(const char_t* str, xpath_allocator* alloc)
  		{
  			bool empty = (*str == 0);
  
  			_buffer = empty ? PUGIHTML_TEXT("") : duplicate_string(str, alloc);
  			_uses_heap = !empty;
  		}
  
  		explicit xpath_string(const char_t* str, bool use_heap): _buffer(str), _uses_heap(use_heap)
  		{
  		}
  
  		xpath_string(const char_t* begin, const char_t* end, xpath_allocator* alloc)
  		{
  			assert(begin <= end);
  
  			bool empty = (begin == end);
  
  			_buffer = empty ? PUGIHTML_TEXT("") : duplicate_string(begin, static_cast<size_t>(end - begin), alloc);
  			_uses_heap = !empty;
  		}
  
  		void append(const xpath_string& o, xpath_allocator* alloc)
  		{
  			// skip empty sources
  			if (!*o._buffer) return;
  
  			// fast append for constant empty target and constant source
  			if (!*_buffer && !_uses_heap && !o._uses_heap)
  			{
  				_buffer = o._buffer;
  			}
  			else
  			{
  				// need to make heap copy
  				size_t target_length = strlength(_buffer);
  				size_t source_length = strlength(o._buffer);
  				size_t length = target_length + source_length;
  
  				// allocate new buffer
  				char_t* result = static_cast<char_t*>(alloc->reallocate(_uses_heap ? const_cast<char_t*>(_buffer) : 0, (target_length + 1) * sizeof(char_t), (length + 1) * sizeof(char_t)));
  				assert(result);
  
  				// append first string to the new buffer in case there was no reallocation
  				if (!_uses_heap) memcpy(result, _buffer, target_length * sizeof(char_t));
  
  				// append second string to the new buffer
  				memcpy(result + target_length, o._buffer, source_length * sizeof(char_t));
  				result[length] = 0;
  
  				// finalize
  				_buffer = result;
  				_uses_heap = true;
  			}
  		}
  
  		const char_t* c_str() const
  		{
  			return _buffer;
  		}
  
  		size_t length() const
  		{
  			return strlength(_buffer);
  		}
  		
  		char_t* data(xpath_allocator* alloc)
  		{
  			// make private heap copy
  			if (!_uses_heap)
  			{
  				_buffer = duplicate_string(_buffer, alloc);
  				_uses_heap = true;
  			}
  
  			return const_cast<char_t*>(_buffer);
  		}
  
  		bool empty() const
  		{
  			return *_buffer == 0;
  		}
  
  		bool operator==(const xpath_string& o) const
  		{
  			return strequal(_buffer, o._buffer);
  		}
  
  		bool operator!=(const xpath_string& o) const
  		{
  			return !strequal(_buffer, o._buffer);
  		}
  
  		bool uses_heap() const
  		{
  			return _uses_heap;
  		}
  	};
  
  	xpath_string xpath_string_const(const char_t* str)
  	{
  		return xpath_string(str, false);
  	}
  }
  
  namespace
  {
  	bool starts_with(const char_t* string, const char_t* pattern)
  	{
  		while (*pattern && *string == *pattern)
  		{
  			string++;
  			pattern++;
  		}
  
  		return *pattern == 0;
  	}
  
  	const char_t* find_char(const char_t* s, char_t c)
  	{
  	#ifdef PUGIHTML_WCHAR_MODE
  		return wcschr(s, c);
  	#else
  		return strchr(s, c);
  	#endif
  	}
  
  	const char_t* find_substring(const char_t* s, const char_t* p)
  	{
  	#ifdef PUGIHTML_WCHAR_MODE
  		// MSVC6 wcsstr bug workaround (if s is empty it always returns 0)
  		return (*p == 0) ? s : wcsstr(s, p);
  	#else
  		return strstr(s, p);
  	#endif
  	}
  
  	// Converts symbol to lower case, if it is an ASCII one
  	char_t tolower_ascii(char_t ch)
  	{
  		return static_cast<unsigned int>(ch - 'A') < 26 ? static_cast<char_t>(ch | ' ') : ch;
  	}
  
  	xpath_string string_value(const xpath_node& na, xpath_allocator* alloc)
  	{
  		if (na.attribute())
  			return xpath_string_const(na.attribute().value());
  		else
  		{
  			const html_node& n = na.node();
  
  			switch (n.type())
  			{
  			case node_pcdata:
  			case node_cdata:
  			case node_comment:
  			case node_pi:
  				return xpath_string_const(n.value());
  			
  			case node_document:
  			case node_element:
  			{
  				xpath_string result;
  
  				html_node cur = n.first_child();
  				
  				while (cur && cur != n)
  				{
  					if (cur.type() == node_pcdata || cur.type() == node_cdata)
  						result.append(xpath_string_const(cur.value()), alloc);
  
  					if (cur.first_child())
  						cur = cur.first_child();
  					else if (cur.next_sibling())
  						cur = cur.next_sibling();
  					else
  					{
  						while (!cur.next_sibling() && cur != n)
  							cur = cur.parent();
  
  						if (cur != n) cur = cur.next_sibling();
  					}
  				}
  				
  				return result;
  			}
  			
  			default:
  				return xpath_string();
  			}
  		}
  	}
  	
  	unsigned int node_height(html_node n)
  	{
  	    unsigned int result = 0;
  	    
  	    while (n)
  	    {
  	        ++result;
  	        n = n.parent();
  	    }
  	    
  	    return result;
  	}
  	
  	bool node_is_before(html_node ln, unsigned int lh, html_node rn, unsigned int rh)
  	{
  		// normalize heights
  		for (unsigned int i = rh; i < lh; i++) ln = ln.parent();
  		for (unsigned int j = lh; j < rh; j++) rn = rn.parent();
  	    
  		// one node is the ancestor of the other
  	    if (ln == rn) return lh < rh;
  	    
  		// find common ancestor
  	    while (ln.parent() != rn.parent())
  	    {
  	        ln = ln.parent();
  	        rn = rn.parent();
  	    }
  
  		// there is no common ancestor (the shared parent is null), nodes are from different documents
  		if (!ln.parent()) return ln < rn;
  
  		// determine sibling order
          for (; ln; ln = ln.next_sibling())
              if (ln == rn)
                  return true;
                  
          return false;
      }
  
      bool node_is_ancestor(html_node parent, html_node node)
      {
      	while (node && node != parent) node = node.parent();
  
      	return parent && node == parent;
      }
  
      const void* document_order(const xpath_node& xnode)
      {
          html_node_struct* node = xnode.node().internal_object();
  
          if (node)
          {
              if (node->name && (node->header & html_memory_page_name_allocated_mask) == 0) return node->name;
              if (node->value && (node->header & html_memory_page_value_allocated_mask) == 0) return node->value;
              return 0;
          }
  
          html_attribute_struct* attr = xnode.attribute().internal_object();
  
          if (attr)
          {
              if ((attr->header & html_memory_page_name_allocated_mask) == 0) return attr->name;
              if ((attr->header & html_memory_page_value_allocated_mask) == 0) return attr->value;
              return 0;
          }
  
  		return 0;
      }
      
  	struct document_order_comparator
  	{
  		bool operator()(const xpath_node& lhs, const xpath_node& rhs) const
  		{
  			// optimized document order based check
  			const void* lo = document_order(lhs);
  			const void* ro = document_order(rhs);
  
  			if (lo && ro) return lo < ro;
  
              // slow comparison
  			html_node ln = lhs.node(), rn = rhs.node();
  
  			// compare attributes
  			if (lhs.attribute() && rhs.attribute())
  			{
  				// shared parent
  				if (lhs.parent() == rhs.parent())
  				{
  					// determine sibling order
  				    for (html_attribute a = lhs.attribute(); a; a = a.next_attribute())
  				        if (a == rhs.attribute())
  				            return true;
  				    
  				    return false;
  				}
  				
  				// compare attribute parents
  				ln = lhs.parent();
  				rn = rhs.parent();
  			}
  			else if (lhs.attribute())
  			{
  				// attributes go after the parent element
  				if (lhs.parent() == rhs.node()) return false;
  				
  				ln = lhs.parent();
  			}
  			else if (rhs.attribute())
  			{
  				// attributes go after the parent element
  				if (rhs.parent() == lhs.node()) return true;
  				
  				rn = rhs.parent();
  			}
  
  			if (ln == rn) return false;
  			
  			unsigned int lh = node_height(ln);
  			unsigned int rh = node_height(rn);
  			
  			return node_is_before(ln, lh, rn, rh);
  		}
  	};
  
  	struct duplicate_comparator
  	{
  		bool operator()(const xpath_node& lhs, const xpath_node& rhs) const
  		{
  			if (lhs.attribute()) return rhs.attribute() ? lhs.attribute() < rhs.attribute() : true;
  			else return rhs.attribute() ? false : lhs.node() < rhs.node();
  		}
  	};
  	
  	double gen_nan()
  	{
  	#if defined(__STDC_IEC_559__) || ((FLT_RADIX - 0 == 2) && (FLT_MAX_EXP - 0 == 128) && (FLT_MANT_DIG - 0 == 24))
  		union { float f; int32_t i; } u[sizeof(float) == sizeof(int32_t) ? 1 : -1];
  		u[0].i = 0x7fc00000;
  		return u[0].f;
  	#else
  		// fallback
  		const volatile double zero = 0.0;
  		return zero / zero;
  	#endif
  	}
  	
  	bool is_nan(double value)
  	{
  	#if defined(_MSC_VER) || defined(__BORLANDC__)
  		return !!_isnan(value);
  	#elif defined(fpclassify) && defined(FP_NAN)
  		return fpclassify(value) == FP_NAN;
  	#else
  		// fallback
  		const volatile double v = value;
  		return v != v;
  	#endif
  	}
  	
  	const char_t* convert_number_to_string_special(double value)
  	{
  	#if defined(_MSC_VER) || defined(__BORLANDC__)
  		if (_finite(value)) return (value == 0) ? PUGIHTML_TEXT("0") : 0;
  		if (_isnan(value)) return PUGIHTML_TEXT("NaN");
  		return PUGIHTML_TEXT("-Infinity") + (value > 0);
  	#elif defined(fpclassify) && defined(FP_NAN) && defined(FP_INFINITE) && defined(FP_ZERO)
  		switch (fpclassify(value))
  		{
  		case FP_NAN:
  			return PUGIHTML_TEXT("NaN");
  
  		case FP_INFINITE:
  			return PUGIHTML_TEXT("-Infinity") + (value > 0);
  
  		case FP_ZERO:
  			return PUGIHTML_TEXT("0");
  
  		default:
  			return 0;
  		}
  	#else
  		// fallback
  		const volatile double v = value;
  
  		if (v == 0) return PUGIHTML_TEXT("0");
  		if (v != v) return PUGIHTML_TEXT("NaN");
  		if (v * 2 == v) return PUGIHTML_TEXT("-Infinity") + (value > 0);
  		return 0;
  	#endif
  	}
  	
  	bool convert_number_to_boolean(double value)
  	{
  		return (value != 0 && !is_nan(value));
  	}
  	
  	void truncate_zeros(char* begin, char* end)
  	{
  		while (begin != end && end[-1] == '0') end--;
  
  		*end = 0;
  	}
  
  	// gets mantissa digits in the form of 0.xxxxx with 0. implied and the exponent
  #if defined(_MSC_VER) && _MSC_VER >= 1400
  	void convert_number_to_mantissa_exponent(double value, char* buffer, size_t buffer_size, char** out_mantissa, int* out_exponent)
  	{
  		// get base values
  		int sign, exponent;
  		_ecvt_s(buffer, buffer_size, value, DBL_DIG + 1, &exponent, &sign);
  
  		// truncate redundant zeros
  		truncate_zeros(buffer, buffer + strlen(buffer));
  
  		// fill results
  		*out_mantissa = buffer;
  		*out_exponent = exponent;
  	}
  #else
  	void convert_number_to_mantissa_exponent(double value, char* buffer, size_t buffer_size, char** out_mantissa, int* out_exponent)
  	{
  		// get a scientific notation value with IEEE DBL_DIG decimals
  		sprintf(buffer, "%.*e", DBL_DIG, value);
  		assert(strlen(buffer) < buffer_size);
  		(void)!buffer_size;
  
  		// get the exponent (possibly negative)
  		char* exponent_string = strchr(buffer, 'e');
  		assert(exponent_string);
  
  		int exponent = atoi(exponent_string + 1);
  
  		// extract mantissa string: skip sign
  		char* mantissa = buffer[0] == '-' ? buffer + 1 : buffer;
  		assert(mantissa[0] != '0' && mantissa[1] == '.');
  
  		// divide mantissa by 10 to eliminate integer part
  		mantissa[1] = mantissa[0];
  		mantissa++;
  		exponent++;
  
  		// remove extra mantissa digits and zero-terminate mantissa
  		truncate_zeros(mantissa, exponent_string);
  
  		// fill results
  		*out_mantissa = mantissa;
  		*out_exponent = exponent;
  	}
  #endif
  
  	xpath_string convert_number_to_string(double value, xpath_allocator* alloc)
  	{
  		// try special number conversion
  		const char_t* special = convert_number_to_string_special(value);
  		if (special) return xpath_string_const(special);
  
  		// get mantissa + exponent form
  		char mantissa_buffer[64];
  
  		char* mantissa;
  		int exponent;
  		convert_number_to_mantissa_exponent(value, mantissa_buffer, sizeof(mantissa_buffer), &mantissa, &exponent);
  
  		// make the number!
  		char_t result[512];
  		char_t* s = result;
  
  		// sign
  		if (value < 0) *s++ = '-';
  
  		// integer part
  		if (exponent <= 0)
  		{
  			*s++ = '0';
  		}
  		else
  		{
  			while (exponent > 0)
  			{
  				assert(*mantissa == 0 || (unsigned)(*mantissa - '0') <= 9);
  				*s++ = *mantissa ? *mantissa++ : '0';
  				exponent--;
  			}
  		}
  
  		// fractional part
  		if (*mantissa)
  		{
  			// decimal point
  			*s++ = '.';
  
  			// extra zeroes from negative exponent
  			while (exponent < 0)
  			{
  				*s++ = '0';
  				exponent++;
  			}
  
  			// extra mantissa digits
  			while (*mantissa)
  			{
  				assert((unsigned)(*mantissa - '0') <= 9);
  				*s++ = *mantissa++;
  			}
  		}
  
  		// zero-terminate
  		assert(s < result + sizeof(result) / sizeof(result[0]));
  		*s = 0;
  
  		return xpath_string(result, alloc);
  	}
  	
  	bool check_string_to_number_format(const char_t* string)
  	{
  		// parse leading whitespace
  		while (IS_CHARTYPE(*string, ct_space)) ++string;
  
  		// parse sign
  		if (*string == '-') ++string;
  
  		if (!*string) return false;
  
  		// if there is no integer part, there should be a decimal part with at least one digit
  		if (!IS_CHARTYPEX(string[0], ctx_digit) && (string[0] != '.' || !IS_CHARTYPEX(string[1], ctx_digit))) return false;
  
  		// parse integer part
  		while (IS_CHARTYPEX(*string, ctx_digit)) ++string;
  
  		// parse decimal part
  		if (*string == '.')
  		{
  			++string;
  
  			while (IS_CHARTYPEX(*string, ctx_digit)) ++string;
  		}
  
  		// parse trailing whitespace
  		while (IS_CHARTYPE(*string, ct_space)) ++string;
  
  		return *string == 0;
  	}
  
  	double convert_string_to_number(const char_t* string)
  	{
  		// check string format
  		if (!check_string_to_number_format(string)) return gen_nan();
  
  		// parse string
  	#ifdef PUGIHTML_WCHAR_MODE
  		return wcstod(string, 0);
  	#else
  		return atof(string);
  	#endif
  	}
  
  	bool convert_string_to_number(const char_t* begin, const char_t* end, double* out_result)
  	{
  		char_t buffer[32];
  
  		size_t length = static_cast<size_t>(end - begin);
  		char_t* scratch = buffer;
  
  		if (length >= sizeof(buffer) / sizeof(buffer[0]))
  		{
  			// need to make dummy on-heap copy
  			scratch = static_cast<char_t*>(global_allocate((length + 1) * sizeof(char_t)));
  			if (!scratch) return false;
  		}
  
  		// copy string to zero-terminated buffer and perform conversion
  		memcpy(scratch, begin, length * sizeof(char_t));
  		scratch[length] = 0;
  
  		*out_result = convert_string_to_number(scratch);
  
  		// free dummy buffer
  		if (scratch != buffer) global_deallocate(scratch);
  
  		return true;
  	}
  	
  	double round_nearest(double value)
  	{
  		return floor(value + 0.5);
  	}
  
  	double round_nearest_nzero(double value)
  	{
  		// same as round_nearest, but returns -0 for [-0.5, -0]
  		// ceil is used to differentiate between +0 and -0 (we return -0 for [-0.5, -0] and +0 for +0)
  		return (value >= -0.5 && value <= 0) ? ceil(value) : floor(value + 0.5);
  	}
  	
  	const char_t* qualified_name(const xpath_node& node)
  	{
  		return node.attribute() ? node.attribute().name() : node.node().name();
  	}
  	
  	const char_t* local_name(const xpath_node& node)
  	{
  		const char_t* name = qualified_name(node);
  		const char_t* p = find_char(name, ':');
  		
  		return p ? p + 1 : name;
  	}
  
  	struct namespace_uri_predicate
  	{
  		const char_t* prefix;
  		size_t prefix_length;
  
  		namespace_uri_predicate(const char_t* name)
  		{
  			const char_t* pos = find_char(name, ':');
  
  			prefix = pos ? name : 0;
  			prefix_length = pos ? static_cast<size_t>(pos - name) : 0;
  		}
  
  		bool operator()(const html_attribute& a) const
  		{
  			const char_t* name = a.name();
  
  			if (!starts_with(name, PUGIHTML_TEXT("htmlns"))) return false;
  
  			return prefix ? name[5] == ':' && strequalrange(name + 6, prefix, prefix_length) : name[5] == 0;
  		}
  	};
  
  	const char_t* namespace_uri(const html_node& node)
  	{
  		namespace_uri_predicate pred = node.name();
  		
  		html_node p = node;
  		
  		while (p)
  		{
  			html_attribute a = p.find_attribute(pred);
  			
  			if (a) return a.value();
  			
  			p = p.parent();
  		}
  		
  		return PUGIHTML_TEXT("");
  	}
  
  	const char_t* namespace_uri(const html_attribute& attr, const html_node& parent)
  	{
  		namespace_uri_predicate pred = attr.name();
  		
  		// Default namespace does not apply to attributes
  		if (!pred.prefix) return PUGIHTML_TEXT("");
  		
  		html_node p = parent;
  		
  		while (p)
  		{
  			html_attribute a = p.find_attribute(pred);
  			
  			if (a) return a.value();
  			
  			p = p.parent();
  		}
  		
  		return PUGIHTML_TEXT("");
  	}
  
  	const char_t* namespace_uri(const xpath_node& node)
  	{
  		return node.attribute() ? namespace_uri(node.attribute(), node.parent()) : namespace_uri(node.node());
  	}
  
  	void normalize_space(char_t* buffer)
  	{
  		char_t* write = buffer;
  
  		for (char_t* it = buffer; *it; )
  		{
  			char_t ch = *it++;
  
  			if (IS_CHARTYPE(ch, ct_space))
  			{
  				// replace whitespace sequence with single space
  				while (IS_CHARTYPE(*it, ct_space)) it++;
  
  				// avoid leading spaces
  				if (write != buffer) *write++ = ' ';
  			}
  			else *write++ = ch;
  		}
  
  		// remove trailing space
  		if (write != buffer && IS_CHARTYPE(write[-1], ct_space)) write--;
  
  		// zero-terminate
  		*write = 0;
  	}
  
  	void translate(char_t* buffer, const char_t* from, const char_t* to)
  	{
  		size_t to_length = strlength(to);
  
  		char_t* write = buffer;
  
  		while (*buffer)
  		{
  			DMC_VOLATILE char_t ch = *buffer++;
  
  			const char_t* pos = find_char(from, ch);
  
  			if (!pos)
  				*write++ = ch; // do not process
  			else if (static_cast<size_t>(pos - from) < to_length)
  				*write++ = to[pos - from]; // replace
  		}
  
  		// zero-terminate
  		*write = 0;
  	}
  
  	struct xpath_variable_boolean: xpath_variable
  	{
  		xpath_variable_boolean(): value(false)
  		{
  		}
  
  		bool value;
  		char_t name[1];
  	};
  
  	struct xpath_variable_number: xpath_variable
  	{
  		xpath_variable_number(): value(0)
  		{
  		}
  
  		double value;
  		char_t name[1];
  	};
  
  	struct xpath_variable_string: xpath_variable
  	{
  		xpath_variable_string(): value(0)
  		{
  		}
  
  		~xpath_variable_string()
  		{
  			if (value) global_deallocate(value);
  		}
  
  		char_t* value;
  		char_t name[1];
  	};
  
  	struct xpath_variable_node_set: xpath_variable
  	{
  		xpath_node_set value;
  		char_t name[1];
  	};
  
  	const xpath_node_set dummy_node_set;
  
  	unsigned int hash_string(const char_t* str)
  	{
  		// Jenkins one-at-a-time hash (http://en.wikipedia.org/wiki/Jenkins_hash_function#one-at-a-time)
  		unsigned int result = 0;
  
  		while (*str)
  		{
  			result += static_cast<unsigned int>(*str++);
  			result += result << 10;
  			result ^= result >> 6;
  		}
  	
  		result += result << 3;
  		result ^= result >> 11;
  		result += result << 15;
  	
  		return result;
  	}
  
  	template <typename T> T* new_xpath_variable(const char_t* name)
  	{
  		size_t length = strlength(name);
  		if (length == 0) return 0; // empty variable names are invalid
  
  		// $$ we can't use offsetof(T, name) because T is non-POD, so we just allocate additional length characters
  		void* memory = global_allocate(sizeof(T) + length * sizeof(char_t));
  		if (!memory) return 0;
  
  		T* result = new (memory) T();
  
  		memcpy(result->name, name, (length + 1) * sizeof(char_t));
  
  		return result;
  	}
  
  	xpath_variable* new_xpath_variable(xpath_value_type type, const char_t* name)
  	{
  		switch (type)
  		{
  		case xpath_type_node_set:
  			return new_xpath_variable<xpath_variable_node_set>(name);
  
  		case xpath_type_number:
  			return new_xpath_variable<xpath_variable_number>(name);
  
  		case xpath_type_string:
  			return new_xpath_variable<xpath_variable_string>(name);
  
  		case xpath_type_boolean:
  			return new_xpath_variable<xpath_variable_boolean>(name);
  
  		default:
  			return 0;
  		}
  	}
  
  	template <typename T> void delete_xpath_variable(T* var)
  	{
  		var->~T();
  		global_deallocate(var);
  	}
  
  	void delete_xpath_variable(xpath_value_type type, xpath_variable* var)
  	{
  		switch (type)
  		{
  		case xpath_type_node_set:
  			delete_xpath_variable(static_cast<xpath_variable_node_set*>(var));
  			break;
  
  		case xpath_type_number:
  			delete_xpath_variable(static_cast<xpath_variable_number*>(var));
  			break;
  
  		case xpath_type_string:
  			delete_xpath_variable(static_cast<xpath_variable_string*>(var));
  			break;
  
  		case xpath_type_boolean:
  			delete_xpath_variable(static_cast<xpath_variable_boolean*>(var));
  			break;
  
  		default:
  			assert(!"Invalid variable type");
  		}
  	}
  
  	xpath_variable* get_variable(xpath_variable_set* set, const char_t* begin, const char_t* end)
  	{
  		char_t buffer[32];
  
  		size_t length = static_cast<size_t>(end - begin);
  		char_t* scratch = buffer;
  
  		if (length >= sizeof(buffer) / sizeof(buffer[0]))
  		{
  			// need to make dummy on-heap copy
  			scratch = static_cast<char_t*>(global_allocate((length + 1) * sizeof(char_t)));
  			if (!scratch) return 0;
  		}
  
  		// copy string to zero-terminated buffer and perform lookup
  		memcpy(scratch, begin, length * sizeof(char_t));
  		scratch[length] = 0;
  
  		xpath_variable* result = set->get(scratch);
  
  		// free dummy buffer
  		if (scratch != buffer) global_deallocate(scratch);
  
  		return result;
  	}
  }
  
  // Internal node set class
  namespace
  {
  	xpath_node_set::type_t xpath_sort(xpath_node* begin, xpath_node* end, xpath_node_set::type_t type, bool rev)
  	{
  		xpath_node_set::type_t order = rev ? xpath_node_set::type_sorted_reverse : xpath_node_set::type_sorted;
  
  		if (type == xpath_node_set::type_unsorted)
  		{
  			sort(begin, end, document_order_comparator());
  
  			type = xpath_node_set::type_sorted;
  		}
  		
  		if (type != order) reverse(begin, end);
  			
  		return order;
  	}
  
  	xpath_node xpath_first(const xpath_node* begin, const xpath_node* end, xpath_node_set::type_t type)
  	{
  		if (begin == end) return xpath_node();
  
  		switch (type)
  		{
  		case xpath_node_set::type_sorted:
  			return *begin;
  
  		case xpath_node_set::type_sorted_reverse:
  			return *(end - 1);
  
  		case xpath_node_set::type_unsorted:
  			return *min_element(begin, end, document_order_comparator());
  
  		default:
  			assert(!"Invalid node set type");
  			return xpath_node();
  		}
  	}
  	class xpath_node_set_raw
  	{
  		xpath_node_set::type_t _type;
  
  		xpath_node* _begin;
  		xpath_node* _end;
  		xpath_node* _eos;
  
  	public:
  		xpath_node_set_raw(): _type(xpath_node_set::type_unsorted), _begin(0), _end(0), _eos(0)
  		{
  		}
  
  		xpath_node* begin() const
  		{
  			return _begin;
  		}
  
  		xpath_node* end() const
  		{
  			return _end;
  		}
  
  		bool empty() const
  		{
  			return _begin == _end;
  		}
  
  		size_t size() const
  		{
  			return static_cast<size_t>(_end - _begin);
  		}
  
  		xpath_node first() const
  		{
  			return xpath_first(_begin, _end, _type);
  		}
  
  		void push_back(const xpath_node& node, xpath_allocator* alloc)
  		{
  			if (_end == _eos)
  			{
  				size_t capacity = static_cast<size_t>(_eos - _begin);
  
  				// get new capacity (1.5x rule)
  				size_t new_capacity = capacity + capacity / 2 + 1;
  
  				// reallocate the old array or allocate a new one
  				xpath_node* data = static_cast<xpath_node*>(alloc->reallocate(_begin, capacity * sizeof(xpath_node), new_capacity * sizeof(xpath_node)));
  				assert(data);
  
  				// finalize
  				_begin = data;
  				_end = data + capacity;
  				_eos = data + new_capacity;
  			}
  
  			*_end++ = node;
  		}
  
  		void append(const xpath_node* begin, const xpath_node* end, xpath_allocator* alloc)
  		{
  			size_t size = static_cast<size_t>(_end - _begin);
  			size_t capacity = static_cast<size_t>(_eos - _begin);
  			size_t count = static_cast<size_t>(end - begin);
  
  			if (size + count > capacity)
  			{
  				// reallocate the old array or allocate a new one
  				xpath_node* data = static_cast<xpath_node*>(alloc->reallocate(_begin, capacity * sizeof(xpath_node), (size + count) * sizeof(xpath_node)));
  				assert(data);
  
  				// finalize
  				_begin = data;
  				_end = data + size;
  				_eos = data + size + count;
  			}
  
  			memcpy(_end, begin, count * sizeof(xpath_node));
  			_end += count;
  		}
  
  		void sort_do()
  		{
  			_type = xpath_sort(_begin, _end, _type, false);
  		}
  
  		void truncate(xpath_node* pos)
  		{
  			assert(_begin <= pos && pos <= _end);
  
  			_end = pos;
  		}
  
  		void remove_duplicates()
  		{
  			if (_type == xpath_node_set::type_unsorted)
  				sort(_begin, _end, duplicate_comparator());
  		
  			_end = unique(_begin, _end);
  		}
  
  		xpath_node_set::type_t type() const
  		{
  			return _type;
  		}
  
  		void set_type(xpath_node_set::type_t type)
  		{
  			_type = type;
  		}
  	};
  }
  
  namespace
  {
  	struct xpath_context
  	{
  		xpath_node n;
  		size_t position, size;
  
  		xpath_context(const xpath_node& n, size_t position, size_t size): n(n), position(position), size(size)
  		{
  		}
  	};
  
  	enum lexeme_t
  	{
  		lex_none = 0,
  		lex_equal,
  		lex_not_equal,
  		lex_less,
  		lex_greater,
  		lex_less_or_equal,
  		lex_greater_or_equal,
  		lex_plus,
  		lex_minus,
  		lex_multiply,
  		lex_union,
  		lex_var_ref,
  		lex_open_brace,
  		lex_close_brace,
  		lex_quoted_string,
  		lex_number,
  		lex_slash,
  		lex_double_slash,
  		lex_open_square_brace,
  		lex_close_square_brace,
  		lex_string,
  		lex_comma,
  		lex_axis_attribute,
  		lex_dot,
  		lex_double_dot,
  		lex_double_colon,
  		lex_eof
  	};
  
  	struct xpath_lexer_string
  	{
  		const char_t* begin;
  		const char_t* end;
  
  		xpath_lexer_string(): begin(0), end(0)
  		{
  		}
  
  		bool operator==(const char_t* other) const
  		{
  			size_t length = static_cast<size_t>(end - begin);
  
  			return strequalrange(other, begin, length);
  		}
  	};
  
  	class xpath_lexer
  	{
  		const char_t* _cur;
  		const char_t* _cur_lexeme_pos;
  		xpath_lexer_string _cur_lexeme_contents;
  
  		lexeme_t _cur_lexeme;
  
  	public:
  		explicit xpath_lexer(const char_t* query): _cur(query)
  		{
  			next();
  		}
  		
  		const char_t* state() const
  		{
  			return _cur;
  		}
  		
  		void next()
  		{
  			const char_t* cur = _cur;
  
  			while (IS_CHARTYPE(*cur, ct_space)) ++cur;
  
  			// save lexeme position for error reporting
  			_cur_lexeme_pos = cur;
  
  			switch (*cur)
  			{
  			case 0:
  				_cur_lexeme = lex_eof;
  				break;
  			
  			case '>':
  				if (*(cur+1) == '=')
  				{
  					cur += 2;
  					_cur_lexeme = lex_greater_or_equal;
  				}
  				else
  				{
  					cur += 1;
  					_cur_lexeme = lex_greater;
  				}
  				break;
  
  			case '<':
  				if (*(cur+1) == '=')
  				{
  					cur += 2;
  					_cur_lexeme = lex_less_or_equal;
  				}
  				else
  				{
  					cur += 1;
  					_cur_lexeme = lex_less;
  				}
  				break;
  
  			case '!':
  				if (*(cur+1) == '=')
  				{
  					cur += 2;
  					_cur_lexeme = lex_not_equal;
  				}
  				else
  				{
  					_cur_lexeme = lex_none;
  				}
  				break;
  
  			case '=':
  				cur += 1;
  				_cur_lexeme = lex_equal;
  
  				break;
  			
  			case '+':
  				cur += 1;
  				_cur_lexeme = lex_plus;
  
  				break;
  
  			case '-':
  				cur += 1;
  				_cur_lexeme = lex_minus;
  
  				break;
  
  			case '*':
  				cur += 1;
  				_cur_lexeme = lex_multiply;
  
  				break;
  
  			case '|':
  				cur += 1;
  				_cur_lexeme = lex_union;
  
  				break;
  			
  			case '$':
  				cur += 1;
  
  				if (IS_CHARTYPEX(*cur, ctx_start_symbol))
  				{
  					_cur_lexeme_contents.begin = cur;
  
  					while (IS_CHARTYPEX(*cur, ctx_symbol)) cur++;
  
  					if (cur[0] == ':' && IS_CHARTYPEX(cur[1], ctx_symbol)) // qname
  					{
  						cur++; // :
  
  						while (IS_CHARTYPEX(*cur, ctx_symbol)) cur++;
  					}
  
  					_cur_lexeme_contents.end = cur;
  				
  					_cur_lexeme = lex_var_ref;
  				}
  				else
  				{
  					_cur_lexeme = lex_none;
  				}
  
  				break;
  
  			case '(':
  				cur += 1;
  				_cur_lexeme = lex_open_brace;
  
  				break;
  
  			case ')':
  				cur += 1;
  				_cur_lexeme = lex_close_brace;
  
  				break;
  			
  			case '[':
  				cur += 1;
  				_cur_lexeme = lex_open_square_brace;
  
  				break;
  
  			case ']':
  				cur += 1;
  				_cur_lexeme = lex_close_square_brace;
  
  				break;
  
  			case ',':
  				cur += 1;
  				_cur_lexeme = lex_comma;
  
  				break;
  
  			case '/':
  				if (*(cur+1) == '/')
  				{
  					cur += 2;
  					_cur_lexeme = lex_double_slash;
  				}
  				else
  				{
  					cur += 1;
  					_cur_lexeme = lex_slash;
  				}
  				break;
  		
  			case '.':
  				if (*(cur+1) == '.')
  				{
  					cur += 2;
  					_cur_lexeme = lex_double_dot;
  				}
  				else if (IS_CHARTYPEX(*(cur+1), ctx_digit))
  				{
  					_cur_lexeme_contents.begin = cur; // .
  
  					++cur;
  
  					while (IS_CHARTYPEX(*cur, ctx_digit)) cur++;
  
  					_cur_lexeme_contents.end = cur;
  					
  					_cur_lexeme = lex_number;
  				}
  				else
  				{
  					cur += 1;
  					_cur_lexeme = lex_dot;
  				}
  				break;
  
  			case '@':
  				cur += 1;
  				_cur_lexeme = lex_axis_attribute;
  
  				break;
  
  			case '"':
  			case '\'':
  			{
  				char_t terminator = *cur;
  
  				++cur;
  
  				_cur_lexeme_contents.begin = cur;
  				while (*cur && *cur != terminator) cur++;
  				_cur_lexeme_contents.end = cur;
  				
  				if (!*cur)
  					_cur_lexeme = lex_none;
  				else
  				{
  					cur += 1;
  					_cur_lexeme = lex_quoted_string;
  				}
  
  				break;
  			}
  
  			case ':':
  				if (*(cur+1) == ':')
  				{
  					cur += 2;
  					_cur_lexeme = lex_double_colon;
  				}
  				else
  				{
  					_cur_lexeme = lex_none;
  				}
  				break;
  
  			default:
  				if (IS_CHARTYPEX(*cur, ctx_digit))
  				{
  					_cur_lexeme_contents.begin = cur;
  
  					while (IS_CHARTYPEX(*cur, ctx_digit)) cur++;
  				
  					if (*cur == '.')
  					{
  						cur++;
  
  						while (IS_CHARTYPEX(*cur, ctx_digit)) cur++;
  					}
  
  					_cur_lexeme_contents.end = cur;
  
  					_cur_lexeme = lex_number;
  				}
  				else if (IS_CHARTYPEX(*cur, ctx_start_symbol))
  				{
  					_cur_lexeme_contents.begin = cur;
  
  					while (IS_CHARTYPEX(*cur, ctx_symbol)) cur++;
  
  					if (cur[0] == ':')
  					{
  						if (cur[1] == '*') // namespace test ncname:*
  						{
  							cur += 2; // :*
  						}
  						else if (IS_CHARTYPEX(cur[1], ctx_symbol)) // namespace test qname
  						{
  							cur++; // :
  
  							while (IS_CHARTYPEX(*cur, ctx_symbol)) cur++;
  						}
  					}
  
  					_cur_lexeme_contents.end = cur;
  				
  					_cur_lexeme = lex_string;
  				}
  				else
  				{
  					_cur_lexeme = lex_none;
  				}
  			}
  
  			_cur = cur;
  		}
  
  		lexeme_t current() const
  		{
  			return _cur_lexeme;
  		}
  
  		const char_t* current_pos() const
  		{
  			return _cur_lexeme_pos;
  		}
  
  		const xpath_lexer_string& contents() const
  		{
  			assert(_cur_lexeme == lex_var_ref || _cur_lexeme == lex_number || _cur_lexeme == lex_string || _cur_lexeme == lex_quoted_string);
  
  			return _cur_lexeme_contents;
  		}
  	};
  
  	enum ast_type_t
  	{
  		ast_op_or,						// left or right
  		ast_op_and,						// left and right
  		ast_op_equal,					// left = right
  		ast_op_not_equal, 				// left != right
  		ast_op_less,					// left < right
  		ast_op_greater,					// left > right
  		ast_op_less_or_equal,			// left <= right
  		ast_op_greater_or_equal,		// left >= right
  		ast_op_add,						// left + right
  		ast_op_subtract,				// left - right
  		ast_op_multiply,				// left * right
  		ast_op_divide,					// left / right
  		ast_op_mod,						// left % right
  		ast_op_negate,					// left - right
  		ast_op_union,					// left | right
  		ast_predicate,					// apply predicate to set; next points to next predicate
  		ast_filter,						// select * from left where right
  		ast_filter_posinv,				// select * from left where right; proximity position invariant
  		ast_string_constant,			// string constant
  		ast_number_constant,			// number constant
  		ast_variable,					// variable
  		ast_func_last,					// last()
  		ast_func_position,				// position()
  		ast_func_count,					// count(left)
  		ast_func_id,					// id(left)
  		ast_func_local_name_0,			// local-name()
  		ast_func_local_name_1,			// local-name(left)
  		ast_func_namespace_uri_0,		// namespace-uri()
  		ast_func_namespace_uri_1,		// namespace-uri(left)
  		ast_func_name_0,				// name()
  		ast_func_name_1,				// name(left)
  		ast_func_string_0,				// string()
  		ast_func_string_1,				// string(left)
  		ast_func_concat,				// concat(left, right, siblings)
  		ast_func_starts_with,			// starts_with(left, right)
  		ast_func_contains,				// contains(left, right)
  		ast_func_substring_before,		// substring-before(left, right)
  		ast_func_substring_after,		// substring-after(left, right)
  		ast_func_substring_2,			// substring(left, right)
  		ast_func_substring_3,			// substring(left, right, third)
  		ast_func_string_length_0,		// string-length()
  		ast_func_string_length_1,		// string-length(left)
  		ast_func_normalize_space_0,		// normalize-space()
  		ast_func_normalize_space_1,		// normalize-space(left)
  		ast_func_translate,				// translate(left, right, third)
  		ast_func_boolean,				// boolean(left)
  		ast_func_not,					// not(left)
  		ast_func_true,					// true()
  		ast_func_false,					// false()
  		ast_func_lang,					// lang(left)
  		ast_func_number_0,				// number()
  		ast_func_number_1,				// number(left)
  		ast_func_sum,					// sum(left)
  		ast_func_floor,					// floor(left)
  		ast_func_ceiling,				// ceiling(left)
  		ast_func_round,					// round(left)
  		ast_step,						// process set left with step
  		ast_step_root					// select root node
  	};
  
  	enum axis_t
  	{
  		axis_ancestor,
  		axis_ancestor_or_self,
  		axis_attribute,
  		axis_child,
  		axis_descendant,
  		axis_descendant_or_self,
  		axis_following,
  		axis_following_sibling,
  		axis_namespace,
  		axis_parent,
  		axis_preceding,
  		axis_preceding_sibling,
  		axis_self
  	};
  	
  	enum nodetest_t
  	{
  		nodetest_none,
  		nodetest_name,
  		nodetest_type_node,
  		nodetest_type_comment,
  		nodetest_type_pi,
  		nodetest_type_text,
  		nodetest_pi,
  		nodetest_all,
  		nodetest_all_in_namespace
  	};
  
  	template <axis_t N> struct axis_to_type
  	{
  		static const axis_t axis;
  	};
  
  	template <axis_t N> const axis_t axis_to_type<N>::axis = N;
  		
  	class xpath_ast_node
  	{
  	private:
  		// node type
  		char _type;
  		char _rettype;
  
  		// for ast_step / ast_predicate
  		char _axis;
  		char _test;
  
  		// tree node structure
  		xpath_ast_node* _left;
  		xpath_ast_node* _right;
  		xpath_ast_node* _next;
  
  		union
  		{
  			// value for ast_string_constant
  			const char_t* string;
  			// value for ast_number_constant
  			double number;
  			// variable for ast_variable
  			xpath_variable* variable;
  			// node test for ast_step (node name/namespace/node type/pi target)
  			const char_t* nodetest;
  		} _data;
  
  		xpath_ast_node(const xpath_ast_node&);
  		xpath_ast_node& operator=(const xpath_ast_node&);
  
  		template <class Comp> static bool compare_eq(xpath_ast_node* lhs, xpath_ast_node* rhs, const xpath_context& c, const xpath_stack& stack, const Comp& comp)
  		{
  			xpath_value_type lt = lhs->rettype(), rt = rhs->rettype();
  
  			if (lt != xpath_type_node_set && rt != xpath_type_node_set)
  			{
  				if (lt == xpath_type_boolean || rt == xpath_type_boolean)
  					return comp(lhs->eval_boolean(c, stack), rhs->eval_boolean(c, stack));
  				else if (lt == xpath_type_number || rt == xpath_type_number)
  					return comp(lhs->eval_number(c, stack), rhs->eval_number(c, stack));
  				else if (lt == xpath_type_string || rt == xpath_type_string)
  				{
  					xpath_allocator_capture cr(stack.result);
  
  					xpath_string ls = lhs->eval_string(c, stack);
  					xpath_string rs = rhs->eval_string(c, stack);
  
  					return comp(ls, rs);
  				}
  			}
  			else if (lt == xpath_type_node_set && rt == xpath_type_node_set)
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				xpath_node_set_raw ls = lhs->eval_node_set(c, stack);
  				xpath_node_set_raw rs = rhs->eval_node_set(c, stack);
  
  				for (const xpath_node* li = ls.begin(); li != ls.end(); ++li)
  					for (const xpath_node* ri = rs.begin(); ri != rs.end(); ++ri)
  					{
  						xpath_allocator_capture cri(stack.result);
  
  						if (comp(string_value(*li, stack.result), string_value(*ri, stack.result)))
  							return true;
  					}
  
  				return false;
  			}
  			else
  			{
  				if (lt == xpath_type_node_set)
  				{
  					swap(lhs, rhs);
  					swap(lt, rt);
  				}
  
  				if (lt == xpath_type_boolean)
  					return comp(lhs->eval_boolean(c, stack), rhs->eval_boolean(c, stack));
  				else if (lt == xpath_type_number)
  				{
  					xpath_allocator_capture cr(stack.result);
  
  					double l = lhs->eval_number(c, stack);
  					xpath_node_set_raw rs = rhs->eval_node_set(c, stack);
  
  					for (const xpath_node* ri = rs.begin(); ri != rs.end(); ++ri)
  					{
  						xpath_allocator_capture cri(stack.result);
  
  						if (comp(l, convert_string_to_number(string_value(*ri, stack.result).c_str())))
  							return true;
  					}
  
  					return false;
  				}
  				else if (lt == xpath_type_string)
  				{
  					xpath_allocator_capture cr(stack.result);
  
  					xpath_string l = lhs->eval_string(c, stack);
  					xpath_node_set_raw rs = rhs->eval_node_set(c, stack);
  
  					for (const xpath_node* ri = rs.begin(); ri != rs.end(); ++ri)
  					{
  						xpath_allocator_capture cri(stack.result);
  
  						if (comp(l, string_value(*ri, stack.result)))
  							return true;
  					}
  
  					return false;
  				}
  			}
  
  			assert(!"Wrong types");
  			return false;
  		}
  
  		template <class Comp> static bool compare_rel(xpath_ast_node* lhs, xpath_ast_node* rhs, const xpath_context& c, const xpath_stack& stack, const Comp& comp)
  		{
  			xpath_value_type lt = lhs->rettype(), rt = rhs->rettype();
  
  			if (lt != xpath_type_node_set && rt != xpath_type_node_set)
  				return comp(lhs->eval_number(c, stack), rhs->eval_number(c, stack));
  			else if (lt == xpath_type_node_set && rt == xpath_type_node_set)
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				xpath_node_set_raw ls = lhs->eval_node_set(c, stack);
  				xpath_node_set_raw rs = rhs->eval_node_set(c, stack);
  
  				for (const xpath_node* li = ls.begin(); li != ls.end(); ++li)
  				{
  					xpath_allocator_capture cri(stack.result);
  
  					double l = convert_string_to_number(string_value(*li, stack.result).c_str());
  
  					for (const xpath_node* ri = rs.begin(); ri != rs.end(); ++ri)
  					{
  						xpath_allocator_capture crii(stack.result);
  
  						if (comp(l, convert_string_to_number(string_value(*ri, stack.result).c_str())))
  							return true;
  					}
  				}
  
  				return false;
  			}
  			else if (lt != xpath_type_node_set && rt == xpath_type_node_set)
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				double l = lhs->eval_number(c, stack);
  				xpath_node_set_raw rs = rhs->eval_node_set(c, stack);
  
  				for (const xpath_node* ri = rs.begin(); ri != rs.end(); ++ri)
  				{
  					xpath_allocator_capture cri(stack.result);
  
  					if (comp(l, convert_string_to_number(string_value(*ri, stack.result).c_str())))
  						return true;
  				}
  
  				return false;
  			}
  			else if (lt == xpath_type_node_set && rt != xpath_type_node_set)
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				xpath_node_set_raw ls = lhs->eval_node_set(c, stack);
  				double r = rhs->eval_number(c, stack);
  
  				for (const xpath_node* li = ls.begin(); li != ls.end(); ++li)
  				{
  					xpath_allocator_capture cri(stack.result);
  
  					if (comp(convert_string_to_number(string_value(*li, stack.result).c_str()), r))
  						return true;
  				}
  
  				return false;
  			}
  			else
  			{
  				assert(!"Wrong types");
  				return false;
  			}
  		}
  
  		void apply_predicate(xpath_node_set_raw& ns, size_t first, xpath_ast_node* expr, const xpath_stack& stack)
  		{
  			assert(ns.size() >= first);
  
  			size_t i = 1;
  			size_t size = ns.size() - first;
  				
  			xpath_node* last = ns.begin() + first;
  				
  			// remove_if... or well, sort of
  			for (xpath_node* it = last; it != ns.end(); ++it, ++i)
  			{
  				xpath_context c(*it, i, size);
  			
  				if (expr->rettype() == xpath_type_number)
  				{
  					if (expr->eval_number(c, stack) == i)
  						*last++ = *it;
  				}
  				else if (expr->eval_boolean(c, stack))
  					*last++ = *it;
  			}
  			
  			ns.truncate(last);
  		}
  
  		void apply_predicates(xpath_node_set_raw& ns, size_t first, const xpath_stack& stack)
  		{
  			if (ns.size() == first) return;
  			
  			for (xpath_ast_node* pred = _right; pred; pred = pred->_next)
  			{
  				apply_predicate(ns, first, pred->_left, stack);
  			}
  		}
  
  		void step_push(xpath_node_set_raw& ns, const html_attribute& a, const html_node& parent, xpath_allocator* alloc)
  		{
  			if (!a) return;
  
  			const char_t* name = a.name();
  
  			// There are no attribute nodes corresponding to attributes that declare namespaces
  			// That is, "htmlns:..." or "htmlns"
  			if (starts_with(name, PUGIHTML_TEXT("htmlns")) && (name[5] == 0 || name[5] == ':')) return;
  			
  			switch (_test)
  			{
  			case nodetest_name:
  				if (strequal(name, _data.nodetest)) ns.push_back(xpath_node(a, parent), alloc);
  				break;
  				
  			case nodetest_type_node:
  			case nodetest_all:
  				ns.push_back(xpath_node(a, parent), alloc);
  				break;
  				
  			case nodetest_all_in_namespace:
  				if (starts_with(name, _data.nodetest))
  					ns.push_back(xpath_node(a, parent), alloc);
  				break;
  			
  			default:
  				;
  			}
  		}
  		
  		void step_push(xpath_node_set_raw& ns, const html_node& n, xpath_allocator* alloc)
  		{
  			if (!n) return;
  
  			switch (_test)
  			{
  			case nodetest_name:
  				if (n.type() == node_element && strequal(n.name(), _data.nodetest)) ns.push_back(n, alloc);
  				break;
  				
  			case nodetest_type_node:
  				ns.push_back(n, alloc);
  				break;
  				
  			case nodetest_type_comment:
  				if (n.type() == node_comment)
  					ns.push_back(n, alloc);
  				break;
  				
  			case nodetest_type_text:
  				if (n.type() == node_pcdata || n.type() == node_cdata)
  					ns.push_back(n, alloc);
  				break;
  				
  			case nodetest_type_pi:
  				if (n.type() == node_pi)
  					ns.push_back(n, alloc);
  				break;
  									
  			case nodetest_pi:
  				if (n.type() == node_pi && strequal(n.name(), _data.nodetest))
  					ns.push_back(n, alloc);
  				break;
  				
  			case nodetest_all:
  				if (n.type() == node_element)
  					ns.push_back(n, alloc);
  				break;
  				
  			case nodetest_all_in_namespace:
  				if (n.type() == node_element && starts_with(n.name(), _data.nodetest))
  					ns.push_back(n, alloc);
  				break;
  
  			default:
  				assert(!"Unknown axis");
  			} 
  		}
  
  		template <class T> void step_fill(xpath_node_set_raw& ns, const html_node& n, xpath_allocator* alloc, T)
  		{
  			const axis_t axis = T::axis;
  
  			switch (axis)
  			{
  			case axis_attribute:
  			{
  				for (html_attribute a = n.first_attribute(); a; a = a.next_attribute())
  					step_push(ns, a, n, alloc);
  				
  				break;
  			}
  			
  			case axis_child:
  			{
  				for (html_node c = n.first_child(); c; c = c.next_sibling())
  					step_push(ns, c, alloc);
  					
  				break;
  			}
  			
  			case axis_descendant:
  			case axis_descendant_or_self:
  			{
  				if (axis == axis_descendant_or_self)
  					step_push(ns, n, alloc);
  					
  				html_node cur = n.first_child();
  				
  				while (cur && cur != n)
  				{
  					step_push(ns, cur, alloc);
  					
  					if (cur.first_child())
  						cur = cur.first_child();
  					else if (cur.next_sibling())
  						cur = cur.next_sibling();
  					else
  					{
  						while (!cur.next_sibling() && cur != n)
  							cur = cur.parent();
  					
  						if (cur != n) cur = cur.next_sibling();
  					}
  				}
  				
  				break;
  			}
  			
  			case axis_following_sibling:
  			{
  				for (html_node c = n.next_sibling(); c; c = c.next_sibling())
  					step_push(ns, c, alloc);
  				
  				break;
  			}
  			
  			case axis_preceding_sibling:
  			{
  				for (html_node c = n.previous_sibling(); c; c = c.previous_sibling())
  					step_push(ns, c, alloc);
  				
  				break;
  			}
  			
  			case axis_following:
  			{
  				html_node cur = n;
  
  				// exit from this node so that we don't include descendants
  				while (cur && !cur.next_sibling()) cur = cur.parent();
  				cur = cur.next_sibling();
  
  				for (;;)
  				{
  					step_push(ns, cur, alloc);
  
  					if (cur.first_child())
  						cur = cur.first_child();
  					else if (cur.next_sibling())
  						cur = cur.next_sibling();
  					else
  					{
  						while (cur && !cur.next_sibling()) cur = cur.parent();
  						cur = cur.next_sibling();
  
  						if (!cur) break;
  					}
  				}
  
  				break;
  			}
  
  			case axis_preceding:
  			{
  				html_node cur = n;
  
  				while (cur && !cur.previous_sibling()) cur = cur.parent();
  				cur = cur.previous_sibling();
  
  				for (;;)
  				{
  					if (cur.last_child())
  						cur = cur.last_child();
  					else
  					{
  						// leaf node, can't be ancestor
  						step_push(ns, cur, alloc);
  
  						if (cur.previous_sibling())
  							cur = cur.previous_sibling();
  						else
  						{
  							do 
  							{
  								cur = cur.parent();
  								if (!cur) break;
  
  								if (!node_is_ancestor(cur, n)) step_push(ns, cur, alloc);
  							}
  							while (!cur.previous_sibling());
  
  							cur = cur.previous_sibling();
  
  							if (!cur) break;
  						}
  					}
  				}
  
  				break;
  			}
  			
  			case axis_ancestor:
  			case axis_ancestor_or_self:
  			{
  				if (axis == axis_ancestor_or_self)
  					step_push(ns, n, alloc);
  
  				html_node cur = n.parent();
  				
  				while (cur)
  				{
  					step_push(ns, cur, alloc);
  					
  					cur = cur.parent();
  				}
  				
  				break;
  			}
  
  			case axis_self:
  			{
  				step_push(ns, n, alloc);
  
  				break;
  			}
  
  			case axis_parent:
  			{
  				if (n.parent()) step_push(ns, n.parent(), alloc);
  
  				break;
  			}
  				
  			default:
  				assert(!"Unimplemented axis");
  			}
  		}
  		
  		template <class T> void step_fill(xpath_node_set_raw& ns, const html_attribute& a, const html_node& p, xpath_allocator* alloc, T v)
  		{
  			const axis_t axis = T::axis;
  
  			switch (axis)
  			{
  			case axis_ancestor:
  			case axis_ancestor_or_self:
  			{
  				if (axis == axis_ancestor_or_self && _test == nodetest_type_node) // reject attributes based on principal node type test
  					step_push(ns, a, p, alloc);
  
  				html_node cur = p;
  				
  				while (cur)
  				{
  					step_push(ns, cur, alloc);
  					
  					cur = cur.parent();
  				}
  				
  				break;
  			}
  
  			case axis_descendant_or_self:
  			case axis_self:
  			{
  				if (_test == nodetest_type_node) // reject attributes based on principal node type test
  					step_push(ns, a, p, alloc);
  
  				break;
  			}
  
  			case axis_following:
  			{
  				html_node cur = p;
  				
  				for (;;)
  				{
  					if (cur.first_child())
  						cur = cur.first_child();
  					else if (cur.next_sibling())
  						cur = cur.next_sibling();
  					else
  					{
  						while (cur && !cur.next_sibling()) cur = cur.parent();
  						cur = cur.next_sibling();
  						
  						if (!cur) break;
  					}
  
  					step_push(ns, cur, alloc);
  				}
  
  				break;
  			}
  
  			case axis_parent:
  			{
  				step_push(ns, p, alloc);
  
  				break;
  			}
  
  			case axis_preceding:
  			{
  				// preceding:: axis does not include attribute nodes and attribute ancestors (they are the same as parent's ancestors), so we can reuse node preceding
  				step_fill(ns, p, alloc, v);
  				break;
  			}
  			
  			default:
  				assert(!"Unimplemented axis");
  			}
  		}
  		
  		template <class T> xpath_node_set_raw step_do(const xpath_context& c, const xpath_stack& stack, T v)
  		{
  			const axis_t axis = T::axis;
  			bool attributes = (axis == axis_ancestor || axis == axis_ancestor_or_self || axis == axis_descendant_or_self || axis == axis_following || axis == axis_parent || axis == axis_preceding || axis == axis_self);
  
  			xpath_node_set_raw ns;
  			ns.set_type((axis == axis_ancestor || axis == axis_ancestor_or_self || axis == axis_preceding || axis == axis_preceding_sibling) ? xpath_node_set::type_sorted_reverse : xpath_node_set::type_sorted);
  
  			if (_left)
  			{
  				xpath_node_set_raw s = _left->eval_node_set(c, stack);
  
  				// self axis preserves the original order
  				if (axis == axis_self) ns.set_type(s.type());
  
  				for (const xpath_node* it = s.begin(); it != s.end(); ++it)
  				{
  					size_t size = ns.size();
  
  					// in general, all axes generate elements in a particular order, but there is no order guarantee if axis is applied to two nodes
  					if (axis != axis_self && size != 0) ns.set_type(xpath_node_set::type_unsorted);
  					
  					if (it->node())
  						step_fill(ns, it->node(), stack.result, v);
  					else if (attributes)
  						step_fill(ns, it->attribute(), it->parent(), stack.result, v);
  						
  					apply_predicates(ns, size, stack);
  				}
  			}
  			else
  			{
  				if (c.n.node())
  					step_fill(ns, c.n.node(), stack.result, v);
  				else if (attributes)
  					step_fill(ns, c.n.attribute(), c.n.parent(), stack.result, v);
  				
  				apply_predicates(ns, 0, stack);
  			}
  
  			// child, attribute and self axes always generate unique set of nodes
  			// for other axis, if the set stayed sorted, it stayed unique because the traversal algorithms do not visit the same node twice
  			if (axis != axis_child && axis != axis_attribute && axis != axis_self && ns.type() == xpath_node_set::type_unsorted)
  				ns.remove_duplicates();
  
  			return ns;
  		}
  		
  	public:
  		xpath_ast_node(ast_type_t type, xpath_value_type rettype, const char_t* value):
  			_type((char)type), _rettype((char)rettype), _axis(0), _test(0), _left(0), _right(0), _next(0)
  		{
  			assert(type == ast_string_constant);
  			_data.string = value;
  		}
  
  		xpath_ast_node(ast_type_t type, xpath_value_type rettype, double value):
  			_type((char)type), _rettype((char)rettype), _axis(0), _test(0), _left(0), _right(0), _next(0)
  		{
  			assert(type == ast_number_constant);
  			_data.number = value;
  		}
  		
  		xpath_ast_node(ast_type_t type, xpath_value_type rettype, xpath_variable* value):
  			_type((char)type), _rettype((char)rettype), _axis(0), _test(0), _left(0), _right(0), _next(0)
  		{
  			assert(type == ast_variable);
  			_data.variable = value;
  		}
  		
  		xpath_ast_node(ast_type_t type, xpath_value_type rettype, xpath_ast_node* left = 0, xpath_ast_node* right = 0):
  			_type((char)type), _rettype((char)rettype), _axis(0), _test(0), _left(left), _right(right), _next(0)
  		{
  		}
  
  		xpath_ast_node(ast_type_t type, xpath_ast_node* left, axis_t axis, nodetest_t test, const char_t* contents):
  			_type((char)type), _rettype(xpath_type_node_set), _axis((char)axis), _test((char)test), _left(left), _right(0), _next(0)
  		{
  			_data.nodetest = contents;
  		}
  
  		void set_next(xpath_ast_node* value)
  		{
  			_next = value;
  		}
  
  		void set_right(xpath_ast_node* value)
  		{
  			_right = value;
  		}
  
  		bool eval_boolean(const xpath_context& c, const xpath_stack& stack)
  		{
  			switch (_type)
  			{
  			case ast_op_or:
  				return _left->eval_boolean(c, stack) || _right->eval_boolean(c, stack);
  				
  			case ast_op_and:
  				return _left->eval_boolean(c, stack) && _right->eval_boolean(c, stack);
  				
  			case ast_op_equal:
  				return compare_eq(_left, _right, c, stack, equal_to());
  
  			case ast_op_not_equal:
  				return compare_eq(_left, _right, c, stack, not_equal_to());
  	
  			case ast_op_less:
  				return compare_rel(_left, _right, c, stack, less());
  			
  			case ast_op_greater:
  				return compare_rel(_right, _left, c, stack, less());
  
  			case ast_op_less_or_equal:
  				return compare_rel(_left, _right, c, stack, less_equal());
  			
  			case ast_op_greater_or_equal:
  				return compare_rel(_right, _left, c, stack, less_equal());
  
  			case ast_func_starts_with:
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				xpath_string lr = _left->eval_string(c, stack);
  				xpath_string rr = _right->eval_string(c, stack);
  
  				return starts_with(lr.c_str(), rr.c_str());
  			}
  
  			case ast_func_contains:
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				xpath_string lr = _left->eval_string(c, stack);
  				xpath_string rr = _right->eval_string(c, stack);
  
  				return find_substring(lr.c_str(), rr.c_str()) != 0;
  			}
  
  			case ast_func_boolean:
  				return _left->eval_boolean(c, stack);
  				
  			case ast_func_not:
  				return !_left->eval_boolean(c, stack);
  				
  			case ast_func_true:
  				return true;
  				
  			case ast_func_false:
  				return false;
  
  			case ast_func_lang:
  			{
  				if (c.n.attribute()) return false;
  				
  				xpath_allocator_capture cr(stack.result);
  
  				xpath_string lang = _left->eval_string(c, stack);
  				
  				for (html_node n = c.n.node(); n; n = n.parent())
  				{
  					html_attribute a = n.attribute(PUGIHTML_TEXT("html:lang"));
  					
  					if (a)
  					{
  						const char_t* value = a.value();
  						
  						// strnicmp / strncasecmp is not portable
  						for (const char_t* lit = lang.c_str(); *lit; ++lit)
  						{
  							if (tolower_ascii(*lit) != tolower_ascii(*value)) return false;
  							++value;
  						}
  						
  						return *value == 0 || *value == '-';
  					}
  				}
  				
  				return false;
  			}
  
  			case ast_variable:
  			{
  				assert(_rettype == _data.variable->type());
  
  				if (_rettype == xpath_type_boolean)
  					return _data.variable->get_boolean();
  
  				// fallthrough to type conversion
  			}
  
  			default:
  			{
  				switch (_rettype)
  				{
  				case xpath_type_number:
  					return convert_number_to_boolean(eval_number(c, stack));
  					
  				case xpath_type_string:
  				{
  					xpath_allocator_capture cr(stack.result);
  
  					return !eval_string(c, stack).empty();
  				}
  					
  				case xpath_type_node_set:				
  				{
  					xpath_allocator_capture cr(stack.result);
  
  					return !eval_node_set(c, stack).empty();
  				}
  
  				default:
  					assert(!"Wrong expression for return type boolean");
  					return false;
  				}
  			}
  			}
  		}
  
  		double eval_number(const xpath_context& c, const xpath_stack& stack)
  		{
  			switch (_type)
  			{
  			case ast_op_add:
  				return _left->eval_number(c, stack) + _right->eval_number(c, stack);
  				
  			case ast_op_subtract:
  				return _left->eval_number(c, stack) - _right->eval_number(c, stack);
  
  			case ast_op_multiply:
  				return _left->eval_number(c, stack) * _right->eval_number(c, stack);
  
  			case ast_op_divide:
  				return _left->eval_number(c, stack) / _right->eval_number(c, stack);
  
  			case ast_op_mod:
  				return fmod(_left->eval_number(c, stack), _right->eval_number(c, stack));
  
  			case ast_op_negate:
  				return -_left->eval_number(c, stack);
  
  			case ast_number_constant:
  				return _data.number;
  
  			case ast_func_last:
  				return (double)c.size;
  			
  			case ast_func_position:
  				return (double)c.position;
  
  			case ast_func_count:
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				return (double)_left->eval_node_set(c, stack).size();
  			}
  			
  			case ast_func_string_length_0:
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				return (double)string_value(c.n, stack.result).length();
  			}
  			
  			case ast_func_string_length_1:
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				return (double)_left->eval_string(c, stack).length();
  			}
  			
  			case ast_func_number_0:
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				return convert_string_to_number(string_value(c.n, stack.result).c_str());
  			}
  			
  			case ast_func_number_1:
  				return _left->eval_number(c, stack);
  
  			case ast_func_sum:
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				double r = 0;
  				
  				xpath_node_set_raw ns = _left->eval_node_set(c, stack);
  				
  				for (const xpath_node* it = ns.begin(); it != ns.end(); ++it)
  				{
  					xpath_allocator_capture cri(stack.result);
  
  					r += convert_string_to_number(string_value(*it, stack.result).c_str());
  				}
  			
  				return r;
  			}
  
  			case ast_func_floor:
  			{
  				double r = _left->eval_number(c, stack);
  				
  				return r == r ? floor(r) : r;
  			}
  
  			case ast_func_ceiling:
  			{
  				double r = _left->eval_number(c, stack);
  				
  				return r == r ? ceil(r) : r;
  			}
  
  			case ast_func_round:
  				return round_nearest_nzero(_left->eval_number(c, stack));
  			
  			case ast_variable:
  			{
  				assert(_rettype == _data.variable->type());
  
  				if (_rettype == xpath_type_number)
  					return _data.variable->get_number();
  
  				// fallthrough to type conversion
  			}
  
  			default:
  			{
  				switch (_rettype)
  				{
  				case xpath_type_boolean:
  					return eval_boolean(c, stack) ? 1 : 0;
  					
  				case xpath_type_string:
  				{
  					xpath_allocator_capture cr(stack.result);
  
  					return convert_string_to_number(eval_string(c, stack).c_str());
  				}
  					
  				case xpath_type_node_set:
  				{
  					xpath_allocator_capture cr(stack.result);
  
  					return convert_string_to_number(eval_string(c, stack).c_str());
  				}
  					
  				default:
  					assert(!"Wrong expression for return type number");
  					return 0;
  				}
  				
  			}
  			}
  		}
  		
  		xpath_string eval_string_concat(const xpath_context& c, const xpath_stack& stack)
  		{
  			assert(_type == ast_func_concat);
  
  			xpath_allocator_capture ct(stack.temp);
  
  			// count the string number
  			size_t count = 1;
  			for (xpath_ast_node* nc = _right; nc; nc = nc->_next) count++;
  
  			// gather all strings
  			xpath_string static_buffer[4];
  			xpath_string* buffer = static_buffer;
  
  			// allocate on-heap for large concats
  			if (count > sizeof(static_buffer) / sizeof(static_buffer[0]))
  			{
  				buffer = static_cast<xpath_string*>(stack.temp->allocate(count * sizeof(xpath_string)));
  				assert(buffer);
  			}
  
  			// evaluate all strings to temporary stack
  			xpath_stack swapped_stack = {stack.temp, stack.result};
  
  			buffer[0] = _left->eval_string(c, swapped_stack);
  
  			size_t pos = 1;
  			for (xpath_ast_node* n = _right; n; n = n->_next, ++pos) buffer[pos] = n->eval_string(c, swapped_stack);
  			assert(pos == count);
  
  			// get total length
  			size_t length = 0;
  			for (size_t i = 0; i < count; ++i) length += buffer[i].length();
  
  			// create final string
  			char_t* result = static_cast<char_t*>(stack.result->allocate((length + 1) * sizeof(char_t)));
  			assert(result);
  
  			char_t* ri = result;
  
  			for (size_t j = 0; j < count; ++j)
  				for (const char_t* bi = buffer[j].c_str(); *bi; ++bi)
  					*ri++ = *bi;
  
  			*ri = 0;
  
  			return xpath_string(result, true);
  		}
  
  		xpath_string eval_string(const xpath_context& c, const xpath_stack& stack)
  		{
  			switch (_type)
  			{
  			case ast_string_constant:
  				return xpath_string_const(_data.string);
  			
  			case ast_func_local_name_0:
  			{
  				xpath_node na = c.n;
  				
  				return xpath_string_const(local_name(na));
  			}
  
  			case ast_func_local_name_1:
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				xpath_node_set_raw ns = _left->eval_node_set(c, stack);
  				xpath_node na = ns.first();
  				
  				return xpath_string_const(local_name(na));
  			}
  
  			case ast_func_name_0:
  			{
  				xpath_node na = c.n;
  				
  				return xpath_string_const(qualified_name(na));
  			}
  
  			case ast_func_name_1:
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				xpath_node_set_raw ns = _left->eval_node_set(c, stack);
  				xpath_node na = ns.first();
  				
  				return xpath_string_const(qualified_name(na));
  			}
  
  			case ast_func_namespace_uri_0:
  			{
  				xpath_node na = c.n;
  				
  				return xpath_string_const(namespace_uri(na));
  			}
  
  			case ast_func_namespace_uri_1:
  			{
  				xpath_allocator_capture cr(stack.result);
  
  				xpath_node_set_raw ns = _left->eval_node_set(c, stack);
  				xpath_node na = ns.first();
  				
  				return xpath_string_const(namespace_uri(na));
  			}
  
  			case ast_func_string_0:
  				return string_value(c.n, stack.result);
  
  			case ast_func_string_1:
  				return _left->eval_string(c, stack);
  
  			case ast_func_concat:
  				return eval_string_concat(c, stack);
  
  			case ast_func_substring_before:
  			{
  				xpath_allocator_capture cr(stack.temp);
  
  				xpath_stack swapped_stack = {stack.temp, stack.result};
  
  				xpath_string s = _left->eval_string(c, swapped_stack);
  				xpath_string p = _right->eval_string(c, swapped_stack);
  
  				const char_t* pos = find_substring(s.c_str(), p.c_str());
  				
  				return pos ? xpath_string(s.c_str(), pos, stack.result) : xpath_string();
  			}
  			
  			case ast_func_substring_after:
  			{
  				xpath_allocator_capture cr(stack.temp);
  
  				xpath_stack swapped_stack = {stack.temp, stack.result};
  
  				xpath_string s = _left->eval_string(c, swapped_stack);
  				xpath_string p = _right->eval_string(c, swapped_stack);
  				
  				const char_t* pos = find_substring(s.c_str(), p.c_str());
  				if (!pos) return xpath_string();
  
  				const char_t* result = pos + p.length();
  
  				return s.uses_heap() ? xpath_string(result, stack.result) : xpath_string_const(result);
  			}
  
  			case ast_func_substring_2:
  			{
  				xpath_allocator_capture cr(stack.temp);
  
  				xpath_stack swapped_stack = {stack.temp, stack.result};
  
  				xpath_string s = _left->eval_string(c, swapped_stack);
  				size_t s_length = s.length();
  
  				double first = round_nearest(_right->eval_number(c, stack));
  				
  				if (is_nan(first)) return xpath_string(); // NaN
  				else if (first >= s_length + 1) return xpath_string();
  				
  				size_t pos = first < 1 ? 1 : (size_t)first;
  				assert(1 <= pos && pos <= s_length + 1);
  
  				const char_t* rbegin = s.c_str() + (pos - 1);
  				
  				return s.uses_heap() ? xpath_string(rbegin, stack.result) : xpath_string_const(rbegin);
  			}
  			
  			case ast_func_substring_3:
  			{
  				xpath_allocator_capture cr(stack.temp);
  
  				xpath_stack swapped_stack = {stack.temp, stack.result};
  
  				xpath_string s = _left->eval_string(c, swapped_stack);
  				size_t s_length = s.length();
  
  				double first = round_nearest(_right->eval_number(c, stack));
  				double last = first + round_nearest(_right->_next->eval_number(c, stack));
  				
  				if (is_nan(first) || is_nan(last)) return xpath_string();
  				else if (first >= s_length + 1) return xpath_string();
  				else if (first >= last) return xpath_string();
  				else if (last < 1) return xpath_string();
  				
  				size_t pos = first < 1 ? 1 : (size_t)first;
  				size_t end = last >= s_length + 1 ? s_length + 1 : (size_t)last;
  
  				assert(1 <= pos && pos <= end && end <= s_length + 1);
  				const char_t* rbegin = s.c_str() + (pos - 1);
  				const char_t* rend = s.c_str() + (end - 1);
  
  				return (end == s_length + 1 && !s.uses_heap()) ? xpath_string_const(rbegin) : xpath_string(rbegin, rend, stack.result);
  			}
  
  			case ast_func_normalize_space_0:
  			{
  				xpath_string s = string_value(c.n, stack.result);
  
  				normalize_space(s.data(stack.result));
  
  				return s;
  			}
  
  			case ast_func_normalize_space_1:
  			{
  				xpath_string s = _left->eval_string(c, stack);
  
  				normalize_space(s.data(stack.result));
  			
  				return s;
  			}
  
  			case ast_func_translate:
  			{
  				xpath_allocator_capture cr(stack.temp);
  
  				xpath_stack swapped_stack = {stack.temp, stack.result};
  
  				xpath_string s = _left->eval_string(c, stack);
  				xpath_string from = _right->eval_string(c, swapped_stack);
  				xpath_string to = _right->_next->eval_string(c, swapped_stack);
  
  				translate(s.data(stack.result), from.c_str(), to.c_str());
  
  				return s;
  			}
  
  			case ast_variable:
  			{
  				assert(_rettype == _data.variable->type());
  
  				if (_rettype == xpath_type_string)
  					return xpath_string_const(_data.variable->get_string());
  
  				// fallthrough to type conversion
  			}
  
  			default:
  			{
  				switch (_rettype)
  				{
  				case xpath_type_boolean:
  					return xpath_string_const(eval_boolean(c, stack) ? PUGIHTML_TEXT("true") : PUGIHTML_TEXT("false"));
  					
  				case xpath_type_number:
  					return convert_number_to_string(eval_number(c, stack), stack.result);
  					
  				case xpath_type_node_set:
  				{
  					xpath_allocator_capture cr(stack.temp);
  
  					xpath_stack swapped_stack = {stack.temp, stack.result};
  
  					xpath_node_set_raw ns = eval_node_set(c, swapped_stack);
  					return ns.empty() ? xpath_string() : string_value(ns.first(), stack.result);
  				}
  				
  				default:
  					assert(!"Wrong expression for return type string");
  					return xpath_string();
  				}
  			}
  			}
  		}
  
  		xpath_node_set_raw eval_node_set(const xpath_context& c, const xpath_stack& stack)
  		{
  			switch (_type)
  			{
  			case ast_op_union:
  			{
  				xpath_allocator_capture cr(stack.temp);
  
  				xpath_stack swapped_stack = {stack.temp, stack.result};
  
  				xpath_node_set_raw ls = _left->eval_node_set(c, swapped_stack);
  				xpath_node_set_raw rs = _right->eval_node_set(c, stack);
  				
  				// we can optimize merging two sorted sets, but this is a very rare operation, so don't bother
    		        rs.set_type(xpath_node_set::type_unsorted);
  
  				rs.append(ls.begin(), ls.end(), stack.result);
  				rs.remove_duplicates();
  				
  				return rs;
  			}
  
  			case ast_filter:
  			case ast_filter_posinv:
  			{
  				xpath_node_set_raw set = _left->eval_node_set(c, stack);
  
  				// either expression is a number or it contains position() call; sort by document order
  				if (_type == ast_filter) set.sort_do();
  
  				apply_predicate(set, 0, _right, stack);
  			
  				return set;
  			}
  			
  			case ast_func_id:
  				return xpath_node_set_raw();
  			
  			case ast_step:
  			{
  				switch (_axis)
  				{
  				case axis_ancestor:
  					return step_do(c, stack, axis_to_type<axis_ancestor>());
  					
  				case axis_ancestor_or_self:
  					return step_do(c, stack, axis_to_type<axis_ancestor_or_self>());
  
  				case axis_attribute:
  					return step_do(c, stack, axis_to_type<axis_attribute>());
  
  				case axis_child:
  					return step_do(c, stack, axis_to_type<axis_child>());
  				
  				case axis_descendant:
  					return step_do(c, stack, axis_to_type<axis_descendant>());
  
  				case axis_descendant_or_self:
  					return step_do(c, stack, axis_to_type<axis_descendant_or_self>());
  
  				case axis_following:
  					return step_do(c, stack, axis_to_type<axis_following>());
  				
  				case axis_following_sibling:
  					return step_do(c, stack, axis_to_type<axis_following_sibling>());
  				
  				case axis_namespace:
  					// namespaced axis is not supported
  					return xpath_node_set_raw();
  				
  				case axis_parent:
  					return step_do(c, stack, axis_to_type<axis_parent>());
  				
  				case axis_preceding:
  					return step_do(c, stack, axis_to_type<axis_preceding>());
  
  				case axis_preceding_sibling:
  					return step_do(c, stack, axis_to_type<axis_preceding_sibling>());
  				
  				case axis_self:
  					return step_do(c, stack, axis_to_type<axis_self>());
  				}
  			}
  
  			case ast_step_root:
  			{
  				assert(!_right); // root step can't have any predicates
  
  				xpath_node_set_raw ns;
  
  				ns.set_type(xpath_node_set::type_sorted);
  
  				if (c.n.node()) ns.push_back(c.n.node().root(), stack.result);
  				else if (c.n.attribute()) ns.push_back(c.n.parent().root(), stack.result);
  
  				return ns;
  			}
  
  			case ast_variable:
  			{
  				assert(_rettype == _data.variable->type());
  
  				if (_rettype == xpath_type_node_set)
  				{
  					const xpath_node_set& s = _data.variable->get_node_set();
  
  					xpath_node_set_raw ns;
  
  					ns.set_type(s.type());
  					ns.append(s.begin(), s.end(), stack.result);
  
  					return ns;
  				}
  
  				// fallthrough to type conversion
  			}
  
  			default:
  				assert(!"Wrong expression for return type node set");
  				return xpath_node_set_raw();
  			}
  		}
  		
  		bool is_posinv()
  		{
  			switch (_type)
  			{
  			case ast_func_position:
  				return false;
  
  			case ast_string_constant:
  			case ast_number_constant:
  			case ast_variable:
  				return true;
  
  			case ast_step:
  			case ast_step_root:
  				return true;
  
  			case ast_predicate:
  			case ast_filter:
  			case ast_filter_posinv:
  				return true;
  
  			default:
  				if (_left && !_left->is_posinv()) return false;
  				
  				for (xpath_ast_node* n = _right; n; n = n->_next)
  					if (!n->is_posinv()) return false;
  					
  				return true;
  			}
  		}
  
  		xpath_value_type rettype() const
  		{
  			return static_cast<xpath_value_type>(_rettype);
  		}
  	};
  
  	struct xpath_parser
  	{
  	    xpath_allocator* _alloc;
  	    xpath_lexer _lexer;
  
  		const char_t* _query;
  		xpath_variable_set* _variables;
  
  		xpath_parse_result* _result;
  
  	#ifdef PUGIHTML_NO_EXCEPTIONS
  		jmp_buf _error_handler;
  	#endif
  
  		void throw_error(const char* message)
  		{
  			_result->error = message;
  			_result->offset = _lexer.current_pos() - _query;
  
  		#ifdef PUGIHTML_NO_EXCEPTIONS
  			longjmp(_error_handler, 1);
  		#else
  			throw xpath_exception(*_result);
  		#endif
  		}
  
  		void throw_error_oom()
          {
          #ifdef PUGIHTML_NO_EXCEPTIONS
              throw_error("Out of memory");
          #else
              throw std::bad_alloc();
          #endif
          }
  
  		void* alloc_node()
  		{
  			void* result = _alloc->allocate_nothrow(sizeof(xpath_ast_node));
  
  			if (!result) throw_error_oom();
  
  			return result;
  		}
  
  		const char_t* alloc_string(const xpath_lexer_string& value)
  		{
  			if (value.begin)
  			{
  				size_t length = static_cast<size_t>(value.end - value.begin);
  
  				char_t* c = static_cast<char_t*>(_alloc->allocate_nothrow((length + 1) * sizeof(char_t)));
  				if (!c) throw_error_oom();
  
  				memcpy(c, value.begin, length * sizeof(char_t));
  				c[length] = 0;
  
  				return c;
  			}
  			else return 0;
  		}
  
  		xpath_ast_node* parse_function_helper(ast_type_t type0, ast_type_t type1, size_t argc, xpath_ast_node* args[2])
  		{
  			assert(argc <= 1);
  
  			if (argc == 1 && args[0]->rettype() != xpath_type_node_set) throw_error("Function has to be applied to node set");
  
  			return new (alloc_node()) xpath_ast_node(argc == 0 ? type0 : type1, xpath_type_string, args[0]);
  		}
  
  		xpath_ast_node* parse_function(const xpath_lexer_string& name, size_t argc, xpath_ast_node* args[2])
  		{
  			switch (name.begin[0])
  			{
  			case 'b':
  				if (name == PUGIHTML_TEXT("boolean") && argc == 1)
  					return new (alloc_node()) xpath_ast_node(ast_func_boolean, xpath_type_boolean, args[0]);
  					
  				break;
  			
  			case 'c':
  				if (name == PUGIHTML_TEXT("count") && argc == 1)
  				{
  					if (args[0]->rettype() != xpath_type_node_set) throw_error("Function has to be applied to node set");
  					return new (alloc_node()) xpath_ast_node(ast_func_count, xpath_type_number, args[0]);
  				}
  				else if (name == PUGIHTML_TEXT("contains") && argc == 2)
  					return new (alloc_node()) xpath_ast_node(ast_func_contains, xpath_type_string, args[0], args[1]);
  				else if (name == PUGIHTML_TEXT("concat") && argc >= 2)
  					return new (alloc_node()) xpath_ast_node(ast_func_concat, xpath_type_string, args[0], args[1]);
  				else if (name == PUGIHTML_TEXT("ceiling") && argc == 1)
  					return new (alloc_node()) xpath_ast_node(ast_func_ceiling, xpath_type_number, args[0]);
  					
  				break;
  			
  			case 'f':
  				if (name == PUGIHTML_TEXT("false") && argc == 0)
  					return new (alloc_node()) xpath_ast_node(ast_func_false, xpath_type_boolean);
  				else if (name == PUGIHTML_TEXT("floor") && argc == 1)
  					return new (alloc_node()) xpath_ast_node(ast_func_floor, xpath_type_number, args[0]);
  					
  				break;
  			
  			case 'i':
  				if (name == PUGIHTML_TEXT("id") && argc == 1)
  					return new (alloc_node()) xpath_ast_node(ast_func_id, xpath_type_node_set, args[0]);
  					
  				break;
  			
  			case 'l':
  				if (name == PUGIHTML_TEXT("last") && argc == 0)
  					return new (alloc_node()) xpath_ast_node(ast_func_last, xpath_type_number);
  				else if (name == PUGIHTML_TEXT("lang") && argc == 1)
  					return new (alloc_node()) xpath_ast_node(ast_func_lang, xpath_type_boolean, args[0]);
  				else if (name == PUGIHTML_TEXT("local-name") && argc <= 1)
  					return parse_function_helper(ast_func_local_name_0, ast_func_local_name_1, argc, args);
  			
  				break;
  			
  			case 'n':
  				if (name == PUGIHTML_TEXT("name") && argc <= 1)
  					return parse_function_helper(ast_func_name_0, ast_func_name_1, argc, args);
  				else if (name == PUGIHTML_TEXT("namespace-uri") && argc <= 1)
  					return parse_function_helper(ast_func_namespace_uri_0, ast_func_namespace_uri_1, argc, args);
  				else if (name == PUGIHTML_TEXT("normalize-space") && argc <= 1)
  					return new (alloc_node()) xpath_ast_node(argc == 0 ? ast_func_normalize_space_0 : ast_func_normalize_space_1, xpath_type_string, args[0], args[1]);
  				else if (name == PUGIHTML_TEXT("not") && argc == 1)
  					return new (alloc_node()) xpath_ast_node(ast_func_not, xpath_type_boolean, args[0]);
  				else if (name == PUGIHTML_TEXT("number") && argc <= 1)
  					return new (alloc_node()) xpath_ast_node(argc == 0 ? ast_func_number_0 : ast_func_number_1, xpath_type_number, args[0]);
  			
  				break;
  			
  			case 'p':
  				if (name == PUGIHTML_TEXT("position") && argc == 0)
  					return new (alloc_node()) xpath_ast_node(ast_func_position, xpath_type_number);
  				
  				break;
  			
  			case 'r':
  				if (name == PUGIHTML_TEXT("round") && argc == 1)
  					return new (alloc_node()) xpath_ast_node(ast_func_round, xpath_type_number, args[0]);
  
  				break;
  			
  			case 's':
  				if (name == PUGIHTML_TEXT("string") && argc <= 1)
  					return new (alloc_node()) xpath_ast_node(argc == 0 ? ast_func_string_0 : ast_func_string_1, xpath_type_string, args[0]);
  				else if (name == PUGIHTML_TEXT("string-length") && argc <= 1)
  					return new (alloc_node()) xpath_ast_node(argc == 0 ? ast_func_string_length_0 : ast_func_string_length_1, xpath_type_string, args[0]);
  				else if (name == PUGIHTML_TEXT("starts-with") && argc == 2)
  					return new (alloc_node()) xpath_ast_node(ast_func_starts_with, xpath_type_boolean, args[0], args[1]);
  				else if (name == PUGIHTML_TEXT("substring-before") && argc == 2)
  					return new (alloc_node()) xpath_ast_node(ast_func_substring_before, xpath_type_string, args[0], args[1]);
  				else if (name == PUGIHTML_TEXT("substring-after") && argc == 2)
  					return new (alloc_node()) xpath_ast_node(ast_func_substring_after, xpath_type_string, args[0], args[1]);
  				else if (name == PUGIHTML_TEXT("substring") && (argc == 2 || argc == 3))
  					return new (alloc_node()) xpath_ast_node(argc == 2 ? ast_func_substring_2 : ast_func_substring_3, xpath_type_string, args[0], args[1]);
  				else if (name == PUGIHTML_TEXT("sum") && argc == 1)
  				{
  					if (args[0]->rettype() != xpath_type_node_set) throw_error("Function has to be applied to node set");
  					return new (alloc_node()) xpath_ast_node(ast_func_sum, xpath_type_number, args[0]);
  				}
  
  				break;
  			
  			case 't':
  				if (name == PUGIHTML_TEXT("translate") && argc == 3)
  					return new (alloc_node()) xpath_ast_node(ast_func_translate, xpath_type_string, args[0], args[1]);
  				else if (name == PUGIHTML_TEXT("true") && argc == 0)
  					return new (alloc_node()) xpath_ast_node(ast_func_true, xpath_type_boolean);
  					
  				break;
  			}
  
  			throw_error("Unrecognized function or wrong parameter count");
  
  			return 0;
  		}
  
  		axis_t parse_axis_name(const xpath_lexer_string& name, bool& specified)
  		{
  			specified = true;
  
  			switch (name.begin[0])
  			{
  			case 'a':
  				if (name == PUGIHTML_TEXT("ancestor"))
  					return axis_ancestor;
  				else if (name == PUGIHTML_TEXT("ancestor-or-self"))
  					return axis_ancestor_or_self;
  				else if (name == PUGIHTML_TEXT("attribute"))
  					return axis_attribute;
  				
  				break;
  			
  			case 'c':
  				if (name == PUGIHTML_TEXT("child"))
  					return axis_child;
  				
  				break;
  			
  			case 'd':
  				if (name == PUGIHTML_TEXT("descendant"))
  					return axis_descendant;
  				else if (name == PUGIHTML_TEXT("descendant-or-self"))
  					return axis_descendant_or_self;
  				
  				break;
  			
  			case 'f':
  				if (name == PUGIHTML_TEXT("following"))
  					return axis_following;
  				else if (name == PUGIHTML_TEXT("following-sibling"))
  					return axis_following_sibling;
  				
  				break;
  			
  			case 'n':
  				if (name == PUGIHTML_TEXT("namespace"))
  					return axis_namespace;
  				
  				break;
  			
  			case 'p':
  				if (name == PUGIHTML_TEXT("parent"))
  					return axis_parent;
  				else if (name == PUGIHTML_TEXT("preceding"))
  					return axis_preceding;
  				else if (name == PUGIHTML_TEXT("preceding-sibling"))
  					return axis_preceding_sibling;
  				
  				break;
  			
  			case 's':
  				if (name == PUGIHTML_TEXT("self"))
  					return axis_self;
  				
  				break;
  			}
  
  			specified = false;
  			return axis_child;
  		}
  
  		nodetest_t parse_node_test_type(const xpath_lexer_string& name)
  		{
  			switch (name.begin[0])
  			{
  			case 'c':
  				if (name == PUGIHTML_TEXT("comment"))
  					return nodetest_type_comment;
  
  				break;
  
  			case 'n':
  				if (name == PUGIHTML_TEXT("node"))
  					return nodetest_type_node;
  
  				break;
  
  			case 'p':
  				if (name == PUGIHTML_TEXT("processing-instruction"))
  					return nodetest_type_pi;
  
  				break;
  
  			case 't':
  				if (name == PUGIHTML_TEXT("text"))
  					return nodetest_type_text;
  
  				break;
  			}
  
  			return nodetest_none;
  		}
  
  	    // PrimaryExpr ::= VariableReference | '(' Expr ')' | Literal | Number | FunctionCall
  	    xpath_ast_node* parse_primary_expression()
  	    {
  	    	switch (_lexer.current())
  	    	{
  	    	case lex_var_ref:
  	    	{
  				xpath_lexer_string name = _lexer.contents();
  
  				if (!_variables)
  					throw_error("Unknown variable: variable set is not provided");
  
  				xpath_variable* var = get_variable(_variables, name.begin, name.end);
  
  				if (!var)
  					throw_error("Unknown variable: variable set does not contain the given name");
  
  				_lexer.next();
  
  	    		return new (alloc_node()) xpath_ast_node(ast_variable, var->type(), var);
  			}
  
  			case lex_open_brace:
  			{
  				_lexer.next();
  
  				xpath_ast_node* n = parse_expression();
  
  				if (_lexer.current() != lex_close_brace)
  					throw_error("Unmatched braces");
  
  				_lexer.next();
  
  				return n;
  			}
  
  			case lex_quoted_string:
  			{
  				const char_t* value = alloc_string(_lexer.contents());
  
  				xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_string_constant, xpath_type_string, value);
  				_lexer.next();
  
  				return n;
  			}
  
  			case lex_number:
  			{
  				double value = 0;
  
  				if (!convert_string_to_number(_lexer.contents().begin, _lexer.contents().end, &value))
  					throw_error_oom();
  
  				xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_number_constant, xpath_type_number, value);
  				_lexer.next();
  
  				return n;
  			}
  
  			case lex_string:
  			{
  				xpath_ast_node* args[2] = {0};
  				size_t argc = 0;
  				
  				xpath_lexer_string function = _lexer.contents();
  				_lexer.next();
  				
  				xpath_ast_node* last_arg = 0;
  				
  				if (_lexer.current() != lex_open_brace)
  					throw_error("Unrecognized function call");
  				_lexer.next();
  
  				if (_lexer.current() != lex_close_brace)
  					args[argc++] = parse_expression();
  
  				while (_lexer.current() != lex_close_brace)
  				{
  					if (_lexer.current() != lex_comma)
  						throw_error("No comma between function arguments");
  					_lexer.next();
  					
  					xpath_ast_node* n = parse_expression();
  					
  					if (argc < 2) args[argc] = n;
  					else last_arg->set_next(n);
  
  					argc++;
  					last_arg = n;
  				}
  				
  				_lexer.next();
  
  				return parse_function(function, argc, args);
  			}
  
  	    	default:
  	    		throw_error("Unrecognizable primary expression");
  
  	    		return 0;
  	    	}
  	    }
  	    
  	    // FilterExpr ::= PrimaryExpr | FilterExpr Predicate
  	    // Predicate ::= '[' PredicateExpr ']'
  	    // PredicateExpr ::= Expr
  	    xpath_ast_node* parse_filter_expression()
  	    {
  	    	xpath_ast_node* n = parse_primary_expression();
  
  	    	while (_lexer.current() == lex_open_square_brace)
  	    	{
  	    		_lexer.next();
  
  				xpath_ast_node* expr = parse_expression();
  
  				if (n->rettype() != xpath_type_node_set) throw_error("Predicate has to be applied to node set");
  
  				bool posinv = expr->rettype() != xpath_type_number && expr->is_posinv();
  
  	    		n = new (alloc_node()) xpath_ast_node(posinv ? ast_filter_posinv : ast_filter, xpath_type_node_set, n, expr);
  
  	    		if (_lexer.current() != lex_close_square_brace)
  	    			throw_error("Unmatched square brace");
  	    	
  	    		_lexer.next();
  	    	}
  	    	
  	    	return n;
  	    }
  	    
  	    // Step ::= AxisSpecifier NodeTest Predicate* | AbbreviatedStep
  	    // AxisSpecifier ::= AxisName '::' | '@'?
  	    // NodeTest ::= NameTest | NodeType '(' ')' | 'processing-instruction' '(' Literal ')'
  	    // NameTest ::= '*' | NCName ':' '*' | QName
  	    // AbbreviatedStep ::= '.' | '..'
  	    xpath_ast_node* parse_step(xpath_ast_node* set)
  	    {
  			if (set && set->rettype() != xpath_type_node_set)
  				throw_error("Step has to be applied to node set");
  
  			bool axis_specified = false;
  			axis_t axis = axis_child; // implied child axis
  
  			if (_lexer.current() == lex_axis_attribute)
  			{
  				axis = axis_attribute;
  				axis_specified = true;
  				
  				_lexer.next();
  			}
  			else if (_lexer.current() == lex_dot)
  			{
  				_lexer.next();
  				
  				return new (alloc_node()) xpath_ast_node(ast_step, set, axis_self, nodetest_type_node, 0);
  			}
  			else if (_lexer.current() == lex_double_dot)
  			{
  				_lexer.next();
  				
  				return new (alloc_node()) xpath_ast_node(ast_step, set, axis_parent, nodetest_type_node, 0);
  			}
  	    
  			nodetest_t nt_type = nodetest_none;
  			xpath_lexer_string nt_name;
  			
  			if (_lexer.current() == lex_string)
  			{
  				// node name test
  				nt_name = _lexer.contents();
  				_lexer.next();
  
  				// was it an axis name?
  				if (_lexer.current() == lex_double_colon)
  				{
  					// parse axis name
  					if (axis_specified) throw_error("Two axis specifiers in one step");
  
  					axis = parse_axis_name(nt_name, axis_specified);
  
  					if (!axis_specified) throw_error("Unknown axis");
  
  					// read actual node test
  					_lexer.next();
  
  					if (_lexer.current() == lex_multiply)
  					{
  						nt_type = nodetest_all;
  						nt_name = xpath_lexer_string();
  						_lexer.next();
  					}
  					else if (_lexer.current() == lex_string)
  					{
  						nt_name = _lexer.contents();
  						_lexer.next();
  					}
  					else throw_error("Unrecognized node test");
  				}
  				
  				if (nt_type == nodetest_none)
  				{
  					// node type test or processing-instruction
  					if (_lexer.current() == lex_open_brace)
  					{
  						_lexer.next();
  						
  						if (_lexer.current() == lex_close_brace)
  						{
  							_lexer.next();
  
  							nt_type = parse_node_test_type(nt_name);
  
  							if (nt_type == nodetest_none) throw_error("Unrecognized node type");
  							
  							nt_name = xpath_lexer_string();
  						}
  						else if (nt_name == PUGIHTML_TEXT("processing-instruction"))
  						{
  							if (_lexer.current() != lex_quoted_string)
  								throw_error("Only literals are allowed as arguments to processing-instruction()");
  						
  							nt_type = nodetest_pi;
  							nt_name = _lexer.contents();
  							_lexer.next();
  							
  							if (_lexer.current() != lex_close_brace)
  								throw_error("Unmatched brace near processing-instruction()");
  							_lexer.next();
  						}
  						else
  							throw_error("Unmatched brace near node type test");
  
  					}
  					// QName or NCName:*
  					else
  					{
  						if (nt_name.end - nt_name.begin > 2 && nt_name.end[-2] == ':' && nt_name.end[-1] == '*') // NCName:*
  						{
  							nt_name.end--; // erase *
  							
  							nt_type = nodetest_all_in_namespace;
  						}
  						else nt_type = nodetest_name;
  					}
  				}
  			}
  			else if (_lexer.current() == lex_multiply)
  			{
  				nt_type = nodetest_all;
  				_lexer.next();
  			}
  			else throw_error("Unrecognized node test");
  			
  			xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_step, set, axis, nt_type, alloc_string(nt_name));
  			
  			xpath_ast_node* last = 0;
  			
  			while (_lexer.current() == lex_open_square_brace)
  			{
  				_lexer.next();
  				
  				xpath_ast_node* expr = parse_expression();
  
  				xpath_ast_node* pred = new (alloc_node()) xpath_ast_node(ast_predicate, xpath_type_node_set, expr);
  				
  				if (_lexer.current() != lex_close_square_brace)
  	    			throw_error("Unmatched square brace");
  				_lexer.next();
  				
  				if (last) last->set_next(pred);
  				else n->set_right(pred);
  				
  				last = pred;
  			}
  			
  			return n;
  	    }
  	    
  	    // RelativeLocationPath ::= Step | RelativeLocationPath '/' Step | RelativeLocationPath '//' Step
  	    xpath_ast_node* parse_relative_location_path(xpath_ast_node* set)
  	    {
  			xpath_ast_node* n = parse_step(set);
  			
  			while (_lexer.current() == lex_slash || _lexer.current() == lex_double_slash)
  			{
  				lexeme_t l = _lexer.current();
  				_lexer.next();
  
  				if (l == lex_double_slash)
  					n = new (alloc_node()) xpath_ast_node(ast_step, n, axis_descendant_or_self, nodetest_type_node, 0);
  				
  				n = parse_step(n);
  			}
  			
  			return n;
  	    }
  	    
  	    // LocationPath ::= RelativeLocationPath | AbsoluteLocationPath
  	    // AbsoluteLocationPath ::= '/' RelativeLocationPath? | '//' RelativeLocationPath
  	    xpath_ast_node* parse_location_path()
  	    {
  			if (_lexer.current() == lex_slash)
  			{
  				_lexer.next();
  				
  				xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_step_root, xpath_type_node_set);
  
  				// relative location path can start from axis_attribute, dot, double_dot, multiply and string lexemes; any other lexeme means standalone root path
  				lexeme_t l = _lexer.current();
  
  				if (l == lex_string || l == lex_axis_attribute || l == lex_dot || l == lex_double_dot || l == lex_multiply)
  					return parse_relative_location_path(n);
  				else
  					return n;
  			}
  			else if (_lexer.current() == lex_double_slash)
  			{
  				_lexer.next();
  				
  				xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_step_root, xpath_type_node_set);
  				n = new (alloc_node()) xpath_ast_node(ast_step, n, axis_descendant_or_self, nodetest_type_node, 0);
  				
  				return parse_relative_location_path(n);
  			}
  
  			// else clause moved outside of if because of bogus warning 'control may reach end of non-void function being inlined' in gcc 4.0.1
  			return parse_relative_location_path(0);
  	    }
  	    
  	    // PathExpr ::= LocationPath
  	    //				| FilterExpr
  	    //				| FilterExpr '/' RelativeLocationPath
  	    //				| FilterExpr '//' RelativeLocationPath
  	    xpath_ast_node* parse_path_expression()
  	    {
  			// Clarification.
  			// PathExpr begins with either LocationPath or FilterExpr.
  			// FilterExpr begins with PrimaryExpr
  			// PrimaryExpr begins with '$' in case of it being a variable reference,
  			// '(' in case of it being an expression, string literal, number constant or
  			// function call.
  
  			if (_lexer.current() == lex_var_ref || _lexer.current() == lex_open_brace || 
  				_lexer.current() == lex_quoted_string || _lexer.current() == lex_number ||
  				_lexer.current() == lex_string)
  	    	{
  	    		if (_lexer.current() == lex_string)
  	    		{
  	    			// This is either a function call, or not - if not, we shall proceed with location path
  	    			const char_t* state = _lexer.state();
  	    			
  					while (IS_CHARTYPE(*state, ct_space)) ++state;
  	    			
  	    			if (*state != '(') return parse_location_path();
  
  					// This looks like a function call; however this still can be a node-test. Check it.
  					if (parse_node_test_type(_lexer.contents()) != nodetest_none) return parse_location_path();
  	    		}
  	    		
  	    		xpath_ast_node* n = parse_filter_expression();
  
  	    		if (_lexer.current() == lex_slash || _lexer.current() == lex_double_slash)
  	    		{
  					lexeme_t l = _lexer.current();
  	    			_lexer.next();
  	    			
  					if (l == lex_double_slash)
  					{
  						if (n->rettype() != xpath_type_node_set) throw_error("Step has to be applied to node set");
  
  						n = new (alloc_node()) xpath_ast_node(ast_step, n, axis_descendant_or_self, nodetest_type_node, 0);
  					}
  	
  	    			// select from location path
  	    			return parse_relative_location_path(n);
  	    		}
  
  	    		return n;
  	    	}
  	    	else return parse_location_path();
  	    }
  
  	    // UnionExpr ::= PathExpr | UnionExpr '|' PathExpr
  	    xpath_ast_node* parse_union_expression()
  	    {
  	    	xpath_ast_node* n = parse_path_expression();
  
  	    	while (_lexer.current() == lex_union)
  	    	{
  	    		_lexer.next();
  
  				xpath_ast_node* expr = parse_union_expression();
  
  				if (n->rettype() != xpath_type_node_set || expr->rettype() != xpath_type_node_set)
  					throw_error("Union operator has to be applied to node sets");
  
  	    		n = new (alloc_node()) xpath_ast_node(ast_op_union, xpath_type_node_set, n, expr);
  	    	}
  
  	    	return n;
  	    }
  
  	    // UnaryExpr ::= UnionExpr | '-' UnaryExpr
  	    xpath_ast_node* parse_unary_expression()
  	    {
  	    	if (_lexer.current() == lex_minus)
  	    	{
  	    		_lexer.next();
  
  				xpath_ast_node* expr = parse_unary_expression();
  
  	    		return new (alloc_node()) xpath_ast_node(ast_op_negate, xpath_type_number, expr);
  	    	}
  	    	else return parse_union_expression();
  	    }
  	    
  	    // MultiplicativeExpr ::= UnaryExpr
  	    //						  | MultiplicativeExpr '*' UnaryExpr
  	    //						  | MultiplicativeExpr 'div' UnaryExpr
  	    //						  | MultiplicativeExpr 'mod' UnaryExpr
  	    xpath_ast_node* parse_multiplicative_expression()
  	    {
  	    	xpath_ast_node* n = parse_unary_expression();
  
  	    	while (_lexer.current() == lex_multiply || (_lexer.current() == lex_string &&
  	    		   (_lexer.contents() == PUGIHTML_TEXT("mod") || _lexer.contents() == PUGIHTML_TEXT("div"))))
  	    	{
  	    		ast_type_t op = _lexer.current() == lex_multiply ? ast_op_multiply :
  	    			_lexer.contents().begin[0] == 'd' ? ast_op_divide : ast_op_mod;
  	    		_lexer.next();
  
  				xpath_ast_node* expr = parse_unary_expression();
  
  	    		n = new (alloc_node()) xpath_ast_node(op, xpath_type_number, n, expr);
  	    	}
  
  	    	return n;
  	    }
  
  	    // AdditiveExpr ::= MultiplicativeExpr
  	    //					| AdditiveExpr '+' MultiplicativeExpr
  	    //					| AdditiveExpr '-' MultiplicativeExpr
  	    xpath_ast_node* parse_additive_expression()
  	    {
  	    	xpath_ast_node* n = parse_multiplicative_expression();
  
  	    	while (_lexer.current() == lex_plus || _lexer.current() == lex_minus)
  	    	{
  	    		lexeme_t l = _lexer.current();
  
  	    		_lexer.next();
  
  				xpath_ast_node* expr = parse_multiplicative_expression();
  
  	    		n = new (alloc_node()) xpath_ast_node(l == lex_plus ? ast_op_add : ast_op_subtract, xpath_type_number, n, expr);
  	    	}
  
  	    	return n;
  	    }
  
  	    // RelationalExpr ::= AdditiveExpr
  	    //					  | RelationalExpr '<' AdditiveExpr
  	    //					  | RelationalExpr '>' AdditiveExpr
  	    //					  | RelationalExpr '<=' AdditiveExpr
  	    //					  | RelationalExpr '>=' AdditiveExpr
  	    xpath_ast_node* parse_relational_expression()
  	    {
  	    	xpath_ast_node* n = parse_additive_expression();
  
  	    	while (_lexer.current() == lex_less || _lexer.current() == lex_less_or_equal || 
  	    		   _lexer.current() == lex_greater || _lexer.current() == lex_greater_or_equal)
  	    	{
  	    		lexeme_t l = _lexer.current();
  	    		_lexer.next();
  
  				xpath_ast_node* expr = parse_additive_expression();
  
  	    		n = new (alloc_node()) xpath_ast_node(l == lex_less ? ast_op_less : l == lex_greater ? ast_op_greater :
  	    						l == lex_less_or_equal ? ast_op_less_or_equal : ast_op_greater_or_equal, xpath_type_boolean, n, expr);
  	    	}
  
  	    	return n;
  	    }
  	    
  	    // EqualityExpr ::= RelationalExpr
  	    //					| EqualityExpr '=' RelationalExpr
  	    //					| EqualityExpr '!=' RelationalExpr
  	    xpath_ast_node* parse_equality_expression()
  	    {
  	    	xpath_ast_node* n = parse_relational_expression();
  
  	    	while (_lexer.current() == lex_equal || _lexer.current() == lex_not_equal)
  	    	{
  	    		lexeme_t l = _lexer.current();
  
  	    		_lexer.next();
  
  				xpath_ast_node* expr = parse_relational_expression();
  
  	    		n = new (alloc_node()) xpath_ast_node(l == lex_equal ? ast_op_equal : ast_op_not_equal, xpath_type_boolean, n, expr);
  	    	}
  
  	    	return n;
  	    }
  	    
  	    // AndExpr ::= EqualityExpr | AndExpr 'and' EqualityExpr
  	    xpath_ast_node* parse_and_expression()
  	    {
  	    	xpath_ast_node* n = parse_equality_expression();
  
  	    	while (_lexer.current() == lex_string && _lexer.contents() == PUGIHTML_TEXT("and"))
  	    	{
  	    		_lexer.next();
  
  				xpath_ast_node* expr = parse_equality_expression();
  
  	    		n = new (alloc_node()) xpath_ast_node(ast_op_and, xpath_type_boolean, n, expr);
  	    	}
  
  	    	return n;
  	    }
  
  	    // OrExpr ::= AndExpr | OrExpr 'or' AndExpr
  	    xpath_ast_node* parse_or_expression()
  	    {
  	    	xpath_ast_node* n = parse_and_expression();
  
  	    	while (_lexer.current() == lex_string && _lexer.contents() == PUGIHTML_TEXT("or"))
  	    	{
  	    		_lexer.next();
  
  				xpath_ast_node* expr = parse_and_expression();
  
  	    		n = new (alloc_node()) xpath_ast_node(ast_op_or, xpath_type_boolean, n, expr);
  	    	}
  
  	    	return n;
  	    }
  		
  		// Expr ::= OrExpr
  		xpath_ast_node* parse_expression()
  		{
  			return parse_or_expression();
  		}
  
  		xpath_parser(const char_t* query, xpath_variable_set* variables, xpath_allocator* alloc, xpath_parse_result* result): _alloc(alloc), _lexer(query), _query(query), _variables(variables), _result(result)
  		{
  		}
  
  		xpath_ast_node* parse()
  		{
  			xpath_ast_node* result = parse_expression();
  			
  			if (_lexer.current() != lex_eof)
  			{
  				// there are still unparsed tokens left, error
  				throw_error("Incorrect query");
  			}
  			
  			return result;
  		}
  
  		static xpath_ast_node* parse(const char_t* query, xpath_variable_set* variables, xpath_allocator* alloc, xpath_parse_result* result)
  		{
  			xpath_parser parser(query, variables, alloc, result);
  
  		#ifdef PUGIHTML_NO_EXCEPTIONS
  			int error = setjmp(parser._error_handler);
  
  			return (error == 0) ? parser.parse() : 0;
  		#else
  			return parser.parse();
  		#endif
  		}
  	};
  
      struct xpath_query_impl
      {
  		static xpath_query_impl* create()
  		{
  			void* memory = global_allocate(sizeof(xpath_query_impl));
  
              return new (memory) xpath_query_impl();
  		}
  
  		static void destroy(void* ptr)
  		{
  			if (!ptr) return;
  			
  			// free all allocated pages
  			static_cast<xpath_query_impl*>(ptr)->alloc.release();
  
  			// free allocator memory (with the first page)
  			global_deallocate(ptr);
  		}
  
          xpath_query_impl(): root(0), alloc(&block)
          {
              block.next = 0;
          }
  
          xpath_ast_node* root;
          xpath_allocator alloc;
          xpath_memory_block block;
      };
  
  	xpath_string evaluate_string_impl(xpath_query_impl* impl, const xpath_node& n, xpath_stack_data& sd)
  	{
  		if (!impl) return xpath_string();
  
  	#ifdef PUGIHTML_NO_EXCEPTIONS
  		if (setjmp(sd.error_handler)) return xpath_string();
  	#endif
  
  		xpath_context c(n, 1, 1);
  
  		return impl->root->eval_string(c, sd.stack);
  	}
  }
  
  namespace pugihtml
  {
  #ifndef PUGIHTML_NO_EXCEPTIONS
  	xpath_exception::xpath_exception(const xpath_parse_result& result): _result(result)
  	{
  		assert(result.error);
  	}
  	
  	const char* xpath_exception::what() const throw()
  	{
  		return _result.error;
  	}
  
  	const xpath_parse_result& xpath_exception::result() const
  	{
  		return _result;
  	}
  #endif
  	
  	xpath_node::xpath_node()
  	{
  	}
  		
  	xpath_node::xpath_node(const html_node& node): _node(node)
  	{
  	}
  		
  	xpath_node::xpath_node(const html_attribute& attribute, const html_node& parent): _node(attribute ? parent : html_node()), _attribute(attribute)
  	{
  	}
  
  	html_node xpath_node::node() const
  	{
  		return _attribute ? html_node() : _node;
  	}
  		
  	html_attribute xpath_node::attribute() const
  	{
  		return _attribute;
  	}
  	
  	html_node xpath_node::parent() const
  	{
  		return _attribute ? _node : _node.parent();
  	}
  
  	xpath_node::operator xpath_node::unspecified_bool_type() const
  	{
  		return (_node || _attribute) ? &xpath_node::_node : 0;
  	}
  	
  	bool xpath_node::operator!() const
  	{
  		return !(_node || _attribute);
  	}
  
  	bool xpath_node::operator==(const xpath_node& n) const
  	{
  		return _node == n._node && _attribute == n._attribute;
  	}
  	
  	bool xpath_node::operator!=(const xpath_node& n) const
  	{
  		return _node != n._node || _attribute != n._attribute;
  	}
  
  #ifdef __BORLANDC__
  	bool operator&&(const xpath_node& lhs, bool rhs)
  	{
  		return (bool)lhs && rhs;
  	}
  
  	bool operator||(const xpath_node& lhs, bool rhs)
  	{
  		return (bool)lhs || rhs;
  	}
  #endif
  
  	void xpath_node_set::_assign(const_iterator begin, const_iterator end)
  	{
  		assert(begin <= end);
  
  		size_t size = static_cast<size_t>(end - begin);
  
  		if (size <= 1)
  		{
  			// deallocate old buffer
  			if (_begin != &_storage) global_deallocate(_begin);
  
  			// use internal buffer
  			if (begin != end) _storage = *begin;
  
  			_begin = &_storage;
  			_end = &_storage + size;
  		}
  		else
  		{
  			// make heap copy
  			xpath_node* storage = static_cast<xpath_node*>(global_allocate(size * sizeof(xpath_node)));
  
  			if (!storage)
  			{
  			#ifdef PUGIHTML_NO_EXCEPTIONS
  				return;
  			#else
  				throw std::bad_alloc();
  			#endif
  			}
  
  			memcpy(storage, begin, size * sizeof(xpath_node));
  			
  			// deallocate old buffer
  			if (_begin != &_storage) global_deallocate(_begin);
  
  			// finalize
  			_begin = storage;
  			_end = storage + size;
  		}
  	}
  
  	xpath_node_set::xpath_node_set(): _type(type_unsorted), _begin(&_storage), _end(&_storage)
  	{
  	}
  
  	xpath_node_set::xpath_node_set(const_iterator begin, const_iterator end, type_t type): _type(type), _begin(&_storage), _end(&_storage)
  	{
  		_assign(begin, end);
  	}
  
  	xpath_node_set::~xpath_node_set()
  	{
  		if (_begin != &_storage) global_deallocate(_begin);
  	}
  		
  	xpath_node_set::xpath_node_set(const xpath_node_set& ns): _type(ns._type), _begin(&_storage), _end(&_storage)
  	{
  		_assign(ns._begin, ns._end);
  	}
  	
  	xpath_node_set& xpath_node_set::operator=(const xpath_node_set& ns)
  	{
  		if (this == &ns) return *this;
  		
  		_type = ns._type;
  		_assign(ns._begin, ns._end);
  
  		return *this;
  	}
  
  	xpath_node_set::type_t xpath_node_set::type() const
  	{
  		return _type;
  	}
  		
  	size_t xpath_node_set::size() const
  	{
  		return _end - _begin;
  	}
  		
  	bool xpath_node_set::empty() const
  	{
  		return _begin == _end;
  	}
  		
  	const xpath_node& xpath_node_set::operator[](size_t index) const
  	{
  		assert(index < size());
  		return _begin[index];
  	}
  
  	xpath_node_set::const_iterator xpath_node_set::begin() const
  	{
  		return _begin;
  	}
  		
  	xpath_node_set::const_iterator xpath_node_set::end() const
  	{
  		return _end;
  	}
  	
  	void xpath_node_set::sort(bool reverse)
  	{
  		_type = xpath_sort(_begin, _end, _type, reverse);
  	}
  
  	xpath_node xpath_node_set::first() const
  	{
  		return xpath_first(_begin, _end, _type);
  	}
  
      xpath_parse_result::xpath_parse_result(): error("Internal error"), offset(0)
      {
      }
  
      xpath_parse_result::operator bool() const
      {
          return error == 0;
      }
  	const char* xpath_parse_result::description() const
  	{
  		return error ? error : "No error";
  	}
  
  	xpath_variable::xpath_variable()
      {
      }
  
  	const char_t* xpath_variable::name() const
  	{
  		switch (_type)
  		{
  		case xpath_type_node_set:
  			return static_cast<const xpath_variable_node_set*>(this)->name;
  
  		case xpath_type_number:
  			return static_cast<const xpath_variable_number*>(this)->name;
  
  		case xpath_type_string:
  			return static_cast<const xpath_variable_string*>(this)->name;
  
  		case xpath_type_boolean:
  			return static_cast<const xpath_variable_boolean*>(this)->name;
  
  		default:
  			assert(!"Invalid variable type");
  			return 0;
  		}
  	}
  
  	xpath_value_type xpath_variable::type() const
  	{
  		return _type;
  	}
  
  	bool xpath_variable::get_boolean() const
  	{
  		return (_type == xpath_type_boolean) ? static_cast<const xpath_variable_boolean*>(this)->value : false;
  	}
  
  	double xpath_variable::get_number() const
  	{
  		return (_type == xpath_type_number) ? static_cast<const xpath_variable_number*>(this)->value : gen_nan();
  	}
  
  	const char_t* xpath_variable::get_string() const
  	{
  		const char_t* value = (_type == xpath_type_string) ? static_cast<const xpath_variable_string*>(this)->value : 0;
  		return value ? value : PUGIHTML_TEXT("");
  	}
  
  	const xpath_node_set& xpath_variable::get_node_set() const
  	{
  		return (_type == xpath_type_node_set) ? static_cast<const xpath_variable_node_set*>(this)->value : dummy_node_set;
  	}
  
  	bool xpath_variable::set(bool value)
  	{
  		if (_type != xpath_type_boolean) return false;
  
  		static_cast<xpath_variable_boolean*>(this)->value = value;
  		return true;
  	}
  
  	bool xpath_variable::set(double value)
  	{
  		if (_type != xpath_type_number) return false;
  
  		static_cast<xpath_variable_number*>(this)->value = value;
  		return true;
  	}
  
  	bool xpath_variable::set(const char_t* value)
  	{
  		if (_type != xpath_type_string) return false;
  
  		xpath_variable_string* var = static_cast<xpath_variable_string*>(this);
  
  		// duplicate string
  		size_t size = (strlength(value) + 1) * sizeof(char_t);
  
  		char_t* copy = static_cast<char_t*>(global_allocate(size));
  		if (!copy) return false;
  
  		memcpy(copy, value, size);
  
  		// replace old string
  		if (var->value) global_deallocate(var->value);
  		var->value = copy;
  
  		return true;
  	}
  
  	bool xpath_variable::set(const xpath_node_set& value)
  	{
  		if (_type != xpath_type_node_set) return false;
  
  		static_cast<xpath_variable_node_set*>(this)->value = value;
  		return true;
  	}
  
  	xpath_variable_set::xpath_variable_set()
  	{
  		for (size_t i = 0; i < sizeof(_data) / sizeof(_data[0]); ++i) _data[i] = 0;
  	}
  
  	xpath_variable_set::~xpath_variable_set()
  	{
  		for (size_t i = 0; i < sizeof(_data) / sizeof(_data[0]); ++i)
  		{
  			xpath_variable* var = _data[i];
  
  			while (var)
  			{
  				xpath_variable* next = var->_next;
  
  				delete_xpath_variable(var->_type, var);
  
  				var = next;
  			}
  		}
  	}
  
  	xpath_variable* xpath_variable_set::find(const char_t* name) const
  	{
  		const size_t hash_size = sizeof(_data) / sizeof(_data[0]);
  		size_t hash = hash_string(name) % hash_size;
  
  		// look for existing variable
  		for (xpath_variable* var = _data[hash]; var; var = var->_next)
  			if (strequal(var->name(), name))
  				return var;
  
  		return 0;
  	}
  
  	xpath_variable* xpath_variable_set::add(const char_t* name, xpath_value_type type)
  	{
  		const size_t hash_size = sizeof(_data) / sizeof(_data[0]);
  		size_t hash = hash_string(name) % hash_size;
  
  		// look for existing variable
  		for (xpath_variable* var = _data[hash]; var; var = var->_next)
  			if (strequal(var->name(), name))
  				return var->type() == type ? var : 0;
  
  		// add new variable
  		xpath_variable* result = new_xpath_variable(type, name);
  
  		if (result)
  		{
  			result->_type = type;
  			result->_next = _data[hash];
  
  			_data[hash] = result;
  		}
  
  		return result;
  	}
  
  	bool xpath_variable_set::set(const char_t* name, bool value)
  	{
  		xpath_variable* var = add(name, xpath_type_boolean);
  		return var ? var->set(value) : false;
  	}
  
  	bool xpath_variable_set::set(const char_t* name, double value)
  	{
  		xpath_variable* var = add(name, xpath_type_number);
  		return var ? var->set(value) : false;
  	}
  
  	bool xpath_variable_set::set(const char_t* name, const char_t* value)
  	{
  		xpath_variable* var = add(name, xpath_type_string);
  		return var ? var->set(value) : false;
  	}
  
  	bool xpath_variable_set::set(const char_t* name, const xpath_node_set& value)
  	{
  		xpath_variable* var = add(name, xpath_type_node_set);
  		return var ? var->set(value) : false;
  	}
  
  	xpath_variable* xpath_variable_set::get(const char_t* name)
  	{
  		return find(name);
  	}
  
  	const xpath_variable* xpath_variable_set::get(const char_t* name) const
  	{
  		return find(name);
  	}
  
  	xpath_query::xpath_query(const char_t* query, xpath_variable_set* variables): _impl(0)
  	{
  		xpath_query_impl* impl = xpath_query_impl::create();
  
  		if (!impl)
  		{
  		#ifdef PUGIHTML_NO_EXCEPTIONS
  			_result.error = "Out of memory";
          #else
  			throw std::bad_alloc();
  		#endif
  		}
  		else
  		{
  			buffer_holder impl_holder(impl, xpath_query_impl::destroy);
  
  			impl->root = xpath_parser::parse(query, variables, &impl->alloc, &_result);
  
  			if (impl->root)
  			{
                  _impl = static_cast<xpath_query_impl*>(impl_holder.release());
  				_result.error = 0;
  			}
  		}
  	}
  
  	xpath_query::~xpath_query()
  	{
  		xpath_query_impl::destroy(_impl);
  	}
  
  	xpath_value_type xpath_query::return_type() const
  	{
  		if (!_impl) return xpath_type_none;
  
  		return static_cast<xpath_query_impl*>(_impl)->root->rettype();
  	}
  
  	bool xpath_query::evaluate_boolean(const xpath_node& n) const
  	{
  		if (!_impl) return false;
  		
  		xpath_context c(n, 1, 1);
  		xpath_stack_data sd;
  
  	#ifdef PUGIHTML_NO_EXCEPTIONS
  		if (setjmp(sd.error_handler)) return false;
  	#endif
  		
  		return static_cast<xpath_query_impl*>(_impl)->root->eval_boolean(c, sd.stack);
  	}
  	
  	double xpath_query::evaluate_number(const xpath_node& n) const
  	{
  		if (!_impl) return gen_nan();
  		
  		xpath_context c(n, 1, 1);
  		xpath_stack_data sd;
  
  	#ifdef PUGIHTML_NO_EXCEPTIONS
  		if (setjmp(sd.error_handler)) return gen_nan();
  	#endif
  
  		return static_cast<xpath_query_impl*>(_impl)->root->eval_number(c, sd.stack);
  	}
  
  #ifndef PUGIHTML_NO_STL
  	string_t xpath_query::evaluate_string(const xpath_node& n) const
  	{
  		xpath_stack_data sd;
  
  		return evaluate_string_impl(static_cast<xpath_query_impl*>(_impl), n, sd).c_str();
  	}
  #endif
  
  	size_t xpath_query::evaluate_string(char_t* buffer, size_t capacity, const xpath_node& n) const
  	{
  		xpath_stack_data sd;
  
  		xpath_string r = evaluate_string_impl(static_cast<xpath_query_impl*>(_impl), n, sd);
  
  		size_t full_size = r.length() + 1;
  		
  		if (capacity > 0)
          {
              size_t size = (full_size < capacity) ? full_size : capacity;
              assert(size > 0);
  
              memcpy(buffer, r.c_str(), (size - 1) * sizeof(char_t));
              buffer[size - 1] = 0;
          }
  		
  		return full_size;
  	}
  
  	xpath_node_set xpath_query::evaluate_node_set(const xpath_node& n) const
  	{
  		if (!_impl) return xpath_node_set();
  
          xpath_ast_node* root = static_cast<xpath_query_impl*>(_impl)->root;
  
  		if (root->rettype() != xpath_type_node_set)
  		{
  		#ifdef PUGIHTML_NO_EXCEPTIONS
  			return xpath_node_set();
  		#else
  			xpath_parse_result result;
  			result.error = "Expression does not evaluate to node set";
  
  			throw xpath_exception(result);
  		#endif
  		}
  		
  		xpath_context c(n, 1, 1);
  		xpath_stack_data sd;
  
  	#ifdef PUGIHTML_NO_EXCEPTIONS
  		if (setjmp(sd.error_handler)) return xpath_node_set();
  	#endif
  
  		xpath_node_set_raw r = root->eval_node_set(c, sd.stack);
  
  		return xpath_node_set(r.begin(), r.end(), r.type());
  	}
  
  	const xpath_parse_result& xpath_query::result() const
  	{
  		return _result;
  	}
  
  	xpath_query::operator xpath_query::unspecified_bool_type() const
  	{
  		return _impl ? &xpath_query::_impl : 0;
  	}
  
  	bool xpath_query::operator!() const
  	{
  		return !_impl;
  	}
  
  	xpath_node html_node::select_single_node(const char_t* query, xpath_variable_set* variables) const
  	{
  		xpath_query q(query, variables);
  		return select_single_node(q);
  	}
  
  	xpath_node html_node::select_single_node(const xpath_query& query) const
  	{
  		xpath_node_set s = query.evaluate_node_set(*this);
  		return s.empty() ? xpath_node() : s.first();
  	}
  
  	xpath_node_set html_node::select_nodes(const char_t* query, xpath_variable_set* variables) const
  	{
  		xpath_query q(query, variables);
  		return select_nodes(q);
  	}
  
  	xpath_node_set html_node::select_nodes(const xpath_query& query) const
  	{
  		return query.evaluate_node_set(*this);
  	}
  }
  
  #endif
  