text: /*
   * Copyright (c) 2008, 2009, Wayne Meissner
   *
   * Copyright (c) 2008-2013, Ruby FFI project contributors
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *     * Redistributions of source code must retain the above copyright
   *       notice, this list of conditions and the following disclaimer.
   *     * Redistributions in binary form must reproduce the above copyright
   *       notice, this list of conditions and the following disclaimer in the
   *       documentation and/or other materials provided with the distribution.
   *     * Neither the name of the Ruby FFI project nor the
   *       names of its contributors may be used to endorse or promote products
   *       derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
   * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #ifndef _MSC_VER
  # include <stdint.h>
  # include <stdbool.h>
  #else
  # include "win32/stdint.h"
  # include "win32/stdbool.h"
  #endif
  #include <limits.h>
  #include <ruby.h>
  #include "rbffi.h"
  #include "rbffi_endian.h"
  #include "AbstractMemory.h"
  #include "Pointer.h"
  
  #define POINTER(obj) rbffi_AbstractMemory_Cast((obj), rbffi_PointerClass)
  
  VALUE rbffi_PointerClass = Qnil;
  VALUE rbffi_NullPointerSingleton = Qnil;
  
  static void ptr_release(Pointer* ptr);
  static void ptr_mark(Pointer* ptr);
  
  VALUE
  rbffi_Pointer_NewInstance(void* addr)
  {
      Pointer* p;
      VALUE obj;
  
      if (addr == NULL) {
          return rbffi_NullPointerSingleton;
      }
  
      obj = Data_Make_Struct(rbffi_PointerClass, Pointer, NULL, -1, p);
      p->memory.address = addr;
      p->memory.size = LONG_MAX;
      p->memory.flags = (addr == NULL) ? 0 : (MEM_RD | MEM_WR);
      p->memory.typeSize = 1;
      p->rbParent = Qnil;
  
      return obj;
  }
  
  static VALUE
  ptr_allocate(VALUE klass)
  {
      Pointer* p;
      VALUE obj;
  
      obj = Data_Make_Struct(klass, Pointer, ptr_mark, ptr_release, p);
      p->rbParent = Qnil;
      p->memory.flags = MEM_RD | MEM_WR;
  
      return obj;
  }
  
  /*
   * @overload initialize(pointer)
   *  @param [Pointer] pointer another pointer to initialize from
   *  Create a new pointer from another {Pointer}.
   * @overload initialize(type, address)
   *  @param [Type] type type for pointer
   *  @param [Integer] address base address for pointer
   *  Create a new pointer from a {Type} and a base address
   * @return [self]
   * A new instance of Pointer.
   */
  static VALUE
  ptr_initialize(int argc, VALUE* argv, VALUE self)
  {
      Pointer* p;
      VALUE rbType = Qnil, rbAddress = Qnil;
      int typeSize = 1;
  
      Data_Get_Struct(self, Pointer, p);
  
      switch (rb_scan_args(argc, argv, "11", &rbType, &rbAddress)) {
          case 1:
              rbAddress = rbType;
              typeSize = 1;
              break;
          case 2:
              typeSize = rbffi_type_size(rbType);
              break;
          default:
              rb_raise(rb_eArgError, "Invalid arguments");
      }
  
      switch (TYPE(rbAddress)) {
          case T_FIXNUM:
          case T_BIGNUM:
              p->memory.address = (void*) (uintptr_t) NUM2LL(rbAddress);
              p->memory.size = LONG_MAX;
              if (p->memory.address == NULL) {
                  p->memory.flags = 0;
              }
              break;
  
          default:
              if (rb_obj_is_kind_of(rbAddress, rbffi_PointerClass)) {
                  Pointer* orig;
  
                  p->rbParent = rbAddress;
                  Data_Get_Struct(rbAddress, Pointer, orig);
                  p->memory = orig->memory;
              } else {
                  rb_raise(rb_eTypeError, "wrong argument type, expected Integer or FFI::Pointer");
              }
              break;
      }
  
      p->memory.typeSize = typeSize;
  
      return self;
  }
  
  /*
   * call-seq: ptr.initialize_copy(other)
   * @param [Pointer] other source for cloning or dupping
   * @return [self]
   * @raise {RuntimeError} if +other+ is an unbounded memory area, or is unreadable/unwritable
   * @raise {NoMemError} if failed to allocate memory for new object
   * DO NOT CALL THIS METHOD.
   *
   * This method is internally used by #dup and #clone. Memory content is copied from +other+.
   */
  static VALUE
  ptr_initialize_copy(VALUE self, VALUE other)
  {
      AbstractMemory* src;
      Pointer* dst;
  
      Data_Get_Struct(self, Pointer, dst);
      src = POINTER(other);
      if (src->size == LONG_MAX) {
          rb_raise(rb_eRuntimeError, "cannot duplicate unbounded memory area");
          return Qnil;
      }
  
      if ((dst->memory.flags & (MEM_RD | MEM_WR)) != (MEM_RD | MEM_WR)) {
          rb_raise(rb_eRuntimeError, "cannot duplicate unreadable/unwritable memory area");
          return Qnil;
      }
  
      if (dst->storage != NULL) {
          xfree(dst->storage);
          dst->storage = NULL;
      }
  
      dst->storage = xmalloc(src->size + 7);
      if (dst->storage == NULL) {
          rb_raise(rb_eNoMemError, "failed to allocate memory size=%lu bytes", src->size);
          return Qnil;
      }
  
      dst->allocated = true;
      dst->autorelease = true;
      dst->memory.address = (void *) (((uintptr_t) dst->storage + 0x7) & (uintptr_t) ~0x7ULL);
      dst->memory.size = src->size;
      dst->memory.typeSize = src->typeSize;
  
      /* finally, copy the actual memory contents */
      memcpy(dst->memory.address, src->address, src->size);
  
      return self;
  }
  
  static VALUE
  slice(VALUE self, long offset, long size)
  {
      AbstractMemory* ptr;
      Pointer* p;
      VALUE retval;
  
      Data_Get_Struct(self, AbstractMemory, ptr);
      checkBounds(ptr, offset, size == LONG_MAX ? 1 : size);
  
      retval = Data_Make_Struct(rbffi_PointerClass, Pointer, ptr_mark, -1, p);
  
      p->memory.address = ptr->address + offset;
      p->memory.size = size;
      p->memory.flags = ptr->flags;
      p->memory.typeSize = ptr->typeSize;
      p->rbParent = self;
  
      return retval;
  }
  
  /*
   * Document-method: +
   * call-seq: ptr + offset
   * @param [Numeric] offset
   * @return [Pointer]
   * Return a new {Pointer} from an existing pointer and an +offset+.
   */
  static VALUE
  ptr_plus(VALUE self, VALUE offset)
  {
      AbstractMemory* ptr;
      long off = NUM2LONG(offset);
  
      Data_Get_Struct(self, AbstractMemory, ptr);
  
      return slice(self, off, ptr->size == LONG_MAX ? LONG_MAX : ptr->size - off);
  }
  
  /*
   * call-seq: ptr.slice(offset, length)
   * @param [Numeric] offset
   * @param [Numeric] length
   * @return [Pointer]
   * Return a new {Pointer} from an existing one. This pointer points on same contents
   * from +offset+ for a length +length+.
   */
  static VALUE
  ptr_slice(VALUE self, VALUE rbOffset, VALUE rbLength)
  {
      return slice(self, NUM2LONG(rbOffset), NUM2LONG(rbLength));
  }
  
  /*
   * call-seq: ptr.inspect
   * @return [String]
   * Inspect pointer object.
   */
  static VALUE
  ptr_inspect(VALUE self)
  {
      char buf[100];
      Pointer* ptr;
  
      Data_Get_Struct(self, Pointer, ptr);
  
      if (ptr->memory.size != LONG_MAX) {
          snprintf(buf, sizeof(buf), "#<%s address=%p size=%lu>",
                  rb_obj_classname(self), ptr->memory.address, ptr->memory.size);
      } else {
          snprintf(buf, sizeof(buf), "#<%s address=%p>", rb_obj_classname(self), ptr->memory.address);
      }
  
      return rb_str_new2(buf);
  }
  
  /*
   * Document-method: null?
   * call-seq: ptr.null?
   * @return [Boolean]
   * Return +true+ if +self+ is a {NULL} pointer.
   */
  static VALUE
  ptr_null_p(VALUE self)
  {
      Pointer* ptr;
  
      Data_Get_Struct(self, Pointer, ptr);
  
      return ptr->memory.address == NULL ? Qtrue : Qfalse;
  }
  
  /*
   * Document-method: ==
   * call-seq: ptr == other
   * @param [Pointer] other
   * Check equality between +self+ and +other+. Equality is tested on {#address}.
   */
  static VALUE
  ptr_equals(VALUE self, VALUE other)
  {
      Pointer* ptr;
  
      Data_Get_Struct(self, Pointer, ptr);
  
      if (NIL_P(other)) {
          return ptr->memory.address == NULL ? Qtrue : Qfalse;
      }
  
      return ptr->memory.address == POINTER(other)->address ? Qtrue : Qfalse;
  }
  
  /*
   * call-seq: ptr.address
   * @return [Numeric] pointer's base address
   * Return +self+'s base address (alias: #to_i).
   */
  static VALUE
  ptr_address(VALUE self)
  {
      Pointer* ptr;
  
      Data_Get_Struct(self, Pointer, ptr);
  
      return ULL2NUM((uintptr_t) ptr->memory.address);
  }
  
  #if BYTE_ORDER == LITTLE_ENDIAN
  # define SWAPPED_ORDER BIG_ENDIAN
  #else
  # define SWAPPED_ORDER LITTLE_ENDIAN
  #endif
  
  /*
   * Get or set +self+'s endianness
   * @overload order
   *  @return [:big, :little] endianness of +self+
   * @overload order(order)
   *  @param  [Symbol] order endianness to set (+:little+, +:big+ or +:network+). +:big+ and +:network+
   *   are synonymous.
   *  @return [self]
   */
  static VALUE
  ptr_order(int argc, VALUE* argv, VALUE self)
  {
      Pointer* ptr;
  
      Data_Get_Struct(self, Pointer, ptr);
      if (argc == 0) {
          int order = (ptr->memory.flags & MEM_SWAP) == 0 ? BYTE_ORDER : SWAPPED_ORDER;
          return order == BIG_ENDIAN ? ID2SYM(rb_intern("big")) : ID2SYM(rb_intern("little"));
      } else {
          VALUE rbOrder = Qnil;
          int order = BYTE_ORDER;
  
          if (rb_scan_args(argc, argv, "1", &rbOrder) < 1) {
              rb_raise(rb_eArgError, "need byte order");
          }
          if (SYMBOL_P(rbOrder)) {
              ID id = SYM2ID(rbOrder);
              if (id == rb_intern("little")) {
                  order = LITTLE_ENDIAN;
  
              } else if (id == rb_intern("big") || id == rb_intern("network")) {
                  order = BIG_ENDIAN;
              }
          }
          if (order != BYTE_ORDER) {
              Pointer* p2;
              VALUE retval = slice(self, 0, ptr->memory.size);
  
              Data_Get_Struct(retval, Pointer, p2);
              p2->memory.flags |= MEM_SWAP;
              return retval;
          }
  
          return self;
      }
  }
  
  
  /*
   * call-seq: ptr.free
   * @return [self]
   * Free memory pointed by +self+.
   */
  static VALUE
  ptr_free(VALUE self)
  {
      Pointer* ptr;
  
      Data_Get_Struct(self, Pointer, ptr);
  
      if (ptr->allocated) {
          if (ptr->storage != NULL) {
              xfree(ptr->storage);
              ptr->storage = NULL;
          }
          ptr->allocated = false;
  
      } else {
          VALUE caller = rb_funcall(rb_funcall(Qnil, rb_intern("caller"), 0), rb_intern("first"), 0);
  
          rb_warn("calling free on non allocated pointer %s from %s", RSTRING_PTR(ptr_inspect(self)), RSTRING_PTR(rb_str_to_str(caller)));
      }
  
      return self;
  }
  
  static VALUE
  ptr_type_size(VALUE self)
  {
      Pointer* ptr;
  
      Data_Get_Struct(self, Pointer, ptr);
  
      return INT2NUM(ptr->memory.typeSize);
  }
  
  /*
   * call-seq: ptr.autorelease = autorelease
   * @param [Boolean] autorelease
   * @return [Boolean] +autorelease+
   * Set +autorelease+ attribute. See also Autorelease section.
   */
  static VALUE
  ptr_autorelease(VALUE self, VALUE autorelease)
  {
      Pointer* ptr;
  
      Data_Get_Struct(self, Pointer, ptr);
      ptr->autorelease = autorelease == Qtrue;
  
      return autorelease;
  }
  
  /*
   * call-seq: ptr.autorelease?
   * @return [Boolean]
   * Get +autorelease+ attribute. See also Autorelease section.
   */
  static VALUE
  ptr_autorelease_p(VALUE self)
  {
      Pointer* ptr;
  
      Data_Get_Struct(self, Pointer, ptr);
  
      return ptr->autorelease ? Qtrue : Qfalse;
  }
  
  
  static void
  ptr_release(Pointer* ptr)
  {
      if (ptr->autorelease && ptr->allocated && ptr->storage != NULL) {
          xfree(ptr->storage);
          ptr->storage = NULL;
      }
      xfree(ptr);
  }
  
  static void
  ptr_mark(Pointer* ptr)
  {
      rb_gc_mark(ptr->rbParent);
  }
  
  void
  rbffi_Pointer_Init(VALUE moduleFFI)
  {
      VALUE rbNullAddress = ULL2NUM(0);
      VALUE ffi_AbstractMemory =  rbffi_AbstractMemoryClass;
  
      /*
       * Document-class: FFI::Pointer < FFI::AbstractMemory
       * Pointer class is used to manage C pointers with ease. A {Pointer} object is defined by his
       * {#address} (as a C pointer). It permits additions with an integer for pointer arithmetic.
       *
       * == Autorelease
       * By default a pointer object frees its content when it's garbage collected.
       * Therefore it's usually not necessary to call {#free} explicit.
       * This behaviour may be changed with {#autorelease=} method.
       * If it's set to +false+, the memory isn't freed by the garbage collector, but stays valid until +free()+ is called on C level or when the process terminates.
       */
      rbffi_PointerClass = rb_define_class_under(moduleFFI, "Pointer", ffi_AbstractMemory);
      /*
       * Document-variable: Pointer
       */
      rb_global_variable(&rbffi_PointerClass);
  
      rb_define_alloc_func(rbffi_PointerClass, ptr_allocate);
      rb_define_method(rbffi_PointerClass, "initialize", ptr_initialize, -1);
      rb_define_method(rbffi_PointerClass, "initialize_copy", ptr_initialize_copy, 1);
      rb_define_method(rbffi_PointerClass, "inspect", ptr_inspect, 0);
      rb_define_method(rbffi_PointerClass, "to_s", ptr_inspect, 0);
      rb_define_method(rbffi_PointerClass, "+", ptr_plus, 1);
      rb_define_method(rbffi_PointerClass, "slice", ptr_slice, 2);
      rb_define_method(rbffi_PointerClass, "null?", ptr_null_p, 0);
      rb_define_method(rbffi_PointerClass, "address", ptr_address, 0);
      rb_define_alias(rbffi_PointerClass, "to_i", "address");
      rb_define_method(rbffi_PointerClass, "==", ptr_equals, 1);
      rb_define_method(rbffi_PointerClass, "order", ptr_order, -1);
      rb_define_method(rbffi_PointerClass, "autorelease=", ptr_autorelease, 1);
      rb_define_method(rbffi_PointerClass, "autorelease?", ptr_autorelease_p, 0);
      rb_define_method(rbffi_PointerClass, "free", ptr_free, 0);
      rb_define_method(rbffi_PointerClass, "type_size", ptr_type_size, 0);
  
      rbffi_NullPointerSingleton = rb_class_new_instance(1, &rbNullAddress, rbffi_PointerClass);
      /*
       * NULL pointer
       */
      rb_define_const(rbffi_PointerClass, "NULL", rbffi_NullPointerSingleton);
  }
  
  