text: /*
   * Copyright (C) 2009 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. 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.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. OR
   * CONTRIBUTORS 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 ParserArena_h
  #define ParserArena_h
  
  #include "Identifier.h"
  #include <wtf/SegmentedVector.h>
  
  namespace JSC {
  
      class ParserArenaDeletable;
      class ParserArenaRefCounted;
  
      class IdentifierArena {
          WTF_MAKE_FAST_ALLOCATED;
      public:
          IdentifierArena()
          {
              clear();
          }
  
          template <typename T>
          ALWAYS_INLINE const Identifier& makeIdentifier(JSGlobalData*, const T* characters, size_t length);
          ALWAYS_INLINE const Identifier& makeIdentifierLCharFromUChar(JSGlobalData*, const UChar* characters, size_t length);
  
          const Identifier& makeNumericIdentifier(JSGlobalData*, double number);
  
          bool isEmpty() const { return m_identifiers.isEmpty(); }
  
      public:
          static const int MaximumCachableCharacter = 128;
          typedef SegmentedVector<Identifier, 64> IdentifierVector;
          void clear()
          {
              m_identifiers.clear();
              for (int i = 0; i < MaximumCachableCharacter; i++)
                  m_shortIdentifiers[i] = 0;
              for (int i = 0; i < MaximumCachableCharacter; i++)
                  m_recentIdentifiers[i] = 0;
          }
  
      private:
          IdentifierVector m_identifiers;
          FixedArray<Identifier*, MaximumCachableCharacter> m_shortIdentifiers;
          FixedArray<Identifier*, MaximumCachableCharacter> m_recentIdentifiers;
      };
  
      template <typename T>
      ALWAYS_INLINE const Identifier& IdentifierArena::makeIdentifier(JSGlobalData* globalData, const T* characters, size_t length)
      {
          if (characters[0] >= MaximumCachableCharacter) {
              m_identifiers.append(Identifier(globalData, characters, length));
              return m_identifiers.last();
          }
          if (length == 1) {
              if (Identifier* ident = m_shortIdentifiers[characters[0]])
                  return *ident;
              m_identifiers.append(Identifier(globalData, characters, length));
              m_shortIdentifiers[characters[0]] = &m_identifiers.last();
              return m_identifiers.last();
          }
          Identifier* ident = m_recentIdentifiers[characters[0]];
          if (ident && Identifier::equal(ident->impl(), characters, length))
              return *ident;
          m_identifiers.append(Identifier(globalData, characters, length));
          m_recentIdentifiers[characters[0]] = &m_identifiers.last();
          return m_identifiers.last();
      }
  
      ALWAYS_INLINE const Identifier& IdentifierArena::makeIdentifierLCharFromUChar(JSGlobalData* globalData, const UChar* characters, size_t length)
      {
          if (characters[0] >= MaximumCachableCharacter) {
              m_identifiers.append(Identifier::createLCharFromUChar(globalData, characters, length));
              return m_identifiers.last();
          }
          if (length == 1) {
              if (Identifier* ident = m_shortIdentifiers[characters[0]])
                  return *ident;
              m_identifiers.append(Identifier(globalData, characters, length));
              m_shortIdentifiers[characters[0]] = &m_identifiers.last();
              return m_identifiers.last();
          }
          Identifier* ident = m_recentIdentifiers[characters[0]];
          if (ident && Identifier::equal(ident->impl(), characters, length))
              return *ident;
          m_identifiers.append(Identifier::createLCharFromUChar(globalData, characters, length));
          m_recentIdentifiers[characters[0]] = &m_identifiers.last();
          return m_identifiers.last();
      }
      
      inline const Identifier& IdentifierArena::makeNumericIdentifier(JSGlobalData* globalData, double number)
      {
          m_identifiers.append(Identifier(globalData, UString::number(number)));
          return m_identifiers.last();
      }
  
      class ParserArena {
          WTF_MAKE_NONCOPYABLE(ParserArena);
      public:
          ParserArena();
          ~ParserArena();
  
          void swap(ParserArena& otherArena)
          {
              std::swap(m_freeableMemory, otherArena.m_freeableMemory);
              std::swap(m_freeablePoolEnd, otherArena.m_freeablePoolEnd);
              m_identifierArena.swap(otherArena.m_identifierArena);
              m_freeablePools.swap(otherArena.m_freeablePools);
              m_deletableObjects.swap(otherArena.m_deletableObjects);
              m_refCountedObjects.swap(otherArena.m_refCountedObjects);
          }
  
          void* allocateFreeable(size_t size)
          {
              ASSERT(size);
              ASSERT(size <= freeablePoolSize);
              size_t alignedSize = alignSize(size);
              ASSERT(alignedSize <= freeablePoolSize);
              if (UNLIKELY(static_cast<size_t>(m_freeablePoolEnd - m_freeableMemory) < alignedSize))
                  allocateFreeablePool();
              void* block = m_freeableMemory;
              m_freeableMemory += alignedSize;
              return block;
          }
  
          void* allocateDeletable(size_t size)
          {
              ParserArenaDeletable* deletable = static_cast<ParserArenaDeletable*>(allocateFreeable(size));
              m_deletableObjects.append(deletable);
              return deletable;
          }
  
          void derefWithArena(PassRefPtr<ParserArenaRefCounted>);
          bool contains(ParserArenaRefCounted*) const;
          ParserArenaRefCounted* last() const;
          void removeLast();
  
          bool isEmpty() const;
          void reset();
  
          IdentifierArena& identifierArena() { return *m_identifierArena; }
  
      private:
          static const size_t freeablePoolSize = 8000;
  
          static size_t alignSize(size_t size)
          {
              return (size + sizeof(WTF::AllocAlignmentInteger) - 1) & ~(sizeof(WTF::AllocAlignmentInteger) - 1);
          }
  
          void* freeablePool();
          void allocateFreeablePool();
          void deallocateObjects();
  
          char* m_freeableMemory;
          char* m_freeablePoolEnd;
  
          OwnPtr<IdentifierArena> m_identifierArena;
          Vector<void*> m_freeablePools;
          Vector<ParserArenaDeletable*> m_deletableObjects;
          Vector<RefPtr<ParserArenaRefCounted> > m_refCountedObjects;
      };
  
  }
  
  #endif
  