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* Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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* You should have received a copy of the GNU Library General Public License
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* along with this library; see the file COPYING.LIB. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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#ifndef WTF_FastMalloc_h
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#define WTF_FastMalloc_h
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#include <wtf/Platform.h>
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#include <wtf/PossiblyNull.h>
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// These functions call CRASH() if an allocation fails.
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WTF_EXPORT_PRIVATE void* fastMalloc(size_t);
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WTF_EXPORT_PRIVATE void* fastZeroedMalloc(size_t);
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WTF_EXPORT_PRIVATE void* fastCalloc(size_t numElements, size_t elementSize);
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WTF_EXPORT_PRIVATE void* fastRealloc(void*, size_t);
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WTF_EXPORT_PRIVATE char* fastStrDup(const char*);
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WTF_EXPORT_PRIVATE size_t fastMallocSize(const void*);
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struct TryMallocReturnValue {
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TryMallocReturnValue(void* data)
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TryMallocReturnValue(const TryMallocReturnValue& source)
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: m_data(source.m_data)
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~TryMallocReturnValue() { ASSERT(!m_data); }
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template <typename T> bool getValue(T& data) WARN_UNUSED_RETURN;
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template <typename T> operator PossiblyNull<T>()
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return PossiblyNull<T>(value);
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template <typename T> bool TryMallocReturnValue::getValue(T& data)
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union u { void* data; T target; } res;
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bool returnValue = !!m_data;
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WTF_EXPORT_PRIVATE TryMallocReturnValue tryFastMalloc(size_t n);
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TryMallocReturnValue tryFastZeroedMalloc(size_t n);
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WTF_EXPORT_PRIVATE TryMallocReturnValue tryFastCalloc(size_t n_elements, size_t element_size);
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WTF_EXPORT_PRIVATE TryMallocReturnValue tryFastRealloc(void* p, size_t n);
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WTF_EXPORT_PRIVATE void fastFree(void*);
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WTF_EXPORT_PRIVATE void fastMallocForbid();
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WTF_EXPORT_PRIVATE void fastMallocAllow();
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WTF_EXPORT_PRIVATE void releaseFastMallocFreeMemory();
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struct FastMallocStatistics {
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size_t reservedVMBytes;
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size_t committedVMBytes;
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WTF_EXPORT_PRIVATE FastMallocStatistics fastMallocStatistics();
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// This defines a type which holds an unsigned integer and is the same
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// size as the minimally aligned memory allocation.
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typedef unsigned long long AllocAlignmentInteger;
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enum AllocType { // Start with an unusual number instead of zero, because zero is common.
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AllocTypeMalloc = 0x375d6750, // Encompasses fastMalloc, fastZeroedMalloc, fastCalloc, fastRealloc.
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AllocTypeClassNew, // Encompasses class operator new from FastAllocBase.
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AllocTypeClassNewArray, // Encompasses class operator new[] from FastAllocBase.
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AllocTypeFastNew, // Encompasses fastNew.
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AllocTypeFastNewArray, // Encompasses fastNewArray.
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AllocTypeNew, // Encompasses global operator new.
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AllocTypeNewArray // Encompasses global operator new[].
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ValidationPrefix = 0xf00df00d,
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ValidationSuffix = 0x0badf00d
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typedef unsigned ValidationTag;
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struct ValidationHeader {
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ValidationTag m_prefix;
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unsigned m_alignment;
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static const int ValidationBufferSize = sizeof(ValidationHeader) + sizeof(ValidationTag);
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#if ENABLE(WTF_MALLOC_VALIDATION)
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// Malloc validation is a scheme whereby a tag is attached to an
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// allocation which identifies how it was originally allocated.
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// This allows us to verify that the freeing operation matches the
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// allocation operation. If memory is allocated with operator new[]
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// but freed with free or delete, this system would detect that.
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// In the implementation here, the tag is an integer prepended to
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// the allocation memory which is assigned one of the AllocType
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// enumeration values. An alternative implementation of this
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// scheme could store the tag somewhere else or ignore it.
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// Users of FastMalloc don't need to know or care how this tagging
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// Handle a detected alloc/free mismatch. By default this calls CRASH().
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void fastMallocMatchFailed(void* p);
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inline ValidationHeader* fastMallocValidationHeader(void* p)
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return reinterpret_cast<ValidationHeader*>(static_cast<char*>(p) - sizeof(ValidationHeader));
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inline ValidationTag* fastMallocValidationSuffix(void* p)
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ValidationHeader* header = fastMallocValidationHeader(p);
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if (header->m_prefix != static_cast<unsigned>(ValidationPrefix))
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fastMallocMatchFailed(p);
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return reinterpret_cast<ValidationTag*>(static_cast<char*>(p) + header->m_size);
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// Return the AllocType tag associated with the allocated block p.
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inline AllocType fastMallocMatchValidationType(void* p)
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return fastMallocValidationHeader(p)->m_type;
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// Set the AllocType tag to be associaged with the allocated block p.
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inline void setFastMallocMatchValidationType(void* p, AllocType allocType)
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fastMallocValidationHeader(p)->m_type = allocType;
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} // namespace Internal
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// This is a higher level function which is used by FastMalloc-using code.
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inline void fastMallocMatchValidateMalloc(void* p, Internal::AllocType allocType)
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Internal::setFastMallocMatchValidationType(p, allocType);
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// This is a higher level function which is used by FastMalloc-using code.
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inline void fastMallocMatchValidateFree(void* p, Internal::AllocType)
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Internal::ValidationHeader* header = Internal::fastMallocValidationHeader(p);
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if (header->m_prefix != static_cast<unsigned>(Internal::ValidationPrefix))
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Internal::fastMallocMatchFailed(p);
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if (*Internal::fastMallocValidationSuffix(p) != Internal::ValidationSuffix)
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Internal::fastMallocMatchFailed(p);
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Internal::setFastMallocMatchValidationType(p, Internal::AllocTypeMalloc); // Set it to this so that fastFree thinks it's OK.
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inline void fastMallocValidate(void* p)
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Internal::ValidationHeader* header = Internal::fastMallocValidationHeader(p);
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if (header->m_prefix != static_cast<unsigned>(Internal::ValidationPrefix))
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Internal::fastMallocMatchFailed(p);
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if (*Internal::fastMallocValidationSuffix(p) != Internal::ValidationSuffix)
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Internal::fastMallocMatchFailed(p);
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inline void fastMallocMatchValidateMalloc(void*, Internal::AllocType)
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inline void fastMallocMatchValidateFree(void*, Internal::AllocType)
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using WTF::fastCalloc;
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using WTF::fastMalloc;
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using WTF::fastMallocSize;
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using WTF::fastRealloc;
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using WTF::fastStrDup;
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using WTF::fastZeroedMalloc;
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using WTF::tryFastCalloc;
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using WTF::tryFastMalloc;
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using WTF::tryFastRealloc;
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using WTF::tryFastZeroedMalloc;
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using WTF::fastMallocForbid;
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using WTF::fastMallocAllow;
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#if COMPILER(GCC) && OS(DARWIN)
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#define WTF_PRIVATE_INLINE __private_extern__ inline __attribute__((always_inline))
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#define WTF_PRIVATE_INLINE inline __attribute__((always_inline))
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#elif COMPILER(MSVC) || COMPILER(RVCT)
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#define WTF_PRIVATE_INLINE __forceinline
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#define WTF_PRIVATE_INLINE inline
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#if !defined(_CRTDBG_MAP_ALLOC) && !(defined(USE_SYSTEM_MALLOC) && USE_SYSTEM_MALLOC)
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// The nothrow functions here are actually not all that helpful, because fastMalloc will
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// call CRASH() rather than returning 0, and returning 0 is what nothrow is all about.
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// But since WebKit code never uses exceptions or nothrow at all, this is probably OK.
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// Long term we will adopt FastAllocBase.h everywhere, and and replace this with
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// debug-only code to make sure we don't use the system malloc via the default operator
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#if ENABLE(GLOBAL_FASTMALLOC_NEW)
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#pragma warning(push)
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#pragma warning(disable: 4290) // Disable the C++ exception specification ignored warning.
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WTF_PRIVATE_INLINE void* operator new(size_t size) throw (std::bad_alloc) { return fastMalloc(size); }
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WTF_PRIVATE_INLINE void* operator new(size_t size, const std::nothrow_t&) throw() { return fastMalloc(size); }
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WTF_PRIVATE_INLINE void operator delete(void* p) throw() { fastFree(p); }
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WTF_PRIVATE_INLINE void operator delete(void* p, const std::nothrow_t&) throw() { fastFree(p); }
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WTF_PRIVATE_INLINE void* operator new[](size_t size) throw (std::bad_alloc) { return fastMalloc(size); }
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WTF_PRIVATE_INLINE void* operator new[](size_t size, const std::nothrow_t&) throw() { return fastMalloc(size); }
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WTF_PRIVATE_INLINE void operator delete[](void* p) throw() { fastFree(p); }
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WTF_PRIVATE_INLINE void operator delete[](void* p, const std::nothrow_t&) throw() { fastFree(p); }
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#endif /* WTF_FastMalloc_h */