Leaked source code of windows server 2003
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118 lines
2.6 KiB

//----------------------------------------------------------------------------
//
// Specialized allocators.
//
// Copyright (C) Microsoft Corporation, 2001.
//
//----------------------------------------------------------------------------
#include "pch.hpp"
#ifdef NT_NATIVE
#include "ntnative.h"
#endif
#include "cmnutil.hpp"
#include "alloc.hpp"
//----------------------------------------------------------------------------
//
// FixedSizeStackAllocator.
//
//----------------------------------------------------------------------------
FixedSizeStackAllocator::FixedSizeStackAllocator(ULONG ChunkSize,
ULONG ChunksPerBlock,
BOOL KeepLastBlock)
{
C_ASSERT((sizeof(FixedSizeStackBlock) & 7) == 0);
if (ChunkSize == 0)
{
ChunkSize = sizeof(ULONG64);
}
else
{
ChunkSize = (ChunkSize + 7) & ~7;
}
if (ChunksPerBlock == 0)
{
ChunksPerBlock = 32;
}
m_ChunkSize = ChunkSize;
m_KeepLastBlock = KeepLastBlock;
m_BlockSize = ChunkSize * ChunksPerBlock + sizeof(FixedSizeStackBlock);
m_NumAllocs = 0;
m_Blocks = NULL;
}
FixedSizeStackAllocator::~FixedSizeStackAllocator(void)
{
m_KeepLastBlock = FALSE;
FreeAll();
}
void
FixedSizeStackAllocator::FreeAll(void)
{
FixedSizeStackBlock* Block;
while (m_Blocks)
{
Block = m_Blocks;
if (!Block->Next && m_KeepLastBlock)
{
Block->MemLimit = (PUCHAR)(Block + 1);
break;
}
m_Blocks = m_Blocks->Next;
RawFree(Block);
}
m_NumAllocs = 0;
}
void*
FixedSizeStackAllocator::RawAlloc(ULONG Bytes)
{
return malloc(Bytes);
}
void
FixedSizeStackAllocator::RawFree(void* Mem)
{
free(Mem);
}
FixedSizeStackBlock*
FixedSizeStackAllocator::AllocBlock(void)
{
FixedSizeStackBlock* Block = (FixedSizeStackBlock*)RawAlloc(m_BlockSize);
if (!Block)
{
return NULL;
}
Block->Next = m_Blocks;
Block->MemLimit = (PUCHAR)(Block + 1);
m_Blocks = Block;
return Block;
}
void
FixedSizeStackAllocator::FreeBlock(void)
{
FixedSizeStackBlock* Block = m_Blocks;
if (!Block->Next && m_KeepLastBlock)
{
// Sometimes it's desirable to keep the last block
// around to avoid forcing an alloc the next time
// the allocator is used.
return;
}
m_Blocks = Block->Next;
RawFree(Block);
}