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