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144 lines
3.1 KiB
144 lines
3.1 KiB
/*++
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Copyright (c) 2000-2001 Microsoft Corporation
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Module Name:
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bsfixalloc.cpp
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Abstract:
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Adapted from MFC 6 SR 1 release of fixalloc.cpp. Removed all MFC stuff.
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Author:
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Stefan R. Steiner [ssteiner] 4-10-2000
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Revision History:
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--*/
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// fixalloc.cpp - implementation of fixed block allocator
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#include "stdafx.h"
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#include "bsfixalloc.h"
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#ifdef _DEBUG
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#undef THIS_FILE
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static char THIS_FILE[] = __FILE__;
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// #define new DEBUG_NEW
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#endif
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/////////////////////////////////////////////////////////////////////////////
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// CBsFixedAlloc
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CBsFixedAlloc::CBsFixedAlloc(UINT nAllocSize, UINT nBlockSize)
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{
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ASSERT(nAllocSize >= sizeof(CNode));
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ASSERT(nBlockSize > 1);
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//wprintf( L"CBsFixedAlloc called, nAllocSize: %d, nBlockSize: %d\n", nAllocSize, nBlockSize );
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m_nAllocSize = nAllocSize;
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m_nBlockSize = nBlockSize;
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m_pNodeFree = NULL;
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m_pBlocks = NULL;
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InitializeCriticalSection(&m_protect);
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}
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CBsFixedAlloc::~CBsFixedAlloc()
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{
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FreeAll();
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DeleteCriticalSection(&m_protect);
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}
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void CBsFixedAlloc::FreeAll()
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{
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EnterCriticalSection(&m_protect);
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m_pBlocks->FreeDataChain();
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m_pBlocks = NULL;
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m_pNodeFree = NULL;
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LeaveCriticalSection(&m_protect);
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}
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void* CBsFixedAlloc::Alloc()
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{
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EnterCriticalSection(&m_protect);
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if (m_pNodeFree == NULL)
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{
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CBsPlex* pNewBlock = NULL;
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try
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{
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// add another block
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pNewBlock = CBsPlex::Create(m_pBlocks, m_nBlockSize, m_nAllocSize);
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//wprintf( L"Alloc getting more core, nAllocSize: %d\n", m_nAllocSize );
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}
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catch( ... )
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{
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LeaveCriticalSection(&m_protect);
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throw;
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}
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// chain them into free list
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CNode* pNode = (CNode*)pNewBlock->data();
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// free in reverse order to make it easier to debug
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(BYTE*&)pNode += (m_nAllocSize * m_nBlockSize) - m_nAllocSize;
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for (int i = m_nBlockSize-1; i >= 0; i--, (BYTE*&)pNode -= m_nAllocSize)
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{
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pNode->pNext = m_pNodeFree;
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m_pNodeFree = pNode;
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}
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}
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ASSERT(m_pNodeFree != NULL); // we must have something
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// remove the first available node from the free list
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void* pNode = m_pNodeFree;
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m_pNodeFree = m_pNodeFree->pNext;
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LeaveCriticalSection(&m_protect);
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return pNode;
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}
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void CBsFixedAlloc::Free(void* p)
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{
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if (p != NULL)
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{
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EnterCriticalSection(&m_protect);
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// simply return the node to the free list
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CNode* pNode = (CNode*)p;
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pNode->pNext = m_pNodeFree;
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m_pNodeFree = pNode;
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LeaveCriticalSection(&m_protect);
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}
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}
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/////////////////////////////////////////////////////////////////////////////
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// CBsPlex
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// throws E_OUTOFMEMORY
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CBsPlex* PASCAL CBsPlex::Create(CBsPlex*& pHead, UINT nMax, UINT cbElement)
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{
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ASSERT(nMax > 0 && cbElement > 0);
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CBsPlex* p = (CBsPlex*) new BYTE[sizeof(CBsPlex) + nMax * cbElement];
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if ( p == NULL ) // prefix #118827
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throw E_OUTOFMEMORY;
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p->pNext = pHead;
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pHead = p; // change head (adds in reverse order for simplicity)
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return p;
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}
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void CBsPlex::FreeDataChain() // free this one and links
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{
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CBsPlex* p = this;
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while (p != NULL)
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{
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BYTE* bytes = (BYTE*) p;
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CBsPlex* pNext = p->pNext;
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delete[] bytes;
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p = pNext;
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}
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}
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