Leaked source code of windows server 2003
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///////////////////////////////////////////////////////////////////////////
//
// Copyright(C) 1997-1998 Microsoft Corporation all rights reserved.
//
// Module: iascompool.h
//
// Project: Everest
//
// Description: Object pool that uses CoTaskMemAlloc() / CoTaskMemFree()
//
// Author: TLP 11/11/97
//
///////////////////////////////////////////////////////////////////////////
#ifndef __IAS_COM_MEMPOOL_H_
#define __IAS_COM_MEMPOOL_H_
// Assume another include has #included ias.h
#include <vector>
#include <list>
using namespace std;
#define COM_MEMPOOL_INITIALIZED 1
#define COM_MEMPOOL_UNINITIALIZED 0
//
// NOTE: m_lState must be aligned on 32 bit value or calls to
// InterlockedExchange will fail on multi-processor x86 systems.
template < class T, DWORD dwPerAllocT, bool bFixedSize >
class CComMemPool
{
// State flag - 1 = mem pool initialized, 0 = mem pool uninitialized
LONG m_lState;
// Total number of items allocated
DWORD m_dwCountTotal;
// Number of items on the free list
DWORD m_dwCountFree;
// Highest number of outstanding allocations
DWORD m_dwHighWater;
// Number of objects per system memory allocation
DWORD m_dwPerAllocT;
// Fixed size pool flag
bool m_bFixedSize;
// Critical Section - serializes free item list access
CRITICAL_SECTION m_CritSec;
// Memory block list
typedef list<PVOID> MemBlockList;
typedef MemBlockList::iterator MemBlockListIterator;
MemBlockList m_listMemBlocks;
// Free item list
typedef list<T*> FreeList;
typedef FreeList::iterator FreeListIterator;
FreeList m_listFreeT;
// Disallow copy and assignment
CComMemPool(const CComMemPool& theClass);
CComMemPool& operator=(const CComMemPool& theClass);
public:
//
// Constructor
//
CComMemPool()
: m_listMemBlocks(0),
m_listFreeT(0) // pre-alloc space for list nodes
{
m_lState = COM_MEMPOOL_UNINITIALIZED;
m_dwPerAllocT = dwPerAllocT;
m_bFixedSize = bFixedSize;
m_dwCountTotal = 0;
m_dwCountFree = 0;
m_dwHighWater = 0;
InitializeCriticalSection(&m_CritSec);
}
//
// Destructor
//
~CComMemPool()
{
_ASSERT( COM_MEMPOOL_UNINITIALIZED == m_lState );
DeleteCriticalSection(&m_CritSec);
}
//////////////////////////////////////////////////////////////////////////
// Init() - Initialize the memory pool
//////////////////////////////////////////////////////////////////////////
bool Init(void)
{
bool bReturn = false;
if ( COM_MEMPOOL_UNINITIALIZED == InterlockedExchange(&m_lState, COM_MEMPOOL_INITIALIZED) )
{
if ( AllocateMemBlock() )
{
bReturn = true;
}
else
{
InterlockedExchange(&m_lState, COM_MEMPOOL_UNINITIALIZED);
}
}
else
{
_ASSERTE(FALSE);
}
return bReturn;
}
//////////////////////////////////////////////////////////////////////////
// Shutdown() - Shutdown the memory pool freeing any system resources used
//////////////////////////////////////////////////////////////////////////
void Shutdown(void)
{
MemBlockListIterator p;
MemBlockListIterator q;
if ( COM_MEMPOOL_INITIALIZED == InterlockedExchange(&m_lState, COM_MEMPOOL_UNINITIALIZED) )
{
if ( m_dwCountTotal != m_dwCountFree )
{
// Still have blocks outstanding...
//
_ASSERTE( FALSE );
}
if ( ! m_listMemBlocks.empty() )
{
p = m_listMemBlocks.begin();
q = m_listMemBlocks.end();
while ( p != q )
{
CoTaskMemFree(*p);
p++;
}
m_listMemBlocks.clear();
}
m_dwCountTotal = 0;
m_dwCountFree = 0;
}
else
{
// COM pool is not inititalized
//
_ASSERTE( FALSE );
}
}
//////////////////////////////////////////////////////////////////////////
// Alloc() - Allocate an unitialized object from the pool
//////////////////////////////////////////////////////////////////////////
T* Alloc(void)
{
T* pMemBlk = NULL;
TraceFunctEnter("CComMemPool::Alloc()");
if ( COM_MEMPOOL_INITIALIZED == m_lState )
{
EnterCriticalSection(&m_CritSec);
if ( m_listFreeT.empty() )
{
if ( ! m_bFixedSize )
{
if ( AllocateMemBlock() )
{
pMemBlk = m_listFreeT.front();
m_listFreeT.pop_front();
m_dwCountFree--;
if ( m_dwHighWater < (m_dwCountTotal - m_dwCountFree) )
{
m_dwHighWater++;
}
}
else
{
ErrorTrace(0,"Could not allocate memory!");
}
}
else
{
ErrorTrace(0,"Fixed size pool is exhausted!");
}
}
else
{
pMemBlk = m_listFreeT.front();
m_listFreeT.pop_front();
m_dwCountFree--;
if ( m_dwHighWater < (m_dwCountTotal - m_dwCountFree) )
{
m_dwHighWater++;
}
}
LeaveCriticalSection(&m_CritSec);
}
else
{
ErrorTrace(0,"The memory pool is not initialized!");
_ASSERTE( FALSE );
}
if ( pMemBlk )
{
memset(pMemBlk, 0, sizeof(T));
new (pMemBlk) T(); // Placement new for class T - requires default contructor
}
TraceFunctLeave();
return pMemBlk;
}
//////////////////////////////////////////////////////////////////////////
// Free() - Return an object to the memory pool
//////////////////////////////////////////////////////////////////////////
void Free(T *pMemBlk)
{
TraceFunctEnter("CComMemPool::Free()");
if ( COM_MEMPOOL_INITIALIZED == m_lState )
{
pMemBlk->~T(); // Explicit call to destructor due to placement new
EnterCriticalSection(&m_CritSec);
m_listFreeT.insert(m_listFreeT.begin(),pMemBlk);
m_dwCountFree++;
LeaveCriticalSection(&m_CritSec);
}
else
{
ErrorTrace(0,"The memory pool is not initialized!");
_ASSERTE( FALSE );
}
TraceFunctLeave();
}
//////////////////////////////////////////////////////////////////////////
// Dump() - Dump the contents of the memory pool - Debug Service
//////////////////////////////////////////////////////////////////////////
void Dump(void)
{
#ifdef DEBUG
UINT i;
MemBlockListIterator p;
FreeListIterator r;
FreeListIterator s;
TraceFunctEnter("CComMemPool::Dump()");
if ( COM_MEMPOOL_INITIALIZED == m_lState )
{
// Dump the counts
EnterCriticalSection(&m_CritSec);
DebugTrace(0,"m_dwCountTotal = %d", m_dwCountTotal);
DebugTrace(0,"m_dwCountFree = %d", m_dwCountFree);
DebugTrace(0,"m_dwHighWater = %d", m_dwHighWater);
// Dump the pointers to memory blocks
DebugTrace(0,"m_listMemBlocks.size() = %d", m_listMemBlocks.size());
p = m_listMemBlocks.begin();
i = 0;
while ( p != m_listMemBlocks.end() )
{
DebugTrace(0,"m_listMemBlocks block %d = $%p", i, *p);
i++;
p++;
}
// Dump the pointers to items
DebugTrace(0,"CComMemPool::Dump() - m_listFreeT.size() = %d", m_listFreeT.size());
r = m_listFreeT.begin();
i = 0;
while ( r != m_listFreeT.end() )
{
DebugTrace(0,"CComMemPool::Dump() - m_listFreeT item %d = $%p", i, *r);
i++;
r++;
}
LeaveCriticalSection(&m_CritSec);
}
else
{
ErrorTrace(0,"The memory pool is not initialized!");
_ASSERTE( FALSE );
}
TraceFunctLeave();
#endif // DEBUG
}
private:
//////////////////////////////////////////////////////////////////////////
// AllocateMemBlock() - Allocate some system memory and chop it into
// T sized blocks
//////////////////////////////////////////////////////////////////////////
bool AllocateMemBlock()
{
bool bReturn = false;
UINT i;
UINT uBlkSize;
T* lpMemBlock;
TraceFunctEnter("CComMemPool::AllocateMemBlock()");
uBlkSize = m_dwPerAllocT * sizeof(T);
lpMemBlock = (T*) CoTaskMemAlloc(uBlkSize);
if ( lpMemBlock )
{
memset(lpMemBlock, 0, uBlkSize);
m_listMemBlocks.insert(m_listMemBlocks.begin(), (PVOID)lpMemBlock);
// Chop up the newly allocated memory block into sizeof(T) sized elements and place
// the elements on the list of pointers to Ts.
for ( i = 0; i < m_dwPerAllocT; i++ )
{
m_listFreeT.insert(m_listFreeT.end(),lpMemBlock);
lpMemBlock++;
}
// Update the pool memory use variables
m_dwCountTotal += m_dwPerAllocT;
m_dwCountFree += m_dwPerAllocT;
bReturn = true;
}
TraceFunctLeave();
return bReturn;
}
}; // End of CComMemPool
#endif // __IAS_COM_MEMPOOL_H_