91 lines
2.5 KiB
C++
91 lines
2.5 KiB
C++
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//Copyright (c) 1997-2000 Microsoft Corporation
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// Memory mapped file routines
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#include <windows.h>
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#include "w95trace.h"
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#include "mappedfile.h"
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BOOL CMemMappedFile::Open(
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LPCTSTR szName, // name of the mapped file
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unsigned long ulMemSize // size of the mapped file
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)
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{
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// assumption: the code isn't going to call Open twice w/different szName
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if (!m_hMappedFile)
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{
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// Create the mapped file from system page file. If it has been created
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// previously, then CreateFileMapping acts like OpenFileMapping.
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m_hMappedFile = CreateFileMapping(
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INVALID_HANDLE_VALUE, // Current file handle.
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NULL, // Default security.
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PAGE_READWRITE, // Read/write permission.
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0, // Hi-order DWORD of file size
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ulMemSize, // Lo-order DWORD of file size
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szName); // Name of mapping object.
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if (!m_hMappedFile)
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{
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DBPRINTF(TEXT("CMemMappedFile::Open: CreateFileMapping %s failed 0x%x\r\n"), szName, GetLastError());
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return FALSE;
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}
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// Note if this is the first open for the file?
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m_fFirstOpen = (GetLastError() == ERROR_SUCCESS)?TRUE:FALSE;
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}
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return TRUE;
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}
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BOOL CMemMappedFile::AccessMem(
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void **ppvMappedAddr // returned pointer into memory
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)
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{
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if (IsBadWritePtr(ppvMappedAddr, sizeof(void *)))
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return FALSE;
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if (!m_hMappedFile)
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return FALSE;
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// Get a pointer to the mapped memory if we don't already have it
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if (!m_pvMappedAddr)
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{
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DBPRINTF(TEXT("MapViewOfFile\r\n"));
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m_pvMappedAddr = MapViewOfFile(
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m_hMappedFile, // Handle to mapping object.
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FILE_MAP_ALL_ACCESS, // Read/write permission
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0, // Max. object size.
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0, // Size of hFile.
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0); // Map entire file.
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*ppvMappedAddr = m_pvMappedAddr;
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}
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if (NULL == m_pvMappedAddr)
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{
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DBPRINTF(TEXT("CMemMappedFile::AccessMem: MapViewOfFile failed 0x%x\r\n"), GetLastError());
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return FALSE;
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}
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return TRUE;
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}
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void CMemMappedFile::Close()
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{
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if (m_pvMappedAddr)
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{
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UnmapViewOfFile(m_pvMappedAddr);
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m_pvMappedAddr = 0;
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}
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if (m_hMappedFile)
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{
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CloseHandle(m_hMappedFile);
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m_hMappedFile = 0;
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}
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m_fFirstOpen = FALSE;
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}
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