📄 memmapfile.cpp
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/////////////////////////////////////////////////////////////////////////////
// MemMapFile.cpp 内存映射的 - 文件操作 ( Memory Mapping File ) //
// CopyRight(C) 1996,2008 TCSY 公司 //
// Pentium Working Room ShanChengKun 2003.10.28 更新 //
/////////////////////////////////////////////////////////////////////////////
#include "stdafx.h"
#include "MemMapFile.h"
//===========================================================================
// 执着地按指定大小映射文件,没有则创建,有则直接打开,覆盖只读文件会失败
//===========================================================================
void * CMemMapFile::CreateNewFile (LPCTSTR szFileName, DWORD dwMaxFileSize)
{
this->UnMapFile () ;
m_hFile = ::CreateFile (szFileName, GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ, NULL, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL) ;
if (m_hFile == INVALID_HANDLE_VALUE)
return NULL ;
m_hFileMap = ::CreateFileMapping (m_hFile, NULL, PAGE_READWRITE, 0, dwMaxFileSize, NULL) ;
if (m_hFileMap == NULL)
{
::CloseHandle (m_hFile) ;
m_hFile = INVALID_HANDLE_VALUE ;
return NULL ;
}
m_pMapAddress = ::MapViewOfFile (m_hFileMap, FILE_MAP_ALL_ACCESS, 0, 0, 0) ;
if (m_pMapAddress == NULL)
this->UnMapFile () ;
return (void *)m_pMapAddress ;
}
//===========================================================================
// 执着地按指定大小映射文件,没有则创建,有则直接打开,覆盖只读文件会失败
//===========================================================================
void * CMemMapFile::OpenExistFile (LPCTSTR szFileName, DWORD dwMaxFileSize)
{
this->UnMapFile () ;
m_hFile = ::CreateFile (szFileName, GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ, NULL, OPEN_ALWAYS,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL) ;
if (m_hFile == INVALID_HANDLE_VALUE)
return NULL ;
m_hFileMap = ::CreateFileMapping (m_hFile, NULL, PAGE_READWRITE, 0, dwMaxFileSize, NULL) ;
if (m_hFileMap == NULL)
{
::CloseHandle (m_hFile) ;
m_hFile = INVALID_HANDLE_VALUE ;
return NULL ;
}
m_pMapAddress = ::MapViewOfFile (m_hFileMap, FILE_MAP_ALL_ACCESS, 0, 0, 0) ;
if (m_pMapAddress == NULL)
this->UnMapFile () ;
return (void *)m_pMapAddress ;
}
//===========================================================================
// 只读方式打开并映射指定的已经存在的文件,并发的程序可以只读的方式访问
//===========================================================================
void * CMemMapFile::OpenReadFile (LPCTSTR szFileName)
{
this->UnMapFile () ;
m_hFile = ::CreateFile (szFileName, GENERIC_READ, FILE_SHARE_READ, NULL,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL) ;
if (m_hFile == INVALID_HANDLE_VALUE)
return NULL ;
m_hFileMap = ::CreateFileMapping (m_hFile, NULL, PAGE_READONLY, 0, 0, NULL) ;
if (m_hFileMap == NULL)
{
::CloseHandle (m_hFile) ;
m_hFile = INVALID_HANDLE_VALUE ;
return NULL ;
}
m_pMapAddress = ::MapViewOfFile (m_hFileMap, FILE_MAP_READ, 0, 0, 0) ;
if (m_pMapAddress == NULL)
this->UnMapFile () ;
return (void *)m_pMapAddress ;
}
/////////////////////////////////////////////////////////////////////////////
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