184 lines
5.4 KiB
C++
Executable File
184 lines
5.4 KiB
C++
Executable File
/*===========================================================================
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FILE:
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MemoryMappedFile.cpp
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DESCRIPTION:
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Implementation of cMemoryMappedFile class
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PUBLIC CLASSES AND METHODS:
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cMemoryMappedFile
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The cMemoryMappedFile class provides the ability to read in a file
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via Linux memory maps
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Note: cMemoryMappedFiles are read only
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Copyright (c) 2011, Code Aurora Forum. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of Code Aurora Forum nor
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the names of its contributors may be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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===========================================================================*/
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//-----------------------------------------------------------------------------
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// Include Files
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//-----------------------------------------------------------------------------
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#include "StdAfx.h"
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#include "MemoryMappedFile.h"
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#include <sys/mman.h>
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//-----------------------------------------------------------------------------
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// Definitions
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//-----------------------------------------------------------------------------
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// Maximum size of a file this interface will try to open (64 MB)
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const DWORD MAX_FILE_SZ = 1024 * 1024 * 64;
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/*=========================================================================*/
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// cMemoryMappedFile Methods
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/*=========================================================================*/
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/*===========================================================================
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METHOD:
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cMemoryMappedFile (Public Method)
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DESCRIPTION:
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Construct object/load file into memory
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PARAMETERS
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pFile [ I ] - File name
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RETURN VALUE:
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None
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===========================================================================*/
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cMemoryMappedFile::cMemoryMappedFile( LPCSTR pFile )
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: mbResourceBased( false ),
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mpBuffer( 0 ),
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mFileSize( 0 ),
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mStatus( ERROR_FILE_NOT_FOUND )
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{
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if (pFile == 0 || pFile[0] == 0)
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{
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return;
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}
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// Open the file
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mFile = open( pFile, O_RDONLY );
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if (mFile == -1)
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{
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TRACE( "Unable to Map %s to memory. Error %d: %s\n",
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pFile,
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errno,
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strerror( errno ) );
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return;
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}
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// Grab the file size
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struct stat fileInfo;
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if (fstat( mFile, &fileInfo ) != 0)
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{
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TRACE( "Unable to get info for %s. Error %d: %s\n",
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pFile,
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errno,
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strerror( errno ) );
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return;
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}
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DWORD fileSize = fileInfo.st_size;
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// Map to mpBuffer
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mpBuffer = mmap( 0,
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fileSize,
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PROT_READ,
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MAP_SHARED | MAP_POPULATE,
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mFile,
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0 );
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if (mpBuffer == 0 || mpBuffer == MAP_FAILED )
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{
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TRACE( "Memory map failed error %d:, %s\n",
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errno,
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strerror( errno ) );
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return;
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}
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// Success!
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mFileSize = fileSize;
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mStatus = NO_ERROR;
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}
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/*===========================================================================
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METHOD:
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cMemoryMappedFile (Public Method)
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DESCRIPTION:
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Construct object/load resource based file into memory
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PARAMETERS
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pStart [ I ] - Start location of object
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nSize [ I ] - Size of object
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RETURN VALUE:
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None
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===========================================================================*/
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cMemoryMappedFile::cMemoryMappedFile(
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const char * pStart,
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const int nSize )
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: mbResourceBased( true ),
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mpBuffer( 0 ),
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mFileSize( 0 ),
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mStatus( INVALID_HANDLE_VALUE )
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{
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// Set size
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mFileSize = nSize;
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// Set memory pointer
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mpBuffer = (void * )pStart;
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// Success!
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mStatus = NO_ERROR;
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}
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/*===========================================================================
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METHOD:
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~cMemoryMappedFile (Public Method)
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DESCRIPTION:
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Destructor
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RETURN VALUE:
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None
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===========================================================================*/
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cMemoryMappedFile::~cMemoryMappedFile()
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{
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if (mbResourceBased == false)
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{
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if (munmap( mpBuffer, mFileSize ) == -1)
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{
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TRACE( "Memory unmapping error %d: %s\n",
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errno,
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strerror( errno ) );
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return;
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}
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}
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}
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