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00001 /******************************************************************************** 00002 * * 00003 * M e m o r y M a p p e d F i l e * 00004 * * 00005 ********************************************************************************* 00006 * Copyright (C) 2004,2009 by Jeroen van der Zijp. All Rights Reserved. * 00007 ********************************************************************************* 00008 * This library is free software; you can redistribute it and/or modify * 00009 * it under the terms of the GNU Lesser General Public License as published by * 00010 * the Free Software Foundation; either version 3 of the License, or * 00011 * (at your option) any later version. * 00012 * * 00013 * This library is distributed in the hope that it will be useful, * 00014 * but WITHOUT ANY WARRANTY; without even the implied warranty of * 00015 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * 00016 * GNU Lesser General Public License for more details. * 00017 * * 00018 * You should have received a copy of the GNU Lesser General Public License * 00019 * along with this program. If not, see <http://www.gnu.org/licenses/> * 00020 ********************************************************************************* 00021 * $Id: FXMemMap.h,v 1.18 2009/01/06 13:07:25 fox Exp $ * 00022 ********************************************************************************/ 00023 #ifndef FXMEMMAP_H 00024 #define FXMEMMAP_H 00025 00026 00027 #ifndef FXFILE_H 00028 #include "FXFile.h" 00029 #endif 00030 00031 namespace FX { 00032 00033 00034 /** 00035 * A Memory Map provides a view of a file as an array of memory; 00036 * this allows the file itself to be used as backing for the data 00037 * and very simplified file access results. 00038 * Moreover, mapped files may be shared by processes, resuling 00039 * in far less "real" memory being used than would otherwise be 00040 * the case. 00041 */ 00042 class FXAPI FXMemMap : public FXFile { 00043 private: 00044 FXInputHandle maphandle; // Handle for the map 00045 FXuchar* mapbase; // Memory base where it is mapped 00046 FXlong mapoffset; // Offset of the map 00047 FXlong mapposition; // Position in file 00048 FXival maplength; // Length of the map 00049 private: 00050 FXMemMap(const FXMemMap&); 00051 FXMemMap &operator=(const FXMemMap&); 00052 public: 00053 00054 /// Construct a memory map 00055 FXMemMap(); 00056 00057 /// Open a file, and map a view of it into memory; the offset must be a multiple of the page size 00058 void* openMap(const FXString& filename,FXlong off=0,FXival len=-1L,FXuint m=FXIO::Reading,FXuint p=FXIO::AllReadWrite); 00059 00060 /// Open map using existing file handle, and map a view of it into memory 00061 void* openMap(FXInputHandle h,FXlong off=0,FXival len=-1L,FXuint m=FXIO::Reading); 00062 00063 /// Map a view of the already open file into memory 00064 void *map(FXlong off=0,FXival len=-1L); 00065 00066 /// Return pointer to memory area 00067 void* base() const { return mapbase; } 00068 00069 /// Obtain length of the map 00070 long length() const { return maplength; } 00071 00072 /// Obtain offset of the map 00073 long offset() const { return mapoffset; } 00074 00075 /// Get current file position 00076 virtual FXlong position() const; 00077 00078 /// Change file position, returning new position from start 00079 virtual FXlong position(FXlong off,FXuint from=FXIO::Begin); 00080 00081 /// Unmap the view of the file 00082 void* unmap(); 00083 00084 /// Read block of bytes, returning number of bytes read 00085 virtual FXival readBlock(void* data,FXival count); 00086 00087 /// Write block of bytes, returning number of bytes written 00088 virtual FXival writeBlock(const void* data,FXival count); 00089 00090 /// Flush to disk 00091 virtual FXbool flush(); 00092 00093 /// Close file, and also the map 00094 virtual FXbool close(); 00095 00096 /// Destroy the map 00097 ~FXMemMap(); 00098 }; 00099 00100 00101 } 00102 00103 #endif
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