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mmapio.h

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00001 /*
00002     Copyright (C) 2002 by Jorrit Tyberghein
00003 
00004     This library is free software; you can redistribute it and/or
00005     modify it under the terms of the GNU Library General Public
00006     License as published by the Free Software Foundation; either
00007     version 2 of the License, or (at your option) any later version.
00008 
00009     This library is distributed in the hope that it will be useful,
00010     but WITHOUT ANY WARRANTY; without even the implied warranty of
00011     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012     Library General Public License for more details.
00013 
00014     You should have received a copy of the GNU Library General Public
00015     License along with this library; if not, write to the Free
00016     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00017 */
00018 
00019 #ifndef __CS_MEMORY_MAPPED_IO__
00020 #define __CS_MEMORY_MAPPED_IO__
00021 
00026 #include "csextern.h"
00027 #include "bitarray.h"
00028 
00029 struct iVFS;
00030 
00034 const unsigned csmmioDefaultCacheBlockSize = 256;
00035 
00039 const unsigned csmmioDefaultCacheSize = 256;//2048;
00040 
00044 const unsigned csmmioDefaultHashSize = 211;//1559;
00045 
00046 
00078 class CS_CSUTIL_EXPORT csMemoryMappedIO
00079 {
00080 private:
00082   unsigned int block_size;
00083   
00085   bool valid_mmio_object;
00086 
00088   unsigned cache_block_size;
00089 
00094   unsigned int cache_max_size;
00095 
00097   unsigned int cache_block_count;
00098   
00103   csBitArray *page_map;
00104 
00105 #ifdef CS_DEBUG
00106 
00107 public:
00109   unsigned int hits;
00110 
00112   unsigned int misses;
00113 
00114 private:
00115 #endif
00116 
00118   struct CacheBlock
00119   {    
00121     unsigned age;
00122 
00124     unsigned offset;
00125 
00127     unsigned page;
00128     
00130     CacheBlock *next;
00131 
00133     unsigned char *data;
00134   };
00135 
00137   CacheBlock *cache[csmmioDefaultHashSize];
00138 
00139   // Software specific csMemMapInfo struct, should only be defined for
00140   // platforms w/o hardware mmio.
00141   struct emulatedMmioInfo 
00142   {          
00144     FILE *hMappedFile;
00145 
00147     unsigned char *data;
00148 
00150     unsigned int file_size;
00151   } emulatedPlatform;
00152   
00153 #ifdef CS_HAS_MEMORY_MAPPED_IO
00154 
00155   csMemMapInfo platform;
00156   
00158   bool valid_platform;
00159 #endif
00160 public:
00168   csMemoryMappedIO(unsigned _block_size, char const *filename, iVFS* vfs = 0);
00169 
00173   ~csMemoryMappedIO();
00174 
00181   void *GetPointer(unsigned int index);
00182   
00186   bool IsValid();
00187 
00188 private:
00190   void CachePage(unsigned int page);
00191 
00193   bool SoftMemoryMapFile(emulatedMmioInfo *platform, char const *filename);
00194 
00196   void SoftUnMemoryMapFile(emulatedMmioInfo *platform);
00197 };
00198 
00199 #endif // __CS_MEMORY_MAPPED_IO__
00200 

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