mmapifstream.cpp

   1 /*
   2  *  mmapifstream.cpp
   3  *  openc2e
   4  *
   5  *  Created by Alyssa Milburn on Sat Jul 24 2004.
   6  *  Copyright (c) 2004 Alyssa Milburn. All rights reserved.
   7  *
   8  *  This library is free software; you can redistribute it and/or
   9  *  modify it under the terms of the GNU Lesser General Public
  10  *  License as published by the Free Software Foundation; either
  11  *  version 2 of the License, or (at your option) any later version.
  12  *
  13  *  This library is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  *  Lesser General Public License for more details.
  17  *
  18  */
  19
  20 #include "mmapifstream.h"
  21 #include "openc2e.h"
  22 #ifdef _WIN32
  23 #include <windows.h>
  24 #else // assume POSIX
  25 #include <sys/types.h>
  26 #include <sys/mman.h>
  27 #endif
  28 #include <iostream> // debug needs only
  29
  30 mmapifstream::mmapifstream(std::string filename) {
  31         live = false;
  32         mmapopen(filename);
  33 }
  34
  35 void mmapifstream::mmapopen(std::string filename) {
  36         open(filename.c_str(), std::ios::binary);
  37         if (!is_open()) return;
  38
  39 #ifdef _WIN32
  40         // todo: store the handle somewhere?
  41         HANDLE hFile = CreateFileA(filename.c_str(), GENERIC_READ, FILE_SHARE_READ,
  42                 NULL, OPEN_EXISTING, 0, NULL);
  43         HANDLE hMap = CreateFileMapping(hFile, NULL, PAGE_READONLY, 0, 0, NULL);
  44         void *mapr = MapViewOfFile(hMap, FILE_MAP_READ, 0, 0, 0);
  45 #else
  46         FILE *f = fopen(filename.c_str(), "r");
  47         assert(f);
  48 /*      if (!f) {
  49                 close();
  50                 setstate(failbit);
  51                 perror("fopen");
  52                 return;
  53         } */
  54
  55         // now do the mmap (work out filesize, then mmap)
  56         int fno = fileno(f);
  57         seekg(0, std::ios::end);
  58         filesize = tellg();
  59         assert((int)filesize != -1);
  60         seekg(0, std::ios::beg);
  61
  62         void *mapr = mmap(0, filesize, PROT_READ, MAP_PRIVATE, fno, 0);
  63         fclose(f); // we don't need it, now!
  64 #endif
  65
  66         assert(mapr != (void *)-1);
  67         map = (char *)mapr;
  68         live = true;
  69 }
  70
  71 mmapifstream::~mmapifstream() {
  72         if (live)
  73 #ifdef _WIN32
  74                 UnmapViewOfFile(map);
  75 #else
  76                 munmap(map, filesize);
  77 #endif
  78 }
  79 /* vim: set noet: */