src/tarfile-ops-nt.cc

   1 ///
   2 /// \file       tarfile-ops-nt.cc
   3 ///             Non-thread safe operation functions for a libtar-compatible
   4 ///             zlib compression interface.
   5
   6 /*
   7     Copyright (C) 2007-2013, Chris Frey <cdfrey@foursquare.net>
   8
   9     This program is free software; you can redistribute it and/or modify
  10     it under the terms of the GNU General Public License as published by
  11     the Free Software Foundation; either version 2 of the License, or
  12     (at your option) any later version.
  13
  14     This program is distributed in the hope that it will be useful,
  15     but WITHOUT ANY WARRANTY; without even the implied warranty of
  16     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  17
  18     See the GNU General Public License in the COPYING file at the
  19     root directory of this project for more details.
  20 */
  21
  22 #include "tarfile.h"
  23
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #include <fcntl.h>
  27 #include <stdlib.h>
  28
  29 #include <zlib.h>
  30
  31 #include <assert.h>
  32
  33 namespace reuse {
  34
  35 namespace gztar_nonthread {
  36
  37         namespace {
  38                 // array of compressed file handles... needed for architectures
  39                 // where sizeof(int) != sizeof(gzFile)
  40                 gzFile *gzHandles = 0;
  41                 unsigned int gzArraySize = 0;
  42         }
  43
  44         int open_compressed(const char *file, int flags, mode_t mode)
  45         {
  46                 unsigned int index = 0;
  47                 for( ; index < gzArraySize; index++ ) {
  48                         if( gzHandles[index] == 0 )
  49                                 break;
  50                 }
  51                 if( index >= gzArraySize ) {
  52                         gzFile *h = (gzFile*) realloc(gzHandles,
  53                                 (gzArraySize + 100) * sizeof(gzFile));
  54                         if( h ) {
  55                                 gzHandles = h;
  56                                 gzArraySize += 100;
  57                         }
  58                         else {
  59                                 return -1;
  60                         }
  61                 }
  62
  63                 int fd = open(file, flags, mode);
  64                 if( fd == -1 )
  65                         return -1;
  66
  67                 gzFile gfd = gzdopen(fd, (flags & O_WRONLY) ? "wb9" : "rb");
  68                 if( gfd == NULL ) {
  69                         close(fd);
  70                         return -1;
  71                 }
  72
  73                 gzHandles[index] = gfd;
  74                 return index;
  75         }
  76
  77         int close_compressed(int fd)
  78         {
  79                 unsigned int ufd = fd;
  80                 assert( ufd < gzArraySize );
  81                 int ret = gzclose(gzHandles[ufd]);
  82                 gzHandles[ufd] = 0;
  83                 return ret;
  84         }
  85
  86         ssize_t read_compressed(int fd, void *buf, size_t size)
  87         {
  88                 unsigned int ufd = fd;
  89                 assert( ufd < gzArraySize );
  90                 return gzread(gzHandles[ufd], buf, size);
  91         }
  92
  93         ssize_t write_compressed(int fd, const void *buf, size_t size)
  94         {
  95                 unsigned int ufd = fd;
  96                 assert( ufd < gzArraySize );
  97                 return gzwrite(gzHandles[ufd], buf, size);
  98         }
  99
 100 } // namespace gztar_nonthread
 101
 102
 103 tartype_t gztar_ops_nonthread = {
 104         (openfunc_t) gztar_nonthread::open_compressed,
 105         gztar_nonthread::close_compressed,
 106         gztar_nonthread::read_compressed,
 107         gztar_nonthread::write_compressed
 108 };
 109
 110
 111 } // namespace reuse
 112