tarfile-ops-nt.cc

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00001 ///
00002 /// \file       tarfile-ops-nt.cc
00003 ///             Non-thread safe operation functions for a libtar-compatible
00004 ///             zlib compression interface.
00005 
00006 /*
00007     Copyright (C) 2007-2012, Chris Frey <cdfrey@foursquare.net>
00008 
00009     This program is free software; you can redistribute it and/or modify
00010     it under the terms of the GNU General Public License as published by
00011     the Free Software Foundation; either version 2 of the License, or
00012     (at your option) any later version.
00013 
00014     This program is distributed in the hope that it will be useful,
00015     but WITHOUT ANY WARRANTY; without even the implied warranty of
00016     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
00017 
00018     See the GNU General Public License in the COPYING file at the
00019     root directory of this project for more details.
00020 */
00021 
00022 #include "tarfile.h"
00023 
00024 #include <sys/types.h>
00025 #include <sys/stat.h>
00026 #include <fcntl.h>
00027 #include <stdlib.h>
00028 
00029 #include <zlib.h>
00030 
00031 #include <assert.h>
00032 
00033 namespace reuse {
00034 
00035 namespace gztar_nonthread {
00036 
00037         namespace {
00038                 // array of compressed file handles... needed for architectures
00039                 // where sizeof(int) != sizeof(gzFile)
00040                 gzFile *gzHandles = 0;
00041                 unsigned int gzArraySize = 0;
00042         }
00043 
00044         int open_compressed(const char *file, int flags, mode_t mode)
00045         {
00046                 unsigned int index = 0;
00047                 for( ; index < gzArraySize; index++ ) {
00048                         if( gzHandles[index] == 0 )
00049                                 break;
00050                 }
00051                 if( index >= gzArraySize ) {
00052                         gzFile *h = (gzFile*) realloc(gzHandles,
00053                                 (gzArraySize + 100) * sizeof(gzFile));
00054                         if( h ) {
00055                                 gzHandles = h;
00056                                 gzArraySize += 100;
00057                         }
00058                         else {
00059                                 return -1;
00060                         }
00061                 }
00062 
00063                 int fd = open(file, flags, mode);
00064                 if( fd == -1 )
00065                         return -1;
00066 
00067                 gzFile gfd = gzdopen(fd, (flags & O_WRONLY) ? "wb9" : "rb");
00068                 if( gfd == NULL ) {
00069                         close(fd);
00070                         return -1;
00071                 }
00072 
00073                 gzHandles[index] = gfd;
00074                 return index;
00075         }
00076 
00077         int close_compressed(int fd)
00078         {
00079                 unsigned int ufd = fd;
00080                 assert( ufd < gzArraySize );
00081                 int ret = gzclose(gzHandles[ufd]);
00082                 gzHandles[ufd] = 0;
00083                 return ret;
00084         }
00085 
00086         ssize_t read_compressed(int fd, void *buf, size_t size)
00087         {
00088                 unsigned int ufd = fd;
00089                 assert( ufd < gzArraySize );
00090                 return gzread(gzHandles[ufd], buf, size);
00091         }
00092 
00093         ssize_t write_compressed(int fd, const void *buf, size_t size)
00094         {
00095                 unsigned int ufd = fd;
00096                 assert( ufd < gzArraySize );
00097                 return gzwrite(gzHandles[ufd], buf, size);
00098         }
00099 
00100 } // namespace gztar_nonthread
00101 
00102 
00103 tartype_t gztar_ops_nonthread = {
00104         (openfunc_t) gztar_nonthread::open_compressed,
00105         gztar_nonthread::close_compressed,
00106         gztar_nonthread::read_compressed,
00107         gztar_nonthread::write_compressed
00108 };
00109 
00110 
00111 } // namespace reuse
00112