Dogcows Code - chaz/tar/blob - src/suffix.c

   1 /* This file is part of GNU tar.
   2    Copyright 2007, 2009, 2013-2014 Free Software Foundation, Inc.
   3
   4    Written by Sergey Poznyakoff.
   5
   6    GNU tar is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by the
   8    Free Software Foundation; either version 3, or (at your option) any later
   9    version.
  10
  11    GNU tar is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
  14    Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License along
  17    with GNU tar.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #include <system.h>
  20 #include "common.h"
  21
  22 struct compression_suffix
  23 {
  24   const char *suffix;
  25   size_t length;
  26   const char *program;
  27 };
  28
  29 static struct compression_suffix compression_suffixes[] = {
  30 #define __CAT2__(a,b) a ## b
  31 #define S(s,p) #s, sizeof (#s) - 1, __CAT2__(p,_PROGRAM)
  32   { "tar", 3, NULL },
  33   { S(gz,   GZIP) },
  34   { S(tgz,  GZIP) },
  35   { S(taz,  GZIP) },
  36   { S(Z,    COMPRESS) },
  37   { S(taZ,  COMPRESS) },
  38   { S(bz2,  BZIP2) },
  39   { S(tbz,  BZIP2) },
  40   { S(tbz2, BZIP2) },
  41   { S(tz2,  BZIP2) },
  42   { S(lz,   LZIP) },
  43   { S(lzma, LZMA) },
  44   { S(tlz,  LZMA) },
  45   { S(lzo,  LZOP) },
  46   { S(xz,   XZ) },
  47   { S(txz,  XZ) }, /* Slackware */
  48   { NULL }
  49 #undef S
  50 #undef __CAT2__
  51 };
  52
  53 static struct compression_suffix const *
  54 find_compression_suffix (const char *name, size_t *base_len)
  55 {
  56   char *suf = strrchr (name, '.');
  57
  58   if (suf)
  59     {
  60       size_t len;
  61       struct compression_suffix *p;
  62
  63       suf++;
  64       len = strlen (suf);
  65
  66       for (p = compression_suffixes; p->suffix; p++)
  67         {
  68           if (p->length == len && memcmp (p->suffix, suf, len) == 0)
  69             {
  70               if (*base_len)
  71                 *base_len = strlen (name) - len - 1;
  72               return p;
  73             }
  74         }
  75     }
  76   return NULL;
  77 }
  78
  79 static const char *
  80 find_compression_program (const char *name, const char *defprog)
  81 {
  82   struct compression_suffix const *p = find_compression_suffix (name, NULL);
  83   if (p)
  84     return p->program;
  85   return defprog;
  86 }
  87
  88 void
  89 set_compression_program_by_suffix (const char *name, const char *defprog)
  90 {
  91   const char *program = find_compression_program (name, defprog);
  92   if (program)
  93     use_compress_program_option = program;
  94 }
  95
  96 char *
  97 strip_compression_suffix (const char *name)
  98 {
  99   char *s = NULL;
 100   size_t len;
 101
 102   if (find_compression_suffix (name, &len))
 103     {
 104       if (strncmp (name + len - 4, ".tar", 4) == 0)
 105         len -= 4;
 106       if (len == 0)
 107         return NULL;
 108       s = xmalloc (len + 1);
 109       memcpy (s, name, len);
 110       s[len] = 0;
 111     }
 112   return s;
 113 }
 114