suffix.c

gnu tar 源码包。 tar 软件是 Unix 系统下的一个打包软件

/* This file is part of GNU tar.
   Copyright (C) 2007 Free Software Foundation, Inc.

   Written by Sergey Poznyakoff.

   GNU tar is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by the
   Free Software Foundation; either version 3, or (at your option) any later
   version.

   GNU tar is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
   Public License for more details.

   You should have received a copy of the GNU General Public License along
   with GNU tar.  If not, see <http://www.gnu.org/licenses/>.  */

#include <system.h>
#include "common.h"

struct compression_suffix
{
  const char *suffix;
  size_t length;
  const char *program;
};

struct compression_suffix compression_suffixes[] = {
#define S(s,p) #s, sizeof (#s) - 1, #p
  { S(gz, gzip) },
  { S(tgz, gzip) },
  { S(taz, gzip) },
  { S(Z, compress) },
  { S(taZ, compress) },
  { S(bz2, bzip2) },
  { S(tbz, bzip2) },
  { S(tbz2, bzip2) },
  { S(tz2, bzip2) },
  { S(lzma, lzma) },
  { S(tlz, lzma) },
#undef S
};

int nsuffixes = sizeof (compression_suffixes) /
                  sizeof (compression_suffixes[0]);

static const char *
find_compression_program (const char *name, const char *defprog)
{
  char *suf = strrchr (name, '.');
    
  if (suf)
    {
      int i;
      size_t len;

      suf++;
      len = strlen (suf);

      for (i = 0; i < nsuffixes; i++)
	{
	  if (compression_suffixes[i].length == len
	      && memcmp (compression_suffixes[i].suffix, suf, len) == 0)
	    return compression_suffixes[i].program;
	}
    }
  return defprog;
}

void
set_comression_program_by_suffix (const char *name, const char *defprog)
{
  const char *program = find_compression_program (name, defprog);
  if (program)
    use_compress_program_option = program;
}