source/texk/kpathsea/kdefault.c

   1 /* kdefault.c: expand extra colons.
   2    (This is not named default.c because then the OSF/1 make tries to
   3    make a program `default' from it, since we have a target `default';
   4    and OSF/1 make doesn't understand .PHONY.)
   5
   6    Copyright 1993, 1994, 1996, 2008, 2009, 2011 Karl Berry.
   7    Copyright 2002, 2005 Olaf Weber.
   8
   9    This library is free software; you can redistribute it and/or
  10    modify it under the terms of the GNU Lesser General Public
  11    License as published by the Free Software Foundation; either
  12    version 2.1 of the License, or (at your option) any later version.
  13
  14    This library 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.  See the GNU
  17    Lesser General Public License for more details.
  18
  19    You should have received a copy of the GNU Lesser General Public License
  20    along with this library; if not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include <kpathsea/config.h>
  23
  24 #include <kpathsea/c-pathch.h>
  25 #include <kpathsea/default.h>
  26
  27
  28 /* Check for leading colon first, then trailing, then doubled, since
  29    that is fastest.  Usually it will be leading or trailing.  */
  30
  31 string
  32 kpathsea_expand_default (kpathsea kpse, const_string path,
  33                          const_string fallback)
  34 {
  35   unsigned path_length;
  36   string expansion;
  37   (void)kpse; /* currenty not used */
  38
  39   /* The default path better not be null.  */
  40   assert (fallback);
  41
  42   if (path == NULL)
  43     expansion = xstrdup (fallback);
  44
  45   /* Solitary or leading :?  */
  46   else if (IS_ENV_SEP (*path))
  47     {
  48       expansion = path[1] == 0 ? xstrdup (fallback) : concat (fallback, path);
  49     }
  50
  51   /* Sorry about the assignment in the middle of the expression, but
  52      conventions were made to be flouted and all that.  I don't see the
  53      point of calling strlen twice or complicating the logic just to
  54      avoid the assignment (especially now that I've pointed it out at
  55      such great length).  */
  56   else if (path[(path_length = strlen (path)) - 1] == ENV_SEP)
  57     expansion = concat (path, fallback);
  58
  59   /* OK, not leading or trailing.  Check for doubled.  */
  60   else
  61     {
  62       const_string loc;
  63
  64       for (loc = path; *loc; loc++)
  65         if (IS_ENV_SEP (loc[0]) && IS_ENV_SEP (loc[1]))
  66           break;
  67       if (*loc)
  68         { /* We have a doubled colon.  */
  69           expansion = (string)xmalloc (path_length + strlen(fallback) + 1);
  70
  71           /* Copy stuff up to and including the first colon.  */
  72           strncpy (expansion, path, loc - path + 1);
  73           expansion[loc - path + 1] = 0;
  74
  75           /* Copy in FALLBACK, and then the rest of PATH.  */
  76           strcat (expansion, fallback);
  77           strcat (expansion, loc + 1);
  78         }
  79       else
  80         { /* No doubled colon. */
  81           expansion = xstrdup(path);
  82         }
  83     }
  84
  85   return expansion;
  86 }
  87 \f
  88 #ifdef TEST
  89
  90 void
  91 test_expand_default (const_string path, const_string def)
  92 {
  93   string answer;
  94
  95   printf ("Expansion of `%s':\t", path ? path : "(nil)");
  96   answer = kpathsea_expand_default (kpse_def, path, def);
  97   puts (answer);
  98 }
  99
 100 int
 101 main ()
 102 {
 103   string default_path = "default";
 104
 105   test_expand_default (NULL, default_path);
 106   test_expand_default ("", default_path);
 107   test_expand_default ("none", default_path);
 108   test_expand_default (ENV_SEP_STRING, default_path);
 109   test_expand_default (ENV_SEP_STRING "first", default_path);
 110   test_expand_default ("last" ENV_SEP_STRING, default_path);
 111   test_expand_default ("middle" ENV_SEP_STRING ENV_SEP_STRING "elddim",
 112                        default_path);
 113
 114   return 0;
 115 }
 116
 117 #endif /* TEST */
 118
 119 \f
 120 /*
 121 Local variables:
 122 standalone-compile-command: "gcc -g -I. -I.. -DTEST kdefault.c kpathsea.a"
 123 End:
 124 */