summaryrefslogtreecommitdiff
path: root/Build/source/texk/kpathsea/kdefault.c
blob: 235be28cd9bec716d105100647ba02f3bd937d85 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
/* kdefault.c: expand extra colons.
   (This is not named default.c because then the OSF/1 make tries to
   make a program `default' from it, since we have a target `default';
   and OSF/1 make doesn't understand .PHONY.)

   Copyright 1993, 1994, 1996, 2008 Karl Berry.
   Copyright 2002, 2005 Olaf Weber.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   This library 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
   Lesser General Public License for more details.

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

#include <kpathsea/config.h>

#include <kpathsea/c-pathch.h>
#include <kpathsea/default.h>


/* Check for leading colon first, then trailing, then doubled, since
   that is fastest.  Usually it will be leading or trailing.  */

string 
kpathsea_expand_default (kpathsea kpse, const_string path,  const_string fallback)
{
  unsigned path_length;
  string expansion;
  (void)kpse; /* currenty not used */
  
  /* The default path better not be null.  */
  assert (fallback);
  
  if (path == NULL)
    expansion = xstrdup (fallback);

  /* Solitary or leading :?  */
  else if (IS_ENV_SEP (*path))
    {
      expansion = path[1] == 0 ? xstrdup (fallback) : concat (fallback, path);
    }

  /* Sorry about the assignment in the middle of the expression, but
     conventions were made to be flouted and all that.  I don't see the
     point of calling strlen twice or complicating the logic just to
     avoid the assignment (especially now that I've pointed it out at
     such great length).  */
  else if (path[(path_length = strlen (path)) - 1] == ENV_SEP)
    expansion = concat (path, fallback);

  /* OK, not leading or trailing.  Check for doubled.  */
  else
    {
      const_string loc;

      for (loc = path; *loc; loc++)
        if (IS_ENV_SEP (loc[0]) && IS_ENV_SEP (loc[1]))
          break;
      if (*loc)
        { /* We have a doubled colon.  */
          expansion = (string)xmalloc (path_length + strlen(fallback) + 1);

          /* Copy stuff up to and including the first colon.  */
          strncpy (expansion, path, loc - path + 1);
          expansion[loc - path + 1] = 0;

          /* Copy in FALLBACK, and then the rest of PATH.  */
          strcat (expansion, fallback);
          strcat (expansion, loc + 1);
        }
      else
        { /* No doubled colon. */
          expansion = xstrdup(path);
        }
    }
  
  return expansion;
}
#if defined (KPSE_COMPAT_API)
string 
kpse_expand_default (const_string path,  const_string fallback)
{
    return kpathsea_expand_default (kpse_def, path, fallback);
}
#endif


#ifdef TEST

void
test_expand_default (const_string path, const_string def)
{
  string answer;
  
  printf ("Expansion of `%s':\t", path ? path : "(nil)");
  answer = kpse_expand_default (path, def);
  puts (answer);
}

int
main ()
{
  string default_path = "default";

  test_expand_default (NULL, default_path);
  test_expand_default ("", default_path);
  test_expand_default ("none", default_path);
  test_expand_default (ENV_SEP_STRING, default_path);
  test_expand_default (ENV_SEP_STRING "first", default_path);
  test_expand_default ("last" ENV_SEP_STRING, default_path);
  test_expand_default ("middle" ENV_SEP_STRING ENV_SEP_STRING "elddim", default_path);
  
  return 0;
}

#endif /* TEST */


/*
Local variables:
standalone-compile-command: "gcc -g -I. -I.. -DTEST kdefault.c kpathsea.a"
End:
*/