source/texk/kpathsea/fn.c

   1 /* fn.c: arbitrarily long filenames or strings.
   2
   3    Copyright 1993, 2008 Karl Berry.
   4    Copyright 2001, 2005 Olaf Weber.
   5
   6    This library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    This library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public License
  17    along with this library; if not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #include <kpathsea/config.h>
  20
  21 #include <kpathsea/fn.h>
  22
  23
  24 /* /usr/local/lib/texmf/fonts/public/cm/pk/ljfour/cmr10.300pk is 58
  25    chars, so ASCII `K' seems a good choice. */
  26 #define CHUNK_SIZE 75
  27
  28
  29 fn_type
  30 fn_init (void)
  31 {
  32   fn_type ret;
  33
  34   FN_ALLOCATED (ret) = FN_LENGTH (ret) = 0;
  35   FN_STRING (ret) = NULL;
  36
  37   return ret;
  38 }
  39
  40
  41 fn_type
  42 fn_copy0 (const_string s,  unsigned len)
  43 {
  44   fn_type ret;
  45
  46   FN_ALLOCATED (ret) = CHUNK_SIZE > len ? CHUNK_SIZE : len + 1;
  47   FN_STRING (ret) = (string)xmalloc (FN_ALLOCATED (ret));
  48
  49   strncpy (FN_STRING (ret), s, len);
  50   FN_STRING (ret)[len] = 0;
  51   FN_LENGTH (ret) = len + 1;
  52
  53   return ret;
  54 }
  55 \f
  56 /* Don't think we ever try to free something that might usefully be
  57    empty, so give fatal error if nothing allocated.  */
  58
  59 void
  60 fn_free (fn_type *f)
  61 {
  62   assert (FN_STRING (*f) != NULL);
  63   free (FN_STRING (*f));
  64   FN_STRING (*f) = NULL;
  65   FN_ALLOCATED (*f) = 0;
  66   FN_LENGTH (*f) = 0;
  67 }
  68 \f
  69 /* An arithmetic increase seems more reasonable than geometric.  We
  70    don't increase the length member since it may be more convenient for
  71    the caller to add than subtract when appending the stuff that will
  72    presumably follow.  */
  73
  74 static void
  75 grow (fn_type *f,  unsigned len)
  76 {
  77   while (FN_LENGTH (*f) + len > FN_ALLOCATED (*f))
  78     {
  79       FN_ALLOCATED (*f) += CHUNK_SIZE;
  80       XRETALLOC (FN_STRING (*f), FN_ALLOCATED (*f), char);
  81     }
  82 }
  83
  84
  85 void
  86 fn_1grow (fn_type *f,  char c)
  87 {
  88   grow (f, 1);
  89   FN_STRING (*f)[FN_LENGTH (*f)] = c;
  90   FN_LENGTH (*f)++;
  91 }
  92
  93
  94 void
  95 fn_grow (fn_type *f,  const_string source,  unsigned len)
  96 {
  97   grow (f, len);
  98   strncpy (FN_STRING (*f) + FN_LENGTH (*f), source, len);
  99   FN_LENGTH (*f) += len;
 100 }
 101
 102
 103 void
 104 fn_str_grow (fn_type *f,  const_string s)
 105 {
 106   unsigned more_len = strlen (s);
 107   grow (f, more_len);
 108   strcat (FN_STRING (*f), s);
 109   FN_LENGTH (*f) += more_len;
 110 }
 111
 112
 113 void
 114 fn_shrink_to (fn_type *f,  unsigned loc)
 115 {
 116   assert (FN_LENGTH (*f) > loc);
 117   FN_STRING (*f)[loc] = 0;
 118   FN_LENGTH (*f) = loc + 1;
 119 }