source/texk/web2c/lib/basechsuffix.c

   1 /* basechsuffix.c: replace the last bit of a filename with something else.
   2
   3    Written in 1995 by Karl Berry.  Public domain.  */
   4
   5 #include <w2c/config.h>
   6 #include "lib.h"
   7
   8 /* Return the basename of NAME, with trailing characters OLD replaced by
   9    NEW.  (If last characters in NAME are not OLD, just append NEW.)
  10    Since this is used to turn, e.g., foo/cmr10.300pk -> cmr10.300gf,
  11    don't assume a `.' preceding OLD or NEW.
  12
  13    In other words, we're implementing `basename NAME OLD`NEW.  */
  14
  15 string
  16 basenamechangesuffix (const_string name,  const_string old_suffix,
  17                       const_string new_suffix)
  18 {
  19   string answer;
  20   unsigned c;
  21   const_string base = xbasename (name);
  22   unsigned base_len = strlen (base);
  23   unsigned copy_limit = base_len;
  24   unsigned old_suffix_len = strlen (old_suffix);
  25
  26   if (old_suffix_len <= base_len) {
  27     for (c = 0; c < old_suffix_len; c++) {
  28       if (!FILECHARCASEEQ (old_suffix[old_suffix_len - c - 1],
  29                        base[base_len - c - 1]))
  30         break;
  31     }
  32     if (c == old_suffix_len) {
  33       copy_limit -= old_suffix_len;
  34     }
  35   }
  36
  37   answer = xmalloc (copy_limit + strlen (new_suffix) + 1);
  38   strncpy (answer, base, copy_limit);
  39   answer[copy_limit] = 0;
  40   strcat (answer, new_suffix);
  41
  42   return answer;
  43 }