timezone/scheck.c

   1 /*
   2 ** This file is in the public domain, so clarified as of
   3 ** 2006-07-17 by Arthur David Olson.
   4 */
   5
   6 /*LINTLIBRARY*/
   7
   8 #include "private.h"
   9
  10 const char *
  11 scheck(const char *const string, const char *const format)
  12 {
  13         register char *         fbuf;
  14         register const char *   fp;
  15         register char *         tp;
  16         register int            c;
  17         register const char *   result;
  18         char                    dummy;
  19
  20         result = "";
  21         if (string == NULL || format == NULL)
  22                 return result;
  23         fbuf = malloc(2 * strlen(format) + 4);
  24         if (fbuf == NULL)
  25                 return result;
  26         fp = format;
  27         tp = fbuf;
  28
  29         /*
  30         ** Copy directives, suppressing each conversion that is not
  31         ** already suppressed.  Scansets containing '%' are not
  32         ** supported; e.g., the conversion specification "%[%]" is not
  33         ** supported.  Also, multibyte characters containing a
  34         ** non-leading '%' byte are not supported.
  35         */
  36         while ((*tp++ = c = *fp++) != '\0') {
  37                 if (c != '%')
  38                         continue;
  39                 if (is_digit(*fp)) {
  40                         char const *f = fp;
  41                         char *t = tp;
  42                         do {
  43                                 *t++ = c = *f++;
  44                         } while (is_digit(c));
  45                         if (c == '$') {
  46                                 fp = f;
  47                                 tp = t;
  48                         }
  49                 }
  50                 *tp++ = '*';
  51                 if (*fp == '*')
  52                         ++fp;
  53                 if ((*tp++ = *fp++) == '\0')
  54                         break;
  55         }
  56
  57         *(tp - 1) = '%';
  58         *tp++ = 'c';
  59         *tp = '\0';
  60         if (sscanf(string, fbuf, &dummy) != 1)
  61                 result = format;
  62         free(fbuf);
  63         return result;
  64 }