lib/libc/time/scheck.c

   1 /*      $NetBSD: scheck.c,v 1.11 2013/07/17 23:09:26 christos Exp $     */
   2
   3 /*
   4 ** This file is in the public domain, so clarified as of
   5 ** 2006-07-17 by Arthur David Olson.
   6 */
   7
   8 #if HAVE_NBTOOL_CONFIG_H
   9 #include "nbtool_config.h"
  10 #endif
  11
  12 #include <sys/cdefs.h>
  13
  14 #ifndef lint
  15 #if 0
  16 static char     elsieid[] = "@(#)scheck.c       8.19";
  17 #else
  18 __RCSID("$NetBSD: scheck.c,v 1.11 2013/07/17 23:09:26 christos Exp $");
  19 #endif
  20 #endif /* !defined lint */
  21
  22 /*LINTLIBRARY*/
  23
  24 #include "private.h"
  25
  26 const char *
  27 scheck(const char *const string, const char *const format)
  28 {
  29         char *          fbuf;
  30         const char *    fp;
  31         char *          tp;
  32         int             c;
  33         const char *    result;
  34         char            dummy;
  35
  36         result = "";
  37         if (string == NULL || format == NULL)
  38                 return result;
  39         fbuf = malloc(2 * strlen(format) + 4);
  40         if (fbuf == NULL)
  41                 return result;
  42         fp = format;
  43         tp = fbuf;
  44
  45         /*
  46         ** Copy directives, suppressing each conversion that is not
  47         ** already suppressed.  Scansets containing '%' are not
  48         ** supported; e.g., the conversion specification "%[%]" is not
  49         ** supported.  Also, multibyte characters containing a
  50         ** non-leading '%' byte are not supported.
  51         */
  52         while ((*tp++ = c = *fp++) != '\0') {
  53                 if (c != '%')
  54                         continue;
  55                 if (is_digit(*fp)) {
  56                         char const *f = fp;
  57                         char *t = tp;
  58                         do {
  59                                 *t++ = c = *f++;
  60                         } while (is_digit(c));
  61                         if (c == '$') {
  62                                 fp = f;
  63                                 tp = t;
  64                         }
  65                 }
  66                 *tp++ = '*';
  67                 if (*fp == '*')
  68                         ++fp;
  69                 if ((*tp++ = *fp++) == '\0')
  70                         break;
  71         }
  72
  73         *(tp - 1) = '%';
  74         *tp++ = 'c';
  75         *tp = '\0';
  76         if (sscanf(string, fbuf, &dummy) != 1)
  77                 result = format;
  78         free(fbuf);
  79         return result;
  80 }