lib/libc/string/strcspn.c

   1 /*      $NetBSD: strcspn.c,v 1.16 2008/07/30 16:13:59 joerg Exp $       */
   2
   3 /*-
   4  * Copyright (c) 2008 Joerg Sonnenberger
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include <sys/cdefs.h>
  29 __RCSID("$NetBSD: strcspn.c,v 1.16 2008/07/30 16:13:59 joerg Exp $");
  30
  31 #include <assert.h>
  32 #include <inttypes.h>
  33 #include <limits.h>
  34 #include <string.h>
  35
  36 /* 64bit version is in strspn.c */
  37 #if ULONG_MAX != 0xffffffffffffffffull
  38
  39 size_t
  40 strcspn(const char *s, const char *charset)
  41 {
  42         static const size_t idx[8] = { 1, 2, 4, 8, 16, 32, 64, 128 };
  43         const char *t;
  44         uint8_t set[32];
  45 #define UC(a) ((unsigned int)(unsigned char)(a))
  46
  47         _DIAGASSERT(s != NULL);
  48         _DIAGASSERT(charset != NULL);
  49
  50         if (charset[0] == '\0')
  51                 return strlen(s);
  52         if (charset[1] == '\0') {
  53                 for (t = s; *t != '\0'; ++t)
  54                         if (*t == *charset)
  55                                 break;
  56                 return t - s;
  57         }
  58
  59         (void)memset(set, 0, sizeof(set));
  60
  61         for (; *charset != '\0'; ++charset)
  62                 set[UC(*charset) >> 3] |= idx[UC(*charset) & 7];
  63
  64         for (t = s; *t != '\0'; ++t)
  65                 if (set[UC(*t) >> 3] & idx[UC(*t) & 7])
  66                         break;
  67         return t - s;
  68 }
  69
  70 #endif