lib/libc/string/strpbrk.c

   1 /*      $NetBSD: strpbrk.c,v 1.20 2011/11/22 00:37:09 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: strpbrk.c,v 1.20 2011/11/22 00:37:09 joerg Exp $");
  30
  31 #include <assert.h>
  32 #include <inttypes.h>
  33 #include <limits.h>
  34 #include <string.h>
  35
  36 #define FAST_STRPBRK 1
  37 #define UC(a) ((unsigned int)(unsigned char)(a))
  38
  39 #ifdef FAST_STRPBRK
  40 #define ADD_NEW_TO_SET(i) (set[inv[i] = idx++] = (i))
  41 #define IS_IN_SET(i) (inv[i] < idx && set[inv[i]] == (i))
  42 #define ADD_TO_SET(i) (void)(IS_IN_SET(i) || /*LINTED no effect*/ADD_NEW_TO_SET(i))
  43 #else
  44 #define IS_IN_SET(i) (set[(i) >> 3] & idx[(i) & 7])
  45 #define ADD_TO_SET(i) (void)(set[(i) >> 3] |= idx[(i) & 7])
  46 #endif
  47
  48 char *
  49 strpbrk(const char *s, const char *charset)
  50 {
  51 #ifdef FAST_STRPBRK
  52         uint8_t set[256], inv[256], idx = 0;
  53 #else
  54         static const size_t idx[8] = { 1, 2, 4, 8, 16, 32, 64, 128 };
  55         uint8_t set[32];
  56
  57         (void)memset(set, 0, sizeof(set));
  58 #endif
  59
  60         _DIAGASSERT(s != NULL);
  61         _DIAGASSERT(charset != NULL);
  62
  63         if (charset[0] == '\0')
  64                 return NULL;
  65         if (charset[1] == '\0')
  66                 return strchr(s, charset[0]);
  67
  68         for (; *charset != '\0'; ++charset)
  69                 ADD_TO_SET(UC(*charset));
  70
  71         for (; *s != '\0'; ++s)
  72                 if (IS_IN_SET(UC(*s)))
  73                         return __UNCONST(s);
  74         return NULL;
  75 }