usr.bin/tn3270/general/genbsubs.c

   1 /*      $NetBSD: genbsubs.c,v 1.5 1998/03/11 16:49:19 thorpej Exp $     */
   2
   3 /*-
   4  * Copyright (c) 1988 The Regents of the University of California.
   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  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #ifndef lint
  34 #if 0
  35 static char sccsid[] = "@(#)genbsubs.c  4.2 (Berkeley) 4/26/91";
  36 #else
  37 __RCSID("$NetBSD: genbsubs.c,v 1.5 1998/03/11 16:49:19 thorpej Exp $");
  38 #endif
  39 #endif /* not lint */
  40
  41 #include "general.h"
  42
  43 /* The output of bunequal is the offset of the byte which didn't match;
  44  * if all the bytes match, then we return n.
  45  * bunequal(s1, s2, n) */
  46
  47 int
  48 bunequal(s1, s2, n)
  49 char *s1, *s2;
  50 int n;
  51 {
  52     int i = 0;
  53
  54     while (i++ < n) {
  55         if (*s1++ != *s2++) {
  56             break;
  57         }
  58     }
  59     return(i-1);
  60 }
  61
  62 /* bskip(s1, n, b) : finds the first occurrence of any byte != 'b' in the 'n'
  63  * bytes beginning at 's1'.
  64  */
  65
  66 int
  67 bskip(s1, n, b)
  68 char *s1;
  69 int n;
  70 int b;
  71 {
  72     int i = 0;
  73
  74     while (i++ < n) {
  75         if (*s1++ != b) {
  76             break;
  77         }
  78     }
  79     return(i-1);
  80 }
  81
  82 /*
  83  * memNSchr(const void *s, int c, size_t n, int and)
  84  *
  85  * Like memchr, but the comparison is '((*s)&and) == c',
  86  * and we increment our way through s by "stride" ('s += stride').
  87  *
  88  * We optimize for the most used strides of +1 and -1.
  89  */
  90
  91 unsigned char *
  92 memNSchr(s, c, n, and, stride)
  93 char *s;
  94 int c;
  95 unsigned int n;
  96 int and;
  97 ssize_t stride;
  98 {
  99     unsigned char _c, *_s, _and;
 100
 101     _and = and;
 102     _c = (c&_and);
 103     _s = (unsigned char *)s;
 104     switch (stride) {
 105     case 1:
 106         while (n--) {
 107             if (((*_s)&_and) == _c) {
 108                 return _s;
 109             }
 110             _s++;
 111         }
 112         break;
 113     case -1:
 114         while (n--) {
 115             if (((*_s)&_and) == _c) {
 116                 return _s;
 117             }
 118             _s--;
 119         }
 120         break;
 121     default:
 122         while (n--) {
 123             if (((*_s)&_and) == _c) {
 124                 return _s;
 125             }
 126             _s += stride;
 127         }
 128     }
 129     return 0;
 130 }