| 1 | /* |
| 2 | * Copyright (c) 1984-1987 by the Regents of the |
| 3 | * University of California and by Gregory Glenn Minshall. |
| 4 | * |
| 5 | * Permission to use, copy, modify, and distribute these |
| 6 | * programs and their documentation for any purpose and |
| 7 | * without fee is hereby granted, provided that this |
| 8 | * copyright and permission appear on all copies and |
| 9 | * supporting documentation, the name of the Regents of |
| 10 | * the University of California not be used in advertising |
| 11 | * or publicity pertaining to distribution of the programs |
| 12 | * without specific prior permission, and notice be given in |
| 13 | * supporting documentation that copying and distribution is |
| 14 | * by permission of the Regents of the University of California |
| 15 | * and by Gregory Glenn Minshall. Neither the Regents of the |
| 16 | * University of California nor Gregory Glenn Minshall make |
| 17 | * representations about the suitability of this software |
| 18 | * for any purpose. It is provided "as is" without |
| 19 | * express or implied warranty. |
| 20 | */ |
| 21 | |
| 22 | #ifndef lint |
| 23 | static char sccsid[] = "@(#)genbsubs.c 1.4 (Berkeley) %G%"; |
| 24 | #endif /* ndef lint */ |
| 25 | |
| 26 | /* The output of bunequal is the offset of the byte which didn't match; |
| 27 | * if all the bytes match, then we return n. |
| 28 | * bunequal(s1, s2, n) */ |
| 29 | |
| 30 | int |
| 31 | bunequal(s1, s2, n) |
| 32 | register char *s1, *s2; |
| 33 | register n; |
| 34 | { |
| 35 | register int i = 0; |
| 36 | |
| 37 | while (i++ < n) { |
| 38 | if (*s1++ != *s2++) { |
| 39 | break; |
| 40 | } |
| 41 | } |
| 42 | return(i-1); |
| 43 | } |
| 44 | |
| 45 | /* bskip(s1, n, b) : finds the first occurrence of any byte != 'b' in the 'n' |
| 46 | * bytes beginning at 's1'. |
| 47 | */ |
| 48 | |
| 49 | int |
| 50 | bskip(s1, n, b) |
| 51 | register char *s1; |
| 52 | register int n; |
| 53 | register int b; |
| 54 | { |
| 55 | register int i = 0; |
| 56 | |
| 57 | while (i++ < n) { |
| 58 | if (*s1++ != b) { |
| 59 | break; |
| 60 | } |
| 61 | } |
| 62 | return(i-1); |
| 63 | } |
| 64 | |
| 65 | /* |
| 66 | * memNSchr(const void *s, int c, size_t n, int and) |
| 67 | * |
| 68 | * Like memchr, but the comparison is '((*s)&and) == c', |
| 69 | * and we increment our way through s by "stride" ('s += stride'). |
| 70 | * |
| 71 | * We optimize for the most used strides of +1 and -1. |
| 72 | */ |
| 73 | |
| 74 | unsigned char * |
| 75 | memNSchr(s, c, n, and, stride) |
| 76 | char *s; |
| 77 | int c; |
| 78 | unsigned int n; |
| 79 | int and; |
| 80 | int stride; |
| 81 | { |
| 82 | register unsigned char _c, *_s, _and; |
| 83 | |
| 84 | _and = and; |
| 85 | _c = (c&_and); |
| 86 | _s = (unsigned char *)s; |
| 87 | switch (stride) { |
| 88 | case 1: |
| 89 | while (n--) { |
| 90 | if (((*_s)&_and) == _c) { |
| 91 | return _s; |
| 92 | } |
| 93 | _s++; |
| 94 | } |
| 95 | break; |
| 96 | case -1: |
| 97 | while (n--) { |
| 98 | if (((*_s)&_and) == _c) { |
| 99 | return _s; |
| 100 | } |
| 101 | _s--; |
| 102 | } |
| 103 | break; |
| 104 | default: |
| 105 | while (n--) { |
| 106 | if (((*_s)&_and) == _c) { |
| 107 | return _s; |
| 108 | } |
| 109 | _s += stride; |
| 110 | } |
| 111 | } |
| 112 | return 0; |
| 113 | } |