1 /* Search character in UTF-8 string.
2 Copyright (C) 1999, 2002, 2006-2007, 2009-2011 Free Software Foundation,
4 Written by Bruno Haible <bruno@clisp.org>, 2002.
6 This program is free software: you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published
8 by the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
27 u8_strchr (const uint8_t *s, ucs4_t uc)
37 /* Unoptimized code. */
51 strchr() is often so well optimized, that it's worth the
52 added function call. */
53 return (uint8_t *) strchr ((const char *) s, c0);
57 /* Loops equivalent to strstr, optimized for a specific length (2, 3, 4)
58 of the needle. We use an algorithm similar to Boyer-Moore which
59 is documented in lib/unistr/u8-chr.c. There is additional
60 complication because we need to check after every byte for
61 a NUL byte, but the idea is the same. */
62 switch (u8_uctomb_aux (c, uc, 6))
65 if (*s == 0 || s[1] == 0)
70 /* Search for { c0, c1 }. */
75 /* Here s[0] != 0, s[1] != 0.
76 Test whether s[0..1] == { c0, c1 }. */
82 /* Skip the search at s + 1, because s[1] = c1 < c0. */
90 /* Skip the search at s + 1, because s[1] != c0. */
108 if (*s == 0 || s[1] == 0 || s[2] == 0)
114 /* Search for { c0, c1, c2 }. */
119 /* Here s[0] != 0, s[1] != 0, s[2] != 0.
120 Test whether s[0..2] == { c0, c1, c2 }. */
123 if (s[1] == c1 && *s == c0)
124 return (uint8_t *) s;
127 Skip the search at s + 1, because s[2] == c2 != c1.
128 Skip the search at s + 2, because s[2] == c2 < c0. */
139 /* Skip the search at s + 1, because s[2] != c1. */
142 /* Skip the search at s + 1, because s[2] != c1.
143 Skip the search at s + 2, because s[2] != c0. */
166 if (*s == 0 || s[1] == 0 || s[2] == 0 || s[3] == 0)
173 /* Search for { c0, c1, c2, c3 }. */
178 /* Here s[0] != 0, s[1] != 0, s[2] != 0, s[3] != 0.
179 Test whether s[0..3] == { c0, c1, c2, c3 }. */
182 if (s[2] == c2 && s[1] == c1 && *s == c0)
183 return (uint8_t *) s;
186 Skip the search at s + 1, because s[3] == c3 != c2.
188 Skip the search at s + 2, because s[3] == c3 != c1.
189 Skip the search at s + 3, because s[3] == c3 < c0. */
202 /* Skip the search at s + 1, because s[3] != c2. */
205 /* Skip the search at s + 1, because s[3] != c2.
206 Skip the search at s + 2, because s[3] != c1. */
209 /* Skip the search at s + 1, because s[3] != c2.
210 Skip the search at s + 2, because s[3] != c1.
211 Skip the search at s + 3, because s[3] != c0. */