diff options
Diffstat (limited to 'lib/unistr/u8-strchr.c')
| -rw-r--r-- | lib/unistr/u8-strchr.c | 191 |
1 files changed, 26 insertions, 165 deletions
diff --git a/lib/unistr/u8-strchr.c b/lib/unistr/u8-strchr.c index dd1cb84c..3be14c79 100644 --- a/lib/unistr/u8-strchr.c +++ b/lib/unistr/u8-strchr.c @@ -1,5 +1,5 @@ /* Search character in UTF-8 string. - Copyright (C) 1999, 2002, 2006-2007, 2009-2015 Free Software Foundation, + Copyright (C) 1999, 2002, 2006-2007, 2009-2010 Free Software Foundation, Inc. Written by Bruno Haible <bruno@clisp.org>, 2002. @@ -21,8 +21,6 @@ /* Specification. */ #include "unistr.h" -#include <string.h> - uint8_t * u8_strchr (const uint8_t *s, ucs4_t uc) { @@ -32,209 +30,72 @@ u8_strchr (const uint8_t *s, ucs4_t uc) { uint8_t c0 = uc; - if (false) - { - /* Unoptimized code. */ - for (;;) - { - uint8_t s0 = *s; - if (s0 == c0) - return (uint8_t *) s; - s++; - if (s0 == 0) - break; - } - } - else + for (;; s++) { - /* Optimized code. - strchr() is often so well optimized, that it's worth the - added function call. */ - return (uint8_t *) strchr ((const char *) s, c0); + if (*s == c0) + break; + if (*s == 0) + goto notfound; } + return (uint8_t *) s; } else - /* Loops equivalent to strstr, optimized for a specific length (2, 3, 4) - of the needle. We use an algorithm similar to Boyer-Moore which - is documented in lib/unistr/u8-chr.c. There is additional - complication because we need to check after every byte for - a NUL byte, but the idea is the same. */ switch (u8_uctomb_aux (c, uc, 6)) { case 2: - if (*s == 0 || s[1] == 0) - break; + if (*s == 0) + goto notfound; { uint8_t c0 = c[0]; uint8_t c1 = c[1]; - /* Search for { c0, c1 }. */ - uint8_t s1 = s[1]; - for (;;) + for (;; s++) { - /* Here s[0] != 0, s[1] != 0. - Test whether s[0..1] == { c0, c1 }. */ - if (s1 == c1) - { - if (*s == c0) - return (uint8_t *) s; - else - /* Skip the search at s + 1, because s[1] = c1 < c0. */ - goto case2_skip2; - } - else - { - if (s1 == c0) - goto case2_skip1; - else - /* Skip the search at s + 1, because s[1] != c0. */ - goto case2_skip2; - } - case2_skip2: - s++; - s1 = s[1]; - if (s[1] == 0) - break; - case2_skip1: - s++; - s1 = s[1]; if (s[1] == 0) + goto notfound; + if (*s == c0 && s[1] == c1) break; } + return (uint8_t *) s; } - break; case 3: - if (*s == 0 || s[1] == 0 || s[2] == 0) - break; + if (*s == 0 || s[1] == 0) + goto notfound; { uint8_t c0 = c[0]; uint8_t c1 = c[1]; uint8_t c2 = c[2]; - /* Search for { c0, c1, c2 }. */ - uint8_t s2 = s[2]; - for (;;) + for (;; s++) { - /* Here s[0] != 0, s[1] != 0, s[2] != 0. - Test whether s[0..2] == { c0, c1, c2 }. */ - if (s2 == c2) - { - if (s[1] == c1 && *s == c0) - return (uint8_t *) s; - else - /* If c2 != c1: - Skip the search at s + 1, because s[2] == c2 != c1. - Skip the search at s + 2, because s[2] == c2 < c0. */ - if (c2 == c1) - goto case3_skip1; - else - goto case3_skip3; - } - else - { - if (s2 == c1) - goto case3_skip1; - else if (s2 == c0) - /* Skip the search at s + 1, because s[2] != c1. */ - goto case3_skip2; - else - /* Skip the search at s + 1, because s[2] != c1. - Skip the search at s + 2, because s[2] != c0. */ - goto case3_skip3; - } - case3_skip3: - s++; - s2 = s[2]; - if (s[2] == 0) - break; - case3_skip2: - s++; - s2 = s[2]; - if (s[2] == 0) - break; - case3_skip1: - s++; - s2 = s[2]; if (s[2] == 0) + goto notfound; + if (*s == c0 && s[1] == c1 && s[2] == c2) break; } + return (uint8_t *) s; } - break; case 4: - if (*s == 0 || s[1] == 0 || s[2] == 0 || s[3] == 0) - break; + if (*s == 0 || s[1] == 0 || s[2] == 0) + goto notfound; { uint8_t c0 = c[0]; uint8_t c1 = c[1]; uint8_t c2 = c[2]; uint8_t c3 = c[3]; - /* Search for { c0, c1, c2, c3 }. */ - uint8_t s3 = s[3]; - for (;;) + for (;; s++) { - /* Here s[0] != 0, s[1] != 0, s[2] != 0, s[3] != 0. - Test whether s[0..3] == { c0, c1, c2, c3 }. */ - if (s3 == c3) - { - if (s[2] == c2 && s[1] == c1 && *s == c0) - return (uint8_t *) s; - else - /* If c3 != c2: - Skip the search at s + 1, because s[3] == c3 != c2. - If c3 != c1: - Skip the search at s + 2, because s[3] == c3 != c1. - Skip the search at s + 3, because s[3] == c3 < c0. */ - if (c3 == c2) - goto case4_skip1; - else if (c3 == c1) - goto case4_skip2; - else - goto case4_skip4; - } - else - { - if (s3 == c2) - goto case4_skip1; - else if (s3 == c1) - /* Skip the search at s + 1, because s[3] != c2. */ - goto case4_skip2; - else if (s3 == c0) - /* Skip the search at s + 1, because s[3] != c2. - Skip the search at s + 2, because s[3] != c1. */ - goto case4_skip3; - else - /* Skip the search at s + 1, because s[3] != c2. - Skip the search at s + 2, because s[3] != c1. - Skip the search at s + 3, because s[3] != c0. */ - goto case4_skip4; - } - case4_skip4: - s++; - s3 = s[3]; - if (s[3] == 0) - break; - case4_skip3: - s++; - s3 = s[3]; - if (s[3] == 0) - break; - case4_skip2: - s++; - s3 = s[3]; - if (s[3] == 0) - break; - case4_skip1: - s++; - s3 = s[3]; if (s[3] == 0) + goto notfound; + if (*s == c0 && s[1] == c1 && s[2] == c2 && s[3] == c3) break; } + return (uint8_t *) s; } - break; } - +notfound: return NULL; } |