Mercurial > hg > octave-lyh > gnulib-hg
changeset 8086:5814790bde53
Move to here from strstr.c.
author | Bruno Haible <bruno@clisp.org> |
---|---|
date | Mon, 05 Feb 2007 01:19:02 +0000 |
parents | 452a78f76352 |
children | 9474e9077766 |
files | lib/mbsstr.c |
diffstat | 1 files changed, 126 insertions(+), 0 deletions(-) [+] |
line wrap: on
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new file mode 100644 --- /dev/null +++ b/lib/mbsstr.c @@ -0,0 +1,126 @@ +/* Searching in a string. + Copyright (C) 2005-2007 Free Software Foundation, Inc. + Written by Bruno Haible <bruno@clisp.org>, 2005. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +#include <config.h> + +/* Specification. */ +#include <string.h> + +#include <stddef.h> /* for NULL, in case a nonstandard string.h lacks it */ + +#if HAVE_MBRTOWC +# include "mbuiter.h" +#endif + +/* Find the first occurrence of NEEDLE in HAYSTACK. */ +char * +strstr (const char *haystack, const char *needle) +{ + /* Be careful not to look at the entire extent of haystack or needle + until needed. This is useful because of these two cases: + - haystack may be very long, and a match of needle found early, + - needle may be very long, and not even a short initial segment of + needle may be found in haystack. */ +#if HAVE_MBRTOWC + if (MB_CUR_MAX > 1) + { + mbui_iterator_t iter_needle; + + mbui_init (iter_needle, needle); + if (mbui_avail (iter_needle)) + { + mbui_iterator_t iter_haystack; + + mbui_init (iter_haystack, haystack); + for (;; mbui_advance (iter_haystack)) + { + if (!mbui_avail (iter_haystack)) + /* No match. */ + return NULL; + + if (mb_equal (mbui_cur (iter_haystack), mbui_cur (iter_needle))) + /* The first character matches. */ + { + mbui_iterator_t rhaystack; + mbui_iterator_t rneedle; + + memcpy (&rhaystack, &iter_haystack, sizeof (mbui_iterator_t)); + mbui_advance (rhaystack); + + mbui_init (rneedle, needle); + if (!mbui_avail (rneedle)) + abort (); + mbui_advance (rneedle); + + for (;; mbui_advance (rhaystack), mbui_advance (rneedle)) + { + if (!mbui_avail (rneedle)) + /* Found a match. */ + return (char *) mbui_cur_ptr (iter_haystack); + if (!mbui_avail (rhaystack)) + /* No match. */ + return NULL; + if (!mb_equal (mbui_cur (rhaystack), mbui_cur (rneedle))) + /* Nothing in this round. */ + break; + } + } + } + } + else + return (char *) haystack; + } + else +#endif + { + if (*needle != '\0') + { + /* Speed up the following searches of needle by caching its first + character. */ + char b = *needle++; + + for (;; haystack++) + { + if (*haystack == '\0') + /* No match. */ + return NULL; + if (*haystack == b) + /* The first character matches. */ + { + const char *rhaystack = haystack + 1; + const char *rneedle = needle; + + for (;; rhaystack++, rneedle++) + { + if (*rneedle == '\0') + /* Found a match. */ + return (char *) haystack; + if (*rhaystack == '\0') + /* No match. */ + return NULL; + if (*rhaystack != *rneedle) + /* Nothing in this round. */ + break; + } + } + } + } + else + return (char *) haystack; + } +}