The module strstr is internationalized, fine. But there are some cases
where it's overkill and the classical and faster byte-per-byte string
traversal can be used instead. I propose to add a new module c-strstr
in the same philosophy as c-ctype, c-strcase, c-strcasestr.
============================ modules/c-strstr ============================
Description:
Search for a substring in a string in C locale.
Files:
lib/c-strstr.h
lib/c-strstr.c
Depends-on:
configure.ac:
Makefile.am:
lib_SOURCES += c-strstr.h c-strstr.c
Include:
"c-strstr.h"
License:
LGPL
Maintainer:
Bruno Haible
============================= lib/c-strstr.h =============================
/* Searching in a string.
Copyright (C) 2001-2003, 2006 Free Software Foundation, Inc.
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. */
/* The functions defined in this file assume the "C" locale and a character
set without diacritics (ASCII-US or EBCDIC-US or something like that).
Even if the "C" locale on a particular system is an extension of the ASCII
character set (like on BeOS, where it is UTF-8, or on AmigaOS, where it
is ISO-8859-1), the functions in this file recognize only the ASCII
characters. More precisely, one of the string arguments must be an ASCII
string with additional restrictions. */
#ifdef __cplusplus
extern "C" {
#endif
/* Find the first occurrence of NEEDLE in HAYSTACK.
This function is safe to be called, even in a multibyte locale, if NEEDLE
1. consists solely of printable ASCII characters excluding '\\' and '~'
[this restriction is needed because of Shift_JIS and JOHAB]
or of the control ASCII characters '\a' '\b' '\f' '\n' '\r' '\t' '\v'
[this restriction is needed because of VISCII], and
2. has at least length 2
[this restriction is needed because of BIG5, BIG5-HKSCS, GBK, GB18030,
Shift_JIS, JOHAB], and
3. does not consist entirely of decimal digits, or has at least length 4
[this restricion is needed because of GB18030]. */
extern char *c_strstr (const char *haystack, const char *needle);
#ifdef __cplusplus
}
#endif
============================= lib/c-strstr.c =============================
/* Copyright (C) 1994, 1999, 2002-2003, 2005-2006 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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. */
/*
* My personal strstr() implementation that beats most other algorithms.
* Until someone tells me otherwise, I assume that this is the
* fastest implementation of strstr() in C.
* I deliberately chose not to comment it. You should have at least
* as much fun trying to understand it, as I had to write it :-).
*
* Stephen R. van den Berg, [EMAIL PROTECTED] */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <string.h>
typedef unsigned chartype;
char *
c_strstr (const char *phaystack, const char *pneedle)
{
register const unsigned char *haystack, *needle;
register chartype b, c;
haystack = (const unsigned char *) phaystack;
needle = (const unsigned char *) pneedle;
b = *needle;
if (b != '\0')
{
haystack--; /* possible ANSI violation */
do
{
c = *++haystack;
if (c == '\0')
goto ret0;
}
while (c != b);
c = *++needle;
if (c == '\0')
goto foundneedle;
++needle;
goto jin;
for (;;)
{
register chartype a;
register const unsigned char *rhaystack, *rneedle;
do
{
a = *++haystack;
if (a == '\0')
goto ret0;
if (a == b)
break;
a = *++haystack;
if (a == '\0')
goto ret0;
shloop:; }
while (a != b);
jin: a = *++haystack;
if (a == '\0')
goto ret0;
if (a != c)
goto shloop;
rhaystack = haystack-- + 1;
rneedle = needle;
a = *rneedle;
if (*rhaystack == a)
do
{
if (a == '\0')
goto foundneedle;
++rhaystack;
a = *++needle;
if (*rhaystack != a)
break;
if (a == '\0')
goto foundneedle;
++rhaystack;
a = *++needle;
}
while (*rhaystack == a);
needle = rneedle; /* took the register-poor approach */
if (a == '\0')
break;
}
}
foundneedle:
return (char*) haystack;
ret0:
return 0;
}
==========================================================================
