gnulib has a module 'memcasecmp', for comparing two strings with possibly
embedded NULs, ignoring case. The file coreutils/src/join.c uses it, with
a FIXME that mentions that memcasecmp does not work in multibyte locales.
mbscasecmp works in multibyte locales, but does not support embedded NULs.
So here I'm committing a generalisation of mbscasecmp to strings with
with embedded NULs.
2009-03-08 Bruno Haible <br...@clisp.org>
New module 'mbmemcasecmp'.
* lib/mbmemcasecmp.h: New file.
* lib/mbmemcasecmp.c: New file.
* modules/mbmemcasecmp: New file.
============================= lib/mbmemcasecmp.h =============================
/* Compare two memory areas with possibly different lengths, case-insensitive.
Copyright (C) 2009 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 3 of the License, 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef MBMEMCASECMP_H
#define MBMEMCASECMP_H
#include <stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
/* Compare the memory regions S1 = [s1..s1+N1-1], S2 = [s2..s2+n2-1], that
contain character sequences, lexicographically, ignoring case.
This function's result is locale dependent. Unlike memcasecmp(), it works
correctly in multibyte locales and also handles Turkish i / dotless i.
Unlike ulc_casecmp(), it does not handle the German sharp s and the Greek
final sigma. Unlike memcoll() and ulc_casecoll(), it ignores collation
order.
Return a negative number if S1 < S2, a positive number if S1 > S2, or
0 if S1 and S2 have the same contents.
Note: This function may, in multibyte locales, return 0 for strings of
different lengths! */
extern int mbmemcasecmp (const char *s1, size_t n1, const char *s2, size_t n2);
#ifdef __cplusplus
}
#endif
#endif /* MBMEMCASECMP_H */
============================= lib/mbmemcasecmp.c =============================
/* Compare two memory areas with possibly different lengths, case-insensitive.
Copyright (C) 1998-1999, 2005-2009 Free Software Foundation, Inc.
Written by Bruno Haible <br...@clisp.org>, 2009,
based on earlier glibc code.
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 3 of the License, 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, see <http://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "mbmemcasecmp.h"
#include <ctype.h>
#include <limits.h>
#include <stdlib.h>
#include "mbiter.h"
#define TOLOWER(Ch) (isupper (Ch) ? tolower (Ch) : (Ch))
int
mbmemcasecmp (const char *s1, size_t n1, const char *s2, size_t n2)
{
if (s1 == s2)
return (n1 < n2 ? -1 : n1 > n2 ? 1 : 0);
if (MB_CUR_MAX > 1)
{
mbi_iterator_t iter1;
mbi_iterator_t iter2;
mbi_init (iter1, s1, n1);
mbi_init (iter2, s2, n2);
while (mbi_avail (iter1) && mbi_avail (iter2))
{
int cmp = mb_casecmp (mbi_cur (iter1), mbi_cur (iter2));
if (cmp != 0)
return cmp;
mbi_advance (iter1);
mbi_advance (iter2);
}
if (mbi_avail (iter1))
/* s2 terminated before s1. */
return 1;
if (mbi_avail (iter2))
/* s1 terminated before s2. */
return -1;
return 0;
}
else
{
const unsigned char *s1_end = (const unsigned char *) (s1 + n1);
const unsigned char *s2_end = (const unsigned char *) (s2 + n2);
const unsigned char *p1 = (const unsigned char *) s1;
const unsigned char *p2 = (const unsigned char *) s2;
while (p1 < s1_end && p2 < s2_end)
{
unsigned char c1 = TOLOWER (*p1);
unsigned char c2 = TOLOWER (*p2);
if (c1 != c2)
{
if (UCHAR_MAX <= INT_MAX)
return c1 - c2;
else
/* On machines where 'char' and 'int' are types of the same
size, the difference of two 'unsigned char' values
- including the sign bit - doesn't fit in an 'int'. */
return (c1 > c2 ? 1 : c1 < c2 ? -1 : 0);
}
++p1;
++p2;
}
if (p1 < s1_end)
/* s2 terminated before s1. */
return 1;
if (p2 < s2_end)
/* s1 terminated before s2. */
return -1;
return 0;
}
}
============================ modules/mbmemcasecmp ============================
Description:
mbmemcasecmp() function: case-insensitive memory area comparison.
Files:
lib/mbmemcasecmp.h
lib/mbmemcasecmp.c
Depends-on:
mbiter
configure.ac:
Makefile.am:
lib_SOURCES += mbmemcasecmp.c
Include:
"mbmemcasecmp.h"
License:
LGPL
Maintainer:
Bruno Haible
==============================================================================
