xref: /illumos-gate/usr/src/lib/libc/port/locale/strcoll.c (revision 83ff55dc)

/*
 * Copyright 2013 Garrett D'Amore <garrett@damore.org>
 * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
 * Copyright (c) 1995 Alex Tatmanjants <alex@elvisti.kiev.ua>
 *		at Electronni Visti IA, Kiev, Ukraine.
 *			All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "lint.h"
#include "file64.h"
#include <alloca.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <wchar.h>
#include <xlocale.h>
#include "localeimpl.h"
#include "collate.h"

#define	ALLOCA_LIMIT	16

/*
 * In order to properly handle multibyte locales, its easiet to just
 * convert to wide characters and then use wcscoll.  However if an
 * error occurs, we gracefully fall back to simple strcmp.  Caller
 * should check errno.
 */
int
strcoll_l(const char *s1, const char *s2, locale_t loc)
{
	int ret;
	wchar_t *t1 = NULL, *t2 = NULL;
	wchar_t *w1 = NULL, *w2 = NULL;
	size_t sz1, sz2;
	const struct lc_collate *lcc = loc->collate;

	if (lcc->lc_is_posix)
		return (strcmp(s1, s2));

	sz1 = strlen(s1) + 1;
	sz2 = strlen(s2) + 1;

	/*
	 * Simple assumption: conversion to wide format is strictly
	 * reducing, i.e. a single byte (or multibyte character)
	 * cannot result in multiple wide characters.
	 *
	 * We gain a bit of performance by giving preference to alloca
	 * for small string allocations.
	 */
	if (sz1 > ALLOCA_LIMIT) {
		if ((t1 = malloc(sz1 * sizeof (wchar_t))) == NULL)
			goto error;
		w1 = t1;
	} else {
		if ((w1 = alloca(sz1 * sizeof (wchar_t))) == NULL)
			goto error;
	}
	if (sz2 > ALLOCA_LIMIT) {
		if ((t2 = malloc(sz2 * sizeof (wchar_t))) == NULL)
			goto error;
		w2 = t2;
	} else {
		if ((w2 = alloca(sz2 * sizeof (wchar_t))) == NULL)
			goto error;
	}

	if ((mbstowcs_l(w1, s1, sz1, loc)) == (size_t)-1)
		goto error;

	if ((mbstowcs_l(w2, s2, sz2, loc)) == (size_t)-1)
		goto error;

	ret = wcscoll_l(w1, w2, loc);
	if (t1)
		free(t1);
	if (t2)
		free(t2);

	return (ret);

error:
	if (t1)
		free(t1);
	if (t2)
		free(t2);
	return (strcmp(s1, s2));
}

int
strcoll(const char *s1, const char *s2)
{
	return (strcoll_l(s1, s2, uselocale(NULL)));
}