port/locale/strcoll.c

	strcoll.c revision 2d08521bd15501c8370ba2153b9cca4f094979d0
/*
 * 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;

    mbstate_t mbs1 = { 0 }; /* initial states */
    mbstate_t mbs2 = { 0 };

    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 ((mbsrtowcs_l(w1, &s1, sz1, &mbs1, loc)) == (size_t)-1)
        goto error;

    if ((mbsrtowcs_l(w2, &s2, sz2, &mbs2, 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)));
}