/******************************************************************************

 * sort.c: sort back-end

 ******************************************************************************

 * Copyright © 2019 VLC authors and VideoLAN

 * Copyright © 2018 Rémi Denis-Courmont

 *

 * 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 2.1 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, write to the Free Software Foundation,

 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.

 *****************************************************************************/

#ifdef HAVE_CONFIG_H

# include <config.h>

#endif

#include <vlc_common.h>

#include <vlc_sort.h>

static thread_local struct

{

    int (*compar)(const void *, const void *, void *);

    void *arg;

} state;

static int compar_wrapper(const void *a, const void *b)

{

    return state.compar(a, b, state.arg);

}

/* Follow the upcoming POSIX prototype, coming from GNU/libc.

 * Note that this differs from the BSD prototype. */

VLC_WEAK void vlc_qsort(void *base, size_t nmemb, size_t size,

                        int (*compar)(const void *, const void *, void *),

                        void *arg)

{

    int (*saved_compar)(const void *, const void *, void *) = state.compar;

    void *saved_arg = state.arg;

    state.compar = compar;

    state.arg = arg;

    qsort(base, nmemb, size, compar_wrapper);

    /* Restore state for nested reentrant calls */

    state.compar = saved_compar;

    state.arg = saved_arg;

}