/*

 * This file is part of mpv.

 *

 * mpv 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.

 *

 * mpv 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 mpv.  If not, see <http://www.gnu.org/licenses/>.

 */

#include "misc/ctype.h"

#include "natural_sort.h"

// Comparison function for an ASCII-only "natural" sort. Case is ignored and

// numbers are ordered by value regardless of padding. Two filenames that differ

// only in the padding of numbers will be considered equal and end up in

// arbitrary order. Bytes outside of A-Z/a-z/0-9 will by sorted by byte value.

int mp_natural_sort_cmp(const char *name1, const char *name2)

{

    while (name1[0] && name2[0]) {

        if (mp_isdigit(name1[0]) && mp_isdigit(name2[0])) {

            while (name1[0] == '0')

                name1++;

            while (name2[0] == '0')

                name2++;

            const char *end1 = name1, *end2 = name2;

            while (mp_isdigit(*end1))

                end1++;

            while (mp_isdigit(*end2))

                end2++;

            // With padding stripped, a number with more digits is bigger.

            if ((end1 - name1) < (end2 - name2))

                return -1;

            if ((end1 - name1) > (end2 - name2))

                return 1;

            // Same length, lexicographical works.

            while (name1 < end1) {

                if (name1[0] < name2[0])

                    return -1;

                if (name1[0] > name2[0])

                    return 1;

                name1++;

                name2++;

            }

        } else {

            if ((unsigned char)mp_tolower(name1[0]) < (unsigned char)mp_tolower(name2[0]))

                return -1;

            if ((unsigned char)mp_tolower(name1[0]) > (unsigned char)mp_tolower(name2[0]))

                return 1;

            name1++;

            name2++;

        }

    }

    if (name2[0])

        return -1;

    if (name1[0])

        return 1;

    return 0;

}