mpd/src/SongSort.cxx
2013-11-28 11:50:54 +01:00

123 lines
2.8 KiB
C++

/*
* Copyright (C) 2003-2013 The Music Player Daemon Project
* http://www.musicpd.org
*
* 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 2 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, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include "SongSort.hxx"
#include "Song.hxx"
#include "tag/Tag.hxx"
extern "C" {
#include "util/list_sort.h"
}
#include <glib.h>
#include <stdlib.h>
static const char *
tag_get_value_checked(const Tag *tag, TagType type)
{
return tag != nullptr
? tag->GetValue(type)
: nullptr;
}
static int
compare_utf8_string(const char *a, const char *b)
{
if (a == nullptr)
return b == nullptr ? 0 : -1;
if (b == nullptr)
return 1;
return g_utf8_collate(a, b);
}
/**
* Compare two string tag values, ignoring case. Either one may be
* nullptr.
*/
static int
compare_string_tag_item(const Tag *a, const Tag *b,
TagType type)
{
return compare_utf8_string(tag_get_value_checked(a, type),
tag_get_value_checked(b, type));
}
/**
* Compare two tag values which should contain an integer value
* (e.g. disc or track number). Either one may be nullptr.
*/
static int
compare_number_string(const char *a, const char *b)
{
long ai = a == nullptr ? 0 : strtol(a, nullptr, 10);
long bi = b == nullptr ? 0 : strtol(b, nullptr, 10);
if (ai <= 0)
return bi <= 0 ? 0 : -1;
if (bi <= 0)
return 1;
return ai - bi;
}
static int
compare_tag_item(const Tag *a, const Tag *b, TagType type)
{
return compare_number_string(tag_get_value_checked(a, type),
tag_get_value_checked(b, type));
}
/* Only used for sorting/searchin a songvec, not general purpose compares */
static int
song_cmp(gcc_unused void *priv, struct list_head *_a, struct list_head *_b)
{
const Song *a = (const Song *)_a;
const Song *b = (const Song *)_b;
int ret;
/* first sort by album */
ret = compare_string_tag_item(a->tag, b->tag, TAG_ALBUM);
if (ret != 0)
return ret;
/* then sort by disc */
ret = compare_tag_item(a->tag, b->tag, TAG_DISC);
if (ret != 0)
return ret;
/* then by track number */
ret = compare_tag_item(a->tag, b->tag, TAG_TRACK);
if (ret != 0)
return ret;
/* still no difference? compare file name */
return g_utf8_collate(a->uri, b->uri);
}
void
song_list_sort(struct list_head *songs)
{
list_sort(nullptr, songs, song_cmp);
}