directory: replace songvec with doubly linked list

src/song_sort.c

@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2003-2012 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 "song_sort.h"
+#include "song.h"
+#include "util/list.h"
+#include "util/list_sort.h"
+#include "tag.h"
+
+#include <glib.h>
+
+#include <assert.h>
+#include <stdlib.h>
+
+static const char *
+tag_get_value_checked(const struct tag *tag, enum tag_type type)
+{
+	return tag != NULL
+		? tag_get_value(tag, type)
+		: NULL;
+}
+
+static int
+compare_utf8_string(const char *a, const char *b)
+{
+	if (a == NULL)
+		return b == NULL ? 0 : -1;
+
+	if (b == NULL)
+		return 1;
+
+	return g_utf8_collate(a, b);
+}
+
+/**
+ * Compare two string tag values, ignoring case.  Either one may be
+ * NULL.
+ */
+static int
+compare_string_tag_item(const struct tag *a, const struct tag *b,
+			enum tag_type 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 NULL.
+ */
+static int
+compare_number_string(const char *a, const char *b)
+{
+	long ai = a == NULL ? 0 : strtol(a, NULL, 10);
+	long bi = b == NULL ? 0 : strtol(b, NULL, 10);
+
+	if (ai <= 0)
+		return bi <= 0 ? 0 : -1;
+
+	if (bi <= 0)
+		return 1;
+
+	return ai - bi;
+}
+
+static int
+compare_tag_item(const struct tag *a, const struct tag *b, enum tag_type 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(G_GNUC_UNUSED void *priv, struct list_head *_a, struct list_head *_b)
+{
+	const struct song *a = (const struct song *)_a;
+	const struct song *b = (const struct 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(NULL, songs, song_cmp);
+}