/*
* Copyright (C) 2003-2009 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.
*/
#ifndef MPD_TAG_H
#define MPD_TAG_H
#include "gcc.h"
#include <stdint.h>
#include <stddef.h>
#include <stdbool.h>
#include <string.h>
/**
* Codes for the type of a tag item.
*/
enum tag_type {
TAG_ITEM_ARTIST,
TAG_ITEM_ALBUM,
TAG_ITEM_ALBUM_ARTIST,
TAG_ITEM_TITLE,
TAG_ITEM_TRACK,
TAG_ITEM_NAME,
TAG_ITEM_GENRE,
TAG_ITEM_DATE,
TAG_ITEM_COMPOSER,
TAG_ITEM_PERFORMER,
TAG_ITEM_COMMENT,
TAG_ITEM_DISC,
TAG_MUSICBRAINZ_ARTISTID,
TAG_MUSICBRAINZ_ALBUMID,
TAG_MUSICBRAINZ_ALBUMARTISTID,
TAG_MUSICBRAINZ_TRACKID,
TAG_NUM_OF_ITEM_TYPES
};
/**
* An array of strings, which map the #tag_type to its machine
* readable name (specific to the MPD protocol).
*/
extern const char *tag_item_names[];
/**
* One tag value. It is a mapping of #tag_type to am arbitrary string
* value. Each tag can have multiple items of one tag type (although
* few clients support that).
*/
struct tag_item {
/** the type of this item */
enum tag_type type;
/**
* the value of this tag; this is a variable length string
*/
char value[sizeof(long)];
} mpd_packed;
/**
* The meta information about a song file. It is a MPD specific
* subset of tags (e.g. from ID3, vorbis comments, ...).
*/
struct tag {
/**
* The duration of the song (in seconds). A value of zero
* means that the length is unknown. If the duration is
* really between zero and one second, you should round up to
* 1.
*/
int time;
/** an array of tag items */
struct tag_item **items;
/** the total number of tag items in the #items array */
unsigned num_items;
};
/**
* Creates an empty #tag.
*/
struct tag *tag_new(void);
/**
* Initializes the tag library.
*/
void tag_lib_init(void);
/**
* Clear all tag items with the specified type.
*/
void tag_clear_items_by_type(struct tag *tag, enum tag_type type);
/**
* Frees a #tag object and all its items.
*/
void tag_free(struct tag *tag);
/**
* Gives an optional hint to the tag library that we will now add
* several tag items; this is used by the library to optimize memory
* allocation. Only one tag may be in this state, and this tag must
* not have any items yet. You must call tag_end_add() when you are
* done.
*/
void tag_begin_add(struct tag *tag);
/**
* Finishes the operation started with tag_begin_add().
*/
void tag_end_add(struct tag *tag);
/**
* Appends a new tag item.
*
* @param tag the #tag object
* @param type the type of the new tag item
* @param value the value of the tag item (not null-terminated)
* @param len the length of #value
*/
void tag_add_item_n(struct tag *tag, enum tag_type type,
const char *value, size_t len);
/**
* Appends a new tag item.
*
* @param tag the #tag object
* @param type the type of the new tag item
* @param value the value of the tag item (null-terminated)
*/
static inline void
tag_add_item(struct tag *tag, enum tag_type type, const char *value)
{
tag_add_item_n(tag, type, value, strlen(value));
}
/**
* Duplicates a #tag object.
*/
struct tag *tag_dup(const struct tag *tag);
/**
* Merges the data from two tags. If both tags share data for the
* same tag_type, only data from "add" is used.
*
* @return a newly allocated tag, which must be freed with tag_free()
*/
struct tag *
tag_merge(const struct tag *base, const struct tag *add);
/**
* Merges the data from two tags. Any of the two may be NULL. Both
* are freed by this function.
*
* @return a newly allocated tag, which must be freed with tag_free()
*/
struct tag *
tag_merge_replace(struct tag *base, struct tag *add);
/**
* Returns true if the tag contains no items. This ignores the "time"
* attribute.
*/
static inline bool
tag_is_empty(const struct tag *tag)
{
return tag->num_items == 0;
}
/**
* Returns true if the tag contains any information.
*/
static inline bool
tag_is_defined(const struct tag *tag)
{
return !tag_is_empty(tag) || tag->time >= 0;
}
/**
* Returns the first value of the specified tag type, or NULL if none
* is present in this tag object.
*/
const char *
tag_get_value(const struct tag *tag, enum tag_type type);
/**
* Checks whether the tag contains one or more items with
* the specified type.
*/
bool tag_has_type(const struct tag *tag, enum tag_type type);
/**
* Compares two tags, including the duration and all tag items. The
* order of the tag items matters.
*/
bool tag_equal(const struct tag *tag1, const struct tag *tag2);
#endif
