ref: 4a7f42e378e27bf70c928b411ac859c870c23f24
dir: /tags.h/
#pragma once
#ifdef __cplusplus
extern "C" {
#endif
typedef union Tag Tag;
typedef struct Tagctx Tagctx;
typedef int (*Tagdecode)(void *buf, int *cnt);
/* Tag type. */
enum {
Tunknown = -1,
Tartist,
Talbum,
Ttitle,
Tdate, /* "2014", "2015/02/01", but the year goes first */
Ttrack, /* "1", "01", "1/4", but the track number goes first */
Talbumgain, /* see GAIN note */
Talbumpeak,
Ttrackgain, /* see GAIN note */
Ttrackpeak,
Tgenre,
Timage,
Tcomposer,
Tcomment,
Talbumartist,
};
/* GAIN note:
*
* Even though the gain value may be expected to look as "52 dB", it
* very well may be a plain integer (such as "12032") for R128_* tags.
* To do things correctly you will have to check 'const char *k' argument
* passed into your callback and parse it accordingly.
*
* FIXME the output gain (opus) is not parsed, btw.
*/
/* Format of the audio file. */
enum {
Funknown = -1,
Fmp3,
Fvorbis,
Fflac,
Fm4a,
Fopus,
Fwav,
Fit,
Fxm,
Fs3m,
Fmod,
Fmax,
Fogg __attribute__((deprecated("use Fvorbis instead"))) = Fvorbis,
};
/* Image types, according to id3v2. */
enum {
ITother,
IT32x32_file_icon,
ITother_file_icon,
ITcover_front,
ITcover_back,
ITleaflet,
ITmedia,
ITlead,
ITartist,
ITconductor,
ITband,
ITcomposer,
ITlyricist,
ITlocation,
ITrecording,
ITperformance,
ITmovie_capture,
ITfish,
ITillustration,
ITlogo_band,
ITlogo_publisher,
ITnum,
};
/* Tag itself, either text or image, depending on the "type" passed to the tag callback. */
union Tag {
/* Any tag type except Timage */
struct {
char *k; /* "TPE1", "replaygain_album_peak" etc */
char *v; /* value */
}text;
/* Tag type Timage */
struct {
/* If not NULL, reading the image cover requires additional decoding of the data.
* In that case you will need to read the raw data (specified by "offset" and "size")
* and call this function on the buffer (tag->decode(offset, &size)).
* "Size" will be updated with the actual image size after decoding if the function
* returned 0, else there was an error.
*/
Tagdecode decode;
const char *mime; /* "image/png", "image/jpeg" etc */
int offset; /* offset from the beginning of the file */
int size; /* number of bytes occupied by the raw image data (not decoded) */
int type; /* type of the image (ITcover_front, ...) */
}image;
};
/* Tag parser context. You need to set it properly before parsing an audio file using libtags. */
struct Tagctx {
/* Read function. This is what libtags uses to read the file. */
int (*read)(Tagctx *ctx, void *buf, int cnt);
/* Seek function. This is what libtags uses to seek through the file. */
int (*seek)(Tagctx *ctx, int offset, int whence);
/* Callback that is used by libtags to inform about the tags of a file.
* "type" is the tag's type (Tartist, ...) or Tunknown if libtags doesn't
* know how to map a tag kind to any of these.
* ANY tag type that isn't Timage is considered a text tag.
*/
void (*tag)(Tagctx *ctx, int type, Tag *tag);
/* Approximate millisecond-to-byte offsets within the file, if available. This callback is optional. */
void (*toc)(Tagctx *ctx, int ms, int offset);
/* Auxiliary data. Not used by libtags, left for the library user. */
void *aux;
/* Memory buffer to work in. */
char *buf;
/* Size of the buffer. Must be at least 256 bytes. */
int bufsz;
/* Here goes the stuff libtags sets. It should be accessed after tagsget() returns.
* A value of 0 means it's undefined.
*/
int channels; /* Number of channels. */
int samplerate; /* Hz */
int bitrate; /* Bitrate, bits/s. */
int duration; /* ms */
int format; /* Fmp3, Fvorbis, Fflac, Fm4a etc */
/* Private, don't touch. */
int found;
int restart;
};
/* Parse the file using this function. Returns 0 on success. */
int tagsget(Tagctx *ctx);
#ifdef __cplusplus
}
#endif