ref: 78aa2362a55bfb147a995a7df2ec5691ef280aa8
dir: /tags.h/
#pragma once
#ifdef __cplusplus
extern "C" {
#endif
typedef struct Tagctx Tagctx;
typedef int (*Tagread)(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,
};
/* 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. "k" is the raw key like "TPE1", "TPE2", etc. "s" is the null-terminated string unless "type" is
* Timage. "offset" and "size" define the placement and size of the image cover ("type" = Timage)
* inside the file, and "f" is not NULL in case reading the image cover requires additional
* operations on the data, in which case you need to read the image cover as a stream and call this
* function to apply these operations on the contents read.
*/
void (*tag)(Tagctx *ctx, int type, const char *k, const char *s, int offset, int size, Tagread f);
/* 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. */
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