cog/Frameworks/GME/gme/gme.h

/* Game music emulator library C interface (also usable from C++) */

/* Game_Music_Emu 0.5.2 */
#ifndef GME_H
#define GME_H

#ifdef __cplusplus
	extern "C" {
#endif

/* Error string returned by library functions, or NULL if no error (success) */
typedef const char* gme_err_t;

/* First parameter of most gme_ functions is a pointer to the Music_Emu */
typedef struct Music_Emu Music_Emu;


/******** Basic operations ********/

/* Create emulator and load game music file/data into it. Sets *out to new emulator. */
gme_err_t gme_open_file( const char* path, Music_Emu** out, long sample_rate );

/* Number of tracks available */
int gme_track_count( Music_Emu const* );

/* Start a track, where 0 is the first track */
gme_err_t gme_start_track( Music_Emu*, int index );

/* Generate 'count' 16-bit signed samples info 'out'. Output is in stereo. */
gme_err_t gme_play( Music_Emu*, long count, short* out );

/* Finish using emulator and free memory */
void gme_delete( Music_Emu* );


/******** Track position/length ********/

/* Set time to start fading track out. Once fade ends track_ended() returns true.
Fade time can be changed while track is playing. */
void gme_set_fade( Music_Emu*, long start_msec );

/* True if a track has reached its end */
int gme_track_ended( Music_Emu const* );

/* Number of milliseconds (1000 = one second) played since beginning of track */
long gme_tell( Music_Emu const* );

/* Seek to new time in track. Seeking backwards or far forward can take a while. */
gme_err_t gme_seek( Music_Emu*, long msec );


/******** Informational ********/

/* If you only need track information from a music file, pass gme_info_only for
sample_rate to open/load. */
enum { gme_info_only = -1 };

/* Most recent warning string, or NULL if none. Clears current warning after returning.
Warning is also cleared when loading a file and starting a track. */
const char* gme_warning( Music_Emu* );

/* Load m3u playlist file (must be done after loading music) */
gme_err_t gme_load_m3u( Music_Emu*, const char* path );

/* Clear any loaded m3u playlist and any internal playlist that the music format
supports (NSFE for example). */
void gme_clear_playlist( Music_Emu* );

/* Get information for a particular track (length, name, author, etc.) */
typedef struct track_info_t track_info_t;
gme_err_t gme_track_info( Music_Emu const*, track_info_t* out, int track );

struct track_info_t
{
	long track_count;
	
	/* times in milliseconds; -1 if unknown */
	long length;
	long intro_length;
	long loop_length;
	
	/* empty string if not available */
	char system    [256];
	char game      [256];
	char song      [256];
	char author    [256];
	char copyright [256];
	char comment   [256];
	char dumper    [256];
};
enum { gme_max_field = 255 };


/******** Advanced playback ********/

/* Adjust stereo echo depth, where 0.0 = off and 1.0 = maximum. Has no effect for
GYM, SPC, and Sega Genesis VGM music */
void gme_set_stereo_depth( Music_Emu*, double depth );

/* Disable automatic end-of-track detection and skipping of silence at beginning
if ignore is true */
void gme_ignore_silence( Music_Emu*, int ignore );

/* Adjust song tempo, where 1.0 = normal, 0.5 = half speed, 2.0 = double speed.
Track length as returned by track_info() assumes a tempo of 1.0. */
void gme_set_tempo( Music_Emu*, double tempo );

/* Number of voices used by currently loaded file */
int gme_voice_count( Music_Emu const* );

/* Names of voices */
const char** gme_voice_names( Music_Emu const* );

/* Mute/unmute voice i, where voice 0 is first voice */
void gme_mute_voice( Music_Emu*, int index, int mute );

/* Set muting state of all voices at once using a bit mask, where -1 mutes all
voices, 0 unmutes them all, 0x01 mutes just the first voice, etc. */
void gme_mute_voices( Music_Emu*, int muting_mask );

/* Frequency equalizer parameters (see gme.txt) */
typedef struct gme_equalizer_t
{
	double treble; /* -50.0 = muffled, 0 = flat, +5.0 = extra-crisp */
	long   bass;   /* 1 = full bass, 90 = average, 16000 = almost no bass */
} gme_equalizer_t;

/* Get current frequency equalizater parameters */
gme_equalizer_t gme_equalizer( Music_Emu const* );

/* Change frequency equalizer parameters */
void gme_set_equalizer( Music_Emu*, gme_equalizer_t const* eq );



/******** Game music types ********/

/* gme_type_t is a pointer to this structure. For example, gme_nsf_type->system is 
"Nintendo NES" and gme_nsf_type->new_emu() is equilvant to new Nsf_Emu (in C++). */
typedef struct gme_type_t_ const* gme_type_t;
struct gme_type_t_
{
	const char* system;         /* name of system this music file type is generally for */
	int track_count;            /* non-zero for formats with a fixed number of tracks */
	Music_Emu* (*new_emu)();    /* Create new emulator for this type (useful in C++ only) */
	Music_Emu* (*new_info)();   /* Create new info reader for this type */
	
	/* internal */
	const char* extension_;
	int flags_;
};

/* Emulator type constants for each supported file type */
extern struct gme_type_t_ const gme_ay_type [], gme_gbs_type [], gme_gym_type [],
		gme_hes_type [], gme_kss_type [], gme_nsf_type [], gme_nsfe_type [],
		gme_sap_type [], gme_spc_type [], gme_vgm_type [], gme_vgz_type [];

/* Type of this emulator */
gme_type_t gme_type( Music_Emu const* );

/* Pointer to array of all music types, with NULL entry at end. Allows a player linked
to this library to support new music types without having to be updated. */
gme_type_t const* gme_type_list();


/******** Advanced file loading ********/

/* Error returned if file type is not supported */
extern const char gme_wrong_file_type [];

/* Same as gme_open_file(), but uses file data already in memory. Makes copy of data. */
gme_err_t gme_open_data( void const* data, long size, Music_Emu** out, long sample_rate );

/* Determine likely game music type based on first four bytes of file. Returns
string containing proper file suffix (i.e. "NSF", "SPC", etc.) or "" if
file header is not recognized. */
const char* gme_identify_header( void const* header );

/* Get corresponding music type for file path or extension passed in. */
gme_type_t gme_identify_extension( const char* path_or_extension );

/* Determine file type based on file's extension or header (if extension isn't recognized).
Sets *type_out to type, or 0 if unrecognized or error. */
gme_err_t gme_identify_file( const char* path, gme_type_t* type_out );

/* Create new emulator and set sample rate. Returns NULL if out of memory. If you only need
track information, pass gme_info_only for sample_rate. */
Music_Emu* gme_new_emu( gme_type_t, long sample_rate );

/* Load music file into emulator */
gme_err_t gme_load_file( Music_Emu*, const char* path );

/* Load music file from memory into emulator. Makes a copy of data passed. */
gme_err_t gme_load_data( Music_Emu*, void const* data, long size );

/* Load music file using custom data reader function that will be called to
read file data. Most emulators load the entire file in one read call. */
typedef gme_err_t (*gme_reader_t)( void* your_data, void* out, long count );
gme_err_t gme_load_custom( Music_Emu*, gme_reader_t, long file_size, void* your_data );

/* Load m3u playlist file from memory (must be done after loading music) */
gme_err_t gme_load_m3u_data( Music_Emu*, void const* data, long size );


/******** User data ********/

/* Set/get pointer to data you want to associate with this emulator.
You can use this for whatever you want. */
void  gme_set_user_data( Music_Emu*, void* new_user_data );
void* gme_user_data( Music_Emu const* );

/* Register cleanup function to be called when deleting emulator, or NULL to
clear it. Passes user_data to cleanup function. */
typedef void (*gme_user_cleanup_t)( void* user_data );
void gme_set_user_cleanup( Music_Emu*, gme_user_cleanup_t func );


#ifdef __cplusplus
	}
#endif

#endif