SDL_mixer: Added decoder enumeration API.

SDL_mixer.h

@@ -41,7 +41,7 @@ extern "C" {
 */
 #define SDL_MIXER_MAJOR_VERSION	1
 #define SDL_MIXER_MINOR_VERSION	2
-#define SDL_MIXER_PATCHLEVEL	8
+#define SDL_MIXER_PATCHLEVEL    9
 
 /* This macro can be used to fill a version structure with the compile-time
  * version of the SDL_mixer library.
@@ -146,6 +146,30 @@ extern DECLSPEC Mix_Chunk * SDLCALL Mix_QuickLoad_RAW(Uint8 *mem, Uint32 len);
 extern DECLSPEC void SDLCALL Mix_FreeChunk(Mix_Chunk *chunk);
 extern DECLSPEC void SDLCALL Mix_FreeMusic(Mix_Music *music);
 
+/* Get a list of chunk/music decoders that this build of SDL_mixer provides.
+   This list can change between builds AND runs of the program, if external
+   libraries that add functionality become available.
+   You must successfully call Mix_OpenAudio() before calling these functions.
+   This API is only available in SDL_mixer 1.2.9 and later.
+
+   // usage...
+   int i;
+   const int total = Mix_GetNumChunkDecoders();
+   for (i = 0; i < total; i++)
+       printf("Supported chunk decoder: [%s]\n", Mix_GetChunkDecoder(i));
+
+   Appearing in this list doesn't promise your specific audio file will
+   decode...but it's handy to know if you have, say, a functioning Timidity
+   install.
+
+   These return values are static, read-only data; do not modify or free it.
+   The pointers remain valid until you call Mix_CloseAudio().
+*/
+extern DECLSPEC int SDLCALL Mix_GetNumChunkDecoders(void);
+extern DECLSPEC const char * SDLCALL Mix_GetChunkDecoder(int index);
+extern DECLSPEC int SDLCALL Mix_GetNumMusicDecoders(void);
+extern DECLSPEC const char * SDLCALL Mix_GetMusicDecoder(int index);
+
 /* Find out the music format of a mixer music, or the currently playing
    music, if 'music' is NULL.
 */

mixer.c

@@ -98,6 +98,32 @@ extern void music_mixer(void *udata, Uint8 *stream, int len);
 static void (*mix_music)(void *udata, Uint8 *stream, int len) = music_mixer;
 static void *music_data = NULL;
 
+/* rcg06042009 report available decoders at runtime. */
+static const char **chunk_decoders = NULL;
+static int num_decoders = 0;
+
+int Mix_NumChunkDecoders(void)
+{
+	return(num_decoders);
+}
+
+const char *Mix_GetChunkDecoder(int index)
+{
+	if ((index < 0) || (index >= num_decoders)) {
+		return NULL;
+	}
+	return(chunk_decoders[index]);
+}
+
+static void add_chunk_decoder(const char *decoder)
+{
+	void *ptr = realloc(chunk_decoders, num_decoders * sizeof (const char **));
+	if (ptr == NULL) {
+		return;  /* oh well, go on without it. */
+	}
+	chunk_decoders = (const char **) ptr;
+	chunk_decoders[num_decoders++] = decoder;
+}
 
 /* rcg06192001 get linked library's version. */
 const SDL_version *Mix_Linked_Version(void)
@@ -334,6 +360,17 @@ int Mix_OpenAudio(int frequency, Uint16 format, int nchannels, int chunksize)
 
 	_Mix_InitEffects();
 
+	/* This list is (currently) decided at build time. */
+	add_chunk_decoder("WAVE");
+	add_chunk_decoder("AIFF");
+	add_chunk_decoder("VOC");
+#ifdef OGG_MUSIC
+	add_chunk_decoder("OGG");
+#endif
+#ifdef FLAC_MUSIC
+	add_chunk_decoder("FLAC");
+#endif
+
 	audio_opened = 1;
 	SDL_PauseAudio(0);
 	return(0);
@@ -978,6 +1015,11 @@ void Mix_CloseAudio(void)
 			SDL_CloseAudio();
 			free(mix_channel);
 			mix_channel = NULL;
+
+			/* rcg06042009 report available decoders at runtime. */
+			free(chunk_decoders);
+			chunk_decoders = NULL;
+			num_decoders = 0;
 		}
 		--audio_opened;
 	}

music.c

@@ -162,6 +162,33 @@ static Uint16 current_output_format;
 /* Used to calculate fading steps */
 static int ms_per_step;
 
+/* rcg06042009 report available decoders at runtime. */
+static const char **music_decoders = NULL;
+static int num_decoders = 0;
+
+int Mix_NumMusicDecoders(void)
+{
+	return(num_decoders);
+}
+
+const char *Mix_GetMusicDecoder(int index)
+{
+	if ((index < 0) || (index >= num_decoders)) {
+		return NULL;
+	}
+	return(music_decoders[index]);
+}
+
+static void add_music_decoder(const char *decoder)
+{
+	void *ptr = realloc(music_decoders, num_decoders * sizeof (const char **));
+	if (ptr == NULL) {
+		return;  /* oh well, go on without it. */
+	}
+    music_decoders = (const char **) ptr;
+	music_decoders[num_decoders++] = decoder;
+}
+
 /* Local low-level functions prototypes */
 static void music_internal_initialize_volume(void);
 static void music_internal_volume(int volume);
@@ -387,6 +414,8 @@ int open_music(SDL_AudioSpec *mixer)
 #ifdef WAV_MUSIC
 	if ( WAVStream_Init(mixer) < 0 ) {
 		++music_error;
+	} else {
+		add_music_decoder("WAVE");
 	}
 #endif
 #if defined(MOD_MUSIC) || defined(LIBMIKMOD_MUSIC)
@@ -458,13 +487,15 @@ int open_music(SDL_AudioSpec *mixer)
 		Mix_SetError("%s", MikMod_strerror(MikMod_errno));
 		++music_error;
 	}
+	add_music_decoder("MIKMOD");
 #endif
 #ifdef MID_MUSIC
 #ifdef USE_TIMIDITY_MIDI
 	samplesize = mixer->size / mixer->samples;
 	if ( Timidity_Init(mixer->freq, mixer->format,
 	                    mixer->channels, mixer->samples) == 0 ) {
 		timidity_ok = 1;
+		add_music_decoder("TIMIDITY");
 	} else {
 		timidity_ok = 0;
 	}
@@ -475,22 +506,30 @@ int open_music(SDL_AudioSpec *mixer)
 	if ( native_midi_ok )
 #endif
 		native_midi_ok = native_midi_detect();
+	if ( native_midi_ok )
+		add_music_decoder("NATIVEMIDI");
 #endif
 #endif
 #ifdef OGG_MUSIC
 	if ( OGG_init(mixer) < 0 ) {
 		++music_error;
+	} else {
+		add_music_decoder("OGG");
 	}
 #endif
 #ifdef FLAC_MUSIC
 	if ( FLAC_init(mixer) < 0 ) {
 		++music_error;
+	} else {
+		add_music_decoder("FLAC");
 	}
 #endif
 #if defined(MP3_MUSIC) || defined(MP3_MAD_MUSIC)
 	/* Keep a copy of the mixer */
 	used_mixer = *mixer;
+	add_music_decoder("MP3");
 #endif
+
 	music_playing = NULL;
 	music_stopped = 0;
 	if ( music_error ) {
@@ -1406,6 +1445,11 @@ void close_music(void)
 	Timidity_Close();
 # endif
 #endif
+
+	/* rcg06042009 report available decoders at runtime. */
+	free(music_decoders);
+	music_decoders = NULL;
+	num_decoders = 0;
 }
 
 # ifdef LIBMIKMOD_MUSIC

playwave.c

@@ -37,6 +37,7 @@
 /*
  * rcg06132001 various mixer tests. Define the ones you want.
  */
+#define TEST_MIX_DECODERS
 /*#define TEST_MIX_VERSIONS*/
 /*#define TEST_MIX_CHANNELFINISHED*/
 /*#define TEST_MIX_PANNING*/
@@ -81,6 +82,24 @@ static void output_test_warnings(void)
 static int audio_open = 0;
 static Mix_Chunk *wave = NULL;
 
+/* rcg06042009 Report available decoders. */
+#if (defined TEST_MIX_DECODERS)
+static void report_decoders(void)
+{
+	int i, total;
+
+    printf("Supported decoders...\n");
+	total = Mix_NumChunkDecoders();
+	for (i = 0; i < total; i++) {
+		fprintf(stderr, " - chunk decoder: %s\n", Mix_GetChunkDecoder(i));
+	}
+
+	total = Mix_NumMusicDecoders();
+	for (i = 0; i < total; i++) {
+		fprintf(stderr, " - music decoder: %s\n", Mix_GetMusicDecoder(i));
+	}
+}
+#endif
 
 /* rcg06192001 Check new Mixer version API. */
 #if (defined TEST_MIX_VERSIONS)
@@ -417,6 +436,10 @@ int main(int argc, char *argv[])
 	test_versions();
 #endif
 
+#if (defined TEST_MIX_DECODERS)
+	report_decoders();
+#endif
+
 	/* Load the requested wave file */
 	wave = Mix_LoadWAV(argv[i]);
 	if ( wave == NULL ) {