better error checking while reading streamed data

include/snd_render.h

@@ -112,8 +112,9 @@ struct sfxbuffer_s {
 		necessary. Null for chached sounds.
 		\param buffer	"this"
 		\param count	number of frames to advance
+		\return			true for success, false if an error occured
 	*/
-	void        (*advance) (sfxbuffer_t *buffer, unsigned int count);
+	int         (*advance) (sfxbuffer_t *buffer, unsigned int count);
 	/** Seek to an absolute position within the stream, resetting the ring
 		buffer.
 		\param buffer	"this"
@@ -134,6 +135,7 @@ struct sfxstream_s {
 	void       *file;			//!< handle for "file" representing the stream
 	wavinfo_t   wavinfo;		//!< description of sound data
 	unsigned    pos;			//!< position of next frame full stream
+	int         error;			//!< an error occured while reading
 
 	void       *state;			//!< resampler state information
 	/** Read data from the stream.
@@ -548,7 +550,7 @@ void SND_StreamRelease (sfx_t *sfx);
 	\param buffer	"this"
 	\param count	number of samples to advance
 */
-void SND_StreamAdvance (sfxbuffer_t *buffer, unsigned int count);
+int SND_StreamAdvance (sfxbuffer_t *buffer, unsigned int count);
 
 /** Seek to an absolute position within the stream, resetting the ring
 	buffer.

libs/audio/renderer/flac.c

@@ -340,7 +340,12 @@ flac_stream_read (void *file, float **buf)
 {
 	sfxstream_t *stream = (sfxstream_t *) file;
 	flacfile_t *ff = (flacfile_t *) stream->file;
-	FLAC__stream_decoder_process_single (ff->decoder);
+	int res = FLAC__stream_decoder_process_single (ff->decoder);
+
+	if (!res) {
+		stream->error = 1;
+		return -1;
+	}
 	*buf = ff->buffer;
 	return ff->size;
 }

libs/audio/renderer/midi.c

@@ -107,8 +107,10 @@ midi_stream_read (void *file, float **buf)
 	byte       *data = alloca (size);
 
 	res = WildMidi_GetOutput (mf->handle, (char *)data, size);
-	if (res < 0)
+	if (res <= 0) {
+		stream->error = 1;
 		return res;
+	}
 	res /= CHANNELS * WIDTH;
 	SND_Convert (data, mf->data, res, CHANNELS, WIDTH);
 	*buf = mf->data;

libs/audio/renderer/snd_mem.c

@@ -225,7 +225,7 @@ SND_StreamSetPos (sfxbuffer_t *buffer, unsigned int pos)
 	fill_buffer (sfx, stream, buffer, info, pos);
 }
 
-void
+int
 SND_StreamAdvance (sfxbuffer_t *buffer, unsigned int count)
 {
 	float       stepscale;
@@ -237,7 +237,7 @@ SND_StreamAdvance (sfxbuffer_t *buffer, unsigned int count)
 	stream->pos += count;
 	count = (stream->pos - buffer->pos) & ~255;
 	if (!count)
-		return;
+		return 1;
 
 	stepscale = (float) info->rate / snd_shm->speed;
 
@@ -291,6 +291,7 @@ SND_StreamAdvance (sfxbuffer_t *buffer, unsigned int count)
 			buffer->tail -= buffer->length;
 	}
 	fill_buffer (sfx, stream, buffer, info, headpos);
+	return !stream->error;
 }
 
 int

libs/audio/renderer/snd_mix.c

@@ -156,8 +156,14 @@ SND_PaintChannels (unsigned endtime)
 				if (count > 0) {
 					if (ch->leftvol || ch->rightvol) {
 						snd_paint_channel (ch, sc, count);
-						if (sc->advance)
-							sc->advance (sc, count);
+						if (sc->advance) {
+							if (!sc->advance (sc, count)) {
+								// this channel can no longer be used as its
+								// source has died.
+								ch->done = 1;
+								break;
+							}
+						}
 					}
 					ltime += count;
 				}

libs/audio/renderer/vorbis.c

@@ -228,8 +228,10 @@ vorbis_stream_read (void *file, float **buf)
 	if (!vf->data)
 		vf->data = malloc (FRAMES * stream->wavinfo.channels * sizeof (float));
 	res = vorbis_read (vf->vf, vf->data, FRAMES, &stream->wavinfo);
-	if (res <= 0)
+	if (res <= 0) {
+		stream->error = 1;
 		return res;
+	}
 	*buf = vf->data;
 	return res;
 }

libs/audio/renderer/wav.c

@@ -112,8 +112,10 @@ wav_stream_read (void *file, float **buf)
 		wf->data = malloc (FRAMES * info->channels * sizeof (float));
 
 	res = Qread (wf->file, data, len);
-	if (res <= 0)
+	if (res <= 0) {
+		stream->error = 1;
 		return res;
+	}
 	res /= (info->channels * info->width);
 	SND_Convert (data, wf->data, res, info->channels, info->width);
 	*buf = wf->data;