audio: Added SDL_AudioStreamFlush().
--HG--
extra : rebase_source : 5bd3136ca1bcda9dcde4b2f6ab4891789e83331b
diff --git a/include/SDL_audio.h b/include/SDL_audio.h
index b30c409..a242ace 100644
--- a/include/SDL_audio.h
+++ b/include/SDL_audio.h
@@ -545,7 +545,27 @@
extern DECLSPEC int SDLCALL SDL_AudioStreamGet(SDL_AudioStream *stream, void *buf, int len);
/**
- * Get the number of converted/resampled bytes available
+ * Get the number of converted/resampled bytes available. The stream may be
+ * buffering data behind the scenes until it has enough to resample
+ * correctly, so this number might be lower than what you expect, or even
+ * be zero. Add more data or flush the stream if you need the data now.
+ *
+ * \sa SDL_NewAudioStream
+ * \sa SDL_AudioStreamPut
+ * \sa SDL_AudioStreamGet
+ * \sa SDL_AudioStreamClear
+ * \sa SDL_AudioStreamFlush
+ * \sa SDL_FreeAudioStream
+ */
+extern DECLSPEC int SDLCALL SDL_AudioStreamAvailable(SDL_AudioStream *stream);
+
+/**
+ * Tell the stream that you're done sending data, and anything being buffered
+ * should be converted/resampled and made available immediately.
+ *
+ * It is legal to add more data to a stream after flushing, but there will
+ * be audio gaps in the output. Generally this is intended to signal the
+ * end of input, so the complete output becomes available.
*
* \sa SDL_NewAudioStream
* \sa SDL_AudioStreamPut
@@ -553,7 +573,7 @@
* \sa SDL_AudioStreamClear
* \sa SDL_FreeAudioStream
*/
-extern DECLSPEC int SDLCALL SDL_AudioStreamAvailable(SDL_AudioStream *stream);
+extern DECLSPEC int SDLCALL SDL_AudioStreamFlush(SDL_AudioStream *stream);
/**
* Clear any pending data in the stream without converting it
diff --git a/src/audio/SDL_audiocvt.c b/src/audio/SDL_audiocvt.c
index 3a10fc9..9dba980 100644
--- a/src/audio/SDL_audiocvt.c
+++ b/src/audio/SDL_audiocvt.c
@@ -1362,7 +1362,7 @@
}
static int
-SDL_AudioStreamPutInternal(SDL_AudioStream *stream, const void *buf, int len)
+SDL_AudioStreamPutInternal(SDL_AudioStream *stream, const void *buf, int len, int *maxputbytes)
{
int buflen = len;
int workbuflen;
@@ -1479,6 +1479,13 @@
printf("AUDIOSTREAM: Final output is %d bytes\n", buflen);
#endif
+ if (maxputbytes) {
+ const int maxbytes = *maxputbytes;
+ if (buflen > maxbytes)
+ buflen = maxbytes;
+ *maxputbytes -= buflen;
+ }
+
/* resamplebuf holds the final output, even if we didn't resample. */
return buflen ? SDL_WriteToDataQueue(stream->queue, resamplebuf, buflen) : 0;
}
@@ -1524,7 +1531,7 @@
we don't need to store it for later, skip the staging process.
*/
if (!stream->staging_buffer_filled && len >= stream->staging_buffer_size) {
- return SDL_AudioStreamPutInternal(stream, buf, len);
+ return SDL_AudioStreamPutInternal(stream, buf, len, NULL);
}
/* If there's not enough data to fill the staging buffer, just save it */
@@ -1539,7 +1546,7 @@
SDL_assert(amount > 0);
SDL_memcpy(stream->staging_buffer + stream->staging_buffer_filled, buf, amount);
stream->staging_buffer_filled = 0;
- if (SDL_AudioStreamPutInternal(stream, stream->staging_buffer, stream->staging_buffer_size) < 0) {
+ if (SDL_AudioStreamPutInternal(stream, stream->staging_buffer, stream->staging_buffer_size, NULL) < 0) {
return -1;
}
buf = (void *)((Uint8 *)buf + amount);
@@ -1548,6 +1555,58 @@
return 0;
}
+int SDL_AudioStreamFlush(SDL_AudioStream *stream)
+{
+ if (!stream) {
+ return SDL_InvalidParamError("stream");
+ }
+
+ #if DEBUG_AUDIOSTREAM
+ printf("AUDIOSTREAM: flushing! staging_buffer_filled=%d bytes\n", stream->staging_buffer_filled);
+ #endif
+
+ /* shouldn't use a staging buffer if we're not resampling. */
+ SDL_assert((stream->dst_rate != stream->src_rate) || (stream->staging_buffer_filled == 0));
+
+ if (stream->staging_buffer_filled > 0) {
+ /* push the staging buffer + silence. We need to flush out not just
+ the staging buffer, but the piece that the stream was saving off
+ for right-side resampler padding. */
+ const SDL_bool first_run = stream->first_run;
+ const int filled = stream->staging_buffer_filled;
+ int actual_input_frames = filled / stream->src_sample_frame_size;
+ if (!first_run)
+ actual_input_frames += stream->resampler_padding_samples / stream->pre_resample_channels;
+
+ if (actual_input_frames > 0) { /* don't bother if nothing to flush. */
+ /* This is how many bytes we're expecting without silence appended. */
+ int flush_remaining = ((int) SDL_ceil(actual_input_frames * stream->rate_incr)) * stream->dst_sample_frame_size;
+
+ #if DEBUG_AUDIOSTREAM
+ printf("AUDIOSTREAM: flushing with padding to get max %d bytes!\n", flush_remaining);
+ #endif
+
+ SDL_memset(stream->staging_buffer + filled, '\0', stream->staging_buffer_size - filled);
+ if (SDL_AudioStreamPutInternal(stream, stream->staging_buffer, stream->staging_buffer_size, &flush_remaining) < 0) {
+ return -1;
+ }
+
+ /* we have flushed out (or initially filled) the pending right-side
+ resampler padding, but we need to push more silence to guarantee
+ the staging buffer is fully flushed out, too. */
+ SDL_memset(stream->staging_buffer, '\0', filled);
+ if (SDL_AudioStreamPutInternal(stream, stream->staging_buffer, stream->staging_buffer_size, &flush_remaining) < 0) {
+ return -1;
+ }
+ }
+ }
+
+ stream->staging_buffer_filled = 0;
+ stream->first_run = SDL_TRUE;
+
+ return 0;
+}
+
/* get converted/resampled data from the stream */
int
SDL_AudioStreamGet(SDL_AudioStream *stream, void *buf, int len)
@@ -1587,6 +1646,7 @@
stream->reset_resampler_func(stream);
}
stream->first_run = SDL_TRUE;
+ stream->staging_buffer_filled = 0;
}
}
diff --git a/src/dynapi/SDL_dynapi_overrides.h b/src/dynapi/SDL_dynapi_overrides.h
index 0770512..ac3980f 100644
--- a/src/dynapi/SDL_dynapi_overrides.h
+++ b/src/dynapi/SDL_dynapi_overrides.h
@@ -646,3 +646,4 @@
#define SDL_AudioStreamClear SDL_AudioStreamClear_REAL
#define SDL_AudioStreamAvailable SDL_AudioStreamAvailable_REAL
#define SDL_FreeAudioStream SDL_FreeAudioStream_REAL
+#define SDL_AudioStreamFlush SDL_AudioStreamFlush_REAL
diff --git a/src/dynapi/SDL_dynapi_procs.h b/src/dynapi/SDL_dynapi_procs.h
index e1372ef..8c0f8b7 100644
--- a/src/dynapi/SDL_dynapi_procs.h
+++ b/src/dynapi/SDL_dynapi_procs.h
@@ -680,3 +680,4 @@
SDL_DYNAPI_PROC(void,SDL_AudioStreamClear,(SDL_AudioStream *a),(a),)
SDL_DYNAPI_PROC(int,SDL_AudioStreamAvailable,(SDL_AudioStream *a),(a),return)
SDL_DYNAPI_PROC(void,SDL_FreeAudioStream,(SDL_AudioStream *a),(a),)
+SDL_DYNAPI_PROC(int,SDL_AudioStreamFlush,(SDL_AudioStream *a),(a),return)
