pcm_convert: return PCM buffer from pcm_convert()

Removed yet another superfluous buffer layer: return the PCM buffer
from pcm_convert() instead of copying PCM data into the
caller-supplied buffer.

7 files changed, 43 insertions, 86 deletions

diff --git a/src/decoder_api.c b/src/decoder_api.c
index 0ddb4ab90..831fb24b2 100644
--- a/src/decoder_api.c
+++ b/src/decoder_api.c
@@ -191,9 +191,7 @@ decoder_data(struct decoder *decoder,
 	     float data_time, uint16_t bitRate,
 	     struct replay_gain_info *replay_gain_info)
 {
-	static char *conv_buffer;
-	static size_t conv_buffer_size;
-	char *data;
+	const char *data = _data;
 
 	assert(dc.state == DECODE_STATE_DECODE);
 	assert(length % audio_format_frame_size(&dc.in_audio_format) == 0);
@@ -224,28 +222,16 @@ decoder_data(struct decoder *decoder,
 			return cmd;
 	}
 
-	if (audio_format_equals(&dc.in_audio_format, &dc.out_audio_format)) {
-		data = _data;
-	} else {
-		size_t out_length =
-			pcm_convert_size(&dc.in_audio_format, length,
-					 &dc.out_audio_format);
-		if (out_length > conv_buffer_size) {
-			g_free(conv_buffer);
-			conv_buffer = g_malloc(out_length);
-			conv_buffer_size = out_length;
-		}
-
-		data = conv_buffer;
-		length = pcm_convert(&dc.in_audio_format, _data,
-				     length, &dc.out_audio_format,
-				     data, &decoder->conv_state);
+	if (!audio_format_equals(&dc.in_audio_format, &dc.out_audio_format)) {
+		data = pcm_convert(&decoder->conv_state,
+				   &dc.in_audio_format, data, length,
+				   &dc.out_audio_format, &length);
 
 		/* under certain circumstances, pcm_convert() may
 		   return an empty buffer - this condition should be
 		   investigated further, but for now, do this check as
 		   a workaround: */
-		if (length == 0)
+		if (data == NULL)
 			return DECODE_COMMAND_NONE;
 	}
 
diff --git a/src/output_control.c b/src/output_control.c
index 503001470..db3ab5622 100644
--- a/src/output_control.c
+++ b/src/output_control.c
@@ -142,8 +142,6 @@ void audio_output_finish(struct audio_output *audioOutput)
 
 	if (audioOutput->plugin->finish)
 		audioOutput->plugin->finish(audioOutput->data);
-	if (audioOutput->convBuffer)
-		free(audioOutput->convBuffer);
 
 	notify_deinit(&audioOutput->notify);
 }
diff --git a/src/output_init.c b/src/output_init.c
index 8423e4bbb..bf92cc852 100644
--- a/src/output_init.c
+++ b/src/output_init.c
@@ -90,9 +90,6 @@ int audio_output_init(struct audio_output *ao, ConfigParam * param)
 	ao->open = false;
 	ao->reopen_after = 0;
 
-	ao->convBuffer = NULL;
-	ao->convBufferLen = 0;
-
 	pcm_convert_init(&ao->convState);
 
 	if (format) {
diff --git a/src/output_internal.h b/src/output_internal.h
index 17209dd5a..dc363a6b9 100644
--- a/src/output_internal.h
+++ b/src/output_internal.h
@@ -79,8 +79,6 @@ struct audio_output {
 	struct audio_format reqAudioFormat;
 
 	struct pcm_convert_state convState;
-	char *convBuffer;
-	size_t convBufferLen;
 
 	/**
 	 * The thread handle, or NULL if the output thread isn't
diff --git a/src/output_thread.c b/src/output_thread.c
index 3d5fe57d6..66f66e88c 100644
--- a/src/output_thread.c
+++ b/src/output_thread.c
@@ -38,29 +38,6 @@ static void ao_command_finished(struct audio_output *ao)
 	notify_signal(&audio_output_client_notify);
 }
 
-static void convertAudioFormat(struct audio_output *audioOutput,
-			       const char **chunkArgPtr, size_t *sizeArgPtr)
-{
-	size_t size = pcm_convert_size(&(audioOutput->inAudioFormat),
-				       *sizeArgPtr,
-				       &(audioOutput->outAudioFormat));
-
-	if (size > audioOutput->convBufferLen) {
-		if (audioOutput->convBuffer != NULL)
-			free(audioOutput->convBuffer);
-		audioOutput->convBuffer = g_malloc(size);
-		audioOutput->convBufferLen = size;
-	}
-
-	*sizeArgPtr = pcm_convert(&(audioOutput->inAudioFormat),
-				  *chunkArgPtr, *sizeArgPtr,
-				  &(audioOutput->outAudioFormat),
-				  audioOutput->convBuffer,
-				  &audioOutput->convState);
-
-	*chunkArgPtr = audioOutput->convBuffer;
-}
-
 static void ao_play(struct audio_output *ao)
 {
 	const char *data = ao->args.play.data;
@@ -70,13 +47,15 @@ static void ao_play(struct audio_output *ao)
 	assert(size > 0);
 
 	if (!audio_format_equals(&ao->inAudioFormat, &ao->outAudioFormat)) {
-		convertAudioFormat(ao, &data, &size);
+		data = pcm_convert(&ao->convState,
+				   &ao->inAudioFormat, data, size,
+				   &ao->outAudioFormat, &size);
 
 		/* under certain circumstances, pcm_convert() may
 		   return an empty buffer - this condition should be
 		   investigated further, but for now, do this check as
 		   a workaround: */
-		if (size == 0)
+		if (data == NULL)
 			return;
 	}
 
diff --git a/src/pcm_convert.c b/src/pcm_convert.c
index 2209249a6..42d72e367 100644
--- a/src/pcm_convert.c
+++ b/src/pcm_convert.c
@@ -48,12 +48,12 @@ void pcm_convert_deinit(struct pcm_convert_state *state)
 	pcm_buffer_deinit(&state->channels_buffer);
 }
 
-static size_t
-pcm_convert_16(const struct audio_format *src_format,
+static const int16_t *
+pcm_convert_16(struct pcm_convert_state *state,
+	       const struct audio_format *src_format,
 	       const void *src_buffer, size_t src_size,
 	       const struct audio_format *dest_format,
-	       int16_t *dest_buffer,
-	       struct pcm_convert_state *state)
+	       size_t *dest_size_r)
 {
 	const int16_t *buf;
 	size_t len;
@@ -82,18 +82,16 @@ pcm_convert_16(const struct audio_format *src_format,
 				      dest_format->sample_rate,
 				      &len);
 
-	assert(pcm_convert_size(src_format, src_size, dest_format) >= len);
-	memcpy(dest_buffer, buf, len);
-
-	return len;
+	*dest_size_r = len;
+	return buf;
 }
 
-static size_t
-pcm_convert_24(const struct audio_format *src_format,
+static const int32_t *
+pcm_convert_24(struct pcm_convert_state *state,
+	       const struct audio_format *src_format,
 	       const void *src_buffer, size_t src_size,
 	       const struct audio_format *dest_format,
-	       int32_t *dest_buffer,
-	       struct pcm_convert_state *state)
+	       size_t *dest_size_r)
 {
 	const int32_t *buf;
 	size_t len;
@@ -121,30 +119,30 @@ pcm_convert_24(const struct audio_format *src_format,
 				      dest_format->sample_rate,
 				      &len);
 
-	assert(pcm_convert_size(src_format, src_size, dest_format) >= len);
-	memcpy(dest_buffer, buf, len);
-
-	return len;
+	*dest_size_r = len;
+	return buf;
 }
 
-size_t pcm_convert(const struct audio_format *inFormat,
-		   const void *src, size_t src_size,
-		   const struct audio_format *outFormat,
-		   void *dest,
-		   struct pcm_convert_state *convState)
+const void *
+pcm_convert(struct pcm_convert_state *state,
+	    const struct audio_format *src_format,
+	    const void *src, size_t src_size,
+	    const struct audio_format *dest_format,
+	    size_t *dest_size_r)
 {
-	switch (outFormat->bits) {
+	switch (dest_format->bits) {
 	case 16:
-		return pcm_convert_16(inFormat, src, src_size,
-				      outFormat, (int16_t*)dest,
-				      convState);
+		return pcm_convert_16(state,
+				      src_format, src, src_size,
+				      dest_format, dest_size_r);
+
 	case 24:
-		return pcm_convert_24(inFormat, src, src_size,
-				      outFormat, (int32_t*)dest,
-				      convState);
+		return pcm_convert_24(state,
+				      src_format, src, src_size,
+				      dest_format, dest_size_r);
 
 	default:
-		g_error("cannot convert to %u bit\n", outFormat->bits);
+		g_error("cannot convert to %u bit\n", dest_format->bits);
 		return 0;
 	}
 }
diff --git a/src/pcm_convert.h b/src/pcm_convert.h
index 46ee55407..49dc64973 100644
--- a/src/pcm_convert.h
+++ b/src/pcm_convert.h
@@ -41,11 +41,12 @@ void pcm_convert_init(struct pcm_convert_state *state);
 
 void pcm_convert_deinit(struct pcm_convert_state *state);
 
-size_t pcm_convert(const struct audio_format *inFormat,
-		   const void *src, size_t src_size,
-		   const struct audio_format *outFormat,
-		   void *dest,
-		   struct pcm_convert_state *convState);
+const void *
+pcm_convert(struct pcm_convert_state *state,
+	    const struct audio_format *src_format,
+	    const void *src, size_t src_size,
+	    const struct audio_format *dest_format,
+	    size_t *dest_size_r);
 
 size_t pcm_convert_size(const struct audio_format *inFormat, size_t inSize,
 			const struct audio_format *outFormat);