MusicChunk: return WritableBuffer

src/DecoderAPI.cxx

@@ -406,7 +406,6 @@ decoder_data(Decoder &decoder,
 
 	while (length > 0) {
 		struct music_chunk *chunk;
-		size_t nbytes;
 		bool full;
 
 		chunk = decoder_get_chunk(decoder);
@@ -415,17 +414,19 @@ decoder_data(Decoder &decoder,
 			return dc.command;
 		}
 
-		void *dest = chunk->Write(dc.out_audio_format,
-					  decoder.timestamp -
-					  dc.song->start_ms / 1000.0,
-					  kbit_rate, &nbytes);
-		if (dest == nullptr) {
+		const auto dest =
+			chunk->Write(dc.out_audio_format,
+				     decoder.timestamp -
+				     dc.song->start_ms / 1000.0,
+				     kbit_rate);
+		if (dest.IsNull()) {
 			/* the chunk is full, flush it */
 			decoder_flush_chunk(decoder);
 			dc.client_cond.signal();
 			continue;
 		}
 
+		size_t nbytes = dest.size;
 		assert(nbytes > 0);
 
 		if (nbytes > length)
@@ -433,7 +434,7 @@ decoder_data(Decoder &decoder,
 
 		/* copy the buffer */
 
-		memcpy(dest, data, nbytes);
+		memcpy(dest.data, data, nbytes);
 
 		/* expand the music pipe chunk */
 

src/MusicChunk.cxx

@@ -39,10 +39,9 @@ music_chunk::CheckFormat(const AudioFormat other_format) const
 }
 #endif
 
-void *
+WritableBuffer<void>
 music_chunk::Write(const AudioFormat af,
-		   float data_time, uint16_t _bit_rate,
-		   size_t *max_length_r)
+		   float data_time, uint16_t _bit_rate)
 {
 	assert(CheckFormat(af));
 	assert(length == 0 || audio_format.IsValid());
@@ -58,14 +57,13 @@ music_chunk::Write(const AudioFormat af,
 	const size_t frame_size = af.GetFrameSize();
 	size_t num_frames = (sizeof(data) - length) / frame_size;
 	if (num_frames == 0)
-		return nullptr;
+		return WritableBuffer<void>::Null();
 
 #ifndef NDEBUG
 	audio_format = af;
 #endif
 
-	*max_length_r = num_frames * frame_size;
-	return data + length;
+	return { data + length, num_frames * frame_size };
 }
 
 bool

src/MusicChunk.hxx

@@ -21,6 +21,7 @@
 #define MPD_MUSIC_CHUNK_HXX
 
 #include "ReplayGainInfo.hxx"
+#include "util/WritableBuffer.hxx"
 
 #ifndef NDEBUG
 #include "AudioFormat.hxx"
@@ -126,9 +127,8 @@ struct music_chunk {
 	 * here
 	 * @return a writable buffer, or nullptr if the chunk is full
 	 */
-	void *Write(AudioFormat af,
-		    float data_time, uint16_t bit_rate,
-		    size_t *max_length_r);
+	WritableBuffer<void> Write(AudioFormat af,
+				   float data_time, uint16_t bit_rate);
 
 	/**
 	 * Increases the length of the chunk after the caller has written to