calculate bytes_per_channel, check for buffer flush once

Check for flushing the chunk buffer only once per sample, before iterating over channels and bytes. This saves another 5% CPU cycles. git-svn-id: https://svn.musicpd.org/mpd/trunk@7326 09075e82-0dd4-0310-85a5-a0d7c8717e4f

calculate bytes_per_channel, check for buffer flush once
0673c9a8 · Max Kellermann · Eric Wong · 51e90440 · 0673c9a8
Commit 0673c9a8 authored Apr 12, 2008 by Max Kellermann Committed by Eric Wong Apr 12, 2008
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Showing with 9 additions and 6 deletions

flac_plugin.c src/inputPlugins/flac_plugin.c +9 -6

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--- a/src/inputPlugins/flac_plugin.c
+++ b/src/inputPlugins/flac_plugin.c
@@ -217,6 +217,8 @@ static FLAC__StreamDecoderWriteStatus flacWrite(const flac_decoder *dec,
 	unsigned char *uc;
 	unsigned int c_samp, c_chan;
 	const unsigned int bytes_per_sample = (data->dc->audioFormat.bits / 8);
+	const unsigned int bytes_per_channel =
+		bytes_per_sample * frame->header.channels;
 	unsigned int i;
 	float timeChange;
 	FLAC__uint64 newPosition = 0;
@@ -238,12 +240,7 @@ static FLAC__StreamDecoderWriteStatus flacWrite(const flac_decoder *dec,
 	data->position = newPosition;

 	for (c_samp = 0; c_samp < frame->header.blocksize; c_samp++) {
-		for (c_chan = 0; c_chan < frame->header.channels;
-		     c_chan++) {
-			u16 = buf[c_chan][c_samp];
-			uc = (unsigned char *)&u16;
-			for (i = 0; i < bytes_per_sample; i++) {
-				if (data->chunk_length >= FLAC_CHUNK_SIZE) {
+		if (data->chunk_length + bytes_per_channel >= FLAC_CHUNK_SIZE) {
 			if (flacSendChunk(data) < 0) {
 				return
 					FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
@@ -254,6 +251,12 @@ static FLAC__StreamDecoderWriteStatus flacWrite(const flac_decoder *dec,
 					FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
 			}
 		}
+
+		for (c_chan = 0; c_chan < frame->header.channels;
+		     c_chan++) {
+			u16 = buf[c_chan][c_samp];
+			uc = (unsigned char *)&u16;
+			for (i = 0; i < bytes_per_sample; i++) {
 				data->chunk[data->chunk_length++] = *(uc++);
 			}
 		}