encoder/lame: use offset variable instead of memmove()

1 files changed, 15 insertions, 8 deletions

diff --git a/src/encoder/LameEncoderPlugin.cxx b/src/encoder/LameEncoderPlugin.cxx
index 9028fcac4..2411d3624 100644
--- a/src/encoder/LameEncoderPlugin.cxx
+++ b/src/encoder/LameEncoderPlugin.cxx
@@ -39,7 +39,7 @@ struct LameEncoder final {
 	lame_global_flags *gfp;
 
 	unsigned char output_buffer[32768];
-	size_t output_buffer_length;
+	size_t output_buffer_length, output_buffer_position;
 
 	LameEncoder():encoder(lame_encoder_plugin) {}
 
@@ -210,6 +210,7 @@ lame_encoder_open(Encoder *_encoder, AudioFormat &audio_format,
 	}
 
 	encoder->output_buffer_length = 0;
+	encoder->output_buffer_position = 0;
 
 	return true;
 }
@@ -230,7 +231,8 @@ lame_encoder_write(Encoder *_encoder,
 	LameEncoder *encoder = (LameEncoder *)_encoder;
 	const int16_t *src = (const int16_t*)data;
 
-	assert(encoder->output_buffer_length == 0);
+	assert(encoder->output_buffer_position ==
+	       encoder->output_buffer_length);
 
 	const unsigned num_frames =
 		length / encoder->audio_format.GetFrameSize();
@@ -259,6 +261,7 @@ lame_encoder_write(Encoder *_encoder,
 	}
 
 	encoder->output_buffer_length = (size_t)bytes_out;
+	encoder->output_buffer_position = 0;
 	return true;
 }
 
@@ -267,14 +270,18 @@ lame_encoder_read(Encoder *_encoder, void *dest, size_t length)
 {
 	LameEncoder *encoder = (LameEncoder *)_encoder;
 
-	if (length > encoder->output_buffer_length)
-		length = encoder->output_buffer_length;
+	assert(encoder->output_buffer_position <=
+	       encoder->output_buffer_length);
 
-	memcpy(dest, encoder->output_buffer, length);
+	const size_t remainning = encoder->output_buffer_length
+		- encoder->output_buffer_position;
+	if (length > remainning)
+		length = remainning;
 
-	encoder->output_buffer_length -= length;
-	memmove(encoder->output_buffer, encoder->output_buffer + length,
-		encoder->output_buffer_length);
+	memcpy(dest, encoder->output_buffer + encoder->output_buffer_position,
+	       length);
+
+	encoder->output_buffer_position += length;
 
 	return length;
 }