DecoderBuffer: add method _clear()

src/DecoderBuffer.cxx

@@ -82,6 +82,12 @@ decoder_buffer_is_full(const DecoderBuffer *buffer)
 	return buffer->consumed == 0 && buffer->length == buffer->size;
 }
 
+void
+decoder_buffer_clear(DecoderBuffer *buffer)
+{
+	buffer->length = buffer->consumed = 0;
+}
+
 static void
 decoder_buffer_shift(DecoderBuffer *buffer)
 {

src/DecoderBuffer.hxx

@@ -56,6 +56,9 @@ decoder_buffer_is_empty(const DecoderBuffer *buffer);
 bool
 decoder_buffer_is_full(const DecoderBuffer *buffer);
 
+void
+decoder_buffer_clear(DecoderBuffer *buffer);
+
 /**
  * Read data from the input_stream and append it to the buffer.
  *

src/decoder/FaadDecoderPlugin.cxx

@@ -81,7 +81,7 @@ adts_find_frame(DecoderBuffer *buffer)
 		const uint8_t *p = (const uint8_t *)memchr(data, 0xff, length);
 		if (p == nullptr) {
 			/* no marker - discard the buffer */
-			decoder_buffer_consume(buffer, length);
+			decoder_buffer_clear(buffer);
 			continue;
 		}
 
@@ -108,10 +108,7 @@ adts_find_frame(DecoderBuffer *buffer)
 				/* not enough data; discard this frame
 				   to prevent a possible buffer
 				   overflow */
-				data = (const uint8_t *)
-					decoder_buffer_read(buffer, &length);
-				if (data != nullptr)
-					decoder_buffer_consume(buffer, length);
+				decoder_buffer_clear(buffer);
 			}
 
 			continue;
@@ -196,9 +193,7 @@ faad_song_duration(DecoderBuffer *buffer, InputStream &is)
 
 		is.LockSeek(tagsize, SEEK_SET, IgnoreError());
 
-		data = (const uint8_t *)decoder_buffer_read(buffer, &length);
-		if (data != nullptr)
-			decoder_buffer_consume(buffer, length);
+		decoder_buffer_clear(buffer);
 		decoder_buffer_fill(buffer);
 
 		return song_length;