decoder/flac: keep track of current frame number

We need this for more exact end-of-subsong detection for CUE files.

src/decoder/_flac_common.c

@@ -35,6 +35,8 @@ flac_data_init(struct flac_data *data, struct decoder * decoder,
 {
 	pcm_buffer_init(&data->buffer);
 
+	data->next_frame = 0;
+
 	data->time = 0;
 	data->position = 0;
 	data->bit_rate = 0;
@@ -122,6 +124,7 @@ flac_common_write(struct flac_data *data, const FLAC__Frame * frame,
 			   buffer, buffer_size,
 			   data->time, data->bit_rate,
 			   data->replay_gain_info);
+	data->next_frame += frame->header.blocksize;
 	switch (cmd) {
 	case DECODE_COMMAND_NONE:
 	case DECODE_COMMAND_START:

src/decoder/_flac_common.h

@@ -148,6 +148,11 @@ typedef size_t flac_read_status_size_t;
 struct flac_data {
 	struct pcm_buffer buffer;
 
+	/**
+	 * The number of the next frame which is going to be decoded.
+	 */
+	FLAC__uint64 next_frame;
+
 	float time;
 	unsigned int bit_rate;
 	struct audio_format audio_format;

src/decoder/flac_plugin.c

@@ -460,6 +460,7 @@ flac_decode_internal(struct decoder * decoder,
 			FLAC__uint64 seek_sample = decoder_seek_where(decoder) *
 			    data.audio_format.sample_rate + 0.5;
 			if (flac_seek_absolute(flac_dec, seek_sample)) {
+				data.next_frame = seek_sample;
 				data.time = ((float)seek_sample) /
 				    data.audio_format.sample_rate;
 				data.position = 0;
@@ -634,6 +635,7 @@ flac_container_decode(struct decoder* decoder,
 
 			if (seek_sample >= t_start && seek_sample <= t_end &&
 			    flac_seek_absolute(flac_dec, (FLAC__uint64)seek_sample)) {
+				data.next_frame = seek_sample;
 				data.time = (float)(seek_sample - t_start) /
 					data.audio_format.sample_rate;
 				data.position = 0;
@@ -756,6 +758,7 @@ flac_filedecode_internal(struct decoder* decoder,
 			    data.audio_format.sample_rate + 0.5;
 			if (flac_seek_absolute(flac_dec, seek_sample))
 			{
+				data.next_frame = seek_sample;
 				data.time = ((float)seek_sample) /
 				    data.audio_format.sample_rate;
 				data.position = 0;

src/decoder/oggflac_plugin.c

@@ -328,6 +328,7 @@ oggflac_decode(struct decoder * mpd_decoder, struct input_stream *input_stream)
 			    data.audio_format.sample_rate + 0.5;
 			if (OggFLAC__seekable_stream_decoder_seek_absolute
 			    (decoder, seek_sample)) {
+				data.next_frame = seek_sample;
 				data.time = ((float)seek_sample) /
 				    data.audio_format.sample_rate;
 				data.position = 0;