text: /* in_flac - Winamp2 FLAC input plugin
   * Copyright (C) 2000,2001,2002,2003,2004,2005,2006,2007  Josh Coalson
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   */
  
  #if HAVE_CONFIG_H
  #  include <config.h>
  #endif
  
  #include <limits.h> /* for INT_MAX */
  #include <stdlib.h>
  #include <string.h> /* for memmove() */
  #include "playback.h"
  #include "share/grabbag.h"
  
  
  static FLAC__int32 reservoir_[FLAC_PLUGIN__MAX_SUPPORTED_CHANNELS][FLAC__MAX_BLOCK_SIZE * 2/*for overflow*/];
  static FLAC__int32 *reservoir__[FLAC_PLUGIN__MAX_SUPPORTED_CHANNELS] = { reservoir_[0], reservoir_[1] }; /*@@@ kind of a hard-coded hack */
  static unsigned wide_samples_in_reservoir_;
  static output_config_t cfg;     /* local copy */
  
  static unsigned bh_index_last_w, bh_index_last_o, written_time_last;
  static FLAC__int64 decode_position, decode_position_last;
  
  /*
   *  callbacks
   */
  
  static FLAC__StreamDecoderWriteStatus write_callback(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data)
  {
  	stream_data_struct *stream_data = (stream_data_struct*)client_data;
  	const unsigned channels = stream_data->channels, wide_samples = frame->header.blocksize;
  	unsigned channel;
  
  	(void)decoder;
  
  	if (stream_data->abort_flag)
  		return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
  
  	for (channel = 0; channel < channels; channel++)
  		memcpy(&reservoir_[channel][wide_samples_in_reservoir_], buffer[channel], sizeof(buffer[0][0]) * wide_samples);
  
  	wide_samples_in_reservoir_ += wide_samples;
  
  	return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
  }
  
  static void metadata_callback(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data)
  {
  	stream_data_struct *stream_data = (stream_data_struct*)client_data;
  	(void)decoder;
  
  	if (metadata->type == FLAC__METADATA_TYPE_STREAMINFO)
  	{
  		stream_data->total_samples = metadata->data.stream_info.total_samples;
  		stream_data->bits_per_sample = metadata->data.stream_info.bits_per_sample;
  		stream_data->channels = metadata->data.stream_info.channels;
  		stream_data->sample_rate = metadata->data.stream_info.sample_rate;
  
  		if (stream_data->bits_per_sample!=8 && stream_data->bits_per_sample!=16 && stream_data->bits_per_sample!=24)
  		{
  			FLAC_plugin__show_error("This plugin can only handle 8/16/24-bit samples.");
  			stream_data->abort_flag = true;
  			return;
  		}
  
  		{
  			/* with VC++ you have to spoon feed it the casting from uint64->int64->double */
  			FLAC__uint64 l = (FLAC__uint64)((double)(FLAC__int64)stream_data->total_samples / (double)stream_data->sample_rate * 1000.0 + 0.5);
  			if (l > INT_MAX)
  				l = INT_MAX;
  			stream_data->length_in_msec = (int)l;
  		}
  	}
  	else if (metadata->type == FLAC__METADATA_TYPE_VORBIS_COMMENT)
  	{
  		double reference, gain, peak;
  		if (grabbag__replaygain_load_from_vorbiscomment(metadata, cfg.replaygain.album_mode, /*strict=*/false, &reference, &gain, &peak))
  		{
  			stream_data->has_replaygain = true;
  			stream_data->replay_scale = grabbag__replaygain_compute_scale_factor(peak, gain, (double)cfg.replaygain.preamp, !cfg.replaygain.hard_limit);
  		}
  	}
  }
  
  static void error_callback(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
  {
  	stream_data_struct *stream_data = (stream_data_struct*)client_data;
  	(void)decoder;
  
  	if (cfg.misc.stop_err || status!=FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC)
  		stream_data->abort_flag = true;
  }
  
  /*
   *  init/delete
   */
  
  FLAC__bool FLAC_plugin__decoder_init(FLAC__StreamDecoder *decoder, const char *filename, FLAC__int64 filesize, stream_data_struct *stream_data, output_config_t *config)
  {
  	FLAC__StreamDecoderInitStatus init_status;
  
  	FLAC__ASSERT(decoder);
  	FLAC_plugin__decoder_finish(decoder);
  	/* init decoder */
  	FLAC__stream_decoder_set_md5_checking(decoder, false);
  	FLAC__stream_decoder_set_metadata_ignore_all(decoder);
  	FLAC__stream_decoder_set_metadata_respond(decoder, FLAC__METADATA_TYPE_STREAMINFO);
  	FLAC__stream_decoder_set_metadata_respond(decoder, FLAC__METADATA_TYPE_VORBIS_COMMENT);
  
  	if ((init_status = FLAC__stream_decoder_init_file(decoder, filename, write_callback, metadata_callback, error_callback, /*client_data=*/stream_data)) != FLAC__STREAM_DECODER_INIT_STATUS_OK)
  	{
  		FLAC_plugin__show_error("Error while initializing decoder (%s [%s]).", FLAC__StreamDecoderInitStatusString[init_status], FLAC__stream_decoder_get_resolved_state_string(decoder));
  		return false;
  	}
  	/* process */
  	cfg = *config;
  	wide_samples_in_reservoir_ = 0;
  	stream_data->is_playing = false;
  	stream_data->abort_flag = false;
  	stream_data->has_replaygain = false;
  
  	if (!FLAC__stream_decoder_process_until_end_of_metadata(decoder))
  	{
  		FLAC_plugin__show_error("Error while processing metadata (%s).", FLAC__stream_decoder_get_resolved_state_string(decoder));
  		return false;
  	}
  	/* check results */
  	if (stream_data->abort_flag) return false;                /* metadata callback already popped up the error dialog */
  	/* init replaygain */
  	stream_data->output_bits_per_sample = stream_data->has_replaygain && cfg.replaygain.enable ?
  		cfg.resolution.replaygain.bps_out :
  		cfg.resolution.normal.dither_24_to_16 ? min(stream_data->bits_per_sample, 16) : stream_data->bits_per_sample;
  
  	if (stream_data->has_replaygain && cfg.replaygain.enable && cfg.resolution.replaygain.dither)
  		FLAC__replaygain_synthesis__init_dither_context(&stream_data->dither_context, stream_data->bits_per_sample, cfg.resolution.replaygain.noise_shaping);
  	/* more inits */
  	stream_data->eof = false;
  	stream_data->seek_to = -1;
  	stream_data->is_playing = true;
  	stream_data->average_bps = (unsigned)(filesize / (125.*(double)(FLAC__int64)stream_data->total_samples/(double)stream_data->sample_rate));
  	
  	bh_index_last_w = 0;
  	bh_index_last_o = BITRATE_HIST_SIZE;
  	decode_position = 0;
  	decode_position_last = 0;
  	written_time_last = 0;
  
  	return true;
  }
  
  void FLAC_plugin__decoder_finish(FLAC__StreamDecoder *decoder)
  {
  	if (decoder && FLAC__stream_decoder_get_state(decoder) != FLAC__STREAM_DECODER_UNINITIALIZED)
  		(void)FLAC__stream_decoder_finish(decoder);
  }
  
  void FLAC_plugin__decoder_delete(FLAC__StreamDecoder *decoder)
  {
  	if (decoder)
  	{
  		FLAC_plugin__decoder_finish(decoder);
  		FLAC__stream_decoder_delete(decoder);
  	}
  }
  
  /*
   *  decode
   */
  
  int FLAC_plugin__seek(FLAC__StreamDecoder *decoder, stream_data_struct *stream_data)
  {
  	int pos;
  	FLAC__uint64 target_sample = stream_data->total_samples * stream_data->seek_to / stream_data->length_in_msec;
  
  	if (stream_data->total_samples > 0 && target_sample >= stream_data->total_samples && target_sample > 0)
  		target_sample = stream_data->total_samples - 1;
  
  	/* even if the seek fails we have to reset these so that we don't repeat the seek */
  	stream_data->seek_to = -1;
  	stream_data->eof = false;
  	wide_samples_in_reservoir_ = 0;
  	pos = (int)(target_sample*1000 / stream_data->sample_rate);
  
  	if (!FLAC__stream_decoder_seek_absolute(decoder, target_sample)) {
  		if(FLAC__stream_decoder_get_state(decoder) == FLAC__STREAM_DECODER_SEEK_ERROR)
  			FLAC__stream_decoder_flush(decoder);
  		pos = -1;
  	}
  
  	bh_index_last_o = bh_index_last_w = (pos/BITRATE_HIST_SEGMENT_MSEC) % BITRATE_HIST_SIZE;
  	if (!FLAC__stream_decoder_get_decode_position(decoder, &decode_position))
  		decode_position = 0;
  
  	return pos;
  }
  
  unsigned FLAC_plugin__decode(FLAC__StreamDecoder *decoder, stream_data_struct *stream_data, char *sample_buffer)
  {
  	/* fill reservoir */
  	while (wide_samples_in_reservoir_ < SAMPLES_PER_WRITE)
  	{
  		if (FLAC__stream_decoder_get_state(decoder) == FLAC__STREAM_DECODER_END_OF_STREAM)
  		{
  			stream_data->eof = true;
  			break;
  		}
  		else if (!FLAC__stream_decoder_process_single(decoder))
  		{
  			FLAC_plugin__show_error("Error while processing frame (%s).", FLAC__stream_decoder_get_resolved_state_string(decoder));
  			stream_data->eof = true;
  			break;
  		}
  		if (!FLAC__stream_decoder_get_decode_position(decoder, &decode_position))
  			decode_position = 0;
  	}
  	/* output samples */
  	if (wide_samples_in_reservoir_ > 0)
  	{
  		const unsigned n = min(wide_samples_in_reservoir_, SAMPLES_PER_WRITE);
  		const unsigned channels = stream_data->channels;
  		unsigned i;
  		int bytes;
  
  		if (cfg.replaygain.enable && stream_data->has_replaygain)
  		{
  			bytes = FLAC__replaygain_synthesis__apply_gain(
  				sample_buffer,
  				true, /* little_endian_data_out */
  				stream_data->output_bits_per_sample == 8, /* unsigned_data_out */
  				reservoir__,
  				n,
  				channels,
  				stream_data->bits_per_sample,
  				stream_data->output_bits_per_sample,
  				stream_data->replay_scale,
  				cfg.replaygain.hard_limit,
  				cfg.resolution.replaygain.dither,
  				&stream_data->dither_context
  			);
  		}
  		else
  		{
  			bytes = FLAC__plugin_common__pack_pcm_signed_little_endian(
  				sample_buffer,
  				reservoir__,
  				n,
  				channels,
  				stream_data->bits_per_sample,
  				stream_data->output_bits_per_sample
  			);
  		}
  
  		wide_samples_in_reservoir_ -= n;
  		for (i = 0; i < channels; i++)
  			memmove(&reservoir_[i][0], &reservoir_[i][n], sizeof(reservoir_[0][0]) * wide_samples_in_reservoir_);
  
  		return bytes;
  	}
  	else
  	{
  		stream_data->eof = true;
  		return 0;
  	}
  }
  
  int FLAC_plugin__get_rate(unsigned written_time, unsigned output_time, stream_data_struct *stream_data)
  {
  	static int bitrate_history_[BITRATE_HIST_SIZE];
  	unsigned bh_index_w = (written_time/BITRATE_HIST_SEGMENT_MSEC) % BITRATE_HIST_SIZE;
  	unsigned bh_index_o = (output_time/BITRATE_HIST_SEGMENT_MSEC) % BITRATE_HIST_SIZE;
  
  	/* written bitrate */
  	if (bh_index_w != bh_index_last_w)
  	{
  		bitrate_history_[(bh_index_w + BITRATE_HIST_SIZE-1)%BITRATE_HIST_SIZE] =
  			decode_position>decode_position_last && written_time > written_time_last ?
  			(unsigned)(8000*(decode_position - decode_position_last)/(written_time - written_time_last)) :
  			stream_data->average_bps;
  
  		bh_index_last_w = bh_index_w;
  		written_time_last = written_time;
  		decode_position_last = decode_position;
  	}
  
  	/* output bitrate */
  	if (bh_index_o!=bh_index_last_o && bh_index_o!=bh_index_last_w)
  	{
  		bh_index_last_o = bh_index_o;
  		return bitrate_history_[bh_index_o];
  	}
  
  	return 0;
  }
  