<?php

/////////////////////////////////////////////////////////////////

/// getID3() by James Heinrich <info@getid3.org>               //

//  available at http://getid3.sourceforge.net                 //

//            or http://www.getid3.org                         //

/////////////////////////////////////////////////////////////////

// See readme.txt for more details                             //

/////////////////////////////////////////////////////////////////

//                                                             //

// module.audio.flac.php                                       //

// module for analyzing FLAC and OggFLAC audio files           //

// dependencies: module.audio.ogg.php                          //

//                                                            ///

/////////////////////////////////////////////////////////////////

getid3_lib::IncludeDependency(GETID3_INCLUDEPATH.'module.audio.ogg.php', __FILE__, true);

/**

* @tutorial http://flac.sourceforge.net/format.html

*/

class getid3_flac extends getid3_handler

{

	const syncword = 'fLaC';

	public function Analyze() {

		$info = &$this->getid3->info;

		$this->fseek($info['avdataoffset']);

		$StreamMarker = $this->fread(4);

		if ($StreamMarker != self::syncword) {

			return $this->error('Expecting "'.getid3_lib::PrintHexBytes(self::syncword).'" at offset '.$info['avdataoffset'].', found "'.getid3_lib::PrintHexBytes($StreamMarker).'"');

		}

		$info['fileformat']            = 'flac';

		$info['audio']['dataformat']   = 'flac';

		$info['audio']['bitrate_mode'] = 'vbr';

		$info['audio']['lossless']     = true;

		// parse flac container

		return $this->parseMETAdata();

	}

	public function parseMETAdata() {

		$info = &$this->getid3->info;

		do {

			$BlockOffset   = $this->ftell();

			$BlockHeader   = $this->fread(4);

			$LBFBT         = getid3_lib::BigEndian2Int(substr($BlockHeader, 0, 1));

			$LastBlockFlag = (bool) ($LBFBT & 0x80);

			$BlockType     =        ($LBFBT & 0x7F);

			$BlockLength   = getid3_lib::BigEndian2Int(substr($BlockHeader, 1, 3));

			$BlockTypeText = self::metaBlockTypeLookup($BlockType);

			if (($BlockOffset + 4 + $BlockLength) > $info['avdataend']) {

				$this->error('METADATA_BLOCK_HEADER.BLOCK_TYPE ('.$BlockTypeText.') at offset '.$BlockOffset.' extends beyond end of file');

				break;

			}

			if ($BlockLength < 1) {

				$this->error('METADATA_BLOCK_HEADER.BLOCK_LENGTH ('.$BlockLength.') at offset '.$BlockOffset.' is invalid');

				break;

			}

			$info['flac'][$BlockTypeText]['raw'] = array();

			$BlockTypeText_raw = &$info['flac'][$BlockTypeText]['raw'];

			$BlockTypeText_raw['offset']          = $BlockOffset;

			$BlockTypeText_raw['last_meta_block'] = $LastBlockFlag;

			$BlockTypeText_raw['block_type']      = $BlockType;

			$BlockTypeText_raw['block_type_text'] = $BlockTypeText;

			$BlockTypeText_raw['block_length']    = $BlockLength;

			if ($BlockTypeText_raw['block_type'] != 0x06) { // do not read attachment data automatically

				$BlockTypeText_raw['block_data']  = $this->fread($BlockLength);

			}

			switch ($BlockTypeText) {

				case 'STREAMINFO':     // 0x00

					if (!$this->parseSTREAMINFO($BlockTypeText_raw['block_data'])) {

						return false;

					}

					break;

				case 'PADDING':        // 0x01

					unset($info['flac']['PADDING']); // ignore

					break;

				case 'APPLICATION':    // 0x02

					if (!$this->parseAPPLICATION($BlockTypeText_raw['block_data'])) {

						return false;

					}

					break;

				case 'SEEKTABLE':      // 0x03

					if (!$this->parseSEEKTABLE($BlockTypeText_raw['block_data'])) {

						return false;

					}

					break;

				case 'VORBIS_COMMENT': // 0x04

					if (!$this->parseVORBIS_COMMENT($BlockTypeText_raw['block_data'])) {

						return false;

					}

					break;

				case 'CUESHEET':       // 0x05

					if (!$this->parseCUESHEET($BlockTypeText_raw['block_data'])) {

						return false;

					}

					break;

				case 'PICTURE':        // 0x06

					if (!$this->parsePICTURE()) {

						return false;

					}

					break;

				default:

					$this->warning('Unhandled METADATA_BLOCK_HEADER.BLOCK_TYPE ('.$BlockType.') at offset '.$BlockOffset);

			}

			unset($info['flac'][$BlockTypeText]['raw']);

			$info['avdataoffset'] = $this->ftell();

		}

		while ($LastBlockFlag === false);

		// handle tags

		if (!empty($info['flac']['VORBIS_COMMENT']['comments'])) {

			$info['flac']['comments'] = $info['flac']['VORBIS_COMMENT']['comments'];

		}

		if (!empty($info['flac']['VORBIS_COMMENT']['vendor'])) {

			$info['audio']['encoder'] = str_replace('reference ', '', $info['flac']['VORBIS_COMMENT']['vendor']);

		}

		// copy attachments to 'comments' array if nesesary

		if (isset($info['flac']['PICTURE']) && ($this->getid3->option_save_attachments !== getID3::ATTACHMENTS_NONE)) {

			foreach ($info['flac']['PICTURE'] as $entry) {

				if (!empty($entry['data'])) {

					$info['flac']['comments']['picture'][] = array('image_mime'=>$entry['image_mime'], 'data'=>$entry['data']);

				}

			}

		}

		if (isset($info['flac']['STREAMINFO'])) {

			if (!$this->isDependencyFor('matroska')) {

				$info['flac']['compressed_audio_bytes'] = $info['avdataend'] - $info['avdataoffset'];

			}

			$info['flac']['uncompressed_audio_bytes'] = $info['flac']['STREAMINFO']['samples_stream'] * $info['flac']['STREAMINFO']['channels'] * ($info['flac']['STREAMINFO']['bits_per_sample'] / 8);

			if ($info['flac']['uncompressed_audio_bytes'] == 0) {

				return $this->error('Corrupt FLAC file: uncompressed_audio_bytes == zero');

			}

			if (!empty($info['flac']['compressed_audio_bytes'])) {

				$info['flac']['compression_ratio'] = $info['flac']['compressed_audio_bytes'] / $info['flac']['uncompressed_audio_bytes'];

			}

		}

		// set md5_data_source - built into flac 0.5+

		if (isset($info['flac']['STREAMINFO']['audio_signature'])) {

			if ($info['flac']['STREAMINFO']['audio_signature'] === str_repeat("\x00", 16)) {

                $this->warning('FLAC STREAMINFO.audio_signature is null (known issue with libOggFLAC)');

			}

			else {

				$info['md5_data_source'] = '';

				$md5 = $info['flac']['STREAMINFO']['audio_signature'];

				for ($i = 0; $i < strlen($md5); $i++) {

					$info['md5_data_source'] .= str_pad(dechex(ord($md5[$i])), 2, '00', STR_PAD_LEFT);

				}

				if (!preg_match('/^[0-9a-f]{32}$/', $info['md5_data_source'])) {

					unset($info['md5_data_source']);

				}

			}

		}

		if (isset($info['flac']['STREAMINFO']['bits_per_sample'])) {

			$info['audio']['bits_per_sample'] = $info['flac']['STREAMINFO']['bits_per_sample'];

			if ($info['audio']['bits_per_sample'] == 8) {

				// special case

				// must invert sign bit on all data bytes before MD5'ing to match FLAC's calculated value

				// MD5sum calculates on unsigned bytes, but FLAC calculated MD5 on 8-bit audio data as signed

				$this->warning('FLAC calculates MD5 data strangely on 8-bit audio, so the stored md5_data_source value will not match the decoded WAV file');

			}

		}

		return true;

	}

	private function parseSTREAMINFO($BlockData) {

		$info = &$this->getid3->info;

		$info['flac']['STREAMINFO'] = array();

		$streaminfo = &$info['flac']['STREAMINFO'];

		$streaminfo['min_block_size']  = getid3_lib::BigEndian2Int(substr($BlockData, 0, 2));

		$streaminfo['max_block_size']  = getid3_lib::BigEndian2Int(substr($BlockData, 2, 2));

		$streaminfo['min_frame_size']  = getid3_lib::BigEndian2Int(substr($BlockData, 4, 3));

		$streaminfo['max_frame_size']  = getid3_lib::BigEndian2Int(substr($BlockData, 7, 3));

		$SRCSBSS                       = getid3_lib::BigEndian2Bin(substr($BlockData, 10, 8));

		$streaminfo['sample_rate']     = getid3_lib::Bin2Dec(substr($SRCSBSS,  0, 20));

		$streaminfo['channels']        = getid3_lib::Bin2Dec(substr($SRCSBSS, 20,  3)) + 1;

		$streaminfo['bits_per_sample'] = getid3_lib::Bin2Dec(substr($SRCSBSS, 23,  5)) + 1;

		$streaminfo['samples_stream']  = getid3_lib::Bin2Dec(substr($SRCSBSS, 28, 36));

		$streaminfo['audio_signature'] = substr($BlockData, 18, 16);

		if (!empty($streaminfo['sample_rate'])) {

			$info['audio']['bitrate_mode']    = 'vbr';

			$info['audio']['sample_rate']     = $streaminfo['sample_rate'];

			$info['audio']['channels']        = $streaminfo['channels'];

			$info['audio']['bits_per_sample'] = $streaminfo['bits_per_sample'];

			$info['playtime_seconds']         = $streaminfo['samples_stream'] / $streaminfo['sample_rate'];

			if ($info['playtime_seconds'] > 0) {

				if (!$this->isDependencyFor('matroska')) {

					$info['audio']['bitrate'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['playtime_seconds'];

				}

				else {

					$this->warning('Cannot determine audio bitrate because total stream size is unknown');

				}

			}

		} else {

			return $this->error('Corrupt METAdata block: STREAMINFO');

		}

		return true;

	}

	private function parseAPPLICATION($BlockData) {

		$info = &$this->getid3->info;

		$ApplicationID = getid3_lib::BigEndian2Int(substr($BlockData, 0, 4));

		$info['flac']['APPLICATION'][$ApplicationID]['name'] = self::applicationIDLookup($ApplicationID);

		$info['flac']['APPLICATION'][$ApplicationID]['data'] = substr($BlockData, 4);

		return true;

	}

	private function parseSEEKTABLE($BlockData) {

		$info = &$this->getid3->info;

		$offset = 0;

		$BlockLength = strlen($BlockData);

		$placeholderpattern = str_repeat("\xFF", 8);

		while ($offset < $BlockLength) {

			$SampleNumberString = substr($BlockData, $offset, 8);

			$offset += 8;

			if ($SampleNumberString == $placeholderpattern) {

				// placeholder point

				getid3_lib::safe_inc($info['flac']['SEEKTABLE']['placeholders'], 1);

				$offset += 10;

			} else {

				$SampleNumber                                        = getid3_lib::BigEndian2Int($SampleNumberString);

				$info['flac']['SEEKTABLE'][$SampleNumber]['offset']  = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 8));

				$offset += 8;

				$info['flac']['SEEKTABLE'][$SampleNumber]['samples'] = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 2));

				$offset += 2;

			}

		}

		return true;

	}

	private function parseVORBIS_COMMENT($BlockData) {

		$info = &$this->getid3->info;

		$getid3_ogg = new getid3_ogg($this->getid3);

		if ($this->isDependencyFor('matroska')) {

			$getid3_ogg->setStringMode($this->data_string);

		}

		$getid3_ogg->ParseVorbisComments();

		if (isset($info['ogg'])) {

			unset($info['ogg']['comments_raw']);

			$info['flac']['VORBIS_COMMENT'] = $info['ogg'];

			unset($info['ogg']);

		}

		unset($getid3_ogg);

		return true;

	}

	private function parseCUESHEET($BlockData) {

		$info = &$this->getid3->info;

		$offset = 0;

		$info['flac']['CUESHEET']['media_catalog_number'] =                              trim(substr($BlockData, $offset, 128), "\0");

		$offset += 128;

		$info['flac']['CUESHEET']['lead_in_samples']      =         getid3_lib::BigEndian2Int(substr($BlockData, $offset, 8));

		$offset += 8;

		$info['flac']['CUESHEET']['flags']['is_cd']       = (bool) (getid3_lib::BigEndian2Int(substr($BlockData, $offset, 1)) & 0x80);

		$offset += 1;

		$offset += 258; // reserved

		$info['flac']['CUESHEET']['number_tracks']        =         getid3_lib::BigEndian2Int(substr($BlockData, $offset, 1));

		$offset += 1;

		for ($track = 0; $track < $info['flac']['CUESHEET']['number_tracks']; $track++) {

			$TrackSampleOffset = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 8));

			$offset += 8;

			$TrackNumber       = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 1));

			$offset += 1;

			$info['flac']['CUESHEET']['tracks'][$TrackNumber]['sample_offset']         = $TrackSampleOffset;

			$info['flac']['CUESHEET']['tracks'][$TrackNumber]['isrc']                  =                           substr($BlockData, $offset, 12);

			$offset += 12;

			$TrackFlagsRaw                                                             = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 1));

			$offset += 1;

			$info['flac']['CUESHEET']['tracks'][$TrackNumber]['flags']['is_audio']     = (bool) ($TrackFlagsRaw & 0x80);

			$info['flac']['CUESHEET']['tracks'][$TrackNumber]['flags']['pre_emphasis'] = (bool) ($TrackFlagsRaw & 0x40);

			$offset += 13; // reserved

			$info['flac']['CUESHEET']['tracks'][$TrackNumber]['index_points']          = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 1));

			$offset += 1;

			for ($index = 0; $index < $info['flac']['CUESHEET']['tracks'][$TrackNumber]['index_points']; $index++) {

				$IndexSampleOffset = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 8));

				$offset += 8;

				$IndexNumber       = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 1));

				$offset += 1;

				$offset += 3; // reserved

				$info['flac']['CUESHEET']['tracks'][$TrackNumber]['indexes'][$IndexNumber] = $IndexSampleOffset;

			}

		}

		return true;

	}

	/**

	* Parse METADATA_BLOCK_PICTURE flac structure and extract attachment

	* External usage: audio.ogg

	*/

	public function parsePICTURE() {

		$info = &$this->getid3->info;

		$picture['typeid']         = getid3_lib::BigEndian2Int($this->fread(4));

		$picture['type']           = self::pictureTypeLookup($picture['typeid']);

		$picture['image_mime']     = $this->fread(getid3_lib::BigEndian2Int($this->fread(4)));

		$descr_length              = getid3_lib::BigEndian2Int($this->fread(4));

		if ($descr_length) {

			$picture['description'] = $this->fread($descr_length);

		}

		$picture['width']          = getid3_lib::BigEndian2Int($this->fread(4));

		$picture['height']         = getid3_lib::BigEndian2Int($this->fread(4));

		$picture['color_depth']    = getid3_lib::BigEndian2Int($this->fread(4));

		$picture['colors_indexed'] = getid3_lib::BigEndian2Int($this->fread(4));

		$data_length               = getid3_lib::BigEndian2Int($this->fread(4));

		if ($picture['image_mime'] == '-->') {

			$picture['data'] = $this->fread($data_length);

		} else {

			$picture['data'] = $this->saveAttachment(

				str_replace('/', '_', $picture['type']).'_'.$this->ftell(),

				$this->ftell(),

				$data_length,

				$picture['image_mime']);

		}

		$info['flac']['PICTURE'][] = $picture;

		return true;

	}

	public static function metaBlockTypeLookup($blocktype) {