<?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);

class getid3_flac
{

    function getid3_flac(&$fd, &$ThisFileInfo) {
        // http://flac.sourceforge.net/format.html

        fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
        $StreamMarker = fread($fd, 4);
        if ($StreamMarker != 'fLaC') {
            $ThisFileInfo['error'][] = 'Expecting "fLaC" at offset '.$ThisFileInfo['avdataoffset'].', found "'.$StreamMarker.'"';
            return false;
        }
        $ThisFileInfo['fileformat']            = 'flac';
        $ThisFileInfo['audio']['dataformat']   = 'flac';
        $ThisFileInfo['audio']['bitrate_mode'] = 'vbr';
        $ThisFileInfo['audio']['lossless']     = true;

        return getid3_flac::FLACparseMETAdata($fd, $ThisFileInfo);
    }


    function FLACparseMETAdata(&$fd, &$ThisFileInfo) {

        do {
            $METAdataBlockOffset          = ftell($fd);
            $METAdataBlockHeader          = fread($fd, 4);
            $METAdataLastBlockFlag        = (bool) (getid3_lib::BigEndian2Int(substr($METAdataBlockHeader, 0, 1)) & 0x80);
            $METAdataBlockType            = getid3_lib::BigEndian2Int(substr($METAdataBlockHeader, 0, 1)) & 0x7F;
            $METAdataBlockLength          = getid3_lib::BigEndian2Int(substr($METAdataBlockHeader, 1, 3));
            $METAdataBlockTypeText        = getid3_flac::FLACmetaBlockTypeLookup($METAdataBlockType);

            if ($METAdataBlockLength < 0) {
                $ThisFileInfo['error'][] = 'corrupt or invalid METADATA_BLOCK_HEADER.BLOCK_TYPE ('.$METAdataBlockType.') at offset '.$METAdataBlockOffset;
                break;
            }

            $ThisFileInfo['flac'][$METAdataBlockTypeText]['raw'] = array();
            $ThisFileInfo_flac_METAdataBlockTypeText_raw = &$ThisFileInfo['flac'][$METAdataBlockTypeText]['raw'];

            $ThisFileInfo_flac_METAdataBlockTypeText_raw['offset']          = $METAdataBlockOffset;
            $ThisFileInfo_flac_METAdataBlockTypeText_raw['last_meta_block'] = $METAdataLastBlockFlag;
            $ThisFileInfo_flac_METAdataBlockTypeText_raw['block_type']      = $METAdataBlockType;
            $ThisFileInfo_flac_METAdataBlockTypeText_raw['block_type_text'] = $METAdataBlockTypeText;
            $ThisFileInfo_flac_METAdataBlockTypeText_raw['block_length']    = $METAdataBlockLength;
            $ThisFileInfo_flac_METAdataBlockTypeText_raw['block_data']      = @fread($fd, $METAdataBlockLength);
            $ThisFileInfo['avdataoffset'] = ftell($fd);

            switch ($METAdataBlockTypeText) {

                case 'STREAMINFO':
                    if (!getid3_flac::FLACparseSTREAMINFO($ThisFileInfo_flac_METAdataBlockTypeText_raw['block_data'], $ThisFileInfo)) {
                        return false;
                    }
                    break;

                case 'PADDING':
                    // ignore
                    break;

                case 'APPLICATION':
                    if (!getid3_flac::FLACparseAPPLICATION($ThisFileInfo_flac_METAdataBlockTypeText_raw['block_data'], $ThisFileInfo)) {
                        return false;
                    }
                    break;

                case 'SEEKTABLE':
                    if (!getid3_flac::FLACparseSEEKTABLE($ThisFileInfo_flac_METAdataBlockTypeText_raw['block_data'], $ThisFileInfo)) {
                        return false;
                    }
                    break;

                case 'VORBIS_COMMENT':
                    $OldOffset = ftell($fd);
                    fseek($fd, 0 - $METAdataBlockLength, SEEK_CUR);
                    getid3_ogg::ParseVorbisCommentsFilepointer($fd, $ThisFileInfo);
                    fseek($fd, $OldOffset, SEEK_SET);
                    break;

                case 'CUESHEET':
                    if (!getid3_flac::FLACparseCUESHEET($ThisFileInfo_flac_METAdataBlockTypeText_raw['block_data'], $ThisFileInfo)) {
                        return false;
                    }
                    break;

                default:
                    $ThisFileInfo['warning'][] = 'Unhandled METADATA_BLOCK_HEADER.BLOCK_TYPE ('.$METAdataBlockType.') at offset '.$METAdataBlockOffset;
                    break;
            }

        } while ($METAdataLastBlockFlag === false);


        if (isset($ThisFileInfo['flac']['STREAMINFO'])) {
            $ThisFileInfo['flac']['compressed_audio_bytes']   = $ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset'];
            $ThisFileInfo['flac']['uncompressed_audio_bytes'] = $ThisFileInfo['flac']['STREAMINFO']['samples_stream'] * $ThisFileInfo['flac']['STREAMINFO']['channels'] * ($ThisFileInfo['flac']['STREAMINFO']['bits_per_sample'] / 8);
            if ($ThisFileInfo['flac']['uncompressed_audio_bytes'] == 0) {
                $ThisFileInfo['error'][] = 'Corrupt FLAC file: uncompressed_audio_bytes == zero';
                return false;
            }
            $ThisFileInfo['flac']['compression_ratio']        = $ThisFileInfo['flac']['compressed_audio_bytes'] / $ThisFileInfo['flac']['uncompressed_audio_bytes'];
        }

        // set md5_data_source - built into flac 0.5+
        if (isset($ThisFileInfo['flac']['STREAMINFO']['audio_signature'])) {

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

                $ThisFileInfo['warning'][] = 'FLAC STREAMINFO.audio_signature is null (known issue with libOggFLAC)';

            } else {

                $ThisFileInfo['md5_data_source'] = '';
                $md5 = $ThisFileInfo['flac']['STREAMINFO']['audio_signature'];
                for ($i = 0; $i < strlen($md5); $i++) {
                    $ThisFileInfo['md5_data_source'] .= str_pad(dechex(ord($md5{$i})), 2, '00', STR_PAD_LEFT);
                }
                if (!preg_match('/^[0-9a-f]{32}$/', $ThisFileInfo['md5_data_source'])) {
                    unset($ThisFileInfo['md5_data_source']);
                }

            }

        }

        $ThisFileInfo['audio']['bits_per_sample'] = $ThisFileInfo['flac']['STREAMINFO']['bits_per_sample'];
        if ($ThisFileInfo['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
            $ThisFileInfo['warning'][] = 'FLAC calculates MD5 data strangely on 8-bit audio, so the stored md5_data_source value will not match the decoded WAV file';
        }
        if (!empty($ThisFileInfo['ogg']['vendor'])) {
            $ThisFileInfo['audio']['encoder'] = $ThisFileInfo['ogg']['vendor'];
        }

        return true;
    }

    function FLACmetaBlockTypeLookup($blocktype) {
        static $FLACmetaBlockTypeLookup = array();
        if (empty($FLACmetaBlockTypeLookup)) {
            $FLACmetaBlockTypeLookup[0] = 'STREAMINFO';
            $FLACmetaBlockTypeLookup[1] = 'PADDING';
            $FLACmetaBlockTypeLookup[2] = 'APPLICATION';
            $FLACmetaBlockTypeLookup[3] = 'SEEKTABLE';
            $FLACmetaBlockTypeLookup[4] = 'VORBIS_COMMENT';
            $FLACmetaBlockTypeLookup[5] = 'CUESHEET';
        }
        return (isset($FLACmetaBlockTypeLookup[$blocktype]) ? $FLACmetaBlockTypeLookup[$blocktype] : 'reserved');
    }

    function FLACapplicationIDLookup($applicationid) {
        static $FLACapplicationIDLookup = array();
        if (empty($FLACapplicationIDLookup)) {
            // http://flac.sourceforge.net/id.html
            $FLACapplicationIDLookup[0x46746F6C] = 'flac-tools';      // 'Ftol'
            $FLACapplicationIDLookup[0x46746F6C] = 'Sound Font FLAC'; // 'SFFL'
        }
        return (isset($FLACapplicationIDLookup[$applicationid]) ? $FLACapplicationIDLookup[$applicationid] : 'reserved');
    }

    function FLACparseSTREAMINFO($METAdataBlockData, &$ThisFileInfo) {
        $offset = 0;
        $ThisFileInfo['flac']['STREAMINFO']['min_block_size']  = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 2));
        $offset += 2;
        $ThisFileInfo['flac']['STREAMINFO']['max_block_size']  = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 2));
        $offset += 2;
        $ThisFileInfo['flac']['STREAMINFO']['min_frame_size']  = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 3));
        $offset += 3;
        $ThisFileInfo['flac']['STREAMINFO']['max_frame_size']  = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 3));
        $offset += 3;

        $SampleRateChannelsSampleBitsStreamSamples             = getid3_lib::BigEndian2Bin(substr($METAdataBlockData, $offset, 8));
        $ThisFileInfo['flac']['STREAMINFO']['sample_rate']     = getid3_lib::Bin2Dec(substr($SampleRateChannelsSampleBitsStreamSamples,  0, 20));
        $ThisFileInfo['flac']['STREAMINFO']['channels']        = getid3_lib::Bin2Dec(substr($SampleRateChannelsSampleBitsStreamSamples, 20,  3)) + 1;
        $ThisFileInfo['flac']['STREAMINFO']['bits_per_sample'] = getid3_lib::Bin2Dec(substr($SampleRateChannelsSampleBitsStreamSamples, 23,  5)) + 1;
        $ThisFileInfo['flac']['STREAMINFO']['samples_stream']  = getid3_lib::Bin2Dec(substr($SampleRateChannelsSampleBitsStreamSamples, 28, 36));
        $offset += 8;

        $ThisFileInfo['flac']['STREAMINFO']['audio_signature'] =               substr($METAdataBlockData, $offset, 16);
        $offset += 16;

        if (!empty($ThisFileInfo['flac']['STREAMINFO']['sample_rate'])) {

            $ThisFileInfo['audio']['bitrate_mode']     = 'vbr';
            $ThisFileInfo['audio']['sample_rate']      = $ThisFileInfo['flac']['STREAMINFO']['sample_rate'];
            $ThisFileInfo['audio']['channels']         = $ThisFileInfo['flac']['STREAMINFO']['channels'];
            $ThisFileInfo['audio']['bits_per_sample']  = $ThisFileInfo['flac']['STREAMINFO']['bits_per_sample'];
            $ThisFileInfo['playtime_seconds']          = $ThisFileInfo['flac']['STREAMINFO']['samples_stream'] / $ThisFileInfo['flac']['STREAMINFO']['sample_rate'];
            $ThisFileInfo['audio']['bitrate']          = (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) * 8) / $ThisFileInfo['playtime_seconds'];

        } else {

            $ThisFileInfo['error'][] = 'Corrupt METAdata block: STREAMINFO';
            return false;

        }
        
        unset($ThisFileInfo['flac']['STREAMINFO']['raw']);
        
        return true;
    }


    function FLACparseAPPLICATION($METAdataBlockData, &$ThisFileInfo) {
        $offset = 0;
        $ApplicationID = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 4));
        $offset += 4;
        $ThisFileInfo['flac']['APPLICATION'][$ApplicationID]['name'] = getid3_flac::FLACapplicationIDLookup($ApplicationID);
        $ThisFileInfo['flac']['APPLICATION'][$ApplicationID]['data'] = substr($METAdataBlockData, $offset);
        $offset = $METAdataBlockLength;

        unset($ThisFileInfo['flac']['APPLICATION']['raw']);
        
        return true;
    }


    function FLACparseSEEKTABLE($METAdataBlockData, &$ThisFileInfo) {
        $offset = 0;
        $METAdataBlockLength = strlen($METAdataBlockData);
        $placeholderpattern = str_repeat("\xFF", 8);
        while ($offset < $METAdataBlockLength) {
            $SampleNumberString = substr($METAdataBlockData, $offset, 8);
            $offset += 8;
            if ($SampleNumberString == $placeholderpattern) {

                // placeholder point
                @$ThisFileInfo['flac']['SEEKTABLE']['placeholders']++;
                $offset += 10;

            } else {

                $SampleNumber                                                = getid3_lib::BigEndian2Int($SampleNumberString);
                $ThisFileInfo['flac']['SEEKTABLE'][$SampleNumber]['offset']  = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 8));
                $offset += 8;
                $ThisFileInfo['flac']['SEEKTABLE'][$SampleNumber]['samples'] = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 2));
                $offset += 2;

            }
        }
        
        unset($ThisFileInfo['flac']['SEEKTABLE']['raw']);
        
        return true;
    }

    function FLACparseCUESHEET($METAdataBlockData, &$ThisFileInfo) {
        $offset = 0;
        $ThisFileInfo['flac']['CUESHEET']['media_catalog_number'] =          trim(substr($METAdataBlockData, $offset, 128), "\0");
        $offset += 128;
        $ThisFileInfo['flac']['CUESHEET']['lead_in_samples']      = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 8));
        $offset += 8;
        $ThisFileInfo['flac']['CUESHEET']['flags']['is_cd']       = (bool) (getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 1)) & 0x80);
        $offset += 1;

        $offset += 258; // reserved

        $ThisFileInfo['flac']['CUESHEET']['number_tracks']        = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 1));
        $offset += 1;

        for ($track = 0; $track < $ThisFileInfo['flac']['CUESHEET']['number_tracks']; $track++) {
            $TrackSampleOffset = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 8));
            $offset += 8;
            $TrackNumber       = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 1));
            $offset += 1;

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

            $ThisFileInfo['flac']['CUESHEET']['tracks'][$TrackNumber]['isrc']                  =               substr($METAdataBlockData, $offset, 12);
            $offset += 12;

            $TrackFlagsRaw                                                                     = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 1));
            $offset += 1;
            $ThisFileInfo['flac']['CUESHEET']['tracks'][$TrackNumber]['flags']['is_audio']     = (bool) ($TrackFlagsRaw & 0x80);
            $ThisFileInfo['flac']['CUESHEET']['tracks'][$TrackNumber]['flags']['pre_emphasis'] = (bool) ($TrackFlagsRaw & 0x40);

            $offset += 13; // reserved

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

            for ($index = 0; $index < $ThisFileInfo['flac']['CUESHEET']['tracks'][$TrackNumber]['index_points']; $index++) {
                $IndexSampleOffset = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 8));
                $offset += 8;
                $IndexNumber       = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 1));
                $offset += 1;

                $offset += 3; // reserved

                $ThisFileInfo['flac']['CUESHEET']['tracks'][$TrackNumber]['indexes'][$IndexNumber] = $IndexSampleOffset;
            }
        }
        
        unset($ThisFileInfo['flac']['CUESHEET']['raw']);
        
        return true;
    }

}

?>