<?php
/////////////////////////////////////////////////////////////////
/// getID3() by James Heinrich <info@getid3.org>               //
//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
//          also https://github.com/JamesHeinrich/getID3       //
/////////////////////////////////////////////////////////////////
// See readme.txt for more details                             //
/////////////////////////////////////////////////////////////////
//                                                             //
// module.audio.voc.php                                        //
// module for analyzing Creative VOC Audio files               //
// dependencies: NONE                                          //
//                                                            ///
/////////////////////////////////////////////////////////////////


class getid3_voc extends getid3_handler
{

    public function 
Analyze() {
        
$info = &$this->getid3->info;

        
$OriginalAVdataOffset $info['avdataoffset'];
        
$this->fseek($info['avdataoffset']);
        
$VOCheader  $this->fread(26);

        
$magic 'Creative Voice File';
        if (
substr($VOCheader019) != $magic) {
            
$info['error'][] = 'Expecting "'.getid3_lib::PrintHexBytes($magic).'" at offset '.$info['avdataoffset'].', found "'.getid3_lib::PrintHexBytes(substr($VOCheader019)).'"';
            return 
false;
        }

        
// shortcuts
        
$thisfile_audio = &$info['audio'];
        
$info['voc'] = array();
        
$thisfile_voc        = &$info['voc'];

        
$info['fileformat']        = 'voc';
        
$thisfile_audio['dataformat']      = 'voc';
        
$thisfile_audio['bitrate_mode']    = 'cbr';
        
$thisfile_audio['lossless']        = true;
        
$thisfile_audio['channels']        = 1// might be overriden below
        
$thisfile_audio['bits_per_sample'] = 8// might be overriden below

        // byte #     Description
        // ------     ------------------------------------------
        // 00-12      'Creative Voice File'
        // 13         1A (eof to abort printing of file)
        // 14-15      Offset of first datablock in .voc file (std 1A 00 in Intel Notation)
        // 16-17      Version number (minor,major) (VOC-HDR puts 0A 01)
        // 18-19      2's Comp of Ver. # + 1234h (VOC-HDR puts 29 11)

        
$thisfile_voc['header']['datablock_offset'] = getid3_lib::LittleEndian2Int(substr($VOCheader202));
        
$thisfile_voc['header']['minor_version']    = getid3_lib::LittleEndian2Int(substr($VOCheader221));
        
$thisfile_voc['header']['major_version']    = getid3_lib::LittleEndian2Int(substr($VOCheader231));

        do {

            
$BlockOffset    $this->ftell();
            
$BlockData      $this->fread(4);
            
$BlockType      ord($BlockData{0});
            
$BlockSize      getid3_lib::LittleEndian2Int(substr($BlockData13));
            
$ThisBlock      = array();

            
getid3_lib::safe_inc($thisfile_voc['blocktypes'][$BlockType], 1);
            switch (
$BlockType) {
                case 
0:  // Terminator
                    // do nothing, we'll break out of the loop down below
                    
break;

                case 
1:  // Sound data
                    
$BlockData .= $this->fread(2);
                    if (
$info['avdataoffset'] <= $OriginalAVdataOffset) {
                        
$info['avdataoffset'] = $this->ftell();
                    }
                    
$this->fseek($BlockSize 2SEEK_CUR);

                    
$ThisBlock['sample_rate_id']   = getid3_lib::LittleEndian2Int(substr($BlockData41));
                    
$ThisBlock['compression_type'] = getid3_lib::LittleEndian2Int(substr($BlockData51));

                    
$ThisBlock['compression_name'] = $this->VOCcompressionTypeLookup($ThisBlock['compression_type']);
                    if (
$ThisBlock['compression_type'] <= 3) {
                        
$thisfile_voc['compressed_bits_per_sample'] = getid3_lib::CastAsInt(str_replace('-bit'''$ThisBlock['compression_name']));
                    }

                    
// Less accurate sample_rate calculation than the Extended block (#8) data (but better than nothing if Extended Block is not available)
                    
if (empty($thisfile_audio['sample_rate'])) {
                        
// SR byte = 256 - (1000000 / sample_rate)
                        
$thisfile_audio['sample_rate'] = getid3_lib::trunc((1000000 / (256 $ThisBlock['sample_rate_id'])) / $thisfile_audio['channels']);
                    }
                    break;

                case 
2:  // Sound continue
                
case 3:  // Silence
                
case 4:  // Marker
                
case 6:  // Repeat
                
case 7:  // End repeat
                    // nothing useful, just skip
                    
$this->fseek($BlockSizeSEEK_CUR);
                    break;

                case 
8:  // Extended
                    
$BlockData .= $this->fread(4);

                    
//00-01  Time Constant:
                    //   Mono: 65536 - (256000000 / sample_rate)
                    // Stereo: 65536 - (256000000 / (sample_rate * 2))
                    
$ThisBlock['time_constant'] =        getid3_lib::LittleEndian2Int(substr($BlockData42));
                    
$ThisBlock['pack_method']   =        getid3_lib::LittleEndian2Int(substr($BlockData61));
                    
$ThisBlock['stereo']        = (bool) getid3_lib::LittleEndian2Int(substr($BlockData71));

                    
$thisfile_audio['channels']    = ($ThisBlock['stereo'] ? 1);
                    
$thisfile_audio['sample_rate'] = getid3_lib::trunc((256000000 / (65536 $ThisBlock['time_constant'])) / $thisfile_audio['channels']);
                    break;

                case 
9:  // data block that supersedes blocks 1 and 8. Used for stereo, 16 bit
                    
$BlockData .= $this->fread(12);
                    if (
$info['avdataoffset'] <= $OriginalAVdataOffset) {
                        
$info['avdataoffset'] = $this->ftell();
                    }
                    
$this->fseek($BlockSize 12SEEK_CUR);

                    
$ThisBlock['sample_rate']      = getid3_lib::LittleEndian2Int(substr($BlockData,  44));
                    
$ThisBlock['bits_per_sample']  = getid3_lib::LittleEndian2Int(substr($BlockData,  81));
                    
$ThisBlock['channels']         = getid3_lib::LittleEndian2Int(substr($BlockData,  91));
                    
$ThisBlock['wFormat']          = getid3_lib::LittleEndian2Int(substr($BlockData102));

                    
$ThisBlock['compression_name'] = $this->VOCwFormatLookup($ThisBlock['wFormat']);
                    if (
$this->VOCwFormatActualBitsPerSampleLookup($ThisBlock['wFormat'])) {
                        
$thisfile_voc['compressed_bits_per_sample'] = $this->VOCwFormatActualBitsPerSampleLookup($ThisBlock['wFormat']);
                    }

                    
$thisfile_audio['sample_rate']     = $ThisBlock['sample_rate'];
                    
$thisfile_audio['bits_per_sample'] = $ThisBlock['bits_per_sample'];
                    
$thisfile_audio['channels']        = $ThisBlock['channels'];
                    break;

                default:
                    
$info['warning'][] = 'Unhandled block type "'.$BlockType.'" at offset '.$BlockOffset;
                    
$this->fseek($BlockSizeSEEK_CUR);
                    break;
            }

            if (!empty(
$ThisBlock)) {
                
$ThisBlock['block_offset']  = $BlockOffset;
                
$ThisBlock['block_size']    = $BlockSize;
                
$ThisBlock['block_type_id'] = $BlockType;
                
$thisfile_voc['blocks'][] = $ThisBlock;
            }

        } while (!
feof($this->getid3->fp) && ($BlockType != 0));

        
// Terminator block doesn't have size field, so seek back 3 spaces
        
$this->fseek(-3SEEK_CUR);

        
ksort($thisfile_voc['blocktypes']);

        if (!empty(
$thisfile_voc['compressed_bits_per_sample'])) {
            
$info['playtime_seconds'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / ($thisfile_voc['compressed_bits_per_sample'] * $thisfile_audio['channels'] * $thisfile_audio['sample_rate']);
            
$thisfile_audio['bitrate'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['playtime_seconds'];
        }

        return 
true;
    }

    public function 
VOCcompressionTypeLookup($index) {
        static 
$VOCcompressionTypeLookup = array(
            
=> '8-bit',
            
=> '4-bit',
            
=> '2.6-bit',
            
=> '2-bit'
        
);
        return (isset(
$VOCcompressionTypeLookup[$index]) ? $VOCcompressionTypeLookup[$index] : 'Multi DAC ('.($index 3).') channels');
    }

    public function 
VOCwFormatLookup($index) {
        static 
$VOCwFormatLookup = array(
            
0x0000 => '8-bit unsigned PCM',
            
0x0001 => 'Creative 8-bit to 4-bit ADPCM',
            
0x0002 => 'Creative 8-bit to 3-bit ADPCM',
            
0x0003 => 'Creative 8-bit to 2-bit ADPCM',
            
0x0004 => '16-bit signed PCM',
            
0x0006 => 'CCITT a-Law',
            
0x0007 => 'CCITT u-Law',
            
0x2000 => 'Creative 16-bit to 4-bit ADPCM'
        
);
        return (isset(
$VOCwFormatLookup[$index]) ? $VOCwFormatLookup[$index] : false);
    }

    public function 
VOCwFormatActualBitsPerSampleLookup($index) {
        static 
$VOCwFormatLookup = array(
            
0x0000 =>  8,
            
0x0001 =>  4,
            
0x0002 =>  3,
            
0x0003 =>  2,
            
0x0004 => 16,
            
0x0006 =>  8,
            
0x0007 =>  8,
            
0x2000 =>  4
        
);
        return (isset(
$VOCwFormatLookup[$index]) ? $VOCwFormatLookup[$index] : false);
    }

}