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<?php |
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/** |
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* Class ID3Helpers |
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* |
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* @created 25.09.2018 |
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* @author smiley <[email protected]> |
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* @copyright 2018 smiley |
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* @license MIT |
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*/ |
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namespace chillerlan\ID3Tag; |
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use DateInterval, DateTime, RuntimeException; |
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use function ord, pow, sprintf, str_replace, strlen; |
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use const PHP_INT_SIZE; |
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final class ID3Helpers{ |
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/** |
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* |
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*/ |
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public static function syncSafeInteger(int $raw):int{ |
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return $raw & 0x0000007F | ($raw & 0x00007F00) >> 1 | ($raw & 0x007F0000) >> 2 | ($raw & 0x7F000000) >> 3; |
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} |
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/** |
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* @link https://github.com/JamesHeinrich/getID3/blob/ec929d85af7b6bc04c10175a37144cdec0f94c72/getid3/getid3.lib.php#L334 |
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* |
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* @throws \Exception |
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*/ |
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public static function bigEndian2Int(string $byteword, bool $syncsafe = null, bool $signed = null):?int{ |
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$intvalue = 0; |
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$bytewordlen = strlen($byteword); |
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if($bytewordlen === 0){ |
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return null; |
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} |
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for($i = 0; $i < $bytewordlen; $i++){ |
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$intvalue += $syncsafe |
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? (ord($byteword[$i]) & 0x7F) * pow(2, ($bytewordlen - 1 - $i) * 7) // disregard MSB, effectively 7-bit bytes |
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: ord($byteword[$i]) * pow(256, ($bytewordlen - 1 - $i)); |
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} |
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if($signed && !$syncsafe){ |
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// syncsafe ints are not allowed to be signed |
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if($bytewordlen <= PHP_INT_SIZE){ |
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$signMaskBit = 0x80 << (8 * ($bytewordlen - 1)); |
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if($intvalue & $signMaskBit){ |
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$intvalue = 0 - ($intvalue & ($signMaskBit - 1)); |
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} |
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} |
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else{ |
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throw new RuntimeException( |
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sprintf('ERROR: Cannot have signed integers larger than %s bits %s', (8 * PHP_INT_SIZE), strlen($byteword)) |
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); |
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} |
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} |
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return $intvalue; |
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} |
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/** |
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* |
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*/ |
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public static function unsyncString(string $string):string{ |
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return str_replace("\xFF\x00", "\xFF", $string); |
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} |
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/** |
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* |
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*/ |
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public static function formatTime(int $duration):string{ |
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$dt = (new DateTime) |
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->add(new DateInterval('PT'.$duration.'S')) |
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->diff(new DateTime) |
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; |
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$format = '%i:%s'; |
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if($dt->h > 0){ |
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$format = '%H:'.$format; |
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} |
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if($dt->h > 24){ |
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$format = '%D:'.$format; |
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} |
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return $dt->format($format); |
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} |
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} |
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If an expression can have both
false
, andnull
as possible values. It is generally a good practice to always use strict comparison to clearly distinguish between those two values.