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<?php |
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|
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/** |
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* Encode in Base32 based on RFC 4648. |
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* Requires 20% more space than base64 |
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* Great for case-insensitive filesystems like Windows and URL's (except for = char which can be excluded using the pad option for urls) |
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* |
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* @package default |
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* @author Bryan Ruiz |
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**/ |
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class Base32 { |
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|
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private static $map = array( |
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'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', // 7 |
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'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', // 15 |
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'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', // 23 |
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'Y', 'Z', '2', '3', '4', '5', '6', '7', // 31 |
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'=' // padding char |
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); |
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|
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private static $flippedMap = array( |
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'A'=>'0', 'B'=>'1', 'C'=>'2', 'D'=>'3', 'E'=>'4', 'F'=>'5', 'G'=>'6', 'H'=>'7', |
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'I'=>'8', 'J'=>'9', 'K'=>'10', 'L'=>'11', 'M'=>'12', 'N'=>'13', 'O'=>'14', 'P'=>'15', |
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'Q'=>'16', 'R'=>'17', 'S'=>'18', 'T'=>'19', 'U'=>'20', 'V'=>'21', 'W'=>'22', 'X'=>'23', |
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'Y'=>'24', 'Z'=>'25', '2'=>'26', '3'=>'27', '4'=>'28', '5'=>'29', '6'=>'30', '7'=>'31' |
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); |
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|
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/** |
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* Use padding false when encoding for urls |
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* |
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* @return base32 encoded string |
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* @author Bryan Ruiz |
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**/ |
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public static function encode($input, $padding = true) { |
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if(empty($input)) return ""; |
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$input = str_split($input); |
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$binaryString = ""; |
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for($i = 0; $i < count($input); $i++) { |
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$binaryString .= str_pad(base_convert(ord($input[$i]), 10, 2), 8, '0', STR_PAD_LEFT); |
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} |
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$fiveBitBinaryArray = str_split($binaryString, 5); |
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$base32 = ""; |
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$i=0; |
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while($i < count($fiveBitBinaryArray)) { |
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$base32 .= self::$map[base_convert(str_pad($fiveBitBinaryArray[$i], 5,'0'), 2, 10)]; |
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$i++; |
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} |
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if($padding && ($x = strlen($binaryString) % 40) != 0) { |
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if($x == 8) $base32 .= str_repeat(self::$map[32], 6); |
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else if($x == 16) $base32 .= str_repeat(self::$map[32], 4); |
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else if($x == 24) $base32 .= str_repeat(self::$map[32], 3); |
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else if($x == 32) $base32 .= self::$map[32]; |
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} |
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return $base32; |
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} |
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|
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public static function decode($input) { |
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if(empty($input)) return; |
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$paddingCharCount = substr_count($input, self::$map[32]); |
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$allowedValues = array(6,4,3,1,0); |
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if(!in_array($paddingCharCount, $allowedValues)) return false; |
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for($i=0; $i<4; $i++){ |
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if($paddingCharCount == $allowedValues[$i] && |
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substr($input, -($allowedValues[$i])) != str_repeat(self::$map[32], $allowedValues[$i])) return false; |
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} |
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$input = str_replace('=','', $input); |
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$input = str_split($input); |
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$binaryString = ""; |
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for($i=0; $i < count($input); $i = $i+8) { |
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$x = ""; |
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if(!in_array($input[$i], self::$map)) return false; |
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for($j=0; $j < 8; $j++) { |
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$x .= str_pad(base_convert(@self::$flippedMap[@$input[$i + $j]], 10, 2), 5, '0', STR_PAD_LEFT); |
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} |
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$eightBits = str_split($x, 8); |
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for($z = 0; $z < count($eightBits); $z++) { |
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$binaryString .= ( ($y = chr(base_convert($eightBits[$z], 2, 10))) || ord($y) == 48 ) ? $y:""; |
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} |
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} |
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return $binaryString; |
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} |
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} |
