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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 URLs |
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* (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 $flippedMap = array( |
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'A' => 0, 'B' => 1, 'C' => 2, 'D' => 3, 'E' => 4, 'F' => 5, 'G' => 6, 'H' => 7, |
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'I' => 8, 'J' => 9, 'K' => 10, 'L' => 11, 'M' => 12, 'N' => 13, 'O' => 14, 'P' => 15, |
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'Q' => 16, 'R' => 17, 'S' => 18, 'T' => 19, 'U' => 20, 'V' => 21, 'W' => 22, 'X' => 23, |
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'Y' => 24, 'Z' => 25, '2' => 26, '3' => 27, '4' => 28, '5' => 29, '6' => 30, '7' => 31 |
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); |
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|
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/** |
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* Use padding false when encoding for URLs. |
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* |
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* @return string |
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*/ |
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public static function encode($input, $padding = true) { |
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if ($input === '' || $input === null) { |
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return ''; |
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} |
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|
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$input = (string) $input; |
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$inputLength = strlen($input); |
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$binaryString = ''; |
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|
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for ($i = 0; $i < $inputLength; $i++) { |
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$binaryString .= str_pad(base_convert((string) ord($input[$i]), 10, 2), 8, '0', STR_PAD_LEFT); |
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} |
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|
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$fiveBitBinaryArray = str_split($binaryString, 5); |
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$base32 = ''; |
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$chunkCount = count($fiveBitBinaryArray); |
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|
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for ($i = 0; $i < $chunkCount; $i++) { |
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$base32 .= self::$map[(int) base_convert(str_pad($fiveBitBinaryArray[$i], 5, '0'), 2, 10)]; |
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} |
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|
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if ($padding) { |
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$x = strlen($binaryString) % 40; |
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if ($x !== 0) { |
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if ($x === 8) { |
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$base32 .= str_repeat(self::$map[32], 6); |
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} elseif ($x === 16) { |
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$base32 .= str_repeat(self::$map[32], 4); |
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} elseif ($x === 24) { |
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$base32 .= str_repeat(self::$map[32], 3); |
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} elseif ($x === 32) { |
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$base32 .= self::$map[32]; |
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} |
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} |
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} |
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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 ($input === '' || $input === null) { |
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return ''; |
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} |
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|
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$input = strtoupper((string) $input); |
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$paddingCharCount = substr_count($input, self::$map[32]); |
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$allowedValues = array(6, 4, 3, 1, 0); |
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|
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if (!in_array($paddingCharCount, $allowedValues, true)) { |
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return false; |
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} |
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|
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for ($i = 0; $i < 4; $i++) { |
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if ( |
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$paddingCharCount === $allowedValues[$i] && |
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substr($input, -$allowedValues[$i]) !== str_repeat(self::$map[32], $allowedValues[$i]) |
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) { |
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return false; |
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} |
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} |
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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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$inputCount = count($input); |
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|
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for ($i = 0; $i < $inputCount; $i++) { |
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if (!isset(self::$flippedMap[$input[$i]])) { |
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return false; |
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} |
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$binaryString .= str_pad(base_convert((string) self::$flippedMap[$input[$i]], 10, 2), 5, '0', STR_PAD_LEFT); |
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} |
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|
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$eightBits = str_split($binaryString, 8); |
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$output = ''; |
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$eightBitCount = count($eightBits); |
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|
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for ($z = 0; $z < $eightBitCount; $z++) { |
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if (strlen($eightBits[$z]) !== 8) { |
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continue; |
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} |
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$output .= chr((int) base_convert($eightBits[$z], 2, 10)); |
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} |
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|
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return $output; |
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} |
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} |
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|
