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388 lines
11 KiB
388 lines
11 KiB
<?php |
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/** |
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* IDNA URL encoder |
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* |
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* Note: Not fully compliant, as nameprep does nothing yet. |
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* |
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* @package Requests |
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* @subpackage Utilities |
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* @see https://tools.ietf.org/html/rfc3490 IDNA specification |
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* @see https://tools.ietf.org/html/rfc3492 Punycode/Bootstrap specification |
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*/ |
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class Requests_IDNAEncoder { |
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/** |
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* ACE prefix used for IDNA |
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* |
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* @see https://tools.ietf.org/html/rfc3490#section-5 |
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* @var string |
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*/ |
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const ACE_PREFIX = 'xn--'; |
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/**#@+ |
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* Bootstrap constant for Punycode |
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* |
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* @see https://tools.ietf.org/html/rfc3492#section-5 |
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* @var int |
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*/ |
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const BOOTSTRAP_BASE = 36; |
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const BOOTSTRAP_TMIN = 1; |
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const BOOTSTRAP_TMAX = 26; |
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const BOOTSTRAP_SKEW = 38; |
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const BOOTSTRAP_DAMP = 700; |
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const BOOTSTRAP_INITIAL_BIAS = 72; |
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const BOOTSTRAP_INITIAL_N = 128; |
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/**#@-*/ |
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/** |
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* Encode a hostname using Punycode |
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* |
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* @param string $string Hostname |
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* @return string Punycode-encoded hostname |
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*/ |
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public static function encode($string) { |
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$parts = explode('.', $string); |
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foreach ($parts as &$part) { |
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$part = self::to_ascii($part); |
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} |
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return implode('.', $parts); |
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} |
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/** |
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* Convert a UTF-8 string to an ASCII string using Punycode |
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* |
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* @throws Requests_Exception Provided string longer than 64 ASCII characters (`idna.provided_too_long`) |
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* @throws Requests_Exception Prepared string longer than 64 ASCII characters (`idna.prepared_too_long`) |
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* @throws Requests_Exception Provided string already begins with xn-- (`idna.provided_is_prefixed`) |
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* @throws Requests_Exception Encoded string longer than 64 ASCII characters (`idna.encoded_too_long`) |
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* |
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* @param string $string ASCII or UTF-8 string (max length 64 characters) |
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* @return string ASCII string |
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*/ |
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public static function to_ascii($string) { |
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// Step 1: Check if the string is already ASCII |
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if (self::is_ascii($string)) { |
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// Skip to step 7 |
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if (strlen($string) < 64) { |
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return $string; |
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} |
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throw new Requests_Exception('Provided string is too long', 'idna.provided_too_long', $string); |
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} |
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// Step 2: nameprep |
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$string = self::nameprep($string); |
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// Step 3: UseSTD3ASCIIRules is false, continue |
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// Step 4: Check if it's ASCII now |
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if (self::is_ascii($string)) { |
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// Skip to step 7 |
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if (strlen($string) < 64) { |
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return $string; |
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} |
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throw new Requests_Exception('Prepared string is too long', 'idna.prepared_too_long', $string); |
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} |
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// Step 5: Check ACE prefix |
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if (strpos($string, self::ACE_PREFIX) === 0) { |
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throw new Requests_Exception('Provided string begins with ACE prefix', 'idna.provided_is_prefixed', $string); |
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} |
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// Step 6: Encode with Punycode |
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$string = self::punycode_encode($string); |
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// Step 7: Prepend ACE prefix |
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$string = self::ACE_PREFIX . $string; |
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// Step 8: Check size |
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if (strlen($string) < 64) { |
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return $string; |
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} |
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throw new Requests_Exception('Encoded string is too long', 'idna.encoded_too_long', $string); |
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} |
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/** |
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* Check whether a given string contains only ASCII characters |
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* |
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* @internal (Testing found regex was the fastest implementation) |
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* |
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* @param string $string |
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* @return bool Is the string ASCII-only? |
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*/ |
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protected static function is_ascii($string) { |
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return (preg_match('/(?:[^\x00-\x7F])/', $string) !== 1); |
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} |
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/** |
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* Prepare a string for use as an IDNA name |
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* |
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* @todo Implement this based on RFC 3491 and the newer 5891 |
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* @param string $string |
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* @return string Prepared string |
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*/ |
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protected static function nameprep($string) { |
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return $string; |
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} |
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/** |
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* Convert a UTF-8 string to a UCS-4 codepoint array |
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* |
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* Based on Requests_IRI::replace_invalid_with_pct_encoding() |
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* |
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* @throws Requests_Exception Invalid UTF-8 codepoint (`idna.invalidcodepoint`) |
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* @param string $input |
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* @return array Unicode code points |
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*/ |
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protected static function utf8_to_codepoints($input) { |
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$codepoints = array(); |
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// Get number of bytes |
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$strlen = strlen($input); |
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for ($position = 0; $position < $strlen; $position++) { |
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$value = ord($input[$position]); |
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// One byte sequence: |
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if ((~$value & 0x80) === 0x80) { |
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$character = $value; |
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$length = 1; |
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$remaining = 0; |
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} |
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// Two byte sequence: |
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elseif (($value & 0xE0) === 0xC0) { |
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$character = ($value & 0x1F) << 6; |
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$length = 2; |
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$remaining = 1; |
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} |
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// Three byte sequence: |
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elseif (($value & 0xF0) === 0xE0) { |
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$character = ($value & 0x0F) << 12; |
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$length = 3; |
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$remaining = 2; |
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} |
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// Four byte sequence: |
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elseif (($value & 0xF8) === 0xF0) { |
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$character = ($value & 0x07) << 18; |
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$length = 4; |
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$remaining = 3; |
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} |
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// Invalid byte: |
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else { |
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throw new Requests_Exception('Invalid Unicode codepoint', 'idna.invalidcodepoint', $value); |
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} |
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if ($remaining > 0) { |
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if ($position + $length > $strlen) { |
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throw new Requests_Exception('Invalid Unicode codepoint', 'idna.invalidcodepoint', $character); |
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} |
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for ($position++; $remaining > 0; $position++) { |
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$value = ord($input[$position]); |
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// If it is invalid, count the sequence as invalid and reprocess the current byte: |
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if (($value & 0xC0) !== 0x80) { |
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throw new Requests_Exception('Invalid Unicode codepoint', 'idna.invalidcodepoint', $character); |
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} |
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$character |= ($value & 0x3F) << (--$remaining * 6); |
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} |
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$position--; |
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} |
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if ( |
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// Non-shortest form sequences are invalid |
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$length > 1 && $character <= 0x7F |
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|| $length > 2 && $character <= 0x7FF |
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|| $length > 3 && $character <= 0xFFFF |
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// Outside of range of ucschar codepoints |
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// Noncharacters |
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|| ($character & 0xFFFE) === 0xFFFE |
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|| $character >= 0xFDD0 && $character <= 0xFDEF |
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|| ( |
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// Everything else not in ucschar |
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$character > 0xD7FF && $character < 0xF900 |
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|| $character < 0x20 |
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|| $character > 0x7E && $character < 0xA0 |
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|| $character > 0xEFFFD |
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) |
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) { |
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throw new Requests_Exception('Invalid Unicode codepoint', 'idna.invalidcodepoint', $character); |
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} |
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$codepoints[] = $character; |
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} |
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return $codepoints; |
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} |
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/** |
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* RFC3492-compliant encoder |
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* |
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* @internal Pseudo-code from Section 6.3 is commented with "#" next to relevant code |
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* @throws Requests_Exception On character outside of the domain (never happens with Punycode) (`idna.character_outside_domain`) |
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* |
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* @param string $input UTF-8 encoded string to encode |
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* @return string Punycode-encoded string |
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*/ |
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public static function punycode_encode($input) { |
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$output = ''; |
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# let n = initial_n |
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$n = self::BOOTSTRAP_INITIAL_N; |
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# let delta = 0 |
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$delta = 0; |
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# let bias = initial_bias |
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$bias = self::BOOTSTRAP_INITIAL_BIAS; |
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# let h = b = the number of basic code points in the input |
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$h = $b = 0; // see loop |
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# copy them to the output in order |
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$codepoints = self::utf8_to_codepoints($input); |
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$extended = array(); |
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foreach ($codepoints as $char) { |
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if ($char < 128) { |
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// Character is valid ASCII |
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// TODO: this should also check if it's valid for a URL |
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$output .= chr($char); |
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$h++; |
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} |
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// Check if the character is non-ASCII, but below initial n |
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// This never occurs for Punycode, so ignore in coverage |
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// @codeCoverageIgnoreStart |
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elseif ($char < $n) { |
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throw new Requests_Exception('Invalid character', 'idna.character_outside_domain', $char); |
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} |
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// @codeCoverageIgnoreEnd |
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else { |
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$extended[$char] = true; |
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} |
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} |
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$extended = array_keys($extended); |
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sort($extended); |
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$b = $h; |
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# [copy them] followed by a delimiter if b > 0 |
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if (strlen($output) > 0) { |
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$output .= '-'; |
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} |
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# {if the input contains a non-basic code point < n then fail} |
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# while h < length(input) do begin |
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while ($h < count($codepoints)) { |
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# let m = the minimum code point >= n in the input |
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$m = array_shift($extended); |
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//printf('next code point to insert is %s' . PHP_EOL, dechex($m)); |
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# let delta = delta + (m - n) * (h + 1), fail on overflow |
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$delta += ($m - $n) * ($h + 1); |
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# let n = m |
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$n = $m; |
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# for each code point c in the input (in order) do begin |
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for ($num = 0; $num < count($codepoints); $num++) { |
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$c = $codepoints[$num]; |
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# if c < n then increment delta, fail on overflow |
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if ($c < $n) { |
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$delta++; |
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} |
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# if c == n then begin |
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elseif ($c === $n) { |
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# let q = delta |
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$q = $delta; |
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# for k = base to infinity in steps of base do begin |
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for ($k = self::BOOTSTRAP_BASE; ; $k += self::BOOTSTRAP_BASE) { |
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# let t = tmin if k <= bias {+ tmin}, or |
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# tmax if k >= bias + tmax, or k - bias otherwise |
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if ($k <= ($bias + self::BOOTSTRAP_TMIN)) { |
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$t = self::BOOTSTRAP_TMIN; |
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} |
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elseif ($k >= ($bias + self::BOOTSTRAP_TMAX)) { |
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$t = self::BOOTSTRAP_TMAX; |
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} |
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else { |
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$t = $k - $bias; |
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} |
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# if q < t then break |
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if ($q < $t) { |
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break; |
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} |
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# output the code point for digit t + ((q - t) mod (base - t)) |
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$digit = $t + (($q - $t) % (self::BOOTSTRAP_BASE - $t)); |
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$output .= self::digit_to_char($digit); |
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# let q = (q - t) div (base - t) |
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$q = floor(($q - $t) / (self::BOOTSTRAP_BASE - $t)); |
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# end |
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} |
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# output the code point for digit q |
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$output .= self::digit_to_char($q); |
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# let bias = adapt(delta, h + 1, test h equals b?) |
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$bias = self::adapt($delta, $h + 1, $h === $b); |
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# let delta = 0 |
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$delta = 0; |
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# increment h |
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$h++; |
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# end |
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} |
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# end |
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} |
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# increment delta and n |
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$delta++; |
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$n++; |
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# end |
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} |
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return $output; |
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} |
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/** |
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* Convert a digit to its respective character |
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* |
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* @see https://tools.ietf.org/html/rfc3492#section-5 |
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* @throws Requests_Exception On invalid digit (`idna.invalid_digit`) |
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* |
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* @param int $digit Digit in the range 0-35 |
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* @return string Single character corresponding to digit |
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*/ |
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protected static function digit_to_char($digit) { |
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// @codeCoverageIgnoreStart |
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// As far as I know, this never happens, but still good to be sure. |
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if ($digit < 0 || $digit > 35) { |
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throw new Requests_Exception(sprintf('Invalid digit %d', $digit), 'idna.invalid_digit', $digit); |
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} |
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// @codeCoverageIgnoreEnd |
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$digits = 'abcdefghijklmnopqrstuvwxyz0123456789'; |
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return substr($digits, $digit, 1); |
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} |
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/** |
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* Adapt the bias |
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* |
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* @see https://tools.ietf.org/html/rfc3492#section-6.1 |
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* @param int $delta |
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* @param int $numpoints |
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* @param bool $firsttime |
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* @return int New bias |
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*/ |
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protected static function adapt($delta, $numpoints, $firsttime) { |
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# function adapt(delta,numpoints,firsttime): |
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# if firsttime then let delta = delta div damp |
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if ($firsttime) { |
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$delta = floor($delta / self::BOOTSTRAP_DAMP); |
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} |
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# else let delta = delta div 2 |
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else { |
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$delta = floor($delta / 2); |
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} |
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# let delta = delta + (delta div numpoints) |
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$delta += floor($delta / $numpoints); |
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# let k = 0 |
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$k = 0; |
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# while delta > ((base - tmin) * tmax) div 2 do begin |
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$max = floor(((self::BOOTSTRAP_BASE - self::BOOTSTRAP_TMIN) * self::BOOTSTRAP_TMAX) / 2); |
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while ($delta > $max) { |
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# let delta = delta div (base - tmin) |
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$delta = floor($delta / (self::BOOTSTRAP_BASE - self::BOOTSTRAP_TMIN)); |
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# let k = k + base |
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$k += self::BOOTSTRAP_BASE; |
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# end |
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} |
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# return k + (((base - tmin + 1) * delta) div (delta + skew)) |
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return $k + floor(((self::BOOTSTRAP_BASE - self::BOOTSTRAP_TMIN + 1) * $delta) / ($delta + self::BOOTSTRAP_SKEW)); |
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} |
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} |