Seditio Source
Root |
./othercms/xenForo 2.2.8/src/vendor/symfony/polyfill-intl-idn/Idn.php
<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com> and Trevor Rowbotham <trevor.rowbotham@pm.me>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Polyfill\Intl\Idn;

use
Exception;
use
Normalizer;
use
Symfony\Polyfill\Intl\Idn\Resources\unidata\DisallowedRanges;
use
Symfony\Polyfill\Intl\Idn\Resources\unidata\Regex;

/**
 * @see https://www.unicode.org/reports/tr46/
 *
 * @internal
 */
final class Idn
{
    const
ERROR_EMPTY_LABEL = 1;
    const
ERROR_LABEL_TOO_LONG = 2;
    const
ERROR_DOMAIN_NAME_TOO_LONG = 4;
    const
ERROR_LEADING_HYPHEN = 8;
    const
ERROR_TRAILING_HYPHEN = 0x10;
    const
ERROR_HYPHEN_3_4 = 0x20;
    const
ERROR_LEADING_COMBINING_MARK = 0x40;
    const
ERROR_DISALLOWED = 0x80;
    const
ERROR_PUNYCODE = 0x100;
    const
ERROR_LABEL_HAS_DOT = 0x200;
    const
ERROR_INVALID_ACE_LABEL = 0x400;
    const
ERROR_BIDI = 0x800;
    const
ERROR_CONTEXTJ = 0x1000;
    const
ERROR_CONTEXTO_PUNCTUATION = 0x2000;
    const
ERROR_CONTEXTO_DIGITS = 0x4000;

    const
INTL_IDNA_VARIANT_2003 = 0;
    const
INTL_IDNA_VARIANT_UTS46 = 1;

    const
IDNA_DEFAULT = 0;
    const
IDNA_ALLOW_UNASSIGNED = 1;
    const
IDNA_USE_STD3_RULES = 2;
    const
IDNA_CHECK_BIDI = 4;
    const
IDNA_CHECK_CONTEXTJ = 8;
    const
IDNA_NONTRANSITIONAL_TO_ASCII = 16;
    const
IDNA_NONTRANSITIONAL_TO_UNICODE = 32;

    const
MAX_DOMAIN_SIZE = 253;
    const
MAX_LABEL_SIZE = 63;

    const
BASE = 36;
    const
TMIN = 1;
    const
TMAX = 26;
    const
SKEW = 38;
    const
DAMP = 700;
    const
INITIAL_BIAS = 72;
    const
INITIAL_N = 128;
    const
DELIMITER = '-';
    const
MAX_INT = 2147483647;

   
/**
     * Contains the numeric value of a basic code point (for use in representing integers) in the
     * range 0 to BASE-1, or -1 if b is does not represent a value.
     *
     * @var array<int, int>
     */
   
private static $basicToDigit = array(
        -
1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -
1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

        -
1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
       
26, 27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1, -1, -1,

        -
1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
       
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,

        -
1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
       
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,

        -
1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -
1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

        -
1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -
1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

        -
1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -
1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

        -
1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -
1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    );

   
/**
     * @var array<int, int>
     */
   
private static $virama;

   
/**
     * @var array<int, string>
     */
   
private static $mapped;

   
/**
     * @var array<int, bool>
     */
   
private static $ignored;

   
/**
     * @var array<int, string>
     */
   
private static $deviation;

   
/**
     * @var array<int, bool>
     */
   
private static $disallowed;

   
/**
     * @var array<int, string>
     */
   
private static $disallowed_STD3_mapped;

   
/**
     * @var array<int, bool>
     */
   
private static $disallowed_STD3_valid;

   
/**
     * @var bool
     */
   
private static $mappingTableLoaded = false;

   
/**
     * @see https://www.unicode.org/reports/tr46/#ToASCII
     *
     * @param string $domainName
     * @param int    $options
     * @param int    $variant
     * @param array  $idna_info
     *
     * @return string|false
     */
   
public static function idn_to_ascii($domainName, $options = self::IDNA_DEFAULT, $variant = self::INTL_IDNA_VARIANT_UTS46, &$idna_info = array())
    {
        if (\
PHP_VERSION_ID >= 70200 && self::INTL_IDNA_VARIANT_2003 === $variant) {
            @
trigger_error('idn_to_ascii(): INTL_IDNA_VARIANT_2003 is deprecated', E_USER_DEPRECATED);
        }

       
$options = array(
           
'CheckHyphens' => true,
           
'CheckBidi' => self::INTL_IDNA_VARIANT_2003 === $variant || 0 !== ($options & self::IDNA_CHECK_BIDI),
           
'CheckJoiners' => self::INTL_IDNA_VARIANT_UTS46 === $variant && 0 !== ($options & self::IDNA_CHECK_CONTEXTJ),
           
'UseSTD3ASCIIRules' => 0 !== ($options & self::IDNA_USE_STD3_RULES),
           
'Transitional_Processing' => self::INTL_IDNA_VARIANT_2003 === $variant || 0 === ($options & self::IDNA_NONTRANSITIONAL_TO_ASCII),
           
'VerifyDnsLength' => true,
        );
       
$info = new Info();
       
$labels = self::process((string) $domainName, $options, $info);

        foreach (
$labels as $i => $label) {
           
// Only convert labels to punycode that contain non-ASCII code points
           
if (1 === preg_match('/[^\x00-\x7F]/', $label)) {
                try {
                   
$label = 'xn--'.self::punycodeEncode($label);
                } catch (
Exception $e) {
                   
$info->errors |= self::ERROR_PUNYCODE;
                }

               
$labels[$i] = $label;
            }
        }

        if (
$options['VerifyDnsLength']) {
           
self::validateDomainAndLabelLength($labels, $info);
        }

       
$idna_info = array(
           
'result' => implode('.', $labels),
           
'isTransitionalDifferent' => $info->transitionalDifferent,
           
'errors' => $info->errors,
        );

        return
0 === $info->errors ? $idna_info['result'] : false;
    }

   
/**
     * @see https://www.unicode.org/reports/tr46/#ToUnicode
     *
     * @param string $domainName
     * @param int    $options
     * @param int    $variant
     * @param array  $idna_info
     *
     * @return string|false
     */
   
public static function idn_to_utf8($domainName, $options = self::IDNA_DEFAULT, $variant = self::INTL_IDNA_VARIANT_UTS46, &$idna_info = array())
    {
        if (\
PHP_VERSION_ID >= 70200 && self::INTL_IDNA_VARIANT_2003 === $variant) {
            @
trigger_error('idn_to_utf8(): INTL_IDNA_VARIANT_2003 is deprecated', E_USER_DEPRECATED);
        }

       
$info = new Info();
       
$labels = self::process((string) $domainName, array(
           
'CheckHyphens' => true,
           
'CheckBidi' => self::INTL_IDNA_VARIANT_2003 === $variant || 0 !== ($options & self::IDNA_CHECK_BIDI),
           
'CheckJoiners' => self::INTL_IDNA_VARIANT_UTS46 === $variant && 0 !== ($options & self::IDNA_CHECK_CONTEXTJ),
           
'UseSTD3ASCIIRules' => 0 !== ($options & self::IDNA_USE_STD3_RULES),
           
'Transitional_Processing' => self::INTL_IDNA_VARIANT_2003 === $variant || 0 === ($options & self::IDNA_NONTRANSITIONAL_TO_UNICODE),
        ),
$info);
       
$idna_info = array(
           
'result' => implode('.', $labels),
           
'isTransitionalDifferent' => $info->transitionalDifferent,
           
'errors' => $info->errors,
        );

        return
0 === $info->errors ? $idna_info['result'] : false;
    }

   
/**
     * @param string $label
     *
     * @return bool
     */
   
private static function isValidContextJ(array $codePoints, $label)
    {
        if (!isset(
self::$virama)) {
           
self::$virama = require __DIR__.\DIRECTORY_SEPARATOR.'Resources'.\DIRECTORY_SEPARATOR.'unidata'.\DIRECTORY_SEPARATOR.'virama.php';
        }

       
$offset = 0;

        foreach (
$codePoints as $i => $codePoint) {
            if (
0x200C !== $codePoint && 0x200D !== $codePoint) {
                continue;
            }

            if (!isset(
$codePoints[$i - 1])) {
                return
false;
            }

           
// If Canonical_Combining_Class(Before(cp)) .eq. Virama Then True;
           
if (isset(self::$virama[$codePoints[$i - 1]])) {
                continue;
            }

           
// If RegExpMatch((Joining_Type:{L,D})(Joining_Type:T)*\u200C(Joining_Type:T)*(Joining_Type:{R,D})) Then
            // True;
            // Generated RegExp = ([Joining_Type:{L,D}][Joining_Type:T]*\u200C[Joining_Type:T]*)[Joining_Type:{R,D}]
           
if (0x200C === $codePoint && 1 === preg_match(Regex::ZWNJ, $label, $matches, PREG_OFFSET_CAPTURE, $offset)) {
               
$offset += \strlen($matches[1][0]);

                continue;
            }

            return
false;
        }

        return
true;
    }

   
/**
     * @see https://www.unicode.org/reports/tr46/#ProcessingStepMap
     *
     * @param string              $input
     * @param array<string, bool> $options
     *
     * @return string
     */
   
private static function mapCodePoints($input, array $options, Info $info)
    {
       
$str = '';
       
$useSTD3ASCIIRules = $options['UseSTD3ASCIIRules'];
       
$transitional = $options['Transitional_Processing'];

        foreach (
self::utf8Decode($input) as $codePoint) {
           
$data = self::lookupCodePointStatus($codePoint, $useSTD3ASCIIRules);

            switch (
$data['status']) {
                case
'disallowed':
                   
$info->errors |= self::ERROR_DISALLOWED;

                   
// no break.

               
case 'valid':
                   
$str .= mb_chr($codePoint, 'utf-8');

                    break;

                case
'ignored':
                   
// Do nothing.
                   
break;

                case
'mapped':
                   
$str .= $data['mapping'];

                    break;

                case
'deviation':
                   
$info->transitionalDifferent = true;
                   
$str .= ($transitional ? $data['mapping'] : mb_chr($codePoint, 'utf-8'));

                    break;
            }
        }

        return
$str;
    }

   
/**
     * @see https://www.unicode.org/reports/tr46/#Processing
     *
     * @param string              $domain
     * @param array<string, bool> $options
     *
     * @return array<int, string>
     */
   
private static function process($domain, array $options, Info $info)
    {
       
// If VerifyDnsLength is not set, we are doing ToUnicode otherwise we are doing ToASCII and
        // we need to respect the VerifyDnsLength option.
       
$checkForEmptyLabels = !isset($options['VerifyDnsLength']) || $options['VerifyDnsLength'];

        if (
$checkForEmptyLabels && '' === $domain) {
           
$info->errors |= self::ERROR_EMPTY_LABEL;

            return array(
$domain);
        }

       
// Step 1. Map each code point in the domain name string
       
$domain = self::mapCodePoints($domain, $options, $info);

       
// Step 2. Normalize the domain name string to Unicode Normalization Form C.
       
if (!Normalizer::isNormalized($domain, Normalizer::FORM_C)) {
           
$domain = Normalizer::normalize($domain, Normalizer::FORM_C);
        }

       
// Step 3. Break the string into labels at U+002E (.) FULL STOP.
       
$labels = explode('.', $domain);
       
$lastLabelIndex = \count($labels) - 1;

       
// Step 4. Convert and validate each label in the domain name string.
       
foreach ($labels as $i => $label) {
           
$validationOptions = $options;

            if (
'xn--' === substr($label, 0, 4)) {
                try {
                   
$label = self::punycodeDecode(substr($label, 4));
                } catch (
Exception $e) {
                   
$info->errors |= self::ERROR_PUNYCODE;

                    continue;
                }

               
$validationOptions['Transitional_Processing'] = false;
               
$labels[$i] = $label;
            }

           
self::validateLabel($label, $info, $validationOptions, $i > 0 && $i === $lastLabelIndex);
        }

        if (
$info->bidiDomain && !$info->validBidiDomain) {
           
$info->errors |= self::ERROR_BIDI;
        }

       
// Any input domain name string that does not record an error has been successfully
        // processed according to this specification. Conversely, if an input domain_name string
        // causes an error, then the processing of the input domain_name string fails. Determining
        // what to do with error input is up to the caller, and not in the scope of this document.
       
return $labels;
    }

   
/**
     * @see https://tools.ietf.org/html/rfc5893#section-2
     *
     * @param string $label
     */
   
private static function validateBidiLabel($label, Info $info)
    {
        if (
1 === preg_match(Regex::RTL_LABEL, $label)) {
           
$info->bidiDomain = true;

           
// Step 1. The first character must be a character with Bidi property L, R, or AL.
            // If it has the R or AL property, it is an RTL label
           
if (1 !== preg_match(Regex::BIDI_STEP_1_RTL, $label)) {
               
$info->validBidiDomain = false;

                return;
            }

           
// Step 2. In an RTL label, only characters with the Bidi properties R, AL, AN, EN, ES,
            // CS, ET, ON, BN, or NSM are allowed.
           
if (1 === preg_match(Regex::BIDI_STEP_2, $label)) {
               
$info->validBidiDomain = false;

                return;
            }

           
// Step 3. In an RTL label, the end of the label must be a character with Bidi property
            // R, AL, EN, or AN, followed by zero or more characters with Bidi property NSM.
           
if (1 !== preg_match(Regex::BIDI_STEP_3, $label)) {
               
$info->validBidiDomain = false;

                return;
            }

           
// Step 4. In an RTL label, if an EN is present, no AN may be present, and vice versa.
           
if (1 === preg_match(Regex::BIDI_STEP_4_AN, $label) && 1 === preg_match(Regex::BIDI_STEP_4_EN, $label)) {
               
$info->validBidiDomain = false;

                return;
            }

            return;
        }

       
// We are a LTR label
        // Step 1. The first character must be a character with Bidi property L, R, or AL.
        // If it has the L property, it is an LTR label.
       
if (1 !== preg_match(Regex::BIDI_STEP_1_LTR, $label)) {
           
$info->validBidiDomain = false;

            return;
        }

       
// Step 5. In an LTR label, only characters with the Bidi properties L, EN,
        // ES, CS, ET, ON, BN, or NSM are allowed.
       
if (1 === preg_match(Regex::BIDI_STEP_5, $label)) {
           
$info->validBidiDomain = false;

            return;
        }

       
// Step 6.In an LTR label, the end of the label must be a character with Bidi property L or
        // EN, followed by zero or more characters with Bidi property NSM.
       
if (1 !== preg_match(Regex::BIDI_STEP_6, $label)) {
           
$info->validBidiDomain = false;

            return;
        }
    }

   
/**
     * @param array<int, string> $labels
     */
   
private static function validateDomainAndLabelLength(array $labels, Info $info)
    {
       
$maxDomainSize = self::MAX_DOMAIN_SIZE;
       
$length = \count($labels);

       
// Number of "." delimiters.
       
$domainLength = $length - 1;

       
// If the last label is empty and it is not the first label, then it is the root label.
        // Increase the max size by 1, making it 254, to account for the root label's "."
        // delimiter. This also means we don't need to check the last label's length for being too
        // long.
       
if ($length > 1 && '' === $labels[$length - 1]) {
            ++
$maxDomainSize;
            --
$length;
        }

        for (
$i = 0; $i < $length; ++$i) {
           
$bytes = \strlen($labels[$i]);
           
$domainLength += $bytes;

            if (
$bytes > self::MAX_LABEL_SIZE) {
               
$info->errors |= self::ERROR_LABEL_TOO_LONG;
            }
        }

        if (
$domainLength > $maxDomainSize) {
           
$info->errors |= self::ERROR_DOMAIN_NAME_TOO_LONG;
        }
    }

   
/**
     * @see https://www.unicode.org/reports/tr46/#Validity_Criteria
     *
     * @param string              $label
     * @param array<string, bool> $options
     * @param bool                $canBeEmpty
     */
   
private static function validateLabel($label, Info $info, array $options, $canBeEmpty)
    {
        if (
'' === $label) {
            if (!
$canBeEmpty && (!isset($options['VerifyDnsLength']) || $options['VerifyDnsLength'])) {
               
$info->errors |= self::ERROR_EMPTY_LABEL;
            }

            return;
        }

       
// Step 1. The label must be in Unicode Normalization Form C.
       
if (!Normalizer::isNormalized($label, Normalizer::FORM_C)) {
           
$info->errors |= self::ERROR_INVALID_ACE_LABEL;
        }

       
$codePoints = self::utf8Decode($label);

        if (
$options['CheckHyphens']) {
           
// Step 2. If CheckHyphens, the label must not contain a U+002D HYPHEN-MINUS character
            // in both the thrid and fourth positions.
           
if (isset($codePoints[2], $codePoints[3]) && 0x002D === $codePoints[2] && 0x002D === $codePoints[3]) {
               
$info->errors |= self::ERROR_HYPHEN_3_4;
            }

           
// Step 3. If CheckHyphens, the label must neither begin nor end with a U+002D
            // HYPHEN-MINUS character.
           
if ('-' === substr($label, 0, 1)) {
               
$info->errors |= self::ERROR_LEADING_HYPHEN;
            }

            if (
'-' === substr($label, -1, 1)) {
               
$info->errors |= self::ERROR_TRAILING_HYPHEN;
            }
        }

       
// Step 4. The label must not contain a U+002E (.) FULL STOP.
       
if (false !== strpos($label, '.')) {
           
$info->errors |= self::ERROR_LABEL_HAS_DOT;
        }

       
// Step 5. The label must not begin with a combining mark, that is: General_Category=Mark.
       
if (1 === preg_match(Regex::COMBINING_MARK, $label)) {
           
$info->errors |= self::ERROR_LEADING_COMBINING_MARK;
        }

       
// Step 6. Each code point in the label must only have certain status values according to
        // Section 5, IDNA Mapping Table:
       
$transitional = $options['Transitional_Processing'];
       
$useSTD3ASCIIRules = $options['UseSTD3ASCIIRules'];

        foreach (
$codePoints as $codePoint) {
           
$data = self::lookupCodePointStatus($codePoint, $useSTD3ASCIIRules);
           
$status = $data['status'];

            if (
'valid' === $status || (!$transitional && 'deviation' === $status)) {
                continue;
            }

           
$info->errors |= self::ERROR_DISALLOWED;

            break;
        }

       
// Step 7. If CheckJoiners, the label must satisify the ContextJ rules from Appendix A, in
        // The Unicode Code Points and Internationalized Domain Names for Applications (IDNA)
        // [IDNA2008].
       
if ($options['CheckJoiners'] && !self::isValidContextJ($codePoints, $label)) {
           
$info->errors |= self::ERROR_CONTEXTJ;
        }

       
// Step 8. If CheckBidi, and if the domain name is a  Bidi domain name, then the label must
        // satisfy all six of the numbered conditions in [IDNA2008] RFC 5893, Section 2.
       
if ($options['CheckBidi'] && (!$info->bidiDomain || $info->validBidiDomain)) {
           
self::validateBidiLabel($label, $info);
        }
    }

   
/**
     * @see https://tools.ietf.org/html/rfc3492#section-6.2
     *
     * @param string $input
     *
     * @return string
     */
   
private static function punycodeDecode($input)
    {
       
$n = self::INITIAL_N;
       
$out = 0;
       
$i = 0;
       
$bias = self::INITIAL_BIAS;
       
$lastDelimIndex = strrpos($input, self::DELIMITER);
       
$b = false === $lastDelimIndex ? 0 : $lastDelimIndex;
       
$inputLength = \strlen($input);
       
$output = array();
       
$bytes = array_map('ord', str_split($input));

        for (
$j = 0; $j < $b; ++$j) {
            if (
$bytes[$j] > 0x7F) {
                throw new
Exception('Invalid input');
            }

           
$output[$out++] = $input[$j];
        }

        if (
$b > 0) {
            ++
$b;
        }

        for (
$in = $b; $in < $inputLength; ++$out) {
           
$oldi = $i;
           
$w = 1;

            for (
$k = self::BASE; /* no condition */; $k += self::BASE) {
                if (
$in >= $inputLength) {
                    throw new
Exception('Invalid input');
                }

               
$digit = self::$basicToDigit[$bytes[$in++] & 0xFF];

                if (
$digit < 0) {
                    throw new
Exception('Invalid input');
                }

                if (
$digit > intdiv(self::MAX_INT - $i, $w)) {
                    throw new
Exception('Integer overflow');
                }

               
$i += $digit * $w;

                if (
$k <= $bias) {
                   
$t = self::TMIN;
                } elseif (
$k >= $bias + self::TMAX) {
                   
$t = self::TMAX;
                } else {
                   
$t = $k - $bias;
                }

                if (
$digit < $t) {
                    break;
                }

               
$baseMinusT = self::BASE - $t;

                if (
$w > intdiv(self::MAX_INT, $baseMinusT)) {
                    throw new
Exception('Integer overflow');
                }

               
$w *= $baseMinusT;
            }

           
$outPlusOne = $out + 1;
           
$bias = self::adaptBias($i - $oldi, $outPlusOne, 0 === $oldi);

            if (
intdiv($i, $outPlusOne) > self::MAX_INT - $n) {
                throw new
Exception('Integer overflow');
            }

           
$n += intdiv($i, $outPlusOne);
           
$i %= $outPlusOne;
           
array_splice($output, $i++, 0, array(mb_chr($n, 'utf-8')));
        }

        return
implode('', $output);
    }

   
/**
     * @see https://tools.ietf.org/html/rfc3492#section-6.3
     *
     * @param string $input
     *
     * @return string
     */
   
private static function punycodeEncode($input)
    {
       
$n = self::INITIAL_N;
       
$delta = 0;
       
$out = 0;
       
$bias = self::INITIAL_BIAS;
       
$inputLength = 0;
       
$output = '';
       
$iter = self::utf8Decode($input);

        foreach (
$iter as $codePoint) {
            ++
$inputLength;

            if (
$codePoint < 0x80) {
               
$output .= \chr($codePoint);
                ++
$out;
            }
        }

       
$h = $out;
       
$b = $out;

        if (
$b > 0) {
           
$output .= self::DELIMITER;
            ++
$out;
        }

        while (
$h < $inputLength) {
           
$m = self::MAX_INT;

            foreach (
$iter as $codePoint) {
                if (
$codePoint >= $n && $codePoint < $m) {
                   
$m = $codePoint;
                }
            }

            if (
$m - $n > intdiv(self::MAX_INT - $delta, $h + 1)) {
                throw new
Exception('Integer overflow');
            }

           
$delta += ($m - $n) * ($h + 1);
           
$n = $m;

            foreach (
$iter as $codePoint) {
                if (
$codePoint < $n && 0 === ++$delta) {
                    throw new
Exception('Integer overflow');
                } elseif (
$codePoint === $n) {
                   
$q = $delta;

                    for (
$k = self::BASE; /* no condition */; $k += self::BASE) {
                        if (
$k <= $bias) {
                           
$t = self::TMIN;
                        } elseif (
$k >= $bias + self::TMAX) {
                           
$t = self::TMAX;
                        } else {
                           
$t = $k - $bias;
                        }

                        if (
$q < $t) {
                            break;
                        }

                       
$qMinusT = $q - $t;
                       
$baseMinusT = self::BASE - $t;
                       
$output .= self::encodeDigit($t + ($qMinusT) % ($baseMinusT), false);
                        ++
$out;
                       
$q = intdiv($qMinusT, $baseMinusT);
                    }

                   
$output .= self::encodeDigit($q, false);
                    ++
$out;
                   
$bias = self::adaptBias($delta, $h + 1, $h === $b);
                   
$delta = 0;
                    ++
$h;
                }
            }

            ++
$delta;
            ++
$n;
        }

        return
$output;
    }

   
/**
     * @see https://tools.ietf.org/html/rfc3492#section-6.1
     *
     * @param int  $delta
     * @param int  $numPoints
     * @param bool $firstTime
     *
     * @return int
     */
   
private static function adaptBias($delta, $numPoints, $firstTime)
    {
       
// xxx >> 1 is a faster way of doing intdiv(xxx, 2)
       
$delta = $firstTime ? intdiv($delta, self::DAMP) : $delta >> 1;
       
$delta += intdiv($delta, $numPoints);
       
$k = 0;

        while (
$delta > ((self::BASE - self::TMIN) * self::TMAX) >> 1) {
           
$delta = intdiv($delta, self::BASE - self::TMIN);
           
$k += self::BASE;
        }

        return
$k + intdiv((self::BASE - self::TMIN + 1) * $delta, $delta + self::SKEW);
    }

   
/**
     * @param int  $d
     * @param bool $flag
     *
     * @return string
     */
   
private static function encodeDigit($d, $flag)
    {
        return \
chr($d + 22 + 75 * ($d < 26 ? 1 : 0) - (($flag ? 1 : 0) << 5));
    }

   
/**
     * Takes a UTF-8 encoded string and converts it into a series of integer code points. Any
     * invalid byte sequences will be replaced by a U+FFFD replacement code point.
     *
     * @see https://encoding.spec.whatwg.org/#utf-8-decoder
     *
     * @param string $input
     *
     * @return array<int, int>
     */
   
private static function utf8Decode($input)
    {
       
$bytesSeen = 0;
       
$bytesNeeded = 0;
       
$lowerBoundary = 0x80;
       
$upperBoundary = 0xBF;
       
$codePoint = 0;
       
$codePoints = array();
       
$length = \strlen($input);

        for (
$i = 0; $i < $length; ++$i) {
           
$byte = \ord($input[$i]);

            if (
0 === $bytesNeeded) {
                if (
$byte >= 0x00 && $byte <= 0x7F) {
                   
$codePoints[] = $byte;

                    continue;
                }

                if (
$byte >= 0xC2 && $byte <= 0xDF) {
                   
$bytesNeeded = 1;
                   
$codePoint = $byte & 0x1F;
                } elseif (
$byte >= 0xE0 && $byte <= 0xEF) {
                    if (
0xE0 === $byte) {
                       
$lowerBoundary = 0xA0;
                    } elseif (
0xED === $byte) {
                       
$upperBoundary = 0x9F;
                    }

                   
$bytesNeeded = 2;
                   
$codePoint = $byte & 0xF;
                } elseif (
$byte >= 0xF0 && $byte <= 0xF4) {
                    if (
0xF0 === $byte) {
                       
$lowerBoundary = 0x90;
                    } elseif (
0xF4 === $byte) {
                       
$upperBoundary = 0x8F;
                    }

                   
$bytesNeeded = 3;
                   
$codePoint = $byte & 0x7;
                } else {
                   
$codePoints[] = 0xFFFD;
                }

                continue;
            }

            if (
$byte < $lowerBoundary || $byte > $upperBoundary) {
               
$codePoint = 0;
               
$bytesNeeded = 0;
               
$bytesSeen = 0;
               
$lowerBoundary = 0x80;
               
$upperBoundary = 0xBF;
                --
$i;
               
$codePoints[] = 0xFFFD;

                continue;
            }

           
$lowerBoundary = 0x80;
           
$upperBoundary = 0xBF;
           
$codePoint = ($codePoint << 6) | ($byte & 0x3F);

            if (++
$bytesSeen !== $bytesNeeded) {
                continue;
            }

           
$codePoints[] = $codePoint;
           
$codePoint = 0;
           
$bytesNeeded = 0;
           
$bytesSeen = 0;
        }

       
// String unexpectedly ended, so append a U+FFFD code point.
       
if (0 !== $bytesNeeded) {
           
$codePoints[] = 0xFFFD;
        }

        return
$codePoints;
    }

   
/**
     * @param int  $codePoint
     * @param bool $useSTD3ASCIIRules
     *
     * @return array{status: string, mapping?: string}
     */
   
private static function lookupCodePointStatus($codePoint, $useSTD3ASCIIRules)
    {
        if (!
self::$mappingTableLoaded) {
           
self::$mappingTableLoaded = true;
           
self::$mapped = require __DIR__.'/Resources/unidata/mapped.php';
           
self::$ignored = require __DIR__.'/Resources/unidata/ignored.php';
           
self::$deviation = require __DIR__.'/Resources/unidata/deviation.php';
           
self::$disallowed = require __DIR__.'/Resources/unidata/disallowed.php';
           
self::$disallowed_STD3_mapped = require __DIR__.'/Resources/unidata/disallowed_STD3_mapped.php';
           
self::$disallowed_STD3_valid = require __DIR__.'/Resources/unidata/disallowed_STD3_valid.php';
        }

        if (isset(
self::$mapped[$codePoint])) {
            return array(
'status' => 'mapped', 'mapping' => self::$mapped[$codePoint]);
        }

        if (isset(
self::$ignored[$codePoint])) {
            return array(
'status' => 'ignored');
        }

        if (isset(
self::$deviation[$codePoint])) {
            return array(
'status' => 'deviation', 'mapping' => self::$deviation[$codePoint]);
        }

        if (isset(
self::$disallowed[$codePoint]) || DisallowedRanges::inRange($codePoint)) {
            return array(
'status' => 'disallowed');
        }

       
$isDisallowedMapped = isset(self::$disallowed_STD3_mapped[$codePoint]);

        if (
$isDisallowedMapped || isset(self::$disallowed_STD3_valid[$codePoint])) {
           
$status = 'disallowed';

            if (!
$useSTD3ASCIIRules) {
               
$status = $isDisallowedMapped ? 'mapped' : 'valid';
            }

            if (
$isDisallowedMapped) {
                return array(
'status' => $status, 'mapping' => self::$disallowed_STD3_mapped[$codePoint]);
            }

            return array(
'status' => $status);
        }

        return array(
'status' => 'valid');
    }
}