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   1  <?php
   2  
   3  namespace Algo26\IdnaConvert\Punycode;
   4  
   5  use Algo26\IdnaConvert\TranscodeUnicode\TranscodeUnicode;
   6  
   7  abstract class AbstractPunycode
   8  {
   9      const punycodePrefix = 'xn--';
  10      const invalidUcs = 0x80000000;
  11      const maxUcs = 0x10FFFF;
  12      const base = 36;
  13      const tMin = 1;
  14      const tMax = 26;
  15      const skew = 38;
  16      const damp = 700;
  17      const initialBias = 72;
  18      const initialN = 0x80;
  19  
  20      protected static $isMbStringOverload;
  21      protected static $prefixAsArray;
  22      protected static $prefixLength;
  23  
  24      /** @var TranscodeUnicode */
  25      protected $unicodeTransCoder;
  26  
  27      public function __construct()
  28      {
  29          $this->unicodeTransCoder = new TranscodeUnicode();
  30  
  31          // populate mbstring overloading cache if not set
  32          if (self::$isMbStringOverload === null) {
  33              self::$isMbStringOverload = (extension_loaded('mbstring')
  34                                           && (ini_get('mbstring.func_overload') & 0x02) === 0x02);
  35          }
  36  
  37          if (self::$prefixAsArray === null) {
  38              self::$prefixAsArray = $this->unicodeTransCoder->convert(
  39                  self::punycodePrefix,
  40                  $this->unicodeTransCoder::FORMAT_UTF8,
  41                  $this->unicodeTransCoder::FORMAT_UCS4_ARRAY
  42              );
  43              self::$prefixLength = $this->byteLength(self::punycodePrefix);
  44          }
  45      }
  46  
  47      public function getPunycodePrefix(): string
  48      {
  49          return self::punycodePrefix;
  50      }
  51  
  52      /**
  53       * Gets the length of a string in bytes even if mbstring function
  54       * overloading is turned on
  55       *
  56       * @param string $string the string for which to get the length.
  57       * @return integer the length of the string in bytes.
  58       */
  59      protected function byteLength($string): int
  60      {
  61          if (self::$isMbStringOverload) {
  62              return mb_strlen($string, '8bit');
  63          }
  64  
  65          return strlen((binary) $string);
  66      }
  67  
  68  
  69      /**
  70       * Adapt the bias according to the current code point and position
  71       * @param int $delta
  72       * @param int $nPoints
  73       * @param int $isFirst
  74       * @return int
  75       */
  76      protected function adapt($delta, $nPoints, $isFirst): int
  77      {
  78          $delta = intval($isFirst ? ($delta / self::damp) : ($delta / 2));
  79          $delta += intval($delta / $nPoints);
  80          for ($k = 0; $delta > ((self::base - self::tMin) * self::tMax) / 2; $k += self::base) {
  81              $delta = intval($delta / (self::base - self::tMin));
  82          }
  83  
  84          return intval($k + (self::base - self::tMin + 1) * $delta / ($delta + self::skew));
  85      }
  86  }