PHP Str::strlen方法代码示例

 /**
  * PKCS #7 unpadding function.
  * 
  * @param string $input Padded string to unpad
  * 
  * @return string
  */
 public static function unpad($input)
 {
     // Determine the padding size by converting the final byte of the
     // input to its decimal value
     $padsize = \ord(Str::substr($input, -1));
     // Return string minus the padding amount
     return Str::substr($input, 0, Str::strlen($input) - $padsize);
 }

 /**
  * This will normalize a hash to a certain length by extending it if
  * too short and truncating it if too long. This ensures that any
  * hash algo will work with any combination of other settings. However,
  * it is probably best to make sure that the keysize and algo size
  * are identical so that the input hash passes through unchanged.
  *
  * @param string $hash Hash to be normalized
  * @param int    $size Size of the desired output hash, in bytes
  * @param string $algo Hashing algorithm to use for internal operations
  *
  * @return string
  */
 private static function hashNormalize($hash, $size, $algo)
 {
     // Extend hash if too short
     while (Str::strlen($hash) < $size) {
         $hash .= \hash($algo, $hash, true);
     }
     // Truncate to specified number of bytes (if needed) and return
     return Str::substr($hash, 0, $size);
 }

 /**
  * Create the initial byte matrix that will be used for swaps. This code
  * is identical between RC4 and Spritz.
  * 
  * @param string $key
  * 
  * @return array
  */
 protected static function initializeState($key)
 {
     $s = \range(0, 255);
     $j = 0;
     foreach (\range(0, 255) as $i) {
         $j = ($j + $s[$i] + \ord($key[$i % Str::strlen($key)])) % 256;
         $x = $s[$i];
         $s[$i] = $s[$j];
         $s[$j] = $x;
     }
     return $s;
 }

 /**
  * Perform (en/de)cryption
  * 
  * @param string $str String to be encrypted
  * @param string $key Key to use for encryption
  * 
  * @return string
  */
 public static function crypt($str, $key)
 {
     $s = self::initializeState($key);
     $i = $j = $k = $z = 0;
     $w = 1;
     $res = '';
     $size = Str::strlen($str);
     for ($y = 0; $y < $size; $y++) {
         $i = ($i + $w) % 256;
         $j = ($k + $s[($j + $s[$i]) % 256]) % 256;
         $k = ($i + $k + $s[$j]) % 256;
         $x = $s[$i];
         $s[$i] = $s[$j];
         $s[$j] = $x;
         $z = $s[($j + $s[($i + $s[($z + $k) % 256]) % 256]) % 256];
         $res .= $str[$y] ^ \chr($z);
     }
     return $res;
 }