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   1  <?php
   2  
   3  /**
   4   * Class ParagonIE_Sodium_Core32_Int32
   5   *
   6   * Encapsulates a 32-bit integer.
   7   *
   8   * These are immutable. It always returns a new instance.
   9   */
  10  class ParagonIE_Sodium_Core32_Int32
  11  {
  12      /**
  13       * @var array<int, int> - two 16-bit integers
  14       *
  15       * 0 is the higher 16 bits
  16       * 1 is the lower 16 bits
  17       */
  18      public $limbs = array(0, 0);
  19  
  20      /**
  21       * @var int
  22       */
  23      public $overflow = 0;
  24  
  25      /**
  26       * @var bool
  27       */
  28      public $unsignedInt = false;
  29  
  30      /**
  31       * ParagonIE_Sodium_Core32_Int32 constructor.
  32       * @param array $array
  33       * @param bool $unsignedInt
  34       */
  35      public function __construct($array = array(0, 0), $unsignedInt = false)
  36      {
  37          $this->limbs = array(
  38              (int) $array[0],
  39              (int) $array[1]
  40          );
  41          $this->overflow = 0;
  42          $this->unsignedInt = $unsignedInt;
  43      }
  44  
  45      /**
  46       * Adds two int32 objects
  47       *
  48       * @param ParagonIE_Sodium_Core32_Int32 $addend
  49       * @return ParagonIE_Sodium_Core32_Int32
  50       */
  51      public function addInt32(ParagonIE_Sodium_Core32_Int32 $addend)
  52      {
  53          $i0 = $this->limbs[0];
  54          $i1 = $this->limbs[1];
  55          $j0 = $addend->limbs[0];
  56          $j1 = $addend->limbs[1];
  57  
  58          $r1 = $i1 + ($j1 & 0xffff);
  59          $carry = $r1 >> 16;
  60  
  61          $r0 = $i0 + ($j0 & 0xffff) + $carry;
  62          $carry = $r0 >> 16;
  63  
  64          $r0 &= 0xffff;
  65          $r1 &= 0xffff;
  66  
  67          $return = new ParagonIE_Sodium_Core32_Int32(
  68              array($r0, $r1)
  69          );
  70          $return->overflow = $carry;
  71          $return->unsignedInt = $this->unsignedInt;
  72          return $return;
  73      }
  74  
  75      /**
  76       * Adds a normal integer to an int32 object
  77       *
  78       * @param int $int
  79       * @return ParagonIE_Sodium_Core32_Int32
  80       * @throws SodiumException
  81       * @throws TypeError
  82       */
  83      public function addInt($int)
  84      {
  85          ParagonIE_Sodium_Core32_Util::declareScalarType($int, 'int', 1);
  86          /** @var int $int */
  87          $int = (int) $int;
  88  
  89          $int = (int) $int;
  90  
  91          $i0 = $this->limbs[0];
  92          $i1 = $this->limbs[1];
  93  
  94          $r1 = $i1 + ($int & 0xffff);
  95          $carry = $r1 >> 16;
  96  
  97          $r0 = $i0 + (($int >> 16) & 0xffff) + $carry;
  98          $carry = $r0 >> 16;
  99          $r0 &= 0xffff;
 100          $r1 &= 0xffff;
 101          $return = new ParagonIE_Sodium_Core32_Int32(
 102              array($r0, $r1)
 103          );
 104          $return->overflow = $carry;
 105          $return->unsignedInt = $this->unsignedInt;
 106          return $return;
 107      }
 108  
 109      /**
 110       * @param int $b
 111       * @return int
 112       */
 113      public function compareInt($b = 0)
 114      {
 115          $gt = 0;
 116          $eq = 1;
 117  
 118          $i = 2;
 119          $j = 0;
 120          while ($i > 0) {
 121              --$i;
 122              /** @var int $x1 */
 123              $x1 = $this->limbs[$i];
 124              /** @var int $x2 */
 125              $x2 = ($b >> ($j << 4)) & 0xffff;
 126              /** @var int $gt */
 127              $gt |= (($x2 - $x1) >> 8) & $eq;
 128              /** @var int $eq */
 129              $eq &= (($x2 ^ $x1) - 1) >> 8;
 130          }
 131          return ($gt + $gt - $eq) + 1;
 132      }
 133  
 134      /**
 135       * @param int $m
 136       * @return ParagonIE_Sodium_Core32_Int32
 137       */
 138      public function mask($m = 0)
 139      {
 140          /** @var int $hi */
 141          $hi = ((int) $m >> 16);
 142          $hi &= 0xffff;
 143          /** @var int $lo */
 144          $lo = ((int) $m) & 0xffff;
 145          return new ParagonIE_Sodium_Core32_Int32(
 146              array(
 147                  (int) ($this->limbs[0] & $hi),
 148                  (int) ($this->limbs[1] & $lo)
 149              ),
 150              $this->unsignedInt
 151          );
 152      }
 153  
 154      /**
 155       * @param array<int, int> $a
 156       * @param array<int, int> $b
 157       * @param int $baseLog2
 158       * @return array<int, int>
 159       */
 160      public function multiplyLong(array $a, array $b, $baseLog2 = 16)
 161      {
 162          $a_l = count($a);
 163          $b_l = count($b);
 164          /** @var array<int, int> $r */
 165          $r = array_fill(0, $a_l + $b_l + 1, 0);
 166          $base = 1 << $baseLog2;
 167          for ($i = 0; $i < $a_l; ++$i) {
 168              $a_i = $a[$i];
 169              for ($j = 0; $j < $a_l; ++$j) {
 170                  $b_j = $b[$j];
 171                  $product = ($a_i * $b_j) + $r[$i + $j];
 172                  $carry = ((int) $product >> $baseLog2 & 0xffff);
 173                  $r[$i + $j] = ((int) $product - (int) ($carry * $base)) & 0xffff;
 174                  $r[$i + $j + 1] += $carry;
 175              }
 176          }
 177          return array_slice($r, 0, 5);
 178      }
 179  
 180      /**
 181       * @param int $int
 182       * @return ParagonIE_Sodium_Core32_Int32
 183       */
 184      public function mulIntFast($int)
 185      {
 186          // Handle negative numbers
 187          $aNeg = ($this->limbs[0] >> 15) & 1;
 188          $bNeg = ($int >> 31) & 1;
 189          $a = array_reverse($this->limbs);
 190          $b = array(
 191              $int & 0xffff,
 192              ($int >> 16) & 0xffff
 193          );
 194          if ($aNeg) {
 195              for ($i = 0; $i < 2; ++$i) {
 196                  $a[$i] = ($a[$i] ^ 0xffff) & 0xffff;
 197              }
 198              ++$a[0];
 199          }
 200          if ($bNeg) {
 201              for ($i = 0; $i < 2; ++$i) {
 202                  $b[$i] = ($b[$i] ^ 0xffff) & 0xffff;
 203              }
 204              ++$b[0];
 205          }
 206          // Multiply
 207          $res = $this->multiplyLong($a, $b);
 208  
 209          // Re-apply negation to results
 210          if ($aNeg !== $bNeg) {
 211              for ($i = 0; $i < 2; ++$i) {
 212                  $res[$i] = (0xffff ^ $res[$i]) & 0xffff;
 213              }
 214              // Handle integer overflow
 215              $c = 1;
 216              for ($i = 0; $i < 2; ++$i) {
 217                  $res[$i] += $c;
 218                  $c = $res[$i] >> 16;
 219                  $res[$i] &= 0xffff;
 220              }
 221          }
 222  
 223          // Return our values
 224          $return = new ParagonIE_Sodium_Core32_Int32();
 225          $return->limbs = array(
 226              $res[1] & 0xffff,
 227              $res[0] & 0xffff
 228          );
 229          if (count($res) > 2) {
 230              $return->overflow = $res[2] & 0xffff;
 231          }
 232          $return->unsignedInt = $this->unsignedInt;
 233          return $return;
 234      }
 235  
 236      /**
 237       * @param ParagonIE_Sodium_Core32_Int32 $right
 238       * @return ParagonIE_Sodium_Core32_Int32
 239       */
 240      public function mulInt32Fast(ParagonIE_Sodium_Core32_Int32 $right)
 241      {
 242          $aNeg = ($this->limbs[0] >> 15) & 1;
 243          $bNeg = ($right->limbs[0] >> 15) & 1;
 244  
 245          $a = array_reverse($this->limbs);
 246          $b = array_reverse($right->limbs);
 247          if ($aNeg) {
 248              for ($i = 0; $i < 2; ++$i) {
 249                  $a[$i] = ($a[$i] ^ 0xffff) & 0xffff;
 250              }
 251              ++$a[0];
 252          }
 253          if ($bNeg) {
 254              for ($i = 0; $i < 2; ++$i) {
 255                  $b[$i] = ($b[$i] ^ 0xffff) & 0xffff;
 256              }
 257              ++$b[0];
 258          }
 259          $res = $this->multiplyLong($a, $b);
 260          if ($aNeg !== $bNeg) {
 261              if ($aNeg !== $bNeg) {
 262                  for ($i = 0; $i < 2; ++$i) {
 263                      $res[$i] = ($res[$i] ^ 0xffff) & 0xffff;
 264                  }
 265                  $c = 1;
 266                  for ($i = 0; $i < 2; ++$i) {
 267                      $res[$i] += $c;
 268                      $c = $res[$i] >> 16;
 269                      $res[$i] &= 0xffff;
 270                  }
 271              }
 272          }
 273          $return = new ParagonIE_Sodium_Core32_Int32();
 274          $return->limbs = array(
 275              $res[1] & 0xffff,
 276              $res[0] & 0xffff
 277          );
 278          if (count($res) > 2) {
 279              $return->overflow = $res[2];
 280          }
 281          return $return;
 282      }
 283  
 284      /**
 285       * @param int $int
 286       * @param int $size
 287       * @return ParagonIE_Sodium_Core32_Int32
 288       * @throws SodiumException
 289       * @throws TypeError
 290       */
 291      public function mulInt($int = 0, $size = 0)
 292      {
 293          ParagonIE_Sodium_Core32_Util::declareScalarType($int, 'int', 1);
 294          ParagonIE_Sodium_Core32_Util::declareScalarType($size, 'int', 2);
 295          if (ParagonIE_Sodium_Compat::$fastMult) {
 296              return $this->mulIntFast((int) $int);
 297          }
 298          /** @var int $int */
 299          $int = (int) $int;
 300          /** @var int $size */
 301          $size = (int) $size;
 302  
 303          if (!$size) {
 304              $size = 31;
 305          }
 306          /** @var int $size */
 307  
 308          $a = clone $this;
 309          $return = new ParagonIE_Sodium_Core32_Int32();
 310          $return->unsignedInt = $this->unsignedInt;
 311  
 312          // Initialize:
 313          $ret0 = 0;
 314          $ret1 = 0;
 315          $a0 = $a->limbs[0];
 316          $a1 = $a->limbs[1];
 317  
 318          /** @var int $size */
 319          /** @var int $i */
 320          for ($i = $size; $i >= 0; --$i) {
 321              $m = (int) (-($int & 1));
 322              $x0 = $a0 & $m;
 323              $x1 = $a1 & $m;
 324  
 325              $ret1 += $x1;
 326              $c = $ret1 >> 16;
 327  
 328              $ret0 += $x0 + $c;
 329  
 330              $ret0 &= 0xffff;
 331              $ret1 &= 0xffff;
 332  
 333              $a1 = ($a1 << 1);
 334              $x1 = $a1 >> 16;
 335              $a0 = ($a0 << 1) | $x1;
 336              $a0 &= 0xffff;
 337              $a1 &= 0xffff;
 338              $int >>= 1;
 339          }
 340          $return->limbs[0] = $ret0;
 341          $return->limbs[1] = $ret1;
 342          return $return;
 343      }
 344  
 345      /**
 346       * @param ParagonIE_Sodium_Core32_Int32 $int
 347       * @param int $size
 348       * @return ParagonIE_Sodium_Core32_Int32
 349       * @throws SodiumException
 350       * @throws TypeError
 351       */
 352      public function mulInt32(ParagonIE_Sodium_Core32_Int32 $int, $size = 0)
 353      {
 354          ParagonIE_Sodium_Core32_Util::declareScalarType($size, 'int', 2);
 355          if (ParagonIE_Sodium_Compat::$fastMult) {
 356              return $this->mulInt32Fast($int);
 357          }
 358          if (!$size) {
 359              $size = 31;
 360          }
 361          /** @var int $size */
 362  
 363          $a = clone $this;
 364          $b = clone $int;
 365          $return = new ParagonIE_Sodium_Core32_Int32();
 366          $return->unsignedInt = $this->unsignedInt;
 367  
 368          // Initialize:
 369          $ret0 = 0;
 370          $ret1 = 0;
 371          $a0 = $a->limbs[0];
 372          $a1 = $a->limbs[1];
 373          $b0 = $b->limbs[0];
 374          $b1 = $b->limbs[1];
 375  
 376          /** @var int $size */
 377          /** @var int $i */
 378          for ($i = $size; $i >= 0; --$i) {
 379              $m = (int) (-($b1 & 1));
 380              $x0 = $a0 & $m;
 381              $x1 = $a1 & $m;
 382  
 383              $ret1 += $x1;
 384              $c = $ret1 >> 16;
 385  
 386              $ret0 += $x0 + $c;
 387  
 388              $ret0 &= 0xffff;
 389              $ret1 &= 0xffff;
 390  
 391              $a1 = ($a1 << 1);
 392              $x1 = $a1 >> 16;
 393              $a0 = ($a0 << 1) | $x1;
 394              $a0 &= 0xffff;
 395              $a1 &= 0xffff;
 396  
 397              $x0 = ($b0 & 1) << 16;
 398              $b0 = ($b0 >> 1);
 399              $b1 = (($b1 | $x0) >> 1);
 400  
 401              $b0 &= 0xffff;
 402              $b1 &= 0xffff;
 403  
 404          }
 405          $return->limbs[0] = $ret0;
 406          $return->limbs[1] = $ret1;
 407  
 408          return $return;
 409      }
 410  
 411      /**
 412       * OR this 32-bit integer with another.
 413       *
 414       * @param ParagonIE_Sodium_Core32_Int32 $b
 415       * @return ParagonIE_Sodium_Core32_Int32
 416       */
 417      public function orInt32(ParagonIE_Sodium_Core32_Int32 $b)
 418      {
 419          $return = new ParagonIE_Sodium_Core32_Int32();
 420          $return->unsignedInt = $this->unsignedInt;
 421          $return->limbs = array(
 422              (int) ($this->limbs[0] | $b->limbs[0]),
 423              (int) ($this->limbs[1] | $b->limbs[1])
 424          );
 425          /** @var int overflow */
 426          $return->overflow = $this->overflow | $b->overflow;
 427          return $return;
 428      }
 429  
 430      /**
 431       * @param int $b
 432       * @return bool
 433       */
 434      public function isGreaterThan($b = 0)
 435      {
 436          return $this->compareInt($b) > 0;
 437      }
 438  
 439      /**
 440       * @param int $b
 441       * @return bool
 442       */
 443      public function isLessThanInt($b = 0)
 444      {
 445          return $this->compareInt($b) < 0;
 446      }
 447  
 448      /**
 449       * @param int $c
 450       * @return ParagonIE_Sodium_Core32_Int32
 451       * @throws SodiumException
 452       * @throws TypeError
 453       * @psalm-suppress MixedArrayAccess
 454       */
 455      public function rotateLeft($c = 0)
 456      {
 457          ParagonIE_Sodium_Core32_Util::declareScalarType($c, 'int', 1);
 458          /** @var int $c */
 459          $c = (int) $c;
 460  
 461          $return = new ParagonIE_Sodium_Core32_Int32();
 462          $return->unsignedInt = $this->unsignedInt;
 463          $c &= 31;
 464          if ($c === 0) {
 465              // NOP, but we want a copy.
 466              $return->limbs = $this->limbs;
 467          } else {
 468              /** @var int $c */
 469  
 470              /** @var int $idx_shift */
 471              $idx_shift = ($c >> 4) & 1;
 472  
 473              /** @var int $sub_shift */
 474              $sub_shift = $c & 15;
 475  
 476              /** @var array<int, int> $limbs */
 477              $limbs =& $return->limbs;
 478  
 479              /** @var array<int, int> $myLimbs */
 480              $myLimbs =& $this->limbs;
 481  
 482              for ($i = 1; $i >= 0; --$i) {
 483                  /** @var int $j */
 484                  $j = ($i + $idx_shift) & 1;
 485                  /** @var int $k */
 486                  $k = ($i + $idx_shift + 1) & 1;
 487                  $limbs[$i] = (int) (
 488                      (
 489                          ((int) ($myLimbs[$j]) << $sub_shift)
 490                              |
 491                          ((int) ($myLimbs[$k]) >> (16 - $sub_shift))
 492                      ) & 0xffff
 493                  );
 494              }
 495          }
 496          return $return;
 497      }
 498  
 499      /**
 500       * Rotate to the right
 501       *
 502       * @param int $c
 503       * @return ParagonIE_Sodium_Core32_Int32
 504       * @throws SodiumException
 505       * @throws TypeError
 506       * @psalm-suppress MixedArrayAccess
 507       */
 508      public function rotateRight($c = 0)
 509      {
 510          ParagonIE_Sodium_Core32_Util::declareScalarType($c, 'int', 1);
 511          /** @var int $c */
 512          $c = (int) $c;
 513  
 514          $return = new ParagonIE_Sodium_Core32_Int32();
 515          $return->unsignedInt = $this->unsignedInt;
 516          $c &= 31;
 517          /** @var int $c */
 518          if ($c === 0) {
 519              // NOP, but we want a copy.
 520              $return->limbs = $this->limbs;
 521          } else {
 522              /** @var int $c */
 523  
 524              /** @var int $idx_shift */
 525              $idx_shift = ($c >> 4) & 1;
 526  
 527              /** @var int $sub_shift */
 528              $sub_shift = $c & 15;
 529  
 530              /** @var array<int, int> $limbs */
 531              $limbs =& $return->limbs;
 532  
 533              /** @var array<int, int> $myLimbs */
 534              $myLimbs =& $this->limbs;
 535  
 536              for ($i = 1; $i >= 0; --$i) {
 537                  /** @var int $j */
 538                  $j = ($i - $idx_shift) & 1;
 539                  /** @var int $k */
 540                  $k = ($i - $idx_shift - 1) & 1;
 541                  $limbs[$i] = (int) (
 542                      (
 543                          ((int) ($myLimbs[$j]) >> (int) ($sub_shift))
 544                              |
 545                          ((int) ($myLimbs[$k]) << (16 - (int) ($sub_shift)))
 546                      ) & 0xffff
 547                  );
 548              }
 549          }
 550          return $return;
 551      }
 552  
 553      /**
 554       * @param bool $bool
 555       * @return self
 556       */
 557      public function setUnsignedInt($bool = false)
 558      {
 559          $this->unsignedInt = !empty($bool);
 560          return $this;
 561      }
 562  
 563      /**
 564       * @param int $c
 565       * @return ParagonIE_Sodium_Core32_Int32
 566       * @throws SodiumException
 567       * @throws TypeError
 568       */
 569      public function shiftLeft($c = 0)
 570      {
 571          ParagonIE_Sodium_Core32_Util::declareScalarType($c, 'int', 1);
 572          /** @var int $c */
 573          $c = (int) $c;
 574  
 575          $return = new ParagonIE_Sodium_Core32_Int32();
 576          $return->unsignedInt = $this->unsignedInt;
 577          $c &= 63;
 578          /** @var int $c */
 579          if ($c === 0) {
 580              $return->limbs = $this->limbs;
 581          } elseif ($c < 0) {
 582              /** @var int $c */
 583              return $this->shiftRight(-$c);
 584          } else {
 585              /** @var int $c */
 586              /** @var int $tmp */
 587              $tmp = $this->limbs[1] << $c;
 588              $return->limbs[1] = (int)($tmp & 0xffff);
 589              /** @var int $carry */
 590              $carry = $tmp >> 16;
 591  
 592              /** @var int $tmp */
 593              $tmp = ($this->limbs[0] << $c) | ($carry & 0xffff);
 594              $return->limbs[0] = (int) ($tmp & 0xffff);
 595          }
 596          return $return;
 597      }
 598  
 599      /**
 600       * @param int $c
 601       * @return ParagonIE_Sodium_Core32_Int32
 602       * @throws SodiumException
 603       * @throws TypeError
 604       * @psalm-suppress MixedAssignment
 605       * @psalm-suppress MixedOperand
 606       */
 607      public function shiftRight($c = 0)
 608      {
 609          ParagonIE_Sodium_Core32_Util::declareScalarType($c, 'int', 1);
 610          /** @var int $c */
 611          $c = (int) $c;
 612  
 613          $return = new ParagonIE_Sodium_Core32_Int32();
 614          $return->unsignedInt = $this->unsignedInt;
 615          $c &= 63;
 616          /** @var int $c */
 617          if ($c >= 16) {
 618              $return->limbs = array(
 619                  (int) ($this->overflow & 0xffff),
 620                  (int) ($this->limbs[0])
 621              );
 622              $return->overflow = $this->overflow >> 16;
 623              return $return->shiftRight($c & 15);
 624          }
 625          if ($c === 0) {
 626              $return->limbs = $this->limbs;
 627          } elseif ($c < 0) {
 628              /** @var int $c */
 629              return $this->shiftLeft(-$c);
 630          } else {
 631              if (!is_int($c)) {
 632                  throw new TypeError();
 633              }
 634              /** @var int $c */
 635              // $return->limbs[0] = (int) (($this->limbs[0] >> $c) & 0xffff);
 636              $carryLeft = (int) ($this->overflow & ((1 << ($c + 1)) - 1));
 637              $return->limbs[0] = (int) ((($this->limbs[0] >> $c) | ($carryLeft << (16 - $c))) & 0xffff);
 638              $carryRight = (int) ($this->limbs[0] & ((1 << ($c + 1)) - 1));
 639              $return->limbs[1] = (int) ((($this->limbs[1] >> $c) | ($carryRight << (16 - $c))) & 0xffff);
 640              $return->overflow >>= $c;
 641          }
 642          return $return;
 643      }
 644  
 645      /**
 646       * Subtract a normal integer from an int32 object.
 647       *
 648       * @param int $int
 649       * @return ParagonIE_Sodium_Core32_Int32
 650       * @throws SodiumException
 651       * @throws TypeError
 652       */
 653      public function subInt($int)
 654      {
 655          ParagonIE_Sodium_Core32_Util::declareScalarType($int, 'int', 1);
 656          /** @var int $int */
 657          $int = (int) $int;
 658  
 659          $return = new ParagonIE_Sodium_Core32_Int32();
 660          $return->unsignedInt = $this->unsignedInt;
 661  
 662          /** @var int $tmp */
 663          $tmp = $this->limbs[1] - ($int & 0xffff);
 664          /** @var int $carry */
 665          $carry = $tmp >> 16;
 666          $return->limbs[1] = (int) ($tmp & 0xffff);
 667  
 668          /** @var int $tmp */
 669          $tmp = $this->limbs[0] - (($int >> 16) & 0xffff) + $carry;
 670          $return->limbs[0] = (int) ($tmp & 0xffff);
 671          return $return;
 672      }
 673  
 674      /**
 675       * Subtract two int32 objects from each other
 676       *
 677       * @param ParagonIE_Sodium_Core32_Int32 $b
 678       * @return ParagonIE_Sodium_Core32_Int32
 679       */
 680      public function subInt32(ParagonIE_Sodium_Core32_Int32 $b)
 681      {
 682          $return = new ParagonIE_Sodium_Core32_Int32();
 683          $return->unsignedInt = $this->unsignedInt;
 684  
 685          /** @var int $tmp */
 686          $tmp = $this->limbs[1] - ($b->limbs[1] & 0xffff);
 687          /** @var int $carry */
 688          $carry = $tmp >> 16;
 689          $return->limbs[1] = (int) ($tmp & 0xffff);
 690  
 691          /** @var int $tmp */
 692          $tmp = $this->limbs[0] - ($b->limbs[0] & 0xffff) + $carry;
 693          $return->limbs[0] = (int) ($tmp & 0xffff);
 694          return $return;
 695      }
 696  
 697      /**
 698       * XOR this 32-bit integer with another.
 699       *
 700       * @param ParagonIE_Sodium_Core32_Int32 $b
 701       * @return ParagonIE_Sodium_Core32_Int32
 702       */
 703      public function xorInt32(ParagonIE_Sodium_Core32_Int32 $b)
 704      {
 705          $return = new ParagonIE_Sodium_Core32_Int32();
 706          $return->unsignedInt = $this->unsignedInt;
 707          $return->limbs = array(
 708              (int) ($this->limbs[0] ^ $b->limbs[0]),
 709              (int) ($this->limbs[1] ^ $b->limbs[1])
 710          );
 711          return $return;
 712      }
 713  
 714      /**
 715       * @param int $signed
 716       * @return self
 717       * @throws SodiumException
 718       * @throws TypeError
 719       */
 720      public static function fromInt($signed)
 721      {
 722          ParagonIE_Sodium_Core32_Util::declareScalarType($signed, 'int', 1);;
 723          /** @var int $signed */
 724          $signed = (int) $signed;
 725  
 726          return new ParagonIE_Sodium_Core32_Int32(
 727              array(
 728                  (int) (($signed >> 16) & 0xffff),
 729                  (int) ($signed & 0xffff)
 730              )
 731          );
 732      }
 733  
 734      /**
 735       * @param string $string
 736       * @return self
 737       * @throws SodiumException
 738       * @throws TypeError
 739       */
 740      public static function fromString($string)
 741      {
 742          ParagonIE_Sodium_Core32_Util::declareScalarType($string, 'string', 1);
 743          $string = (string) $string;
 744          if (ParagonIE_Sodium_Core32_Util::strlen($string) !== 4) {
 745              throw new RangeException(
 746                  'String must be 4 bytes; ' . ParagonIE_Sodium_Core32_Util::strlen($string) . ' given.'
 747              );
 748          }
 749          $return = new ParagonIE_Sodium_Core32_Int32();
 750  
 751          $return->limbs[0]  = (int) ((ParagonIE_Sodium_Core32_Util::chrToInt($string[0]) & 0xff) << 8);
 752          $return->limbs[0] |= (ParagonIE_Sodium_Core32_Util::chrToInt($string[1]) & 0xff);
 753          $return->limbs[1]  = (int) ((ParagonIE_Sodium_Core32_Util::chrToInt($string[2]) & 0xff) << 8);
 754          $return->limbs[1] |= (ParagonIE_Sodium_Core32_Util::chrToInt($string[3]) & 0xff);
 755          return $return;
 756      }
 757  
 758      /**
 759       * @param string $string
 760       * @return self
 761       * @throws SodiumException
 762       * @throws TypeError
 763       */
 764      public static function fromReverseString($string)
 765      {
 766          ParagonIE_Sodium_Core32_Util::declareScalarType($string, 'string', 1);
 767          $string = (string) $string;
 768          if (ParagonIE_Sodium_Core32_Util::strlen($string) !== 4) {
 769              throw new RangeException(
 770                  'String must be 4 bytes; ' . ParagonIE_Sodium_Core32_Util::strlen($string) . ' given.'
 771              );
 772          }
 773          $return = new ParagonIE_Sodium_Core32_Int32();
 774  
 775          $return->limbs[0]  = (int) ((ParagonIE_Sodium_Core32_Util::chrToInt($string[3]) & 0xff) << 8);
 776          $return->limbs[0] |= (ParagonIE_Sodium_Core32_Util::chrToInt($string[2]) & 0xff);
 777          $return->limbs[1]  = (int) ((ParagonIE_Sodium_Core32_Util::chrToInt($string[1]) & 0xff) << 8);
 778          $return->limbs[1] |= (ParagonIE_Sodium_Core32_Util::chrToInt($string[0]) & 0xff);
 779          return $return;
 780      }
 781  
 782      /**
 783       * @return array<int, int>
 784       */
 785      public function toArray()
 786      {
 787          return array((int) ($this->limbs[0] << 16 | $this->limbs[1]));
 788      }
 789  
 790      /**
 791       * @return string
 792       * @throws TypeError
 793       */
 794      public function toString()
 795      {
 796          return
 797              ParagonIE_Sodium_Core32_Util::intToChr(($this->limbs[0] >> 8) & 0xff) .
 798              ParagonIE_Sodium_Core32_Util::intToChr($this->limbs[0] & 0xff) .
 799              ParagonIE_Sodium_Core32_Util::intToChr(($this->limbs[1] >> 8) & 0xff) .
 800              ParagonIE_Sodium_Core32_Util::intToChr($this->limbs[1] & 0xff);
 801      }
 802  
 803      /**
 804       * @return int
 805       */
 806      public function toInt()
 807      {
 808          return (int) (
 809              (($this->limbs[0] & 0xffff) << 16)
 810                  |
 811              ($this->limbs[1] & 0xffff)
 812          );
 813      }
 814  
 815      /**
 816       * @return ParagonIE_Sodium_Core32_Int32
 817       */
 818      public function toInt32()
 819      {
 820          $return = new ParagonIE_Sodium_Core32_Int32();
 821          $return->limbs[0] = (int) ($this->limbs[0] & 0xffff);
 822          $return->limbs[1] = (int) ($this->limbs[1] & 0xffff);
 823          $return->unsignedInt = $this->unsignedInt;
 824          $return->overflow = (int) ($this->overflow & 0x7fffffff);
 825          return $return;
 826      }
 827  
 828      /**
 829       * @return ParagonIE_Sodium_Core32_Int64
 830       */
 831      public function toInt64()
 832      {
 833          $return = new ParagonIE_Sodium_Core32_Int64();
 834          $return->unsignedInt = $this->unsignedInt;
 835          if ($this->unsignedInt) {
 836              $return->limbs[0] += (($this->overflow >> 16) & 0xffff);
 837              $return->limbs[1] += (($this->overflow) & 0xffff);
 838          } else {
 839              $neg = -(($this->limbs[0] >> 15) & 1);
 840              $return->limbs[0] = (int)($neg & 0xffff);
 841              $return->limbs[1] = (int)($neg & 0xffff);
 842          }
 843          $return->limbs[2] = (int) ($this->limbs[0] & 0xffff);
 844          $return->limbs[3] = (int) ($this->limbs[1] & 0xffff);
 845          return $return;
 846      }
 847  
 848      /**
 849       * @return string
 850       * @throws TypeError
 851       */
 852      public function toReverseString()
 853      {
 854          return ParagonIE_Sodium_Core32_Util::intToChr($this->limbs[1] & 0xff) .
 855              ParagonIE_Sodium_Core32_Util::intToChr(($this->limbs[1] >> 8) & 0xff) .
 856              ParagonIE_Sodium_Core32_Util::intToChr($this->limbs[0] & 0xff) .
 857              ParagonIE_Sodium_Core32_Util::intToChr(($this->limbs[0] >> 8) & 0xff);
 858      }
 859  
 860      /**
 861       * @return string
 862       */
 863      public function __toString()
 864      {
 865          try {
 866              return $this->toString();
 867          } catch (TypeError $ex) {
 868              // PHP engine can't handle exceptions from __toString()
 869              return '';
 870          }
 871      }
 872  }