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