Base64DotSlash.php 3.0 KB

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  1. <?php
  2. declare(strict_types=1);
  3. namespace ParagonIE\ConstantTime;
  4. /**
  5. * Copyright (c) 2016 - 2018 Paragon Initiative Enterprises.
  6. * Copyright (c) 2014 Steve "Sc00bz" Thomas (steve at tobtu dot com)
  7. *
  8. * Permission is hereby granted, free of charge, to any person obtaining a copy
  9. * of this software and associated documentation files (the "Software"), to deal
  10. * in the Software without restriction, including without limitation the rights
  11. * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12. * copies of the Software, and to permit persons to whom the Software is
  13. * furnished to do so, subject to the following conditions:
  14. *
  15. * The above copyright notice and this permission notice shall be included in all
  16. * copies or substantial portions of the Software.
  17. *
  18. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19. * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20. * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21. * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22. * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23. * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  24. * SOFTWARE.
  25. */
  26. /**
  27. * Class Base64DotSlash
  28. * ./[A-Z][a-z][0-9]
  29. *
  30. * @package ParagonIE\ConstantTime
  31. */
  32. abstract class Base64DotSlash extends Base64
  33. {
  34. /**
  35. * Uses bitwise operators instead of table-lookups to turn 6-bit integers
  36. * into 8-bit integers.
  37. *
  38. * Base64 character set:
  39. * ./ [A-Z] [a-z] [0-9]
  40. * 0x2e-0x2f, 0x41-0x5a, 0x61-0x7a, 0x30-0x39
  41. *
  42. * @param int $src
  43. * @return int
  44. */
  45. protected static function decode6Bits(int $src): int
  46. {
  47. $ret = -1;
  48. // if ($src > 0x2d && $src < 0x30) ret += $src - 0x2e + 1; // -45
  49. $ret += (((0x2d - $src) & ($src - 0x30)) >> 8) & ($src - 45);
  50. // if ($src > 0x40 && $src < 0x5b) ret += $src - 0x41 + 2 + 1; // -62
  51. $ret += (((0x40 - $src) & ($src - 0x5b)) >> 8) & ($src - 62);
  52. // if ($src > 0x60 && $src < 0x7b) ret += $src - 0x61 + 28 + 1; // -68
  53. $ret += (((0x60 - $src) & ($src - 0x7b)) >> 8) & ($src - 68);
  54. // if ($src > 0x2f && $src < 0x3a) ret += $src - 0x30 + 54 + 1; // 7
  55. $ret += (((0x2f - $src) & ($src - 0x3a)) >> 8) & ($src + 7);
  56. return $ret;
  57. }
  58. /**
  59. * Uses bitwise operators instead of table-lookups to turn 8-bit integers
  60. * into 6-bit integers.
  61. *
  62. * @param int $src
  63. * @return string
  64. */
  65. protected static function encode6Bits(int $src): string
  66. {
  67. $src += 0x2e;
  68. // if ($src > 0x2f) $src += 0x41 - 0x30; // 17
  69. $src += ((0x2f - $src) >> 8) & 17;
  70. // if ($src > 0x5a) $src += 0x61 - 0x5b; // 6
  71. $src += ((0x5a - $src) >> 8) & 6;
  72. // if ($src > 0x7a) $src += 0x30 - 0x7b; // -75
  73. $src -= ((0x7a - $src) >> 8) & 75;
  74. return \pack('C', $src);
  75. }
  76. }