ByteBufferEqualityComparer.cs 2.1 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778
  1. //
  2. // ByteBufferEqualityComparer.cs
  3. //
  4. // Author:
  5. // Jb Evain (jbevain@gmail.com)
  6. //
  7. // Copyright (c) 2008 - 2011 Jb Evain
  8. //
  9. // Permission is hereby granted, free of charge, to any person obtaining
  10. // a copy of this software and associated documentation files (the
  11. // "Software"), to deal in the Software without restriction, including
  12. // without limitation the rights to use, copy, modify, merge, publish,
  13. // distribute, sublicense, and/or sell copies of the Software, and to
  14. // permit persons to whom the Software is furnished to do so, subject to
  15. // the following conditions:
  16. //
  17. // The above copyright notice and this permission notice shall be
  18. // included in all copies or substantial portions of the Software.
  19. //
  20. // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21. // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22. // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23. // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24. // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25. // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26. // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27. //
  28. using System;
  29. using System.Collections.Generic;
  30. namespace Mono.Cecil.PE {
  31. sealed class ByteBufferEqualityComparer : IEqualityComparer<ByteBuffer> {
  32. public bool Equals (ByteBuffer x, ByteBuffer y)
  33. {
  34. if (x.length != y.length)
  35. return false;
  36. var x_buffer = x.buffer;
  37. var y_buffer = y.buffer;
  38. for (int i = 0; i < x.length; i++)
  39. if (x_buffer [i] != y_buffer [i])
  40. return false;
  41. return true;
  42. }
  43. public int GetHashCode (ByteBuffer buffer)
  44. {
  45. #if !BYTE_BUFFER_WELL_DISTRIBUTED_HASH
  46. var hash = 0;
  47. var bytes = buffer.buffer;
  48. for (int i = 0; i < buffer.length; i++)
  49. hash = (hash * 37) ^ bytes [i];
  50. return hash;
  51. #else
  52. const uint p = 16777619;
  53. uint hash = 2166136261;
  54. var bytes = buffer.buffer;
  55. for (int i = 0; i < buffer.length; i++)
  56. hash = (hash ^ bytes [i]) * p;
  57. hash += hash << 13;
  58. hash ^= hash >> 7;
  59. hash += hash << 3;
  60. hash ^= hash >> 17;
  61. hash += hash << 5;
  62. return (int) hash;
  63. #endif
  64. }
  65. }
  66. }