DeflaterConstants.cs 3.6 KB

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  1. using System;
  2. namespace System.Net.ApiService.Compression.Zip.Compression {
  3. /// <summary>
  4. /// This class contains constants used for deflation.
  5. /// </summary>
  6. public static class DeflaterConstants
  7. {
  8. /// <summary>
  9. /// Set to true to enable debugging
  10. /// </summary>
  11. public const bool DEBUGGING = false;
  12. /// <summary>
  13. /// Written to Zip file to identify a stored block
  14. /// </summary>
  15. public const int STORED_BLOCK = 0;
  16. /// <summary>
  17. /// Identifies static tree in Zip file
  18. /// </summary>
  19. public const int STATIC_TREES = 1;
  20. /// <summary>
  21. /// Identifies dynamic tree in Zip file
  22. /// </summary>
  23. public const int DYN_TREES = 2;
  24. /// <summary>
  25. /// Header flag indicating a preset dictionary for deflation
  26. /// </summary>
  27. public const int PRESET_DICT = 0x20;
  28. /// <summary>
  29. /// Sets internal buffer sizes for Huffman encoding
  30. /// </summary>
  31. public const int DEFAULT_MEM_LEVEL = 8;
  32. /// <summary>
  33. /// Internal compression engine constant
  34. /// </summary>
  35. public const int MAX_MATCH = 258;
  36. /// <summary>
  37. /// Internal compression engine constant
  38. /// </summary>
  39. public const int MIN_MATCH = 3;
  40. /// <summary>
  41. /// Internal compression engine constant
  42. /// </summary>
  43. public const int MAX_WBITS = 15;
  44. /// <summary>
  45. /// Internal compression engine constant
  46. /// </summary>
  47. public const int WSIZE = 1 << MAX_WBITS;
  48. /// <summary>
  49. /// Internal compression engine constant
  50. /// </summary>
  51. public const int WMASK = WSIZE - 1;
  52. /// <summary>
  53. /// Internal compression engine constant
  54. /// </summary>
  55. public const int HASH_BITS = DEFAULT_MEM_LEVEL + 7;
  56. /// <summary>
  57. /// Internal compression engine constant
  58. /// </summary>
  59. public const int HASH_SIZE = 1 << HASH_BITS;
  60. /// <summary>
  61. /// Internal compression engine constant
  62. /// </summary>
  63. public const int HASH_MASK = HASH_SIZE - 1;
  64. /// <summary>
  65. /// Internal compression engine constant
  66. /// </summary>
  67. public const int HASH_SHIFT = (HASH_BITS + MIN_MATCH - 1) / MIN_MATCH;
  68. /// <summary>
  69. /// Internal compression engine constant
  70. /// </summary>
  71. public const int MIN_LOOKAHEAD = MAX_MATCH + MIN_MATCH + 1;
  72. /// <summary>
  73. /// Internal compression engine constant
  74. /// </summary>
  75. public const int MAX_DIST = WSIZE - MIN_LOOKAHEAD;
  76. /// <summary>
  77. /// Internal compression engine constant
  78. /// </summary>
  79. public const int PENDING_BUF_SIZE = 1 << (DEFAULT_MEM_LEVEL + 8);
  80. /// <summary>
  81. /// Internal compression engine constant
  82. /// </summary>
  83. public static int MAX_BLOCK_SIZE = Math.Min(65535, PENDING_BUF_SIZE - 5);
  84. /// <summary>
  85. /// Internal compression engine constant
  86. /// </summary>
  87. public const int DEFLATE_STORED = 0;
  88. /// <summary>
  89. /// Internal compression engine constant
  90. /// </summary>
  91. public const int DEFLATE_FAST = 1;
  92. /// <summary>
  93. /// Internal compression engine constant
  94. /// </summary>
  95. public const int DEFLATE_SLOW = 2;
  96. /// <summary>
  97. /// Internal compression engine constant
  98. /// </summary>
  99. public static int[] GOOD_LENGTH = { 0, 4, 4, 4, 4, 8, 8, 8, 32, 32 };
  100. /// <summary>
  101. /// Internal compression engine constant
  102. /// </summary>
  103. public static int[] MAX_LAZY = { 0, 4, 5, 6, 4, 16, 16, 32, 128, 258 };
  104. /// <summary>
  105. /// Internal compression engine constant
  106. /// </summary>
  107. public static int[] NICE_LENGTH = { 0, 8, 16, 32, 16, 32, 128, 128, 258, 258 };
  108. /// <summary>
  109. /// Internal compression engine constant
  110. /// </summary>
  111. public static int[] MAX_CHAIN = { 0, 4, 8, 32, 16, 32, 128, 256, 1024, 4096 };
  112. /// <summary>
  113. /// Internal compression engine constant
  114. /// </summary>
  115. public static int[] COMPR_FUNC = { 0, 1, 1, 1, 1, 2, 2, 2, 2, 2 };
  116. }
  117. }