DeflaterConstants.cs 3.7 KB

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  1. using System;
  2. namespace ICSharpCode.SharpZipLib.Zip.Compression
  3. {
  4. /// <summary>
  5. /// This class contains constants used for deflation.
  6. /// </summary>
  7. public static class DeflaterConstants
  8. {
  9. /// <summary>
  10. /// Set to true to enable debugging
  11. /// </summary>
  12. public const bool DEBUGGING = false;
  13. /// <summary>
  14. /// Written to Zip file to identify a stored block
  15. /// </summary>
  16. public const int STORED_BLOCK = 0;
  17. /// <summary>
  18. /// Identifies static tree in Zip file
  19. /// </summary>
  20. public const int STATIC_TREES = 1;
  21. /// <summary>
  22. /// Identifies dynamic tree in Zip file
  23. /// </summary>
  24. public const int DYN_TREES = 2;
  25. /// <summary>
  26. /// Header flag indicating a preset dictionary for deflation
  27. /// </summary>
  28. public const int PRESET_DICT = 0x20;
  29. /// <summary>
  30. /// Sets internal buffer sizes for Huffman encoding
  31. /// </summary>
  32. public const int DEFAULT_MEM_LEVEL = 8;
  33. /// <summary>
  34. /// Internal compression engine constant
  35. /// </summary>
  36. public const int MAX_MATCH = 258;
  37. /// <summary>
  38. /// Internal compression engine constant
  39. /// </summary>
  40. public const int MIN_MATCH = 3;
  41. /// <summary>
  42. /// Internal compression engine constant
  43. /// </summary>
  44. public const int MAX_WBITS = 15;
  45. /// <summary>
  46. /// Internal compression engine constant
  47. /// </summary>
  48. public const int WSIZE = 1 << MAX_WBITS;
  49. /// <summary>
  50. /// Internal compression engine constant
  51. /// </summary>
  52. public const int WMASK = WSIZE - 1;
  53. /// <summary>
  54. /// Internal compression engine constant
  55. /// </summary>
  56. public const int HASH_BITS = DEFAULT_MEM_LEVEL + 7;
  57. /// <summary>
  58. /// Internal compression engine constant
  59. /// </summary>
  60. public const int HASH_SIZE = 1 << HASH_BITS;
  61. /// <summary>
  62. /// Internal compression engine constant
  63. /// </summary>
  64. public const int HASH_MASK = HASH_SIZE - 1;
  65. /// <summary>
  66. /// Internal compression engine constant
  67. /// </summary>
  68. public const int HASH_SHIFT = (HASH_BITS + MIN_MATCH - 1) / MIN_MATCH;
  69. /// <summary>
  70. /// Internal compression engine constant
  71. /// </summary>
  72. public const int MIN_LOOKAHEAD = MAX_MATCH + MIN_MATCH + 1;
  73. /// <summary>
  74. /// Internal compression engine constant
  75. /// </summary>
  76. public const int MAX_DIST = WSIZE - MIN_LOOKAHEAD;
  77. /// <summary>
  78. /// Internal compression engine constant
  79. /// </summary>
  80. public const int PENDING_BUF_SIZE = 1 << (DEFAULT_MEM_LEVEL + 8);
  81. /// <summary>
  82. /// Internal compression engine constant
  83. /// </summary>
  84. public static int MAX_BLOCK_SIZE = Math.Min(65535, PENDING_BUF_SIZE - 5);
  85. /// <summary>
  86. /// Internal compression engine constant
  87. /// </summary>
  88. public const int DEFLATE_STORED = 0;
  89. /// <summary>
  90. /// Internal compression engine constant
  91. /// </summary>
  92. public const int DEFLATE_FAST = 1;
  93. /// <summary>
  94. /// Internal compression engine constant
  95. /// </summary>
  96. public const int DEFLATE_SLOW = 2;
  97. /// <summary>
  98. /// Internal compression engine constant
  99. /// </summary>
  100. public static int[] GOOD_LENGTH = { 0, 4, 4, 4, 4, 8, 8, 8, 32, 32 };
  101. /// <summary>
  102. /// Internal compression engine constant
  103. /// </summary>
  104. public static int[] MAX_LAZY = { 0, 4, 5, 6, 4, 16, 16, 32, 128, 258 };
  105. /// <summary>
  106. /// Internal compression engine constant
  107. /// </summary>
  108. public static int[] NICE_LENGTH = { 0, 8, 16, 32, 16, 32, 128, 128, 258, 258 };
  109. /// <summary>
  110. /// Internal compression engine constant
  111. /// </summary>
  112. public static int[] MAX_CHAIN = { 0, 4, 8, 32, 16, 32, 128, 256, 1024, 4096 };
  113. /// <summary>
  114. /// Internal compression engine constant
  115. /// </summary>
  116. public static int[] COMPR_FUNC = { 0, 1, 1, 1, 1, 2, 2, 2, 2, 2 };
  117. }
  118. }