1 // DeflateConst.h
2 
3 #ifndef __DEFLATE_CONST_H
4 #define __DEFLATE_CONST_H
5 
6 namespace NCompress {
7 namespace NDeflate {
8 
9 const unsigned kNumHuffmanBits = 15;
10 
11 const UInt32 kHistorySize32 = (1 << 15);
12 const UInt32 kHistorySize64 = (1 << 16);
13 
14 const unsigned kDistTableSize32 = 30;
15 const unsigned kDistTableSize64 = 32;
16 
17 const unsigned kNumLenSymbols32 = 256;
18 const unsigned kNumLenSymbols64 = 255; // don't change it. It must be <= 255.
19 const unsigned kNumLenSymbolsMax = kNumLenSymbols32;
20 
21 const unsigned kNumLenSlots = 29;
22 
23 const unsigned kFixedDistTableSize = 32;
24 const unsigned kFixedLenTableSize = 31;
25 
26 const unsigned kSymbolEndOfBlock = 0x100;
27 const unsigned kSymbolMatch = kSymbolEndOfBlock + 1;
28 
29 const unsigned kMainTableSize = kSymbolMatch + kNumLenSlots;
30 const unsigned kFixedMainTableSize = kSymbolMatch + kFixedLenTableSize;
31 
32 const unsigned kLevelTableSize = 19;
33 
34 const unsigned kTableDirectLevels = 16;
35 const unsigned kTableLevelRepNumber = kTableDirectLevels;
36 const unsigned kTableLevel0Number = kTableLevelRepNumber + 1;
37 const unsigned kTableLevel0Number2 = kTableLevel0Number + 1;
38 
39 const unsigned kLevelMask = 0xF;
40 
41 const Byte kLenStart32[kFixedLenTableSize] =
42   {0,1,2,3,4,5,6,7,8,10,12,14,16,20,24,28,32,40,48,56,64,80,96,112,128,160,192,224, 255, 0, 0};
43 const Byte kLenStart64[kFixedLenTableSize] =
44   {0,1,2,3,4,5,6,7,8,10,12,14,16,20,24,28,32,40,48,56,64,80,96,112,128,160,192,224, 0, 0, 0};
45 
46 const Byte kLenDirectBits32[kFixedLenTableSize] =
47   {0,0,0,0,0,0,0,0,1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4,  4,  5,  5,  5,  5, 0, 0, 0};
48 const Byte kLenDirectBits64[kFixedLenTableSize] =
49   {0,0,0,0,0,0,0,0,1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4,  4,  5,  5,  5,  5, 16, 0, 0};
50 
51 const UInt32 kDistStart[kDistTableSize64] =
52   {0,1,2,3,4,6,8,12,16,24,32,48,64,96,128,192,256,384,512,768,
53   1024,1536,2048,3072,4096,6144,8192,12288,16384,24576,32768,49152};
54 const Byte kDistDirectBits[kDistTableSize64] =
55   {0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,14,14};
56 
57 const Byte kLevelDirectBits[3] = {2, 3, 7};
58 
59 const Byte kCodeLengthAlphabetOrder[kLevelTableSize] = {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
60 
61 const unsigned kMatchMinLen = 3;
62 const unsigned kMatchMaxLen32 = kNumLenSymbols32 + kMatchMinLen - 1; // 256 + 2
63 const unsigned kMatchMaxLen64 = kNumLenSymbols64 + kMatchMinLen - 1; // 255 + 2
64 const unsigned kMatchMaxLen = kMatchMaxLen32;
65 
66 const unsigned kFinalBlockFieldSize = 1;
67 
68 namespace NFinalBlockField
69 {
70   enum
71   {
72     kNotFinalBlock = 0,
73     kFinalBlock = 1
74   };
75 }
76 
77 const unsigned kBlockTypeFieldSize = 2;
78 
79 namespace NBlockType
80 {
81   enum
82   {
83     kStored = 0,
84     kFixedHuffman = 1,
85     kDynamicHuffman = 2
86   };
87 }
88 
89 const unsigned kNumLenCodesFieldSize = 5;
90 const unsigned kNumDistCodesFieldSize = 5;
91 const unsigned kNumLevelCodesFieldSize = 4;
92 
93 const unsigned kNumLitLenCodesMin = 257;
94 const unsigned kNumDistCodesMin = 1;
95 const unsigned kNumLevelCodesMin = 4;
96 
97 const unsigned kLevelFieldSize = 3;
98 
99 const unsigned kStoredBlockLengthFieldSize = 16;
100 
101 struct CLevels
102 {
103   Byte litLenLevels[kFixedMainTableSize];
104   Byte distLevels[kFixedDistTableSize];
105 
SubClearCLevels106   void SubClear()
107   {
108     unsigned i;
109     for (i = kNumLitLenCodesMin; i < kFixedMainTableSize; i++)
110       litLenLevels[i] = 0;
111     for (i = 0; i < kFixedDistTableSize; i++)
112       distLevels[i] = 0;
113   }
114 
SetFixedLevelsCLevels115   void SetFixedLevels()
116   {
117     unsigned i = 0;
118 
119     for (; i < 144; i++) litLenLevels[i] = 8;
120     for (; i < 256; i++) litLenLevels[i] = 9;
121     for (; i < 280; i++) litLenLevels[i] = 7;
122     for (; i < 288; i++) litLenLevels[i] = 8;
123 
124     for (i = 0; i < kFixedDistTableSize; i++)  // test it: InfoZip only uses kDistTableSize
125       distLevels[i] = 5;
126   }
127 };
128 
129 }}
130 
131 #endif
132