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comparison: other-licenses/7zstub/src/7zip/Compress/RangeCoder/RangeCoderBit.cpp
other-licenses/7zstub/src/7zip/Compress/RangeCoder/RangeCoderBit.cpp
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
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| -1:000000000000 | 0:b044ad332ef6 |
|---|---|
| 1 // Compress/RangeCoder/RangeCoderBit.cpp | |
| 2 | |
| 3 #include "StdAfx.h" | |
| 4 | |
| 5 #include "RangeCoderBit.h" | |
| 6 | |
| 7 namespace NCompress { | |
| 8 namespace NRangeCoder { | |
| 9 | |
| 10 UInt32 CPriceTables::ProbPrices[kBitModelTotal >> kNumMoveReducingBits]; | |
| 11 static CPriceTables g_PriceTables; | |
| 12 | |
| 13 CPriceTables::CPriceTables() { Init(); } | |
| 14 | |
| 15 void CPriceTables::Init() | |
| 16 { | |
| 17 const int kNumBits = (kNumBitModelTotalBits - kNumMoveReducingBits); | |
| 18 for(int i = kNumBits - 1; i >= 0; i--) | |
| 19 { | |
| 20 UInt32 start = 1 << (kNumBits - i - 1); | |
| 21 UInt32 end = 1 << (kNumBits - i); | |
| 22 for (UInt32 j = start; j < end; j++) | |
| 23 ProbPrices[j] = (i << kNumBitPriceShiftBits) + | |
| 24 (((end - j) << kNumBitPriceShiftBits) >> (kNumBits - i - 1)); | |
| 25 } | |
| 26 | |
| 27 /* | |
| 28 // simplest: bad solution | |
| 29 for(UInt32 i = 1; i < (kBitModelTotal >> kNumMoveReducingBits) - 1; i++) | |
| 30 ProbPrices[i] = kBitPrice; | |
| 31 */ | |
| 32 | |
| 33 /* | |
| 34 const double kDummyMultMid = (1.0 / kBitPrice) / 2; | |
| 35 const double kDummyMultMid = 0; | |
| 36 // float solution | |
| 37 double ln2 = log(double(2)); | |
| 38 double lnAll = log(double(kBitModelTotal >> kNumMoveReducingBits)); | |
| 39 for(UInt32 i = 1; i < (kBitModelTotal >> kNumMoveReducingBits) - 1; i++) | |
| 40 ProbPrices[i] = UInt32((fabs(lnAll - log(double(i))) / ln2 + kDummyMultMid) * kBitPrice); | |
| 41 */ | |
| 42 | |
| 43 /* | |
| 44 // experimental, slow, solution: | |
| 45 for(UInt32 i = 1; i < (kBitModelTotal >> kNumMoveReducingBits) - 1; i++) | |
| 46 { | |
| 47 const int kCyclesBits = 5; | |
| 48 const UInt32 kCycles = (1 << kCyclesBits); | |
| 49 | |
| 50 UInt32 range = UInt32(-1); | |
| 51 UInt32 bitCount = 0; | |
| 52 for (UInt32 j = 0; j < kCycles; j++) | |
| 53 { | |
| 54 range >>= (kNumBitModelTotalBits - kNumMoveReducingBits); | |
| 55 range *= i; | |
| 56 while(range < (1 << 31)) | |
| 57 { | |
| 58 range <<= 1; | |
| 59 bitCount++; | |
| 60 } | |
| 61 } | |
| 62 bitCount <<= kNumBitPriceShiftBits; | |
| 63 range -= (1 << 31); | |
| 64 for (int k = kNumBitPriceShiftBits - 1; k >= 0; k--) | |
| 65 { | |
| 66 range <<= 1; | |
| 67 if (range > (1 << 31)) | |
| 68 { | |
| 69 bitCount += (1 << k); | |
| 70 range -= (1 << 31); | |
| 71 } | |
| 72 } | |
| 73 ProbPrices[i] = (bitCount | |
| 74 // + (1 << (kCyclesBits - 1)) | |
| 75 ) >> kCyclesBits; | |
| 76 } | |
| 77 */ | |
| 78 } | |
| 79 | |
| 80 }} |
