1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/other-licenses/7zstub/src/7zip/Compress/RangeCoder/RangeCoderBit.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,80 @@
1.4 +// Compress/RangeCoder/RangeCoderBit.cpp
1.5 +
1.6 +#include "StdAfx.h"
1.7 +
1.8 +#include "RangeCoderBit.h"
1.9 +
1.10 +namespace NCompress {
1.11 +namespace NRangeCoder {
1.12 +
1.13 +UInt32 CPriceTables::ProbPrices[kBitModelTotal >> kNumMoveReducingBits];
1.14 +static CPriceTables g_PriceTables;
1.15 +
1.16 +CPriceTables::CPriceTables() { Init(); }
1.17 +
1.18 +void CPriceTables::Init()
1.19 +{
1.20 + const int kNumBits = (kNumBitModelTotalBits - kNumMoveReducingBits);
1.21 + for(int i = kNumBits - 1; i >= 0; i--)
1.22 + {
1.23 + UInt32 start = 1 << (kNumBits - i - 1);
1.24 + UInt32 end = 1 << (kNumBits - i);
1.25 + for (UInt32 j = start; j < end; j++)
1.26 + ProbPrices[j] = (i << kNumBitPriceShiftBits) +
1.27 + (((end - j) << kNumBitPriceShiftBits) >> (kNumBits - i - 1));
1.28 + }
1.29 +
1.30 + /*
1.31 + // simplest: bad solution
1.32 + for(UInt32 i = 1; i < (kBitModelTotal >> kNumMoveReducingBits) - 1; i++)
1.33 + ProbPrices[i] = kBitPrice;
1.34 + */
1.35 +
1.36 + /*
1.37 + const double kDummyMultMid = (1.0 / kBitPrice) / 2;
1.38 + const double kDummyMultMid = 0;
1.39 + // float solution
1.40 + double ln2 = log(double(2));
1.41 + double lnAll = log(double(kBitModelTotal >> kNumMoveReducingBits));
1.42 + for(UInt32 i = 1; i < (kBitModelTotal >> kNumMoveReducingBits) - 1; i++)
1.43 + ProbPrices[i] = UInt32((fabs(lnAll - log(double(i))) / ln2 + kDummyMultMid) * kBitPrice);
1.44 + */
1.45 +
1.46 + /*
1.47 + // experimental, slow, solution:
1.48 + for(UInt32 i = 1; i < (kBitModelTotal >> kNumMoveReducingBits) - 1; i++)
1.49 + {
1.50 + const int kCyclesBits = 5;
1.51 + const UInt32 kCycles = (1 << kCyclesBits);
1.52 +
1.53 + UInt32 range = UInt32(-1);
1.54 + UInt32 bitCount = 0;
1.55 + for (UInt32 j = 0; j < kCycles; j++)
1.56 + {
1.57 + range >>= (kNumBitModelTotalBits - kNumMoveReducingBits);
1.58 + range *= i;
1.59 + while(range < (1 << 31))
1.60 + {
1.61 + range <<= 1;
1.62 + bitCount++;
1.63 + }
1.64 + }
1.65 + bitCount <<= kNumBitPriceShiftBits;
1.66 + range -= (1 << 31);
1.67 + for (int k = kNumBitPriceShiftBits - 1; k >= 0; k--)
1.68 + {
1.69 + range <<= 1;
1.70 + if (range > (1 << 31))
1.71 + {
1.72 + bitCount += (1 << k);
1.73 + range -= (1 << 31);
1.74 + }
1.75 + }
1.76 + ProbPrices[i] = (bitCount
1.77 + // + (1 << (kCyclesBits - 1))
1.78 + ) >> kCyclesBits;
1.79 + }
1.80 + */
1.81 +}
1.82 +
1.83 +}}
