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-rw-r--r--other-licenses/7zstub/src/7zip/Compress/RangeCoder/RangeCoderBit.cpp80
1 files changed, 80 insertions, 0 deletions
diff --git a/other-licenses/7zstub/src/7zip/Compress/RangeCoder/RangeCoderBit.cpp b/other-licenses/7zstub/src/7zip/Compress/RangeCoder/RangeCoderBit.cpp
new file mode 100644
index 000000000..8d273c8f9
--- /dev/null
+++ b/other-licenses/7zstub/src/7zip/Compress/RangeCoder/RangeCoderBit.cpp
@@ -0,0 +1,80 @@
+// Compress/RangeCoder/RangeCoderBit.cpp
+
+#include "StdAfx.h"
+
+#include "RangeCoderBit.h"
+
+namespace NCompress {
+namespace NRangeCoder {
+
+UInt32 CPriceTables::ProbPrices[kBitModelTotal >> kNumMoveReducingBits];
+static CPriceTables g_PriceTables;
+
+CPriceTables::CPriceTables() { Init(); }
+
+void CPriceTables::Init()
+{
+ const int kNumBits = (kNumBitModelTotalBits - kNumMoveReducingBits);
+ for(int i = kNumBits - 1; i >= 0; i--)
+ {
+ UInt32 start = 1 << (kNumBits - i - 1);
+ UInt32 end = 1 << (kNumBits - i);
+ for (UInt32 j = start; j < end; j++)
+ ProbPrices[j] = (i << kNumBitPriceShiftBits) +
+ (((end - j) << kNumBitPriceShiftBits) >> (kNumBits - i - 1));
+ }
+
+ /*
+ // simplest: bad solution
+ for(UInt32 i = 1; i < (kBitModelTotal >> kNumMoveReducingBits) - 1; i++)
+ ProbPrices[i] = kBitPrice;
+ */
+
+ /*
+ const double kDummyMultMid = (1.0 / kBitPrice) / 2;
+ const double kDummyMultMid = 0;
+ // float solution
+ double ln2 = log(double(2));
+ double lnAll = log(double(kBitModelTotal >> kNumMoveReducingBits));
+ for(UInt32 i = 1; i < (kBitModelTotal >> kNumMoveReducingBits) - 1; i++)
+ ProbPrices[i] = UInt32((fabs(lnAll - log(double(i))) / ln2 + kDummyMultMid) * kBitPrice);
+ */
+
+ /*
+ // experimental, slow, solution:
+ for(UInt32 i = 1; i < (kBitModelTotal >> kNumMoveReducingBits) - 1; i++)
+ {
+ const int kCyclesBits = 5;
+ const UInt32 kCycles = (1 << kCyclesBits);
+
+ UInt32 range = UInt32(-1);
+ UInt32 bitCount = 0;
+ for (UInt32 j = 0; j < kCycles; j++)
+ {
+ range >>= (kNumBitModelTotalBits - kNumMoveReducingBits);
+ range *= i;
+ while(range < (1 << 31))
+ {
+ range <<= 1;
+ bitCount++;
+ }
+ }
+ bitCount <<= kNumBitPriceShiftBits;
+ range -= (1 << 31);
+ for (int k = kNumBitPriceShiftBits - 1; k >= 0; k--)
+ {
+ range <<= 1;
+ if (range > (1 << 31))
+ {
+ bitCount += (1 << k);
+ range -= (1 << 31);
+ }
+ }
+ ProbPrices[i] = (bitCount
+ // + (1 << (kCyclesBits - 1))
+ ) >> kCyclesBits;
+ }
+ */
+}
+
+}}