38 lines
1.0 KiB
C++
38 lines
1.0 KiB
C++
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#include <numerical_limits>
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template <int n, int mask = 1 << 7> struct bitcount {
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enum { value = (n & mask ? 1:0) + bitcount<n, mask >> 1>::value };
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};
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template <int n> struct bitcount<n, 0> { enum { value = 0 }; };
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template <int n, int current, int mask = 1 << 8> struct bitposition {
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enum
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template <int index = 0, typename op> class CompileTimeByteTable {
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public:
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CompileTimeByteTable : current(op<index>::value) { }
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int operator[] (int i) { return *(¤t + i); }
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private:
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unsigned char current;
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CompileTimeByteTable<next> next;
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};
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static CompileTimeByteTable<256, bitcount> BitcountTable;
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#define mix(a,b,c) \
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{ \
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a -= b; a -= c; a ^= (c>>13); \
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b -= c; b -= a; b ^= (a<<8); \
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c -= a; c -= b; c ^= (b>>13); \
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a -= b; a -= c; a ^= (c>>12); \
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b -= c; b -= a; b ^= (a<<16); \
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c -= a; c -= b; c ^= (b>>5); \
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a -= b; a -= c; a ^= (c>>3); \
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b -= c; b -= a; b ^= (a<<10); \
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c -= a; c -= b; c ^= (b>>15); \
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}
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static const int kMaskStepSelectTable = std::limit<char>::max;
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