1 #ifndef MARISA_ALPHA_POPCOUNT_H_ 2 #define MARISA_ALPHA_POPCOUNT_H_ 3 4 #include "base.h" 5 6 namespace marisa_alpha { 7 8 class PopCount { 9 public: 10 PopCount(UInt32 x) : value_() { 11 x = (x & 0x55555555U) + ((x & 0xAAAAAAAAU) >> 1); 12 x = (x & 0x33333333U) + ((x & 0xCCCCCCCCU) >> 2); 13 x = (x + (x >> 4)) & 0x0F0F0F0FU; 14 x += x << 8; 15 x += x << 16; 16 value_ = x; 17 } 18 19 UInt32 lo8() const { 20 return value_ & 0xFFU; 21 } 22 UInt32 lo16() const { 23 return (value_ >> 8) & 0xFFU; 24 } 25 UInt32 lo24() const { 26 return (value_ >> 16) & 0xFFU; 27 } 28 UInt32 lo32() const { 29 return value_ >> 24; 30 } 31 32 private: 33 UInt32 value_; 34 }; 35 36 } // namespace marisa_alpha 37 38 #endif // MARISA_ALPHA_POPCOUNT_H_ 39
