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package farmhash
// Based on the original C++ platform.cc
// A small optimisation I switched from binary.LittleEndian.Uint32/64 to
// hand coded. The benchmark, on my system, went from
// around 64ns/op to around 51ns/op
/*
import (
"encoding/binary"
)
*/
// Note: I used to call binary.LittleEndian.Uint32 and Uint64 inline but it
// made comparing the code to the original much trickier
func fetch32(p []byte) uint32 {
//return binary.LittleEndian.Uint32(p)
return uint32(p[0]) | uint32(p[1])<<8 | uint32(p[2])<<16 | uint32(p[3])<<24
}
func fetch64(p []byte) uint64 {
//return binary.LittleEndian.Uint64(p)
return uint64(p[0]) | uint64(p[1])<<8 | uint64(p[2])<<16 | uint64(p[3])<<24 |
uint64(p[4])<<32 | uint64(p[5])<<40 | uint64(p[6])<<48 | uint64(p[7])<<56
}
// rotate32 is a bitwise rotate
func rotate32(val uint32, shift uint) uint32 {
if shift == 0 {
return val
}
return val>>shift | val<<(32-shift)
}
// rotate64 is a bitwise rotate
func rotate64(val uint64, shift uint) uint64 {
if shift == 0 {
return val
}
return val>>shift | val<<(64-shift)
}
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