github.com/songzhibin97/go-baseutils@v0.0.2-0.20240302024150-487d8ce9c082/sys/xxhash3/util.go (about)

     1  // Package xxhash3 implements https://github.com/Cyan4973/xxHash/blob/dev/xxhash.h
     2  package xxhash3
     3  
     4  import (
     5  	"math/bits"
     6  	"unsafe"
     7  
     8  	"github.com/songzhibin97/go-baseutils/sys/cpu"
     9  )
    10  
    11  var (
    12  	avx2        = cpu.X86.HasAVX2
    13  	sse2        = cpu.X86.HasSSE2
    14  	hashfunc    = [2]func(unsafe.Pointer, int) uint64{xxh3HashSmall, xxh3HashLarge}
    15  	hashfunc128 = [2]func(unsafe.Pointer, int) [2]uint64{xxh3HashSmall128, xxh3HashLarge128}
    16  )
    17  
    18  type funcUnsafe int
    19  
    20  const (
    21  	hashSmall funcUnsafe = iota
    22  	hashLarge
    23  )
    24  
    25  func mix(a, b uint64) uint64 {
    26  	hi, lo := bits.Mul64(a, b)
    27  	return hi ^ lo
    28  }
    29  func xxh3RRMXMX(h64 uint64, length uint64) uint64 {
    30  	h64 ^= bits.RotateLeft64(h64, 49) ^ bits.RotateLeft64(h64, 24)
    31  	h64 *= 0x9fb21c651e98df25
    32  	h64 ^= (h64 >> 35) + length
    33  	h64 *= 0x9fb21c651e98df25
    34  	h64 ^= (h64 >> 28)
    35  	return h64
    36  }
    37  
    38  func xxh64Avalanche(h64 uint64) uint64 {
    39  	h64 *= prime64_2
    40  	h64 ^= h64 >> 29
    41  	h64 *= prime64_3
    42  	h64 ^= h64 >> 32
    43  	return h64
    44  }
    45  
    46  func xxh3Avalanche(x uint64) uint64 {
    47  	x ^= x >> 37
    48  	x *= 0x165667919e3779f9
    49  	x ^= x >> 32
    50  	return x
    51  }