mirror of https://github.com/tidwall/tile38.git
250 lines
8.2 KiB
Go
250 lines
8.2 KiB
Go
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// Package xxHash64 implements the very fast xxHash hashing algorithm (64 bits version).
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// (https://github.com/Cyan4973/xxHash/)
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package xxHash64
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import "hash"
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const (
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prime64_1 = 11400714785074694791
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prime64_2 = 14029467366897019727
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prime64_3 = 1609587929392839161
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prime64_4 = 9650029242287828579
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prime64_5 = 2870177450012600261
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)
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type xxHash struct {
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seed uint64
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v1 uint64
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v2 uint64
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v3 uint64
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v4 uint64
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totalLen uint64
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buf [32]byte
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bufused int
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}
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// New returns a new Hash64 instance.
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func New(seed uint64) hash.Hash64 {
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xxh := &xxHash{seed: seed}
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xxh.Reset()
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return xxh
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}
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// Sum appends the current hash to b and returns the resulting slice.
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// It does not change the underlying hash state.
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func (xxh xxHash) Sum(b []byte) []byte {
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h64 := xxh.Sum64()
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return append(b, byte(h64), byte(h64>>8), byte(h64>>16), byte(h64>>24), byte(h64>>32), byte(h64>>40), byte(h64>>48), byte(h64>>56))
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}
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// Reset resets the Hash to its initial state.
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func (xxh *xxHash) Reset() {
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xxh.v1 = xxh.seed + prime64_1 + prime64_2
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xxh.v2 = xxh.seed + prime64_2
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xxh.v3 = xxh.seed
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xxh.v4 = xxh.seed - prime64_1
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xxh.totalLen = 0
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xxh.bufused = 0
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}
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// Size returns the number of bytes returned by Sum().
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func (xxh *xxHash) Size() int {
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return 8
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}
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// BlockSize gives the minimum number of bytes accepted by Write().
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func (xxh *xxHash) BlockSize() int {
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return 1
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}
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// Write adds input bytes to the Hash.
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// It never returns an error.
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func (xxh *xxHash) Write(input []byte) (int, error) {
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n := len(input)
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m := xxh.bufused
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xxh.totalLen += uint64(n)
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r := len(xxh.buf) - m
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if n < r {
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copy(xxh.buf[m:], input)
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xxh.bufused += len(input)
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return n, nil
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}
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p := 0
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if m > 0 {
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// some data left from previous update
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copy(xxh.buf[xxh.bufused:], input[:r])
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xxh.bufused += len(input) - r
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// fast rotl(31)
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p64 := xxh.v1 + (uint64(xxh.buf[p+7])<<56|uint64(xxh.buf[p+6])<<48|uint64(xxh.buf[p+5])<<40|uint64(xxh.buf[p+4])<<32|uint64(xxh.buf[p+3])<<24|uint64(xxh.buf[p+2])<<16|uint64(xxh.buf[p+1])<<8|uint64(xxh.buf[p]))*prime64_2
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xxh.v1 = (p64<<31 | p64>>33) * prime64_1
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p += 8
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p64 = xxh.v2 + (uint64(xxh.buf[p+7])<<56|uint64(xxh.buf[p+6])<<48|uint64(xxh.buf[p+5])<<40|uint64(xxh.buf[p+4])<<32|uint64(xxh.buf[p+3])<<24|uint64(xxh.buf[p+2])<<16|uint64(xxh.buf[p+1])<<8|uint64(xxh.buf[p]))*prime64_2
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xxh.v2 = (p64<<31 | p64>>33) * prime64_1
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p += 8
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p64 = xxh.v3 + (uint64(xxh.buf[p+7])<<56|uint64(xxh.buf[p+6])<<48|uint64(xxh.buf[p+5])<<40|uint64(xxh.buf[p+4])<<32|uint64(xxh.buf[p+3])<<24|uint64(xxh.buf[p+2])<<16|uint64(xxh.buf[p+1])<<8|uint64(xxh.buf[p]))*prime64_2
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xxh.v3 = (p64<<31 | p64>>33) * prime64_1
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p += 8
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p64 = xxh.v4 + (uint64(xxh.buf[p+7])<<56|uint64(xxh.buf[p+6])<<48|uint64(xxh.buf[p+5])<<40|uint64(xxh.buf[p+4])<<32|uint64(xxh.buf[p+3])<<24|uint64(xxh.buf[p+2])<<16|uint64(xxh.buf[p+1])<<8|uint64(xxh.buf[p]))*prime64_2
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xxh.v4 = (p64<<31 | p64>>33) * prime64_1
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p = r
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xxh.bufused = 0
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}
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for n := n - 32; p <= n; {
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p64 := xxh.v1 + (uint64(input[p+7])<<56|uint64(input[p+6])<<48|uint64(input[p+5])<<40|uint64(input[p+4])<<32|uint64(input[p+3])<<24|uint64(input[p+2])<<16|uint64(input[p+1])<<8|uint64(input[p]))*prime64_2
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xxh.v1 = (p64<<31 | p64>>33) * prime64_1
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p += 8
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p64 = xxh.v2 + (uint64(input[p+7])<<56|uint64(input[p+6])<<48|uint64(input[p+5])<<40|uint64(input[p+4])<<32|uint64(input[p+3])<<24|uint64(input[p+2])<<16|uint64(input[p+1])<<8|uint64(input[p]))*prime64_2
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xxh.v2 = (p64<<31 | p64>>33) * prime64_1
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p += 8
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p64 = xxh.v3 + (uint64(input[p+7])<<56|uint64(input[p+6])<<48|uint64(input[p+5])<<40|uint64(input[p+4])<<32|uint64(input[p+3])<<24|uint64(input[p+2])<<16|uint64(input[p+1])<<8|uint64(input[p]))*prime64_2
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xxh.v3 = (p64<<31 | p64>>33) * prime64_1
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p += 8
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p64 = xxh.v4 + (uint64(input[p+7])<<56|uint64(input[p+6])<<48|uint64(input[p+5])<<40|uint64(input[p+4])<<32|uint64(input[p+3])<<24|uint64(input[p+2])<<16|uint64(input[p+1])<<8|uint64(input[p]))*prime64_2
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xxh.v4 = (p64<<31 | p64>>33) * prime64_1
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p += 8
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}
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copy(xxh.buf[xxh.bufused:], input[p:])
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xxh.bufused += len(input) - p
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return n, nil
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}
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// Sum64 returns the 64bits Hash value.
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func (xxh *xxHash) Sum64() uint64 {
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var h64 uint64
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if xxh.totalLen >= 32 {
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h64 = ((xxh.v1 << 1) | (xxh.v1 >> 63)) +
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((xxh.v2 << 7) | (xxh.v2 >> 57)) +
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((xxh.v3 << 12) | (xxh.v3 >> 52)) +
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((xxh.v4 << 18) | (xxh.v4 >> 46))
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xxh.v1 *= prime64_2
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h64 ^= ((xxh.v1 << 31) | (xxh.v1 >> 33)) * prime64_1
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h64 = h64*prime64_1 + prime64_4
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xxh.v2 *= prime64_2
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h64 ^= ((xxh.v2 << 31) | (xxh.v2 >> 33)) * prime64_1
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h64 = h64*prime64_1 + prime64_4
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xxh.v3 *= prime64_2
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h64 ^= ((xxh.v3 << 31) | (xxh.v3 >> 33)) * prime64_1
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h64 = h64*prime64_1 + prime64_4
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xxh.v4 *= prime64_2
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h64 ^= ((xxh.v4 << 31) | (xxh.v4 >> 33)) * prime64_1
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h64 = h64*prime64_1 + prime64_4 + xxh.totalLen
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} else {
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h64 = xxh.seed + prime64_5 + xxh.totalLen
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}
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p := 0
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n := xxh.bufused
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for n := n - 8; p <= n; p += 8 {
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p64 := (uint64(xxh.buf[p+7])<<56 | uint64(xxh.buf[p+6])<<48 | uint64(xxh.buf[p+5])<<40 | uint64(xxh.buf[p+4])<<32 | uint64(xxh.buf[p+3])<<24 | uint64(xxh.buf[p+2])<<16 | uint64(xxh.buf[p+1])<<8 | uint64(xxh.buf[p])) * prime64_2
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h64 ^= ((p64 << 31) | (p64 >> 33)) * prime64_1
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h64 = ((h64<<27)|(h64>>37))*prime64_1 + prime64_4
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}
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if p+4 <= n {
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h64 ^= (uint64(xxh.buf[p+3])<<24 | uint64(xxh.buf[p+2])<<16 | uint64(xxh.buf[p+1])<<8 | uint64(xxh.buf[p])) * prime64_1
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h64 = ((h64<<23)|(h64>>41))*prime64_2 + prime64_3
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p += 4
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}
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for ; p < n; p++ {
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h64 ^= uint64(xxh.buf[p]) * prime64_5
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h64 = ((h64 << 11) | (h64 >> 53)) * prime64_1
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}
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h64 ^= h64 >> 33
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h64 *= prime64_2
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h64 ^= h64 >> 29
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h64 *= prime64_3
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h64 ^= h64 >> 32
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return h64
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}
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// Checksum returns the 64bits Hash value.
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func Checksum(input []byte, seed uint64) uint64 {
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n := len(input)
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var h64 uint64
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if n >= 32 {
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v1 := seed + prime64_1 + prime64_2
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v2 := seed + prime64_2
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v3 := seed
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v4 := seed - prime64_1
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p := 0
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for n := n - 32; p <= n; {
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p64 := v1 + (uint64(input[p+7])<<56|uint64(input[p+6])<<48|uint64(input[p+5])<<40|uint64(input[p+4])<<32|uint64(input[p+3])<<24|uint64(input[p+2])<<16|uint64(input[p+1])<<8|uint64(input[p]))*prime64_2
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v1 = (p64<<31 | p64>>33) * prime64_1
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p += 8
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p64 = v2 + (uint64(input[p+7])<<56|uint64(input[p+6])<<48|uint64(input[p+5])<<40|uint64(input[p+4])<<32|uint64(input[p+3])<<24|uint64(input[p+2])<<16|uint64(input[p+1])<<8|uint64(input[p]))*prime64_2
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v2 = (p64<<31 | p64>>33) * prime64_1
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p += 8
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p64 = v3 + (uint64(input[p+7])<<56|uint64(input[p+6])<<48|uint64(input[p+5])<<40|uint64(input[p+4])<<32|uint64(input[p+3])<<24|uint64(input[p+2])<<16|uint64(input[p+1])<<8|uint64(input[p]))*prime64_2
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v3 = (p64<<31 | p64>>33) * prime64_1
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p += 8
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p64 = v4 + (uint64(input[p+7])<<56|uint64(input[p+6])<<48|uint64(input[p+5])<<40|uint64(input[p+4])<<32|uint64(input[p+3])<<24|uint64(input[p+2])<<16|uint64(input[p+1])<<8|uint64(input[p]))*prime64_2
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v4 = (p64<<31 | p64>>33) * prime64_1
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p += 8
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}
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h64 = ((v1 << 1) | (v1 >> 63)) +
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((v2 << 7) | (v2 >> 57)) +
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((v3 << 12) | (v3 >> 52)) +
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((v4 << 18) | (v4 >> 46))
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v1 *= prime64_2
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h64 ^= ((v1 << 31) | (v1 >> 33)) * prime64_1
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h64 = h64*prime64_1 + prime64_4
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v2 *= prime64_2
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h64 ^= ((v2 << 31) | (v2 >> 33)) * prime64_1
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h64 = h64*prime64_1 + prime64_4
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v3 *= prime64_2
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h64 ^= ((v3 << 31) | (v3 >> 33)) * prime64_1
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h64 = h64*prime64_1 + prime64_4
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v4 *= prime64_2
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h64 ^= ((v4 << 31) | (v4 >> 33)) * prime64_1
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h64 = h64*prime64_1 + prime64_4 + uint64(n)
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input = input[p:]
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n -= p
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} else {
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h64 = seed + prime64_5 + uint64(n)
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}
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p := 0
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for n := n - 8; p <= n; p += 8 {
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p64 := (uint64(input[p+7])<<56 | uint64(input[p+6])<<48 | uint64(input[p+5])<<40 | uint64(input[p+4])<<32 | uint64(input[p+3])<<24 | uint64(input[p+2])<<16 | uint64(input[p+1])<<8 | uint64(input[p])) * prime64_2
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h64 ^= ((p64 << 31) | (p64 >> 33)) * prime64_1
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h64 = ((h64<<27)|(h64>>37))*prime64_1 + prime64_4
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}
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if p+4 <= n {
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h64 ^= (uint64(input[p+3])<<24 | uint64(input[p+2])<<16 | uint64(input[p+1])<<8 | uint64(input[p])) * prime64_1
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h64 = ((h64<<23)|(h64>>41))*prime64_2 + prime64_3
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p += 4
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}
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for ; p < n; p++ {
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h64 ^= uint64(input[p]) * prime64_5
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h64 = ((h64 << 11) | (h64 >> 53)) * prime64_1
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}
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h64 ^= h64 >> 33
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h64 *= prime64_2
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h64 ^= h64 >> 29
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h64 *= prime64_3
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h64 ^= h64 >> 32
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return h64
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}
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