596 lines
14 KiB
Go
596 lines
14 KiB
Go
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/*
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* Go implementation of Google city hash (MIT license)
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* https://code.google.com/p/cityhash/
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*
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* MIT License http://www.opensource.org/licenses/mit-license.php
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*
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* I don't even want to pretend to understand the details of city hash.
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* I am only reproducing the logic in Go as faithfully as I can.
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*
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*/
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package cityhash
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import (
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"encoding/binary"
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"unsafe"
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)
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/*
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var (
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little bool
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)
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func init() {
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if IsLittleEndian() {
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little = true
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} else {
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little = false
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}
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}
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*/
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func IsLittleEndian() bool {
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var i int32 = 0x01020304
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u := unsafe.Pointer(&i)
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pb := (*byte)(u)
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b := *pb
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return (b == 0x04)
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}
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func unalignedLoad64(p []byte) (result uint64) {
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return binary.LittleEndian.Uint64(p)
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/*
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if little {
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result = binary.LittleEndian.Uint64(p)
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} else {
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result = binary.BigEndian.Uint64(p)
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}
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return result
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*/
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}
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func unalignedLoad32(p []byte) (result uint32) {
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return binary.LittleEndian.Uint32(p)
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/*
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if little {
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result = binary.LittleEndian.Uint32(p)
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} else {
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result = binary.BigEndian.Uint32(p)
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}
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return result
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*/
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}
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func bswap64(x uint64) uint64 {
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// Copied from netbsd's bswap64.c
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return ((x << 56) & 0xff00000000000000) |
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((x << 40) & 0x00ff000000000000) |
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((x << 24) & 0x0000ff0000000000) |
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((x << 8) & 0x000000ff00000000) |
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((x >> 8) & 0x00000000ff000000) |
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((x >> 24) & 0x0000000000ff0000) |
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((x >> 40) & 0x000000000000ff00) |
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((x >> 56) & 0x00000000000000ff)
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}
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func bswap32(x uint32) uint32 {
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// Copied from netbsd's bswap32.c
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return ((x << 24) & 0xff000000) |
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((x << 8) & 0x00ff0000) |
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((x >> 8) & 0x0000ff00) |
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((x >> 24) & 0x000000ff)
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}
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func uint32InExpectedOrder(x uint32) uint32 {
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/*
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if !little {
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return bswap32(x)
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}
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*/
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return x
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}
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func uint64InExpectedOrder(x uint64) uint64 {
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/*
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if !little {
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return bswap64(x)
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}
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*/
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return x
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}
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// If I understand the original code correctly, it's expecting to load either 8 or 4
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// byes in little endian order. so let's just simplify it a bit since we will do that
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// anyway..
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// https://code.google.com/p/cityhash/source/browse/trunk/src/city.cc#112
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func fetch64(p []byte) uint64 {
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return binary.LittleEndian.Uint64(p)
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//return uint64InExpectedOrder(unalignedLoad64(p))
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}
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func fetch32(p []byte) uint32 {
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return binary.LittleEndian.Uint32(p)
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//return uint32InExpectedOrder(unalignedLoad32(p))
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}
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const (
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k0 uint64 = 0xc3a5c85c97cb3127
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k1 uint64 = 0xb492b66fbe98f273
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k2 uint64 = 0x9ae16a3b2f90404f
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c1 uint32 = 0xcc9e2d51
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c2 uint32 = 0x1b873593
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)
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func fmix(h uint32) uint32 {
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h ^= h >> 16
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h *= 0x85ebca6b
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h ^= h >> 13
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h *= 0xc2b2ae35
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h ^= h >> 16
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return h
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}
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func rotate64(val uint64, shift uint32) uint64 {
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// Avoid shifting by 64: doing so yields an undefined result.
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if shift != 0 {
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return ((val >> shift) | (val << (64 - shift)))
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}
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return val
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}
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func rotate32(val uint32, shift uint32) uint32 {
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// Avoid shifting by 32: doing so yields an undefined result.
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if shift != 0 {
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return ((val >> shift) | (val << (32 - shift)))
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}
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return val
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}
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func swap64(a, b *uint64) {
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*a, *b = *b, *a
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}
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func swap32(a, b *uint32) {
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*a, *b = *b, *a
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}
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func permute3(a, b, c *uint32) {
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swap32(a, b)
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swap32(a, c)
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}
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func mur(a, h uint32) uint32 {
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a *= c1
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a = rotate32(a, 17)
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a *= c2
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h ^= a
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h = rotate32(h, 19)
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//return h * 5 + 0xe6546b64
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z := h*5 + 0xe6546b64
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return z
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}
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func hash32Len13to24(s []byte, length uint32) uint32 {
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var a uint32 = fetch32(s[(length>>1)-4:])
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var b uint32 = fetch32(s[4:])
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var c uint32 = fetch32(s[length-8:])
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var d uint32 = fetch32(s[(length >> 1):])
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var e uint32 = fetch32(s)
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var f uint32 = fetch32(s[length-4:])
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var h uint32 = length
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return fmix(mur(f, mur(e, mur(d, mur(c, mur(b, mur(a, h)))))))
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}
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func hash32Len0to4(s []byte, length uint32) uint32 {
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var b, c uint32 = 0, 9
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tmp := s[:length]
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for _, v := range tmp {
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b = uint32(int64(b)*int64(c1) + int64(int8(v)))
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c ^= b
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}
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return fmix(mur(b, mur(length, c)))
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}
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func hash32Len5to12(s []byte, length uint32) uint32 {
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var a, b, c uint32 = length, length * 5, 9
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var d uint32 = b
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a += fetch32(s)
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b += fetch32(s[length-4:])
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c += fetch32(s[((length >> 1) & 4):])
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return fmix(mur(c, mur(b, mur(a, d))))
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}
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func CityHash32(s []byte, length uint32) uint32 {
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if length <= 4 {
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return hash32Len0to4(s, length)
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} else if length <= 12 {
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return hash32Len5to12(s, length)
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} else if length <= 24 {
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return hash32Len13to24(s, length)
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}
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// length > 24
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var h uint32 = length
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var g uint32 = c1 * length
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var f uint32 = g
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var a0 uint32 = rotate32(fetch32(s[length-4:])*c1, 17) * c2
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var a1 uint32 = rotate32(fetch32(s[length-8:])*c1, 17) * c2
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var a2 uint32 = rotate32(fetch32(s[length-16:])*c1, 17) * c2
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var a3 uint32 = rotate32(fetch32(s[length-12:])*c1, 17) * c2
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var a4 uint32 = rotate32(fetch32(s[length-20:])*c1, 17) * c2
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h ^= a0
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h = rotate32(h, 19)
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h = h*5 + 0xe6546b64
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h ^= a2
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h = rotate32(h, 19)
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h = h*5 + 0xe6546b64
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g ^= a1
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g = rotate32(g, 19)
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g = g*5 + 0xe6546b64
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g ^= a3
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g = rotate32(g, 19)
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g = g*5 + 0xe6546b64
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f += a4
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f = rotate32(f, 19)
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f = f*5 + 0xe6546b64
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var iters uint32 = (length - 1) / 20
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for {
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var a0 uint32 = rotate32(fetch32(s)*c1, 17) * c2
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var a1 uint32 = fetch32(s[4:])
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var a2 uint32 = rotate32(fetch32(s[8:])*c1, 17) * c2
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var a3 uint32 = rotate32(fetch32(s[12:])*c1, 17) * c2
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var a4 uint32 = fetch32(s[16:])
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h ^= a0
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h = rotate32(h, 18)
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h = h*5 + 0xe6546b64
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f += a1
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f = rotate32(f, 19)
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f = f * c1
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g += a2
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g = rotate32(g, 18)
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g = g*5 + 0xe6546b64
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h ^= a3 + a1
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h = rotate32(h, 19)
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h = h*5 + 0xe6546b64
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g ^= a4
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g = bswap32(g) * 5
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h += a4 * 5
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h = bswap32(h)
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f += a0
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permute3(&f, &h, &g)
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s = s[20:]
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iters--
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if iters == 0 {
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break
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}
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}
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g = rotate32(g, 11) * c1
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g = rotate32(g, 17) * c1
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f = rotate32(f, 11) * c1
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f = rotate32(f, 17) * c1
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h = rotate32(h+g, 19)
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h = h*5 + 0xe6546b64
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h = rotate32(h, 17) * c1
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h = rotate32(h+f, 19)
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h = h*5 + 0xe6546b64
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h = rotate32(h, 17) * c1
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return h
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}
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func shiftMix(val uint64) uint64 {
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return val ^ (val >> 47)
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}
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type Uint128 [2]uint64
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func (this *Uint128) setLower64(l uint64) {
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this[0] = l
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}
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func (this *Uint128) setHigher64(h uint64) {
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this[1] = h
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}
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func (this Uint128) Lower64() uint64 {
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return this[0]
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}
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func (this Uint128) Higher64() uint64 {
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return this[1]
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}
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func (this Uint128) Bytes() []byte {
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b := make([]byte, 16)
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binary.LittleEndian.PutUint64(b, this[0])
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binary.LittleEndian.PutUint64(b[8:], this[1])
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return b
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}
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func hash128to64(x Uint128) uint64 {
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// Murmur-inspired hashing.
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const kMul uint64 = 0x9ddfea08eb382d69
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var a uint64 = (x.Lower64() ^ x.Higher64()) * kMul
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a ^= (a >> 47)
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var b uint64 = (x.Higher64() ^ a) * kMul
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b ^= (b >> 47)
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b *= kMul
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return b
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}
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func hashLen16(u, v uint64) uint64 {
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return hash128to64(Uint128{u, v})
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}
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func hashLen16_3(u, v, mul uint64) uint64 {
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// Murmur-inspired hashing.
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var a uint64 = (u ^ v) * mul
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a ^= (a >> 47)
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var b uint64 = (v ^ a) * mul
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b ^= (b >> 47)
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b *= mul
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return b
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}
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func hashLen0to16(s []byte, length uint32) uint64 {
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if length >= 8 {
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var mul uint64 = k2 + uint64(length)*2
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var a uint64 = fetch64(s) + k2
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var b uint64 = fetch64(s[length-8:])
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var c uint64 = rotate64(b, 37)*mul + a
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var d uint64 = (rotate64(a, 25) + b) * mul
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return hashLen16_3(c, d, mul)
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}
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if length >= 4 {
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var mul uint64 = k2 + uint64(length)*2
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var a uint64 = uint64(fetch32(s))
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return hashLen16_3(uint64(length)+(a<<3), uint64(fetch32(s[length-4:])), mul)
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}
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if length > 0 {
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var a uint8 = uint8(s[0])
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var b uint8 = uint8(s[length>>1])
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var c uint8 = uint8(s[length-1])
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var y uint32 = uint32(a) + (uint32(b) << 8)
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var z uint32 = length + (uint32(c) << 2)
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return shiftMix(uint64(y)*k2^uint64(z)*k0) * k2
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}
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return k2
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}
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func hashLen17to32(s []byte, length uint32) uint64 {
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var mul uint64 = k2 + uint64(length)*2
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var a uint64 = fetch64(s) * k1
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var b uint64 = fetch64(s[8:])
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var c uint64 = fetch64(s[length-8:]) * mul
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|
|
var d uint64 = fetch64(s[length-16:]) * k2
|
||
|
|
return hashLen16_3(rotate64(a+b, 43)+rotate64(c, 30)+d, a+rotate64(b+k2, 18)+c, mul)
|
||
|
|
}
|
||
|
|
|
||
|
|
func weakHashLen32WithSeeds(w, x, y, z, a, b uint64) Uint128 {
|
||
|
|
a += w
|
||
|
|
b = rotate64(b+a+z, 21)
|
||
|
|
var c uint64 = a
|
||
|
|
a += x
|
||
|
|
a += y
|
||
|
|
b += rotate64(a, 44)
|
||
|
|
return Uint128{a + z, b + c}
|
||
|
|
}
|
||
|
|
|
||
|
|
func weakHashLen32WithSeeds_3(s []byte, a, b uint64) Uint128 {
|
||
|
|
return weakHashLen32WithSeeds(fetch64(s), fetch64(s[8:]), fetch64(s[16:]), fetch64(s[24:]), a, b)
|
||
|
|
}
|
||
|
|
|
||
|
|
func hashLen33to64(s []byte, length uint32) uint64 {
|
||
|
|
var mul uint64 = k2 + uint64(length)*2
|
||
|
|
var a uint64 = fetch64(s) * k2
|
||
|
|
var b uint64 = fetch64(s[8:])
|
||
|
|
var c uint64 = fetch64(s[length-24:])
|
||
|
|
var d uint64 = fetch64(s[length-32:])
|
||
|
|
var e uint64 = fetch64(s[16:]) * k2
|
||
|
|
var f uint64 = fetch64(s[24:]) * 9
|
||
|
|
var g uint64 = fetch64(s[length-8:])
|
||
|
|
var h uint64 = fetch64(s[length-16:]) * mul
|
||
|
|
var u uint64 = rotate64(a+g, 43) + (rotate64(b, 30)+c)*9
|
||
|
|
var v uint64 = ((a + g) ^ d) + f + 1
|
||
|
|
var w uint64 = bswap64((u+v)*mul) + h
|
||
|
|
var x uint64 = rotate64(e+f, 42) + c
|
||
|
|
var y uint64 = (bswap64((v+w)*mul) + g) * mul
|
||
|
|
var z uint64 = e + f + c
|
||
|
|
a = bswap64((x+z)*mul+y) + b
|
||
|
|
b = shiftMix((z+a)*mul+d+h) * mul
|
||
|
|
return b + x
|
||
|
|
}
|
||
|
|
|
||
|
|
func CityHash64(s []byte, length uint32) uint64 {
|
||
|
|
if length <= 32 {
|
||
|
|
if length <= 16 {
|
||
|
|
return hashLen0to16(s, length)
|
||
|
|
} else {
|
||
|
|
return hashLen17to32(s, length)
|
||
|
|
}
|
||
|
|
} else if length <= 64 {
|
||
|
|
return hashLen33to64(s, length)
|
||
|
|
}
|
||
|
|
|
||
|
|
var x uint64 = fetch64(s[length-40:])
|
||
|
|
var y uint64 = fetch64(s[length-16:]) + fetch64(s[length-56:])
|
||
|
|
var z uint64 = hashLen16(fetch64(s[length-48:])+uint64(length), fetch64(s[length-24:]))
|
||
|
|
var v Uint128 = weakHashLen32WithSeeds_3(s[length-64:], uint64(length), z)
|
||
|
|
var w Uint128 = weakHashLen32WithSeeds_3(s[length-32:], y+k1, x)
|
||
|
|
x = x*k1 + fetch64(s)
|
||
|
|
|
||
|
|
length = (length - 1) & ^uint32(63)
|
||
|
|
for {
|
||
|
|
x = rotate64(x+y+v.Lower64()+fetch64(s[8:]), 37) * k1
|
||
|
|
y = rotate64(y+v.Higher64()+fetch64(s[48:]), 42) * k1
|
||
|
|
x ^= w.Higher64()
|
||
|
|
y += v.Lower64() + fetch64(s[40:])
|
||
|
|
z = rotate64(z+w.Lower64(), 33) * k1
|
||
|
|
v = weakHashLen32WithSeeds_3(s, v.Higher64()*k1, x+w.Lower64())
|
||
|
|
w = weakHashLen32WithSeeds_3(s[32:], z+w.Higher64(), y+fetch64(s[16:]))
|
||
|
|
swap64(&z, &x)
|
||
|
|
s = s[64:]
|
||
|
|
length -= 64
|
||
|
|
|
||
|
|
if length == 0 {
|
||
|
|
break
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return hashLen16(hashLen16(v.Lower64(), w.Lower64())+shiftMix(y)*k1+z, hashLen16(v.Higher64(), w.Higher64())+x)
|
||
|
|
}
|
||
|
|
|
||
|
|
func CityHash64WithSeed(s []byte, length uint32, seed uint64) uint64 {
|
||
|
|
return CityHash64WithSeeds(s, length, k2, seed)
|
||
|
|
}
|
||
|
|
|
||
|
|
func CityHash64WithSeeds(s []byte, length uint32, seed0, seed1 uint64) uint64 {
|
||
|
|
return hashLen16(CityHash64(s, length)-seed0, seed1)
|
||
|
|
}
|
||
|
|
|
||
|
|
func cityMurmur(s []byte, length uint32, seed Uint128) Uint128 {
|
||
|
|
var a uint64 = seed.Lower64()
|
||
|
|
var b uint64 = seed.Higher64()
|
||
|
|
var c uint64 = 0
|
||
|
|
var d uint64 = 0
|
||
|
|
var l int32 = int32(length) - 16
|
||
|
|
|
||
|
|
if l <= 0 { // len <= 16
|
||
|
|
a = shiftMix(a*k1) * k1
|
||
|
|
c = b*k1 + hashLen0to16(s, length)
|
||
|
|
|
||
|
|
if length >= 8 {
|
||
|
|
d = shiftMix(a + fetch64(s))
|
||
|
|
} else {
|
||
|
|
d = shiftMix(a + c)
|
||
|
|
}
|
||
|
|
} else { // len > 16
|
||
|
|
c = hashLen16(fetch64(s[length-8:])+k1, a)
|
||
|
|
d = hashLen16(b+uint64(length), c+fetch64(s[length-16:]))
|
||
|
|
a += d
|
||
|
|
|
||
|
|
for {
|
||
|
|
a ^= shiftMix(fetch64(s)*k1) * k1
|
||
|
|
a *= k1
|
||
|
|
b ^= a
|
||
|
|
c ^= shiftMix(fetch64(s[8:])*k1) * k1
|
||
|
|
c *= k1
|
||
|
|
d ^= c
|
||
|
|
s = s[16:]
|
||
|
|
l -= 16
|
||
|
|
|
||
|
|
if l <= 0 {
|
||
|
|
break
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
a = hashLen16(a, c)
|
||
|
|
b = hashLen16(d, b)
|
||
|
|
return Uint128{a ^ b, hashLen16(b, a)}
|
||
|
|
}
|
||
|
|
|
||
|
|
func CityHash128WithSeed(s []byte, length uint32, seed Uint128) Uint128 {
|
||
|
|
if length < 128 {
|
||
|
|
return cityMurmur(s, length, seed)
|
||
|
|
}
|
||
|
|
|
||
|
|
orig_length := length
|
||
|
|
var t []byte = s
|
||
|
|
|
||
|
|
// We expect length >= 128 to be the common case. Keep 56 bytes of state:
|
||
|
|
// v, w, x, y, and z.
|
||
|
|
var v, w Uint128
|
||
|
|
var x uint64 = seed.Lower64()
|
||
|
|
var y uint64 = seed.Higher64()
|
||
|
|
var z uint64 = uint64(length) * k1
|
||
|
|
|
||
|
|
v.setLower64(rotate64(y^k1, 49)*k1 + fetch64(s))
|
||
|
|
v.setHigher64(rotate64(v.Lower64(), 42)*k1 + fetch64(s[8:]))
|
||
|
|
w.setLower64(rotate64(y+z, 35)*k1 + x)
|
||
|
|
w.setHigher64(rotate64(x+fetch64(s[88:]), 53) * k1)
|
||
|
|
|
||
|
|
// This is the same inner loop as CityHash64(), manually unrolled.
|
||
|
|
for {
|
||
|
|
x = rotate64(x+y+v.Lower64()+fetch64(s[8:]), 37) * k1
|
||
|
|
y = rotate64(y+v.Higher64()+fetch64(s[48:]), 42) * k1
|
||
|
|
x ^= w.Higher64()
|
||
|
|
y += v.Lower64() + fetch64(s[40:])
|
||
|
|
z = rotate64(z+w.Lower64(), 33) * k1
|
||
|
|
v = weakHashLen32WithSeeds_3(s, v.Higher64()*k1, x+w.Lower64())
|
||
|
|
w = weakHashLen32WithSeeds_3(s[32:], z+w.Higher64(), y+fetch64(s[16:]))
|
||
|
|
swap64(&z, &x)
|
||
|
|
s = s[64:]
|
||
|
|
x = rotate64(x+y+v.Lower64()+fetch64(s[8:]), 37) * k1
|
||
|
|
y = rotate64(y+v.Higher64()+fetch64(s[48:]), 42) * k1
|
||
|
|
x ^= w.Higher64()
|
||
|
|
y += v.Lower64() + fetch64(s[40:])
|
||
|
|
z = rotate64(z+w.Lower64(), 33) * k1
|
||
|
|
v = weakHashLen32WithSeeds_3(s, v.Higher64()*k1, x+w.Lower64())
|
||
|
|
w = weakHashLen32WithSeeds_3(s[32:], z+w.Higher64(), y+fetch64(s[16:]))
|
||
|
|
swap64(&z, &x)
|
||
|
|
s = s[64:]
|
||
|
|
length -= 128
|
||
|
|
|
||
|
|
if length < 128 {
|
||
|
|
break
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
x += rotate64(v.Lower64()+z, 49) * k0
|
||
|
|
y = y*k0 + rotate64(w.Higher64(), 37)
|
||
|
|
z = z*k0 + rotate64(w.Lower64(), 27)
|
||
|
|
w.setLower64(w.Lower64() * 9)
|
||
|
|
v.setLower64(v.Lower64() * k0)
|
||
|
|
|
||
|
|
// If 0 < length < 128, hash up to 4 chunks of 32 bytes each from the end of s.
|
||
|
|
var tail_done uint32
|
||
|
|
for tail_done = 0; tail_done < length; {
|
||
|
|
tail_done += 32
|
||
|
|
y = rotate64(x+y, 42)*k0 + v.Higher64()
|
||
|
|
w.setLower64(w.Lower64() + fetch64(t[orig_length-tail_done+16:]))
|
||
|
|
x = x*k0 + w.Lower64()
|
||
|
|
z += w.Higher64() + fetch64(t[orig_length-tail_done:])
|
||
|
|
w.setHigher64(w.Higher64() + v.Lower64())
|
||
|
|
v = weakHashLen32WithSeeds_3(t[orig_length-tail_done:], v.Lower64()+z, v.Higher64())
|
||
|
|
v.setLower64(v.Lower64() * k0)
|
||
|
|
}
|
||
|
|
|
||
|
|
// At this point our 56 bytes of state should contain more than
|
||
|
|
// enough information for a strong 128-bit hash. We use two
|
||
|
|
// different 56-byte-to-8-byte hashes to get a 16-byte final result.
|
||
|
|
x = hashLen16(x, v.Lower64())
|
||
|
|
y = hashLen16(y+z, w.Lower64())
|
||
|
|
|
||
|
|
return Uint128{hashLen16(x+v.Higher64(), w.Higher64()) + y,
|
||
|
|
hashLen16(x+w.Higher64(), y+v.Higher64())}
|
||
|
|
}
|
||
|
|
|
||
|
|
func CityHash128(s []byte, length uint32) (result Uint128) {
|
||
|
|
if length >= 16 {
|
||
|
|
result = CityHash128WithSeed(s[16:length], length-16, Uint128{fetch64(s), fetch64(s[8:length]) + k0})
|
||
|
|
} else {
|
||
|
|
result = CityHash128WithSeed(s, length, Uint128{k0, k1})
|
||
|
|
}
|
||
|
|
|
||
|
|
return
|
||
|
|
}
|