mirror of
https://github.com/gogrlx/nats-server.git
synced 2026-04-02 03:38:42 -07:00
Small cleanup
This commit is contained in:
Derek Collison
277
hash/hash.go
277
hash/hash.go
@@ -7,6 +7,143 @@ import (
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"unsafe"
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)
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// Generates a Bernstein Hash.
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func Bernstein(data []byte) uint32 {
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hash := uint32(5381)
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for _, b := range data {
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hash = ((hash << 5) + hash) + uint32(b)
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}
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return hash
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}
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// Constants for FNV1A and derivatives
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const (
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_OFF32 = 2166136261
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_P32 = 16777619
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_YP32 = 709607
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)
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// Generates an FNV1A Hash [http://en.wikipedia.org/wiki/Fowle-Noll-Vo_hash_function]
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func FNV1A(data []byte) uint32 {
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var hash uint32 = _OFF32
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for _, c := range data {
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hash ^= uint32(c)
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hash *= _P32
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}
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return hash
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}
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// Constants for multiples of sizeof(WORD)
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const (
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_WSZ = 4 // 4
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_DWSZ = _WSZ << 1 // 8
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_DDWSZ = _WSZ << 2 // 16
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_DDDWSZ = _WSZ << 3 // 32
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)
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// Jesteress derivative of FNV1A from [http://www.sanmayce.com/Fastest_Hash/]
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func Jesteress(data []byte) uint32 {
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h32 := uint32(_OFF32)
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i, dlen := 0, len(data)
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for ; dlen >= _DDWSZ; dlen -= _DDWSZ {
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k1 := *(*uint64)(unsafe.Pointer(&data[i]))
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k2 := *(*uint64)(unsafe.Pointer(&data[i+4]))
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h32 = uint32((uint64(h32) ^ ((k1<<5 | k1>>27) ^ k2)) * _YP32)
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i += _DDWSZ
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}
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// Cases: 0,1,2,3,4,5,6,7
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if (dlen & _DWSZ) > 0 {
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k1 := *(*uint64)(unsafe.Pointer(&data[i]))
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h32 = uint32(uint64(h32) ^ k1) * _YP32
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i += _DWSZ
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}
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if (dlen & _WSZ) > 0 {
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k1 := *(*uint32)(unsafe.Pointer(&data[i]))
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h32 = (h32 ^ k1) * _YP32
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i += _WSZ
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}
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if (dlen & 1) > 0 {
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h32 = (h32 ^ uint32(data[i])) * _YP32
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}
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return h32 ^ (h32 >> 16)
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}
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// Meiyan derivative of FNV1A from [http://www.sanmayce.com/Fastest_Hash/]
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func Meiyan(data []byte) uint32 {
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h32 := uint32(_OFF32)
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i, dlen := 0, len(data)
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for ; dlen >= _DDWSZ; dlen -= _DDWSZ {
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k1 := *(*uint64)(unsafe.Pointer(&data[i]))
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k2 := *(*uint64)(unsafe.Pointer(&data[i+4]))
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h32 = uint32((uint64(h32) ^ ((k1<<5 | k1>>27) ^ k2)) * _YP32)
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i += _DDWSZ
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}
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// Cases: 0,1,2,3,4,5,6,7
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if (dlen & _DWSZ) > 0 {
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k1 := *(*uint64)(unsafe.Pointer(&data[i]))
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h32 = uint32(uint64(h32)^k1) * _YP32
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i += _WSZ
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k1 = *(*uint64)(unsafe.Pointer(&data[i]))
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h32 = uint32(uint64(h32)^k1) * _YP32
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i += _WSZ
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}
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if (dlen & _WSZ) > 0 {
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k1 := *(*uint32)(unsafe.Pointer(&data[i]))
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h32 = (h32 ^ k1) * _YP32
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i += _WSZ
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}
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if (dlen & 1) > 0 {
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h32 = (h32 ^ uint32(data[i])) * _YP32
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}
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return h32 ^ (h32 >> 16)
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}
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// Yorikke derivative of FNV1A from [http://www.sanmayce.com/Fastest_Hash/]
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func Yorikke(data []byte) uint32 {
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h32 := uint32(_OFF32)
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h32b := uint32(_OFF32)
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i, dlen := 0, len(data)
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for ; dlen >= _DDDWSZ; dlen -= _DDDWSZ {
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k1 := *(*uint64)(unsafe.Pointer(&data[i]))
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k2 := *(*uint64)(unsafe.Pointer(&data[i+4]))
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h32 = uint32((uint64(h32) ^ (((k1<<5 | k1>>27)) ^ k2)) * _YP32)
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k1 = *(*uint64)(unsafe.Pointer(&data[i+8]))
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k2 = *(*uint64)(unsafe.Pointer(&data[i+12]))
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h32b = uint32((uint64(h32b) ^ (((k1<<5 | k1>>27)) ^ k2)) * _YP32)
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i += _DDDWSZ
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}
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if (dlen & _DDWSZ) > 0 {
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k1 := *(*uint64)(unsafe.Pointer(&data[i]))
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k2 := *(*uint64)(unsafe.Pointer(&data[i+4]))
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h32 = uint32((uint64(h32) ^ k1) * _YP32)
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h32b = uint32((uint64(h32b) ^ k2) * _YP32)
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i += _DDWSZ
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}
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// Cases: 0,1,2,3,4,5,6,7
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if (dlen & _DWSZ) > 0 {
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k1 := *(*uint32)(unsafe.Pointer(&data[i]))
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k2 := *(*uint32)(unsafe.Pointer(&data[i+2]))
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h32 = (h32 ^ k1) * _YP32
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h32b = (h32b ^ k2) * _YP32
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i += _DWSZ
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}
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if (dlen & _WSZ) > 0 {
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k1 := *(*uint32)(unsafe.Pointer(&data[i]))
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h32 = (h32 ^ k1) * _YP32
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i += _WSZ
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}
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if (dlen & 1) > 0 {
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h32 = (h32 ^ uint32(data[i])) * _YP32
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}
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h32 = (h32 ^ (h32b<<5 | h32b>>27)) * _YP32
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return h32 ^ (h32 >> 16)
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}
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// Constants defined by the Murmur3 algorithm
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const (
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_C1 = uint32(0xcc9e2d51)
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@@ -65,143 +202,3 @@ func Murmur3(data []byte, seed uint32) uint32 {
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return h1
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}
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// Generates a Bernstein Hash.
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func Bernstein(data []byte) uint32 {
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hash := uint32(5381)
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for _, b := range data {
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hash = ((hash << 5) + hash) + uint32(b)
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}
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return hash
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}
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// Constants for FNV1A and derivatives
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const (
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_OFF32 = 2166136261
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_P32 = 16777619
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_YP32 = 709607
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)
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// Generates an FNV1A Hash [http://en.wikipedia.org/wiki/Fowle-Noll-Vo_hash_function]
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func FNV1A(data []byte) uint32 {
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var hash uint32 = _OFF32
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for _, c := range data {
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hash ^= uint32(c)
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hash *= _P32
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}
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return hash
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}
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// Constants for multiples of sizeof(WORD)
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const (
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_WSZ = 4 // 4
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_DWSZ = _WSZ << 1 // 8
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_DDWSZ = _WSZ << 2 // 16
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_DDDWSZ = _WSZ << 3 // 32
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)
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// Jesteress derivative of FNV1A from [http://www.sanmayce.com/Fastest_Hash/]
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func Jesteress(data []byte) uint32 {
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h32 := uint32(_OFF32)
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dlen := len(data)
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i := 0
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for ; dlen >= _DDWSZ; dlen -= _DDWSZ {
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k1 := *(*uint64)(unsafe.Pointer(&data[i]))
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k2 := *(*uint64)(unsafe.Pointer(&data[i+4]))
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h32 = uint32((uint64(h32) ^ ((k1<<5 | k1>>27) ^ k2)) * _YP32)
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i += _DDWSZ
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}
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// Cases: 0,1,2,3,4,5,6,7
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if (dlen & _DWSZ) > 0 {
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k1 := *(*uint64)(unsafe.Pointer(&data[i]))
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h32 = uint32(uint64(h32) ^ k1) * _YP32
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i += _DWSZ
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}
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if (dlen & _WSZ) > 0 {
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k1 := *(*uint32)(unsafe.Pointer(&data[i]))
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h32 = (h32 ^ k1) * _YP32
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i += _WSZ
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}
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if (dlen & 1) > 0 {
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h32 = (h32 ^ uint32(data[i])) * _YP32
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}
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return h32 ^ (h32 >> 16)
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}
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// Meiyan derivative of FNV1A from [http://www.sanmayce.com/Fastest_Hash/]
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func Meiyan(data []byte) uint32 {
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h32 := uint32(_OFF32)
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dlen := len(data)
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i := 0
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for ; dlen >= _DDWSZ; dlen -= _DDWSZ {
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k1 := *(*uint64)(unsafe.Pointer(&data[i]))
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k2 := *(*uint64)(unsafe.Pointer(&data[i+4]))
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h32 = uint32((uint64(h32) ^ ((k1<<5 | k1>>27) ^ k2)) * _YP32)
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i += _DDWSZ
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}
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// Cases: 0,1,2,3,4,5,6,7
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if (dlen & _DWSZ) > 0 {
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k1 := *(*uint64)(unsafe.Pointer(&data[i]))
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h32 = uint32(uint64(h32)^k1) * _YP32
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i += _WSZ
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k1 = *(*uint64)(unsafe.Pointer(&data[i]))
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h32 = uint32(uint64(h32)^k1) * _YP32
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i += _WSZ
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}
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if (dlen & _WSZ) > 0 {
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k1 := *(*uint32)(unsafe.Pointer(&data[i]))
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h32 = (h32 ^ k1) * _YP32
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i += _WSZ
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}
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if (dlen & 1) > 0 {
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h32 = (h32 ^ uint32(data[i])) * _YP32
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}
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return h32 ^ (h32 >> 16)
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}
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// Yorikke derivative of FNV1A from [http://www.sanmayce.com/Fastest_Hash/]
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func Yorikke(data []byte) uint32 {
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h32 := uint32(_OFF32)
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h32b := uint32(_OFF32)
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dlen := len(data)
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i := 0
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for ; dlen >= _DDDWSZ; dlen -= _DDDWSZ {
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k1 := *(*uint64)(unsafe.Pointer(&data[i]))
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k2 := *(*uint64)(unsafe.Pointer(&data[i+4]))
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h32 = uint32((uint64(h32) ^ (((k1<<5 | k1>>27)) ^ k2)) * _YP32)
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k1 = *(*uint64)(unsafe.Pointer(&data[i+8]))
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k2 = *(*uint64)(unsafe.Pointer(&data[i+12]))
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h32b = uint32((uint64(h32b) ^ (((k1<<5 | k1>>27)) ^ k2)) * _YP32)
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i += _DDDWSZ
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}
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if (dlen & _DDWSZ) > 0 {
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k1 := *(*uint64)(unsafe.Pointer(&data[i]))
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k2 := *(*uint64)(unsafe.Pointer(&data[i+4]))
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h32 = uint32((uint64(h32) ^ k1) * _YP32)
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h32b = uint32((uint64(h32b) ^ k2) * _YP32)
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i += _DDWSZ
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}
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// Cases: 0,1,2,3,4,5,6,7
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if (dlen & _DWSZ) > 0 {
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k1 := *(*uint32)(unsafe.Pointer(&data[i]))
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k2 := *(*uint32)(unsafe.Pointer(&data[i+2]))
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h32 = (h32 ^ k1) * _YP32
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h32b = (h32b ^ k2) * _YP32
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i += _DWSZ
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}
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if (dlen & _WSZ) > 0 {
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k1 := *(*uint32)(unsafe.Pointer(&data[i]))
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h32 = (h32 ^ k1) * _YP32
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i += _WSZ
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}
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if (dlen & 1) > 0 {
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h32 = (h32 ^ uint32(data[i])) * _YP32
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}
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h32 = (h32 ^ (h32b<<5 | h32b>>27)) * _YP32
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return h32 ^ (h32 >> 16)
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}
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