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|
package xxh3
import (
"math/bits"
"unsafe"
)
// Uint128 is a 128 bit value.
// The actual value can be thought of as u.Hi<<64 | u.Lo.
type Uint128 struct {
Hi, Lo uint64
}
// Bytes returns the uint128 as an array of bytes in canonical form (big-endian encoded).
func (u Uint128) Bytes() [16]byte {
return [16]byte{
byte(u.Hi >> 0x38), byte(u.Hi >> 0x30), byte(u.Hi >> 0x28), byte(u.Hi >> 0x20),
byte(u.Hi >> 0x18), byte(u.Hi >> 0x10), byte(u.Hi >> 0x08), byte(u.Hi),
byte(u.Lo >> 0x38), byte(u.Lo >> 0x30), byte(u.Lo >> 0x28), byte(u.Lo >> 0x20),
byte(u.Lo >> 0x18), byte(u.Lo >> 0x10), byte(u.Lo >> 0x08), byte(u.Lo),
}
}
type (
ptr = unsafe.Pointer
ui = uintptr
u8 = uint8
u32 = uint32
u64 = uint64
u128 = Uint128
)
type str struct {
p ptr
l uint
}
func readU8(p ptr, o ui) uint8 {
return *(*uint8)(ptr(ui(p) + o))
}
func readU16(p ptr, o ui) uint16 {
b := (*[2]byte)(ptr(ui(p) + o))
return uint16(b[0]) | uint16(b[1])<<8
}
func readU32(p ptr, o ui) uint32 {
b := (*[4]byte)(ptr(ui(p) + o))
return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}
func readU64(p ptr, o ui) uint64 {
b := (*[8]byte)(ptr(ui(p) + o))
return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
}
func writeU64(p ptr, o ui, v u64) {
b := (*[8]byte)(ptr(ui(p) + o))
b[0] = byte(v)
b[1] = byte(v >> 8)
b[2] = byte(v >> 16)
b[3] = byte(v >> 24)
b[4] = byte(v >> 32)
b[5] = byte(v >> 40)
b[6] = byte(v >> 48)
b[7] = byte(v >> 56)
}
const secretSize = 192
func initSecret(secret ptr, seed u64) {
for i := ui(0); i < secretSize/16; i++ {
lo := readU64(key, 16*i) + seed
hi := readU64(key, 16*i+8) - seed
writeU64(secret, 16*i, lo)
writeU64(secret, 16*i+8, hi)
}
}
func xxh64AvalancheSmall(x u64) u64 {
// x ^= x >> 33 // x must be < 32 bits
// x ^= u64(key32_000 ^ key32_004) // caller must do this
x *= prime64_2
x ^= x >> 29
x *= prime64_3
x ^= x >> 32
return x
}
func xxhAvalancheSmall(x u64) u64 {
x ^= x >> 33
x *= prime64_2
x ^= x >> 29
x *= prime64_3
x ^= x >> 32
return x
}
func xxh64AvalancheFull(x u64) u64 {
x ^= x >> 33
x *= prime64_2
x ^= x >> 29
x *= prime64_3
x ^= x >> 32
return x
}
func xxh3Avalanche(x u64) u64 {
x ^= x >> 37
x *= 0x165667919e3779f9
x ^= x >> 32
return x
}
func rrmxmx(h64 u64, len u64) u64 {
h64 ^= bits.RotateLeft64(h64, 49) ^ bits.RotateLeft64(h64, 24)
h64 *= 0x9fb21c651e98df25
h64 ^= (h64 >> 35) + len
h64 *= 0x9fb21c651e98df25
h64 ^= (h64 >> 28)
return h64
}
func mulFold64(x, y u64) u64 {
hi, lo := bits.Mul64(x, y)
return hi ^ lo
}
|
