127 lines
3.7 KiB
Go
127 lines
3.7 KiB
Go
package xxh3
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import "math/bits"
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// Hash returns the hash of the byte slice.
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func Hash(b []byte) uint64 {
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return hashAny(*(*str)(ptr(&b)))
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}
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// Hash returns the hash of the string slice.
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func HashString(s string) uint64 {
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return hashAny(*(*str)(ptr(&s)))
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}
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func hashAny(s str) (acc u64) {
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p, l := s.p, s.l
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switch {
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case l <= 16:
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switch {
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case l > 8: // 9-16
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inputlo := readU64(p, 0) ^ (key64_024 ^ key64_032)
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inputhi := readU64(p, ui(l)-8) ^ (key64_040 ^ key64_048)
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folded := mulFold64(inputlo, inputhi)
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return xxh3Avalanche(u64(l) + bits.ReverseBytes64(inputlo) + inputhi + folded)
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case l > 3: // 4-8
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input1 := readU32(p, 0)
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input2 := readU32(p, ui(l)-4)
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input64 := u64(input2) + u64(input1)<<32
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keyed := input64 ^ (key64_008 ^ key64_016)
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return rrmxmx(keyed, u64(l))
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case l == 3: // 3
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c12 := u64(readU16(p, 0))
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c3 := u64(readU8(p, 2))
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acc = c12<<16 + c3 + 3<<8
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case l > 1: // 2
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c12 := u64(readU16(p, 0))
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acc = c12*(1<<24+1)>>8 + 2<<8
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case l == 1: // 1
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c1 := u64(readU8(p, 0))
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acc = c1*(1<<24+1<<16+1) + 1<<8
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default: // 0
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return 0x2d06800538d394c2 // xxh_avalanche(key64_056 ^ key64_064)
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}
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acc ^= u64(key32_000 ^ key32_004)
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return xxhAvalancheSmall(acc)
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case l <= 128:
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acc = u64(l) * prime64_1
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if l > 32 {
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if l > 64 {
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if l > 96 {
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acc += mulFold64(readU64(p, 6*8)^key64_096, readU64(p, 7*8)^key64_104)
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acc += mulFold64(readU64(p, ui(l)-8*8)^key64_112, readU64(p, ui(l)-7*8)^key64_120)
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} // 96
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acc += mulFold64(readU64(p, 4*8)^key64_064, readU64(p, 5*8)^key64_072)
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acc += mulFold64(readU64(p, ui(l)-6*8)^key64_080, readU64(p, ui(l)-5*8)^key64_088)
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} // 64
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acc += mulFold64(readU64(p, 2*8)^key64_032, readU64(p, 3*8)^key64_040)
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acc += mulFold64(readU64(p, ui(l)-4*8)^key64_048, readU64(p, ui(l)-3*8)^key64_056)
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} // 32
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acc += mulFold64(readU64(p, 0*8)^key64_000, readU64(p, 1*8)^key64_008)
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acc += mulFold64(readU64(p, ui(l)-2*8)^key64_016, readU64(p, ui(l)-1*8)^key64_024)
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return xxh3Avalanche(acc)
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case l <= 240:
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acc = u64(l) * prime64_1
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acc += mulFold64(readU64(p, 0*16+0)^key64_000, readU64(p, 0*16+8)^key64_008)
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acc += mulFold64(readU64(p, 1*16+0)^key64_016, readU64(p, 1*16+8)^key64_024)
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acc += mulFold64(readU64(p, 2*16+0)^key64_032, readU64(p, 2*16+8)^key64_040)
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acc += mulFold64(readU64(p, 3*16+0)^key64_048, readU64(p, 3*16+8)^key64_056)
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acc += mulFold64(readU64(p, 4*16+0)^key64_064, readU64(p, 4*16+8)^key64_072)
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acc += mulFold64(readU64(p, 5*16+0)^key64_080, readU64(p, 5*16+8)^key64_088)
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acc += mulFold64(readU64(p, 6*16+0)^key64_096, readU64(p, 6*16+8)^key64_104)
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acc += mulFold64(readU64(p, 7*16+0)^key64_112, readU64(p, 7*16+8)^key64_120)
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// avalanche
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acc = xxh3Avalanche(acc)
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// trailing groups after 128
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top := ui(l) &^ 15
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for i := ui(8 * 16); i < top; i += 16 {
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acc += mulFold64(readU64(p, i+0)^readU64(key, i-125), readU64(p, i+8)^readU64(key, i-117))
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}
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// last 16 bytes
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acc += mulFold64(readU64(p, ui(l)-16)^key64_119, readU64(p, ui(l)-8)^key64_127)
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return xxh3Avalanche(acc)
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default:
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acc = u64(l) * prime64_1
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accs := [8]u64{
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prime32_3, prime64_1, prime64_2, prime64_3,
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prime64_4, prime32_2, prime64_5, prime32_1,
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}
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if hasAVX512 && l >= avx512Switch {
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accumAVX512(&accs, p, key, u64(l))
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} else if hasAVX2 {
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accumAVX2(&accs, p, key, u64(l))
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} else if hasSSE2 {
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accumSSE(&accs, p, key, u64(l))
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} else {
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accumScalar(&accs, p, key, u64(l))
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}
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// merge accs
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acc += mulFold64(accs[0]^key64_011, accs[1]^key64_019)
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acc += mulFold64(accs[2]^key64_027, accs[3]^key64_035)
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acc += mulFold64(accs[4]^key64_043, accs[5]^key64_051)
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acc += mulFold64(accs[6]^key64_059, accs[7]^key64_067)
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return xxh3Avalanche(acc)
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}
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}
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