/
xxhash_go17.go
161 lines (126 loc) · 3.54 KB
/
xxhash_go17.go
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package xxhash
func u32(in []byte) uint32 {
return uint32(in[0]) | uint32(in[1])<<8 | uint32(in[2])<<16 | uint32(in[3])<<24
}
func u64(in []byte) uint64 {
return uint64(in[0]) | uint64(in[1])<<8 | uint64(in[2])<<16 | uint64(in[3])<<24 | uint64(in[4])<<32 | uint64(in[5])<<40 | uint64(in[6])<<48 | uint64(in[7])<<56
}
// Checksum32S returns the checksum of the input bytes with the specific seed.
func Checksum32S(in []byte, seed uint32) (h uint32) {
var i int
if len(in) > 15 {
var (
v1 = seed + prime32x1 + prime32x2
v2 = seed + prime32x2
v3 = seed + 0
v4 = seed - prime32x1
)
for ; i < len(in)-15; i += 16 {
in := in[i : i+16 : len(in)]
v1 += u32(in[0:4:len(in)]) * prime32x2
v1 = rotl32_13(v1) * prime32x1
v2 += u32(in[4:8:len(in)]) * prime32x2
v2 = rotl32_13(v2) * prime32x1
v3 += u32(in[8:12:len(in)]) * prime32x2
v3 = rotl32_13(v3) * prime32x1
v4 += u32(in[12:16:len(in)]) * prime32x2
v4 = rotl32_13(v4) * prime32x1
}
h = rotl32_1(v1) + rotl32_7(v2) + rotl32_12(v3) + rotl32_18(v4)
} else {
h = seed + prime32x5
}
h += uint32(len(in))
for ; i <= len(in)-4; i += 4 {
in := in[i : i+4 : len(in)]
h += u32(in[0:4:len(in)]) * prime32x3
h = rotl32_17(h) * prime32x4
}
for ; i < len(in); i++ {
h += uint32(in[i]) * prime32x5
h = rotl32_11(h) * prime32x1
}
h ^= h >> 15
h *= prime32x2
h ^= h >> 13
h *= prime32x3
h ^= h >> 16
return
}
func (xx *XXHash32) Write(in []byte) (n int, err error) {
i, ml := 0, int(xx.memIdx)
n = len(in)
xx.ln += int32(n)
if d := 16 - ml; ml > 0 && ml+len(in) > 16 {
xx.memIdx += int32(copy(xx.mem[xx.memIdx:], in[:d]))
ml, in = 16, in[d:len(in):len(in)]
} else if ml+len(in) < 16 {
xx.memIdx += int32(copy(xx.mem[xx.memIdx:], in))
return
}
if ml > 0 {
i += 16 - ml
xx.memIdx += int32(copy(xx.mem[xx.memIdx:len(xx.mem):len(xx.mem)], in))
in := xx.mem[:16:len(xx.mem)]
xx.v1 += u32(in[0:4:len(in)]) * prime32x2
xx.v1 = rotl32_13(xx.v1) * prime32x1
xx.v2 += u32(in[4:8:len(in)]) * prime32x2
xx.v2 = rotl32_13(xx.v2) * prime32x1
xx.v3 += u32(in[8:12:len(in)]) * prime32x2
xx.v3 = rotl32_13(xx.v3) * prime32x1
xx.v4 += u32(in[12:16:len(in)]) * prime32x2
xx.v4 = rotl32_13(xx.v4) * prime32x1
xx.memIdx = 0
}
for ; i <= len(in)-16; i += 16 {
in := in[i : i+16 : len(in)]
xx.v1 += u32(in[0:4:len(in)]) * prime32x2
xx.v1 = rotl32_13(xx.v1) * prime32x1
xx.v2 += u32(in[4:8:len(in)]) * prime32x2
xx.v2 = rotl32_13(xx.v2) * prime32x1
xx.v3 += u32(in[8:12:len(in)]) * prime32x2
xx.v3 = rotl32_13(xx.v3) * prime32x1
xx.v4 += u32(in[12:16:len(in)]) * prime32x2
xx.v4 = rotl32_13(xx.v4) * prime32x1
}
if len(in)-i != 0 {
xx.memIdx += int32(copy(xx.mem[xx.memIdx:], in[i:len(in):len(in)]))
}
return
}
func (xx *XXHash32) Sum32() (h uint32) {
var i int32
if xx.ln > 15 {
h = rotl32_1(xx.v1) + rotl32_7(xx.v2) + rotl32_12(xx.v3) + rotl32_18(xx.v4)
} else {
h = xx.seed + prime32x5
}
h += uint32(xx.ln)
if xx.memIdx > 0 {
for ; i < xx.memIdx-3; i += 4 {
in := xx.mem[i : i+4 : len(xx.mem)]
h += u32(in[0:4:len(in)]) * prime32x3
h = rotl32_17(h) * prime32x4
}
for ; i < xx.memIdx; i++ {
h += uint32(xx.mem[i]) * prime32x5
h = rotl32_11(h) * prime32x1
}
}
h ^= h >> 15
h *= prime32x2
h ^= h >> 13
h *= prime32x3
h ^= h >> 16
return
}
// Checksum64S returns the 64bit xxhash checksum for a single input
func Checksum64S(in []byte, seed uint64) uint64 {
if len(in) == 0 && seed == 0 {
return 0xef46db3751d8e999
}
if len(in) > 31 {
return checksum64(in, seed)
}
return checksum64Short(in, seed)
}