mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-11-25 15:50:20 +00:00
77 lines
1.5 KiB
Go
77 lines
1.5 KiB
Go
// +build !amd64 appengine !gc purego
|
|
|
|
package xxhash
|
|
|
|
// Sum64 computes the 64-bit xxHash digest of b.
|
|
func Sum64(b []byte) uint64 {
|
|
// A simpler version would be
|
|
// d := New()
|
|
// d.Write(b)
|
|
// return d.Sum64()
|
|
// but this is faster, particularly for small inputs.
|
|
|
|
n := len(b)
|
|
var h uint64
|
|
|
|
if n >= 32 {
|
|
v1 := prime1v + prime2
|
|
v2 := prime2
|
|
v3 := uint64(0)
|
|
v4 := -prime1v
|
|
for len(b) >= 32 {
|
|
v1 = round(v1, u64(b[0:8:len(b)]))
|
|
v2 = round(v2, u64(b[8:16:len(b)]))
|
|
v3 = round(v3, u64(b[16:24:len(b)]))
|
|
v4 = round(v4, u64(b[24:32:len(b)]))
|
|
b = b[32:len(b):len(b)]
|
|
}
|
|
h = rol1(v1) + rol7(v2) + rol12(v3) + rol18(v4)
|
|
h = mergeRound(h, v1)
|
|
h = mergeRound(h, v2)
|
|
h = mergeRound(h, v3)
|
|
h = mergeRound(h, v4)
|
|
} else {
|
|
h = prime5
|
|
}
|
|
|
|
h += uint64(n)
|
|
|
|
i, end := 0, len(b)
|
|
for ; i+8 <= end; i += 8 {
|
|
k1 := round(0, u64(b[i:i+8:len(b)]))
|
|
h ^= k1
|
|
h = rol27(h)*prime1 + prime4
|
|
}
|
|
if i+4 <= end {
|
|
h ^= uint64(u32(b[i:i+4:len(b)])) * prime1
|
|
h = rol23(h)*prime2 + prime3
|
|
i += 4
|
|
}
|
|
for ; i < end; i++ {
|
|
h ^= uint64(b[i]) * prime5
|
|
h = rol11(h) * prime1
|
|
}
|
|
|
|
h ^= h >> 33
|
|
h *= prime2
|
|
h ^= h >> 29
|
|
h *= prime3
|
|
h ^= h >> 32
|
|
|
|
return h
|
|
}
|
|
|
|
func writeBlocks(d *Digest, b []byte) int {
|
|
v1, v2, v3, v4 := d.v1, d.v2, d.v3, d.v4
|
|
n := len(b)
|
|
for len(b) >= 32 {
|
|
v1 = round(v1, u64(b[0:8:len(b)]))
|
|
v2 = round(v2, u64(b[8:16:len(b)]))
|
|
v3 = round(v3, u64(b[16:24:len(b)]))
|
|
v4 = round(v4, u64(b[24:32:len(b)]))
|
|
b = b[32:len(b):len(b)]
|
|
}
|
|
d.v1, d.v2, d.v3, d.v4 = v1, v2, v3, v4
|
|
return n - len(b)
|
|
}
|