diff options
Diffstat (limited to 'vendor/github.com/cespare/xxhash/v2/xxhash_other.go')
-rw-r--r-- | vendor/github.com/cespare/xxhash/v2/xxhash_other.go | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/vendor/github.com/cespare/xxhash/v2/xxhash_other.go b/vendor/github.com/cespare/xxhash/v2/xxhash_other.go new file mode 100644 index 000000000..26df13bba --- /dev/null +++ b/vendor/github.com/cespare/xxhash/v2/xxhash_other.go @@ -0,0 +1,76 @@ +//go:build (!amd64 && !arm64) || appengine || !gc || purego +// +build !amd64,!arm64 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 := primes[0] + prime2 + v2 := prime2 + v3 := uint64(0) + v4 := -primes[0] + 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) + + for ; len(b) >= 8; b = b[8:] { + k1 := round(0, u64(b[:8])) + h ^= k1 + h = rol27(h)*prime1 + prime4 + } + if len(b) >= 4 { + h ^= uint64(u32(b[:4])) * prime1 + h = rol23(h)*prime2 + prime3 + b = b[4:] + } + for ; len(b) > 0; b = b[1:] { + h ^= uint64(b[0]) * 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) +} |