github.com/evanw/esbuild@v0.21.4/internal/xxhash/xxhash_other.go (about) 1 package xxhash 2 3 // Sum64 computes the 64-bit xxHash digest of b. 4 func Sum64(b []byte) uint64 { 5 // A simpler version would be 6 // d := New() 7 // d.Write(b) 8 // return d.Sum64() 9 // but this is faster, particularly for small inputs. 10 11 n := len(b) 12 var h uint64 13 14 if n >= 32 { 15 v1 := prime1v + prime2 16 v2 := prime2 17 v3 := uint64(0) 18 v4 := -prime1v 19 for len(b) >= 32 { 20 v1 = round(v1, u64(b[0:8:len(b)])) 21 v2 = round(v2, u64(b[8:16:len(b)])) 22 v3 = round(v3, u64(b[16:24:len(b)])) 23 v4 = round(v4, u64(b[24:32:len(b)])) 24 b = b[32:len(b):len(b)] 25 } 26 h = rol1(v1) + rol7(v2) + rol12(v3) + rol18(v4) 27 h = mergeRound(h, v1) 28 h = mergeRound(h, v2) 29 h = mergeRound(h, v3) 30 h = mergeRound(h, v4) 31 } else { 32 h = prime5 33 } 34 35 h += uint64(n) 36 37 i, end := 0, len(b) 38 for ; i+8 <= end; i += 8 { 39 k1 := round(0, u64(b[i:i+8:len(b)])) 40 h ^= k1 41 h = rol27(h)*prime1 + prime4 42 } 43 if i+4 <= end { 44 h ^= uint64(u32(b[i:i+4:len(b)])) * prime1 45 h = rol23(h)*prime2 + prime3 46 i += 4 47 } 48 for ; i < end; i++ { 49 h ^= uint64(b[i]) * prime5 50 h = rol11(h) * prime1 51 } 52 53 h ^= h >> 33 54 h *= prime2 55 h ^= h >> 29 56 h *= prime3 57 h ^= h >> 32 58 59 return h 60 } 61 62 func writeBlocks(d *Digest, b []byte) int { 63 v1, v2, v3, v4 := d.v1, d.v2, d.v3, d.v4 64 n := len(b) 65 for len(b) >= 32 { 66 v1 = round(v1, u64(b[0:8:len(b)])) 67 v2 = round(v2, u64(b[8:16:len(b)])) 68 v3 = round(v3, u64(b[16:24:len(b)])) 69 v4 = round(v4, u64(b[24:32:len(b)])) 70 b = b[32:len(b):len(b)] 71 } 72 d.v1, d.v2, d.v3, d.v4 = v1, v2, v3, v4 73 return n - len(b) 74 }