diff options
Diffstat (limited to 'vendor/github.com/cespare/xxhash/xxhash.go')
| -rw-r--r-- | vendor/github.com/cespare/xxhash/xxhash.go | 168 |
1 files changed, 0 insertions, 168 deletions
diff --git a/vendor/github.com/cespare/xxhash/xxhash.go b/vendor/github.com/cespare/xxhash/xxhash.go deleted file mode 100644 index f896bd28f..000000000 --- a/vendor/github.com/cespare/xxhash/xxhash.go +++ /dev/null @@ -1,168 +0,0 @@ -// Package xxhash implements the 64-bit variant of xxHash (XXH64) as described -// at http://cyan4973.github.io/xxHash/. -package xxhash - -import ( - "encoding/binary" - "hash" -) - -const ( - prime1 uint64 = 11400714785074694791 - prime2 uint64 = 14029467366897019727 - prime3 uint64 = 1609587929392839161 - prime4 uint64 = 9650029242287828579 - prime5 uint64 = 2870177450012600261 -) - -// NOTE(caleb): I'm using both consts and vars of the primes. Using consts where -// possible in the Go code is worth a small (but measurable) performance boost -// by avoiding some MOVQs. Vars are needed for the asm and also are useful for -// convenience in the Go code in a few places where we need to intentionally -// avoid constant arithmetic (e.g., v1 := prime1 + prime2 fails because the -// result overflows a uint64). -var ( - prime1v = prime1 - prime2v = prime2 - prime3v = prime3 - prime4v = prime4 - prime5v = prime5 -) - -type xxh struct { - v1 uint64 - v2 uint64 - v3 uint64 - v4 uint64 - total int - mem [32]byte - n int // how much of mem is used -} - -// New creates a new hash.Hash64 that implements the 64-bit xxHash algorithm. -func New() hash.Hash64 { - var x xxh - x.Reset() - return &x -} - -func (x *xxh) Reset() { - x.n = 0 - x.total = 0 - x.v1 = prime1v + prime2 - x.v2 = prime2 - x.v3 = 0 - x.v4 = -prime1v -} - -func (x *xxh) Size() int { return 8 } -func (x *xxh) BlockSize() int { return 32 } - -// Write adds more data to x. It always returns len(b), nil. -func (x *xxh) Write(b []byte) (n int, err error) { - n = len(b) - x.total += len(b) - - if x.n+len(b) < 32 { - // This new data doesn't even fill the current block. - copy(x.mem[x.n:], b) - x.n += len(b) - return - } - - if x.n > 0 { - // Finish off the partial block. - copy(x.mem[x.n:], b) - x.v1 = round(x.v1, u64(x.mem[0:8])) - x.v2 = round(x.v2, u64(x.mem[8:16])) - x.v3 = round(x.v3, u64(x.mem[16:24])) - x.v4 = round(x.v4, u64(x.mem[24:32])) - b = b[32-x.n:] - x.n = 0 - } - - if len(b) >= 32 { - // One or more full blocks left. - b = writeBlocks(x, b) - } - - // Store any remaining partial block. - copy(x.mem[:], b) - x.n = len(b) - - return -} - -func (x *xxh) Sum(b []byte) []byte { - s := x.Sum64() - return append( - b, - byte(s>>56), - byte(s>>48), - byte(s>>40), - byte(s>>32), - byte(s>>24), - byte(s>>16), - byte(s>>8), - byte(s), - ) -} - -func (x *xxh) Sum64() uint64 { - var h uint64 - - if x.total >= 32 { - v1, v2, v3, v4 := x.v1, x.v2, x.v3, x.v4 - 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 = x.v3 + prime5 - } - - h += uint64(x.total) - - i, end := 0, x.n - for ; i+8 <= end; i += 8 { - k1 := round(0, u64(x.mem[i:i+8])) - h ^= k1 - h = rol27(h)*prime1 + prime4 - } - if i+4 <= end { - h ^= uint64(u32(x.mem[i:i+4])) * prime1 - h = rol23(h)*prime2 + prime3 - i += 4 - } - for i < end { - h ^= uint64(x.mem[i]) * prime5 - h = rol11(h) * prime1 - i++ - } - - h ^= h >> 33 - h *= prime2 - h ^= h >> 29 - h *= prime3 - h ^= h >> 32 - - return h -} - -func u64(b []byte) uint64 { return binary.LittleEndian.Uint64(b) } -func u32(b []byte) uint32 { return binary.LittleEndian.Uint32(b) } - -func round(acc, input uint64) uint64 { - acc += input * prime2 - acc = rol31(acc) - acc *= prime1 - return acc -} - -func mergeRound(acc, val uint64) uint64 { - val = round(0, val) - acc ^= val - acc = acc*prime1 + prime4 - return acc -} |
