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Super fast XOR #77

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Apr 29, 2019
Merged

Super fast XOR #77

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1 change: 1 addition & 0 deletions websocket_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -776,6 +776,7 @@ func benchConn(b *testing.B, echo, stream bool, size int) {
func BenchmarkConn(b *testing.B) {
sizes := []int{
2,
16,
32,
512,
4096,
Expand Down
84 changes: 82 additions & 2 deletions xor.go
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Original file line number Diff line number Diff line change
Expand Up @@ -13,10 +13,10 @@ import (
// to be used for masking in the key. This is so that
// unmasking can be performed without the entire frame.
func fastXOR(key [4]byte, keyPos int, b []byte) int {
// If the payload is greater than 16 bytes, then it's worth
// If the payload is greater than or equal to 16 bytes, then it's worth
// masking 8 bytes at a time.
// Optimization from https://github.com/golang/go/issues/31586#issuecomment-485530859
if len(b) > 16 {
if len(b) >= 16 {
// We first create a key that is 8 bytes long
// and is aligned on the position correctly.
var alignedKey [8]byte
Expand All @@ -25,6 +25,86 @@ func fastXOR(key [4]byte, keyPos int, b []byte) int {
}
k := binary.LittleEndian.Uint64(alignedKey[:])

// Then we xor until b is less than 128 bytes.
for len(b) >= 128 {
v := binary.LittleEndian.Uint64(b)
binary.LittleEndian.PutUint64(b, v^k)
v = binary.LittleEndian.Uint64(b[8:])
binary.LittleEndian.PutUint64(b[8:], v^k)
v = binary.LittleEndian.Uint64(b[16:])
binary.LittleEndian.PutUint64(b[16:], v^k)
v = binary.LittleEndian.Uint64(b[24:])
binary.LittleEndian.PutUint64(b[24:], v^k)
v = binary.LittleEndian.Uint64(b[32:])
binary.LittleEndian.PutUint64(b[32:], v^k)
v = binary.LittleEndian.Uint64(b[40:])
binary.LittleEndian.PutUint64(b[40:], v^k)
v = binary.LittleEndian.Uint64(b[48:])
binary.LittleEndian.PutUint64(b[48:], v^k)
v = binary.LittleEndian.Uint64(b[56:])
binary.LittleEndian.PutUint64(b[56:], v^k)
v = binary.LittleEndian.Uint64(b[64:])
binary.LittleEndian.PutUint64(b[64:], v^k)
v = binary.LittleEndian.Uint64(b[72:])
binary.LittleEndian.PutUint64(b[72:], v^k)
v = binary.LittleEndian.Uint64(b[80:])
binary.LittleEndian.PutUint64(b[80:], v^k)
v = binary.LittleEndian.Uint64(b[88:])
binary.LittleEndian.PutUint64(b[88:], v^k)
v = binary.LittleEndian.Uint64(b[96:])
binary.LittleEndian.PutUint64(b[96:], v^k)
v = binary.LittleEndian.Uint64(b[104:])
binary.LittleEndian.PutUint64(b[104:], v^k)
v = binary.LittleEndian.Uint64(b[112:])
binary.LittleEndian.PutUint64(b[112:], v^k)
v = binary.LittleEndian.Uint64(b[120:])
binary.LittleEndian.PutUint64(b[120:], v^k)
b = b[128:]
}

// Then we xor until b is less than 64 bytes.
for len(b) >= 64 {
v := binary.LittleEndian.Uint64(b)
binary.LittleEndian.PutUint64(b, v^k)
v = binary.LittleEndian.Uint64(b[8:])
binary.LittleEndian.PutUint64(b[8:], v^k)
v = binary.LittleEndian.Uint64(b[16:])
binary.LittleEndian.PutUint64(b[16:], v^k)
v = binary.LittleEndian.Uint64(b[24:])
binary.LittleEndian.PutUint64(b[24:], v^k)
v = binary.LittleEndian.Uint64(b[32:])
binary.LittleEndian.PutUint64(b[32:], v^k)
v = binary.LittleEndian.Uint64(b[40:])
binary.LittleEndian.PutUint64(b[40:], v^k)
v = binary.LittleEndian.Uint64(b[48:])
binary.LittleEndian.PutUint64(b[48:], v^k)
v = binary.LittleEndian.Uint64(b[56:])
binary.LittleEndian.PutUint64(b[56:], v^k)
b = b[64:]
}

// Then we xor until b is less than 32 bytes.
for len(b) >= 32 {
v := binary.LittleEndian.Uint64(b)
binary.LittleEndian.PutUint64(b, v^k)
v = binary.LittleEndian.Uint64(b[8:])
binary.LittleEndian.PutUint64(b[8:], v^k)
v = binary.LittleEndian.Uint64(b[16:])
binary.LittleEndian.PutUint64(b[16:], v^k)
v = binary.LittleEndian.Uint64(b[24:])
binary.LittleEndian.PutUint64(b[24:], v^k)
b = b[32:]
}

// Then we xor until b is less than 16 bytes.
for len(b) >= 16 {
v := binary.LittleEndian.Uint64(b)
binary.LittleEndian.PutUint64(b, v^k)
v = binary.LittleEndian.Uint64(b[8:])
binary.LittleEndian.PutUint64(b[8:], v^k)
b = b[16:]
}

// Then we xor until b is less than 8 bytes.
for len(b) >= 8 {
v := binary.LittleEndian.Uint64(b)
Expand Down
1 change: 1 addition & 0 deletions xor_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,7 @@ func basixXOR(maskKey [4]byte, pos int, b []byte) int {
func BenchmarkXOR(b *testing.B) {
sizes := []int{
2,
16,
32,
512,
4096,
Expand Down