55 lines
1.1 KiB
Go
55 lines
1.1 KiB
Go
|
// Copyright 2016 The Gorilla WebSocket Authors. All rights reserved. Use of
|
||
|
|
// this source code is governed by a BSD-style license that can be found in the
|
||
|
|
// LICENSE file.
|
||
|
|
|
||
|
|
// +build !appengine
|
||
|
|
|
||
|
|
package websocket
|
||
|
|
|
||
|
|
import "unsafe"
|
||
|
|
|
||
|
|
const wordSize = int(unsafe.Sizeof(uintptr(0)))
|
||
|
|
|
||
|
|
func maskBytes(key [4]byte, pos int, b []byte) int {
|
||
|
|
// Mask one byte at a time for small buffers.
|
||
|
|
if len(b) < 2*wordSize {
|
||
|
|
for i := range b {
|
||
|
|
b[i] ^= key[pos&3]
|
||
|
|
pos++
|
||
|
|
}
|
||
|
|
return pos & 3
|
||
|
|
}
|
||
|
|
|
||
|
|
// Mask one byte at a time to word boundary.
|
||
|
|
if n := int(uintptr(unsafe.Pointer(&b[0]))) % wordSize; n != 0 {
|
||
|
|
n = wordSize - n
|
||
|
|
for i := range b[:n] {
|
||
|
|
b[i] ^= key[pos&3]
|
||
|
|
pos++
|
||
|
|
}
|
||
|
|
b = b[n:]
|
||
|
|
}
|
||
|
|
|
||
|
|
// Create aligned word size key.
|
||
|
|
var k [wordSize]byte
|
||
|
|
for i := range k {
|
||
|
|
k[i] = key[(pos+i)&3]
|
||
|
|
}
|
||
|
|
kw := *(*uintptr)(unsafe.Pointer(&k))
|
||
|
|
|
||
|
|
// Mask one word at a time.
|
||
|
|
n := (len(b) / wordSize) * wordSize
|
||
|
|
for i := 0; i < n; i += wordSize {
|
||
|
|
*(*uintptr)(unsafe.Pointer(uintptr(unsafe.Pointer(&b[0])) + uintptr(i))) ^= kw
|
||
|
|
}
|
||
|
|
|
||
|
|
// Mask one byte at a time for remaining bytes.
|
||
|
|
b = b[n:]
|
||
|
|
for i := range b {
|
||
|
|
b[i] ^= key[pos&3]
|
||
|
|
pos++
|
||
|
|
}
|
||
|
|
|
||
|
|
return pos & 3
|
||
|
|
}
|