diff options
Diffstat (limited to 'vendor/github.com/gorilla/websocket/mask.go')
-rw-r--r-- | vendor/github.com/gorilla/websocket/mask.go | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/vendor/github.com/gorilla/websocket/mask.go b/vendor/github.com/gorilla/websocket/mask.go new file mode 100644 index 000000000..6758a2cb7 --- /dev/null +++ b/vendor/github.com/gorilla/websocket/mask.go @@ -0,0 +1,61 @@ +// 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. + +package websocket + +import ( + "math/rand" + "unsafe" +) + +const wordSize = int(unsafe.Sizeof(uintptr(0))) + +func newMaskKey() [4]byte { + n := rand.Uint32() + return [4]byte{byte(n), byte(n >> 8), byte(n >> 16), byte(n >> 24)} +} + +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 +} |