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| // 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 | |
| } |