1 files changed, 62 insertions, 0 deletions
diff --git a/vendor/github.com/pion/stun/xor.go b/vendor/github.com/pion/stun/xor.go
new file mode 100644
index 0000000..34365eb
--- /dev/null
+++ b/vendor/github.com/pion/stun/xor.go
@@ -0,0 +1,62 @@
+// Copyright 2013 The Go 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 stun
+
+import (
+	"runtime"
+	"unsafe"
+)
+
+// #nosec
+const wordSize = int(unsafe.Sizeof(uintptr(0)))
+
+var supportsUnaligned = runtime.GOARCH == "386" || runtime.GOARCH == "amd64"
+
+// fastXORBytes xors in bulk. It only works on architectures that
+// support unaligned read/writes.
+//
+// #nosec
+func fastXORBytes(dst, a, b []byte) int {
+	n := len(a)
+	if len(b) < n {
+		n = len(b)
+	}
+
+	w := n / wordSize
+	if w > 0 {
+		dw := *(*[]uintptr)(unsafe.Pointer(&dst))
+		aw := *(*[]uintptr)(unsafe.Pointer(&a))
+		bw := *(*[]uintptr)(unsafe.Pointer(&b))
+		for i := 0; i < w; i++ {
+			dw[i] = aw[i] ^ bw[i]
+		}
+	}
+
+	for i := n - n%wordSize; i < n; i++ {
+		dst[i] = a[i] ^ b[i]
+	}
+
+	return n
+}
+
+func safeXORBytes(dst, a, b []byte) int {
+	n := len(a)
+	if len(b) < n {
+		n = len(b)
+	}
+	for i := 0; i < n; i++ {
+		dst[i] = a[i] ^ b[i]
+	}
+	return n
+}
+
+// xorBytes xors the bytes in a and b. The destination is assumed to have enough
+// space. Returns the number of bytes xor'd.
+func xorBytes(dst, a, b []byte) int {
+	if supportsUnaligned {
+		return fastXORBytes(dst, a, b)
+	}
+	return safeXORBytes(dst, a, b)
+}