diff options
Diffstat (limited to 'src/vendor/golang.org/x/crypto/internal/alias/alias.go')
-rw-r--r-- | src/vendor/golang.org/x/crypto/internal/alias/alias.go | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/src/vendor/golang.org/x/crypto/internal/alias/alias.go b/src/vendor/golang.org/x/crypto/internal/alias/alias.go new file mode 100644 index 0000000..69c17f8 --- /dev/null +++ b/src/vendor/golang.org/x/crypto/internal/alias/alias.go @@ -0,0 +1,32 @@ +// Copyright 2018 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. + +//go:build !purego +// +build !purego + +// Package alias implements memory aliasing tests. +package alias + +import "unsafe" + +// AnyOverlap reports whether x and y share memory at any (not necessarily +// corresponding) index. The memory beyond the slice length is ignored. +func AnyOverlap(x, y []byte) bool { + return len(x) > 0 && len(y) > 0 && + uintptr(unsafe.Pointer(&x[0])) <= uintptr(unsafe.Pointer(&y[len(y)-1])) && + uintptr(unsafe.Pointer(&y[0])) <= uintptr(unsafe.Pointer(&x[len(x)-1])) +} + +// InexactOverlap reports whether x and y share memory at any non-corresponding +// index. The memory beyond the slice length is ignored. Note that x and y can +// have different lengths and still not have any inexact overlap. +// +// InexactOverlap can be used to implement the requirements of the crypto/cipher +// AEAD, Block, BlockMode and Stream interfaces. +func InexactOverlap(x, y []byte) bool { + if len(x) == 0 || len(y) == 0 || &x[0] == &y[0] { + return false + } + return AnyOverlap(x, y) +} |