Tamir Duberstein
be400aefbc
appengine is obsolete and superseded by purego, and gc is a more precise tag for files that use gc-syntax assembly. Change-Id: I716f59de772ebeee4adf4d2a432edf300122cef0 Reviewed-on: https://go-review.googlesource.com/c/crypto/+/269920 Trust: Ian Lance Taylor <iant@golang.org> Run-TryBot: Filippo Valsorda <filippo@golang.org> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Filippo Valsorda <filippo@golang.org>
33 lines
1.2 KiB
Go
33 lines
1.2 KiB
Go
// 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.
|
|
|
|
// +build !purego
|
|
|
|
// Package subtle implements functions that are often useful in cryptographic
|
|
// code but require careful thought to use correctly.
|
|
package subtle // import "golang.org/x/crypto/internal/subtle"
|
|
|
|
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)
|
|
}
|