moby/vendor/golang.org/x/crypto/internal/alias/alias.go
Sebastiaan van Stijn 9d7bd47cb6
vendor: golang.org/x/crypto v0.1.0
The golang.org/x/ projects are now doing tagged releases.

full diff: https://github.com/golang/crypto/compare/3147a52a75dd...v0.1.0

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2022-11-15 13:43:28 +01:00

32 lines
1.1 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.
//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)
}