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Member "buildah-1.27.2/vendor/golang.org/x/crypto/internal/subtle/aliasing.go" (20 Sep 2022, 1278 Bytes) of package /linux/misc/buildah-1.27.2.tar.gz:


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    1 // Copyright 2018 The Go Authors. All rights reserved.
    2 // Use of this source code is governed by a BSD-style
    3 // license that can be found in the LICENSE file.
    4 
    5 //go:build !purego
    6 // +build !purego
    7 
    8 // Package subtle implements functions that are often useful in cryptographic
    9 // code but require careful thought to use correctly.
   10 package subtle // import "golang.org/x/crypto/internal/subtle"
   11 
   12 import "unsafe"
   13 
   14 // AnyOverlap reports whether x and y share memory at any (not necessarily
   15 // corresponding) index. The memory beyond the slice length is ignored.
   16 func AnyOverlap(x, y []byte) bool {
   17     return len(x) > 0 && len(y) > 0 &&
   18         uintptr(unsafe.Pointer(&x[0])) <= uintptr(unsafe.Pointer(&y[len(y)-1])) &&
   19         uintptr(unsafe.Pointer(&y[0])) <= uintptr(unsafe.Pointer(&x[len(x)-1]))
   20 }
   21 
   22 // InexactOverlap reports whether x and y share memory at any non-corresponding
   23 // index. The memory beyond the slice length is ignored. Note that x and y can
   24 // have different lengths and still not have any inexact overlap.
   25 //
   26 // InexactOverlap can be used to implement the requirements of the crypto/cipher
   27 // AEAD, Block, BlockMode and Stream interfaces.
   28 func InexactOverlap(x, y []byte) bool {
   29     if len(x) == 0 || len(y) == 0 || &x[0] == &y[0] {
   30         return false
   31     }
   32     return AnyOverlap(x, y)
   33 }