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Member "dnscrypt-proxy-2.0.25/vendor/golang.org/x/crypto/internal/subtle/aliasing.go" (3 Jun 2019, 1262 Bytes) of package /linux/misc/dns/dnscrypt-proxy-2.0.25.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 // +build !appengine
    6 
    7 // Package subtle implements functions that are often useful in cryptographic
    8 // code but require careful thought to use correctly.
    9 package subtle // import "golang.org/x/crypto/internal/subtle"
   10 
   11 import "unsafe"
   12 
   13 // AnyOverlap reports whether x and y share memory at any (not necessarily
   14 // corresponding) index. The memory beyond the slice length is ignored.
   15 func AnyOverlap(x, y []byte) bool {
   16     return len(x) > 0 && len(y) > 0 &&
   17         uintptr(unsafe.Pointer(&x[0])) <= uintptr(unsafe.Pointer(&y[len(y)-1])) &&
   18         uintptr(unsafe.Pointer(&y[0])) <= uintptr(unsafe.Pointer(&x[len(x)-1]))
   19 }
   20 
   21 // InexactOverlap reports whether x and y share memory at any non-corresponding
   22 // index. The memory beyond the slice length is ignored. Note that x and y can
   23 // have different lengths and still not have any inexact overlap.
   24 //
   25 // InexactOverlap can be used to implement the requirements of the crypto/cipher
   26 // AEAD, Block, BlockMode and Stream interfaces.
   27 func InexactOverlap(x, y []byte) bool {
   28     if len(x) == 0 || len(y) == 0 || &x[0] == &y[0] {
   29         return false
   30     }
   31     return AnyOverlap(x, y)
   32 }