30 lines
1.2 KiB
V
30 lines
1.2 KiB
V
// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
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// Use of this source code is governed by an MIT license
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// that can be found in the LICENSE file.
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// Package subtle implements functions that are often useful in cryptographic
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// code but require careful thought to use correctly.
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module subtle
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// NOTE: require unsafe in future
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// any_overlap reports whether x and y share memory at any (not necessarily
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// corresponding) index. The memory beyond the slice length is ignored.
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pub fn any_overlap(x []byte, y []byte) bool {
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// NOTE: Remember to come back to this (joe-c)
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return x.len > 0 && y.len > 0 && // &x.data[0] <= &y.data[y.len-1] &&
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// &y.data[0] <= &x.data[x.len-1]
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unsafe {&x[0] <= &y[y.len - 1] && &y[0] <= &x[x.len - 1]}
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}
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// inexact_overlap reports whether x and y share memory at any non-corresponding
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// index. The memory beyond the slice length is ignored. Note that x and y can
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// have different lengths and still not have any inexact overlap.
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//
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// inexact_overlap can be used to implement the requirements of the crypto/cipher
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// AEAD, Block, BlockMode and Stream interfaces.
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pub fn inexact_overlap(x []byte, y []byte) bool {
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if x.len == 0 || y.len == 0 || unsafe {&x[0] == &y[0]} {
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return false
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}
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return any_overlap(x, y)
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}
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