34 lines
983 B
TypeScript
34 lines
983 B
TypeScript
// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
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import { assert } from "../_util/asserts.ts";
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/** Compare to array buffers or data views in a way that timing based attacks
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* cannot gain information about the platform. */
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export function timingSafeEqual(
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a: ArrayBufferView | ArrayBufferLike | DataView,
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b: ArrayBufferView | ArrayBufferLike | DataView,
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): boolean {
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if (a.byteLength !== b.byteLength) {
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return false;
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}
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if (!(a instanceof DataView)) {
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a = ArrayBuffer.isView(a)
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? new DataView(a.buffer, a.byteOffset, a.byteLength)
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: new DataView(a);
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}
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if (!(b instanceof DataView)) {
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b = ArrayBuffer.isView(b)
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? new DataView(b.buffer, b.byteOffset, b.byteLength)
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: new DataView(b);
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}
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assert(a instanceof DataView);
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assert(b instanceof DataView);
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const length = a.byteLength;
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let out = 0;
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let i = -1;
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while (++i < length) {
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out |= a.getUint8(i) ^ b.getUint8(i);
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}
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return out === 0;
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}
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