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https://github.com/denoland/std.git
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104 lines
2.6 KiB
TypeScript
104 lines
2.6 KiB
TypeScript
// Copyright 2009 The Go Authors. All rights reserved.
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// https://github.com/golang/go/blob/master/LICENSE
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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
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// This module is browser compatible.
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/**
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* Port of the Go
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* {@link https://github.com/golang/go/blob/go1.12.5/src/encoding/hex/hex.go | encoding/hex}
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* library.
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*
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* This module is browser compatible.
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*
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* ```ts
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* import {
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* decodeHex,
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* encodeHex,
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* } from "@std/encoding/hex";
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*
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* const encoded = encodeHex("abc"); // "616263"
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*
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* decodeHex(encoded); // Uint8Array(3) [ 97, 98, 99 ]
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* ```
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*
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* @module
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*/
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import { validateBinaryLike } from "./_util.ts";
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const hexTable = new TextEncoder().encode("0123456789abcdef");
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const textEncoder = new TextEncoder();
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const textDecoder = new TextDecoder();
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function errInvalidByte(byte: number) {
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return new TypeError(`Invalid byte '${String.fromCharCode(byte)}'`);
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}
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function errLength() {
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return new RangeError("Odd length hex string");
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}
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/** Converts a hex character into its value. */
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function fromHexChar(byte: number): number {
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// '0' <= byte && byte <= '9'
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if (48 <= byte && byte <= 57) return byte - 48;
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// 'a' <= byte && byte <= 'f'
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if (97 <= byte && byte <= 102) return byte - 97 + 10;
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// 'A' <= byte && byte <= 'F'
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if (65 <= byte && byte <= 70) return byte - 65 + 10;
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throw errInvalidByte(byte);
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}
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/**
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* Converts data into a hex-encoded string.
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*
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* @example
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* ```ts
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* import { encodeHex } from "@std/encoding/hex";
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*
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* encodeHex("abc"); // "616263"
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* ```
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*/
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export function encodeHex(src: string | Uint8Array | ArrayBuffer): string {
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const u8 = validateBinaryLike(src);
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const dst = new Uint8Array(u8.length * 2);
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for (let i = 0; i < dst.length; i++) {
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const v = u8[i]!;
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dst[i * 2] = hexTable[v >> 4]!;
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dst[i * 2 + 1] = hexTable[v & 0x0f]!;
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}
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return textDecoder.decode(dst);
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}
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/**
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* Decodes the given hex-encoded string. If the input is malformed, an error is
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* thrown.
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*
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* @example
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* ```ts
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* import { decodeHex } from "@std/encoding/hex";
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*
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* decodeHex("616263"); // Uint8Array(3) [ 97, 98, 99 ]
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* ```
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*/
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export function decodeHex(src: string): Uint8Array {
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const u8 = textEncoder.encode(src);
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const dst = new Uint8Array(u8.length / 2);
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for (let i = 0; i < dst.length; i++) {
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const a = fromHexChar(u8[i * 2]!);
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const b = fromHexChar(u8[i * 2 + 1]!);
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dst[i] = (a << 4) | b;
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}
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if (u8.length % 2 === 1) {
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// Check for invalid char before reporting bad length,
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// since the invalid char (if present) is an earlier problem.
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fromHexChar(u8[dst.length * 2]!);
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throw errLength();
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}
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return dst;
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}
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