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std/encoding/hex.ts

Deno standard library
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// Copyright 2009 The Go Authors. All rights reserved.// https://github.com/golang/go/blob/master/LICENSE// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** Port of the Go * [encoding/hex](https://github.com/golang/go/blob/go1.12.5/src/encoding/hex/hex.go) * library. * * This module is browser compatible. * * @example * ```ts * import { * decode, * encode, * } from "https://deno.land/std@$STD_VERSION/encoding/hex.ts"; * * const binary = new TextEncoder().encode("abc"); * const encoded = encode(binary); * console.log(encoded); * // => Uint8Array(6) [ 54, 49, 54, 50, 54, 51 ] * * console.log(decode(encoded)); * // => Uint8Array(3) [ 97, 98, 99 ] * ``` * * @module */
const hexTable = new TextEncoder().encode("0123456789abcdef");
function errInvalidByte(byte: number) { return new TypeError(`Invalid byte '${String.fromCharCode(byte)}'`);}
function errLength() { return new RangeError("Odd length hex string");}
/** Converts a hex character into its value. */function fromHexChar(byte: number): number { // '0' <= byte && byte <= '9' if (48 <= byte && byte <= 57) return byte - 48; // 'a' <= byte && byte <= 'f' if (97 <= byte && byte <= 102) return byte - 97 + 10; // 'A' <= byte && byte <= 'F' if (65 <= byte && byte <= 70) return byte - 65 + 10;
throw errInvalidByte(byte);}
/** Encodes `src` into `src.length * 2` bytes. */export function encode(src: Uint8Array): Uint8Array { const dst = new Uint8Array(src.length * 2); for (let i = 0; i < dst.length; i++) { const v = src[i]; dst[i * 2] = hexTable[v >> 4]; dst[i * 2 + 1] = hexTable[v & 0x0f]; } return dst;}
/** * Decodes `src` into `src.length / 2` bytes. * If the input is malformed, an error will be thrown. */export function decode(src: Uint8Array): Uint8Array { const dst = new Uint8Array(src.length / 2); for (let i = 0; i < dst.length; i++) { const a = fromHexChar(src[i * 2]); const b = fromHexChar(src[i * 2 + 1]); dst[i] = (a << 4) | b; }
if (src.length % 2 == 1) { // Check for invalid char before reporting bad length, // since the invalid char (if present) is an earlier problem. fromHexChar(src[dst.length * 2]); throw errLength(); }
return dst;}