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std/encoding/base64.ts

Deno standard library
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// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
const base64abc = [ "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "+", "/",];
/** * CREDIT: https://gist.github.com/enepomnyaschih/72c423f727d395eeaa09697058238727 * Encodes a given Uint8Array, ArrayBuffer or string into RFC4648 base64 representation * @param data */export function encode(data: ArrayBuffer | string): string { const uint8 = typeof data === "string" ? new TextEncoder().encode(data) : data instanceof Uint8Array ? data : new Uint8Array(data); let result = "", i; const l = uint8.length; for (i = 2; i < l; i += 3) { result += base64abc[uint8[i - 2] >> 2]; result += base64abc[((uint8[i - 2] & 0x03) << 4) | (uint8[i - 1] >> 4)]; result += base64abc[((uint8[i - 1] & 0x0f) << 2) | (uint8[i] >> 6)]; result += base64abc[uint8[i] & 0x3f]; } if (i === l + 1) { // 1 octet yet to write result += base64abc[uint8[i - 2] >> 2]; result += base64abc[(uint8[i - 2] & 0x03) << 4]; result += "=="; } if (i === l) { // 2 octets yet to write result += base64abc[uint8[i - 2] >> 2]; result += base64abc[((uint8[i - 2] & 0x03) << 4) | (uint8[i - 1] >> 4)]; result += base64abc[(uint8[i - 1] & 0x0f) << 2]; result += "="; } return result;}
/** * Decodes a given RFC4648 base64 encoded string * @param b64 */export function decode(b64: string): Uint8Array { const binString = atob(b64); const size = binString.length; const bytes = new Uint8Array(size); for (let i = 0; i < size; i++) { bytes[i] = binString.charCodeAt(i); } return bytes;}