71 lines
3.4 KiB
JavaScript
71 lines
3.4 KiB
JavaScript
import * as Either from "../../Either.js";
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import { DecodeException } from "./common.js";
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/** @internal */
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export const encode = bytes => {
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const length = bytes.length;
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let result = "";
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let i;
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for (i = 2; i < length; i += 3) {
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result += base64abc[bytes[i - 2] >> 2];
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result += base64abc[(bytes[i - 2] & 0x03) << 4 | bytes[i - 1] >> 4];
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result += base64abc[(bytes[i - 1] & 0x0f) << 2 | bytes[i] >> 6];
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result += base64abc[bytes[i] & 0x3f];
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}
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if (i === length + 1) {
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// 1 octet yet to write
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result += base64abc[bytes[i - 2] >> 2];
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result += base64abc[(bytes[i - 2] & 0x03) << 4];
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result += "==";
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}
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if (i === length) {
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// 2 octets yet to write
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result += base64abc[bytes[i - 2] >> 2];
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result += base64abc[(bytes[i - 2] & 0x03) << 4 | bytes[i - 1] >> 4];
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result += base64abc[(bytes[i - 1] & 0x0f) << 2];
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result += "=";
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}
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return result;
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};
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/** @internal */
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export const decode = str => {
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const stripped = stripCrlf(str);
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const length = stripped.length;
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if (length % 4 !== 0) {
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return Either.left(DecodeException(stripped, `Length must be a multiple of 4, but is ${length}`));
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}
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const index = stripped.indexOf("=");
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if (index !== -1 && (index < length - 2 || index === length - 2 && stripped[length - 1] !== "=")) {
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return Either.left(DecodeException(stripped, "Found a '=' character, but it is not at the end"));
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}
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try {
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const missingOctets = stripped.endsWith("==") ? 2 : stripped.endsWith("=") ? 1 : 0;
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const result = new Uint8Array(3 * (length / 4) - missingOctets);
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for (let i = 0, j = 0; i < length; i += 4, j += 3) {
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const buffer = getBase64Code(stripped.charCodeAt(i)) << 18 | getBase64Code(stripped.charCodeAt(i + 1)) << 12 | getBase64Code(stripped.charCodeAt(i + 2)) << 6 | getBase64Code(stripped.charCodeAt(i + 3));
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result[j] = buffer >> 16;
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result[j + 1] = buffer >> 8 & 0xff;
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result[j + 2] = buffer & 0xff;
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}
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return Either.right(result);
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} catch (e) {
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return Either.left(DecodeException(stripped, e instanceof Error ? e.message : "Invalid input"));
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}
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};
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/** @internal */
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export const stripCrlf = str => str.replace(/[\n\r]/g, "");
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/** @internal */
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function getBase64Code(charCode) {
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if (charCode >= base64codes.length) {
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throw new TypeError(`Invalid character ${String.fromCharCode(charCode)}`);
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}
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const code = base64codes[charCode];
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if (code === 255) {
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throw new TypeError(`Invalid character ${String.fromCharCode(charCode)}`);
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}
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return code;
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}
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/** @internal */
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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", "+", "/"];
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/** @internal */
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const base64codes = [255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 62, 255, 255, 255, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255, 255, 0, 255, 255, 255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 255, 255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51];
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//# sourceMappingURL=base64.js.map
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