112 lines
2.8 KiB
JavaScript
112 lines
2.8 KiB
JavaScript
import {
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WordArray,
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} from './core.js';
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export const parseLoop = (base64Str, base64StrLength, reverseMap) => {
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const words = [];
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let nBytes = 0;
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for (let i = 0; i < base64StrLength; i += 1) {
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if (i % 4) {
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const bits1 = reverseMap[base64Str.charCodeAt(i - 1)] << ((i % 4) * 2);
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const bits2 = reverseMap[base64Str.charCodeAt(i)] >>> (6 - (i % 4) * 2);
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const bitsCombined = bits1 | bits2;
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words[nBytes >>> 2] |= bitsCombined << (24 - (nBytes % 4) * 8);
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nBytes += 1;
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}
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}
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return WordArray.create(words, nBytes);
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};
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/**
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* Base64 encoding strategy.
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*/
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export const Base64 = {
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/**
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* Converts a word array to a Base64 string.
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*
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* @param {WordArray} wordArray The word array.
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*
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* @return {string} The Base64 string.
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*
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* @static
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*
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* @example
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*
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* const base64String = CryptoJS.enc.Base64.stringify(wordArray);
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*/
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stringify(wordArray) {
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// Shortcuts
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const { words, sigBytes } = wordArray;
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const map = this._map;
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// Clamp excess bits
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wordArray.clamp();
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// Convert
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const base64Chars = [];
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for (let i = 0; i < sigBytes; i += 3) {
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const byte1 = (words[i >>> 2] >>> (24 - (i % 4) * 8)) & 0xff;
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const byte2 = (words[(i + 1) >>> 2] >>> (24 - ((i + 1) % 4) * 8)) & 0xff;
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const byte3 = (words[(i + 2) >>> 2] >>> (24 - ((i + 2) % 4) * 8)) & 0xff;
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const triplet = (byte1 << 16) | (byte2 << 8) | byte3;
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for (let j = 0; (j < 4) && (i + j * 0.75 < sigBytes); j += 1) {
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base64Chars.push(map.charAt((triplet >>> (6 * (3 - j))) & 0x3f));
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}
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}
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// Add padding
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const paddingChar = map.charAt(64);
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if (paddingChar) {
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while (base64Chars.length % 4) {
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base64Chars.push(paddingChar);
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}
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}
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return base64Chars.join('');
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},
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/**
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* Converts a Base64 string to a word array.
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*
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* @param {string} base64Str The Base64 string.
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*
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* @return {WordArray} The word array.
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*
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* @static
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*
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* @example
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*
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* const wordArray = CryptoJS.enc.Base64.parse(base64String);
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*/
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parse(base64Str) {
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// Shortcuts
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let base64StrLength = base64Str.length;
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const map = this._map;
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let reverseMap = this._reverseMap;
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if (!reverseMap) {
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this._reverseMap = [];
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reverseMap = this._reverseMap;
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for (let j = 0; j < map.length; j += 1) {
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reverseMap[map.charCodeAt(j)] = j;
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}
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}
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// Ignore padding
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const paddingChar = map.charAt(64);
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if (paddingChar) {
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const paddingIndex = base64Str.indexOf(paddingChar);
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if (paddingIndex !== -1) {
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base64StrLength = paddingIndex;
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}
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}
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// Convert
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return parseLoop(base64Str, base64StrLength, reverseMap);
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},
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_map: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=',
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};
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