101 lines
3.9 KiB
JavaScript
101 lines
3.9 KiB
JavaScript
/* The decoder is the original MPL one from Mozilla. The encoder is a faster MIT one
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from https://github.com/mitschabaude/fast-base64 */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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// From: http://hg.mozilla.org/mozilla-central/raw-file/ec10630b1a54/js/src/devtools/jint/sunspider/string-base64.js
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import * as Log from './util/logging.js';
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const alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
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const encodeLookup = Object.fromEntries(Array.from(alphabet).map((a, i) => [i, a.charCodeAt(0)]));
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const decoder = new TextDecoder();
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export default {
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/* Convert data (an array of integers) to a Base64 string. */
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base64Pad: '=',
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encode(bytes) {
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let m = bytes.length;
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let k = m % 3;
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let n = Math.floor(m / 3) * 4 + (k && k + 1);
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let N = Math.ceil(m / 3) * 4;
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let encoded = new Uint8Array(N);
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for (let i = 0, j = 0; j < m; i += 4, j += 3) {
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let y = (bytes[j] << 16) + (bytes[j + 1] << 8) + (bytes[j + 2] | 0);
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encoded[i] = encodeLookup[y >> 18];
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encoded[i + 1] = encodeLookup[(y >> 12) & 0x3f];
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encoded[i + 2] = encodeLookup[(y >> 6) & 0x3f];
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encoded[i + 3] = encodeLookup[y & 0x3f];
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}
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let base64 = decoder.decode(new Uint8Array(encoded.buffer, 0, n));
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if (k === 1) base64 += '==';
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if (k === 2) base64 += '=';
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return base64;
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},
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/* Convert Base64 data to a string */
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/* eslint-disable comma-spacing */
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toBinaryTable: [
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-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
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-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
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-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,62, -1,-1,-1,63,
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52,53,54,55, 56,57,58,59, 60,61,-1,-1, -1, 0,-1,-1,
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-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11,12,13,14,
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15,16,17,18, 19,20,21,22, 23,24,25,-1, -1,-1,-1,-1,
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-1,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,
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41,42,43,44, 45,46,47,48, 49,50,51,-1, -1,-1,-1,-1
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],
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/* eslint-enable comma-spacing */
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decode(data, offset = 0) {
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let dataLength = data.indexOf('=') - offset;
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if (dataLength < 0) { dataLength = data.length - offset; }
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/* Every four characters is 3 resulting numbers */
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const resultLength = (dataLength >> 2) * 3 + Math.floor((dataLength % 4) / 1.5);
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const result = new Uint8Array(resultLength);
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// Convert one by one.
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let leftbits = 0; // number of bits decoded, but yet to be appended
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let leftdata = 0; // bits decoded, but yet to be appended
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for (let idx = 0, i = offset; i < data.length; i++) {
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const c = this.toBinaryTable[data.charCodeAt(i) & 0x7f];
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const padding = (data.charAt(i) === this.base64Pad);
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// Skip illegal characters and whitespace
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if (c === -1) {
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Log.Error("Illegal character code " + data.charCodeAt(i) + " at position " + i);
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continue;
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}
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// Collect data into leftdata, update bitcount
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leftdata = (leftdata << 6) | c;
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leftbits += 6;
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// If we have 8 or more bits, append 8 bits to the result
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if (leftbits >= 8) {
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leftbits -= 8;
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// Append if not padding.
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if (!padding) {
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result[idx++] = (leftdata >> leftbits) & 0xff;
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}
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leftdata &= (1 << leftbits) - 1;
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}
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}
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// If there are any bits left, the base64 string was corrupted
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if (leftbits) {
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const err = new Error('Corrupted base64 string');
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err.name = 'Base64-Error';
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throw err;
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}
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return result;
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}
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}; /* End of Base64 namespace */
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