63 lines
1.6 KiB
JavaScript
63 lines
1.6 KiB
JavaScript
const Bytes = require("./bytes");
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const inis = "pbtdkgxjfvlrmnsz".split("");
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const mids = "auie".split("");
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const back = [inis,mids].map(chars => {
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let map = {};
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for (let i = 0; i < chars.length; ++i)
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map[chars[i]] = i;
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return map;
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});
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const syllableFromB64 = b64 => {
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const ini = (b64 >>> 2) & 15;
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const mid = (b64 >>> 0) & 3;
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return inis[ini] + mids[mid];
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}
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const syllableToB64 = syllable => {
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const ini = back[0][syllable[0]];
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const mid = back[1][syllable[1]];
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return ini * 4 + mid;
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}
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const b64sFromBytes = bytes => {
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//BoooooBoooooBoooooBooooo
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//BoooooooBoooooooBooooooo
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let b64s = [], b64;
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for (let i = 0, l = Math.ceil(bytes.length * 8 / 6); i < l; ++i) {
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let j = i / 8 * 6 | 0;
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b64s.push
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( i % 4 === 0 ? (bytes[j+0] / 4 | 0)
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: i % 4 === 1 ? bytes[j+0] % 4 * 16 + (bytes[j+1] / 16 | 0)
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: i % 4 === 2 ? bytes[j+0] % 16 * 4 + (bytes[j+1] / 64 | 0)
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: bytes[j+0] % 64 * 1);
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}
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return b64s;
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}
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const b64sToBytes = b64s => {
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let bytes = [];
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for (let i = 0, l = Math.floor(b64s.length * 6 / 8); i < l; ++i) {
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let j = i / 6 * 8 | 0;
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bytes.push
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( i % 3 === 0 ? b64s[j+0] % 64 * 4 + (b64s[j+1] / 16 | 0)
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: i % 3 === 1 ? b64s[j+0] % 16 * 16 + (b64s[j+1] / 4 | 0)
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: b64s[j+0] % 4 * 64 + (b64s[j+1] / 1 | 0));
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}
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return bytes;
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}
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const fromBytes = bytes =>
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b64sFromBytes(Bytes.toArray(bytes)).map(syllableFromB64).join("");
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const toBytes = syllables =>
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Bytes.fromArray(b64sToBytes(syllables.match(/\w\w/g).map(syllableToB64)));
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module.exports = {
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fromBytes,
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toBytes
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}
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