48 lines
1.5 KiB
JavaScript
48 lines
1.5 KiB
JavaScript
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const subsChrs = " !#$%&'()*+,-./<=>?@[]^_`{|}~";
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const Word = /^[a-z]*$/i;
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function unfold(words, sep) {
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let initial = 97;
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return words.reduce((accum, word) => {
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if (word === sep) {
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initial++;
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}
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else if (word.match(Word)) {
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accum.push(String.fromCharCode(initial) + word);
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}
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else {
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initial = 97;
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accum.push(word);
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}
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return accum;
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}, []);
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}
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export function decode(data, subs) {
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// Replace all the substitutions with their expanded form
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for (let i = subsChrs.length - 1; i >= 0; i--) {
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data = data.split(subsChrs[i]).join(subs.substring(2 * i, 2 * i + 2));
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}
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// Get all tle clumps; each suffix, first-increment and second-increment
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const clumps = [];
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const leftover = data.replace(/(:|([0-9])|([A-Z][a-z]*))/g, (all, item, semi, word) => {
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if (semi) {
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for (let i = parseInt(semi); i >= 0; i--) {
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clumps.push(";");
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}
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}
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else {
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clumps.push(item.toLowerCase());
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}
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return "";
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});
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if (leftover) {
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throw new Error(`leftovers: ${JSON.stringify(leftover)}`);
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}
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return unfold(unfold(clumps, ";"), ":");
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}
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export function decodeOwl(data) {
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if (data[0] !== "0") {
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throw TypeError("unsupported auwl data");
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}
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return decode(data.substring(1 + 2 * subsChrs.length), data.substring(1, 1 + 2 * subsChrs.length));
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}
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//# sourceMappingURL=decode-owl.js.map
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