MacPro
102 lines
3.2 KiB
JavaScript
102 lines
3.2 KiB
JavaScript
"use strict";
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// a,g,h,A-Z,,,,-
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.getRandomCharInSet = getRandomCharInSet;
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function getRandomCharInSet(charset) {
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const set = stringToCharSet(charset);
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let charIdx = Math.floor((crypto.getRandomValues(new Uint32Array(1))[0] / 2 ** 32) * set.len);
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for (let range of set.ranges) {
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if (range.len > charIdx) {
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return String.fromCharCode(range.start.charCodeAt(0) + charIdx);
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}
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charIdx -= range.len;
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}
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throw new Error('unreachable');
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}
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function stringToCharSet(charset) {
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let set = { ranges: [], len: 0 };
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let start = null;
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let end = null;
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let in_range = false;
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for (let char of charset) {
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switch (char) {
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case ',':
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if (start !== null && end !== null) {
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if (start.charCodeAt(0) > end.charCodeAt(0)) {
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throw new Error('start > end of charset');
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}
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const len = end.charCodeAt(0) - start.charCodeAt(0) + 1;
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set.ranges.push({
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start,
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end,
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len,
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});
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set.len += len;
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start = null;
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end = null;
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in_range = false;
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}
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else if (start !== null && !in_range) {
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set.len += 1;
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set.ranges.push({ start, end: start, len: 1 });
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start = null;
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}
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else if (start !== null && in_range) {
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end = ',';
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}
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else if (start === null && end === null && !in_range) {
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start = ',';
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}
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else {
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throw new Error('unexpected ","');
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}
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break;
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case '-':
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if (start === null) {
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start = '-';
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}
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else if (!in_range) {
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in_range = true;
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}
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else if (in_range && end === null) {
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end = '-';
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}
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else {
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throw new Error('unexpected "-"');
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}
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break;
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default:
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if (start === null) {
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start = char;
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}
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else if (in_range && end === null) {
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end = char;
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}
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else {
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throw new Error(`unexpected "${char}"`);
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}
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}
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}
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if (start !== null && end !== null) {
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if (start.charCodeAt(0) > end.charCodeAt(0)) {
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throw new Error('start > end of charset');
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}
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const len = end.charCodeAt(0) - start.charCodeAt(0) + 1;
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set.ranges.push({
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start,
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end,
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len,
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});
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set.len += len;
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}
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else if (start !== null) {
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set.len += 1;
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set.ranges.push({
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start,
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end: start,
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len: 1,
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});
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}
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return set;
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}
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//# sourceMappingURL=getRandomCharInSet.js.map
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