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1// entityTries.js2// Builds integer-keyed tries so the decoder never allocates a string object3// during lookup — every key is a plain charCode number.4//5// trie1: Map<code0, entity>6// trie2: Map<code0, Map<code1, entity>>7// trie3: Map<code0, Map<code1, Map<code2, entity>>>8 9import { ALL_ENTITIES } from './entities.js';10 11// Reverse map: character sequence → "&name;"12const CHAR_TO_ENTITY = new Map();13for (const [name, chars] of Object.entries(ALL_ENTITIES)) {14  CHAR_TO_ENTITY.set(chars, `&${name};`);15}16 17export const trie1 = new Map();   // code0          → entity string18export const trie2 = new Map();   // code0 → Map    → entity string19export const trie3 = new Map();   // code0 → Map → Map → entity string20 21for (const [chars, entity] of CHAR_TO_ENTITY) {22  const len = chars.length;23 24  if (len === 1) {25    const c0 = chars.charCodeAt(0);26    // Keep shortest match only if no longer match already claimed this code27    // (longer matches are inserted in the same pass so we just overwrite —28    //  trie1 is only consulted after trie2/trie3 both miss, so no conflict)29    trie1.set(c0, entity);30 31  } else if (len === 2) {32    const c0 = chars.charCodeAt(0);33    const c1 = chars.charCodeAt(1);34    let inner = trie2.get(c0);35    if (inner === undefined) { inner = new Map(); trie2.set(c0, inner); }36    inner.set(c1, entity);37 38  } else if (len === 3) {39    const c0 = chars.charCodeAt(0);40    const c1 = chars.charCodeAt(1);41    const c2 = chars.charCodeAt(2);42    let mid = trie3.get(c0);43    if (mid === undefined) { mid = new Map(); trie3.set(c0, mid); }44    let inner = mid.get(c1);45    if (inner === undefined) { inner = new Map(); mid.set(c1, inner); }46    inner.set(c2, entity);47  }48  // HTML5 has no named entity whose character sequence is longer than 3 chars49}