284 lines
8.1 KiB
TypeScript
284 lines
8.1 KiB
TypeScript
/**
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* MIT License
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*
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* Copyright (c) 2021 Andrew Raffensperger
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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* This is a near carbon-copy of the original source (link below) with the
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* TypeScript typings added and a few tweaks to make it ES3-compatible.
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*
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* See: https://github.com/adraffy/ens-normalize.js
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*/
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export type Numbers = Uint8Array | Array<number>;
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export type NextFunc = (...args: Array<any>) => number;
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// https://github.com/behnammodi/polyfill/blob/master/array.polyfill.js
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function flat(array: Array<any>, depth?: number): Array<any> {
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if (depth == null) { depth = 1; }
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const result: Array<any> = [];
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const forEach = result.forEach;
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const flatDeep = function (arr: Array<any>, depth: number) {
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forEach.call(arr, function (val: any) {
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if (depth > 0 && Array.isArray(val)) {
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flatDeep(val, depth - 1);
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} else {
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result.push(val);
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}
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});
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};
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flatDeep(array, depth);
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return result;
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}
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function fromEntries<T extends string | number | symbol = string | number | symbol, U = any>(array: Array<[T, U]>): Record<T, U> {
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const result: Record<T, U> = <Record<T, U>>{ };
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for (let i = 0; i < array.length; i++) {
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const value = array[i];
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result[value[0]] = value[1];
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}
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return result;
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}
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export function decode_arithmetic(bytes: Numbers): Array<number> {
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let pos = 0;
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function u16() { return (bytes[pos++] << 8) | bytes[pos++]; }
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// decode the frequency table
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let symbol_count = u16();
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let total = 1;
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let acc = [0, 1]; // first symbol has frequency 1
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for (let i = 1; i < symbol_count; i++) {
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acc.push(total += u16());
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}
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// skip the sized-payload that the last 3 symbols index into
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let skip = u16();
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let pos_payload = pos;
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pos += skip;
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let read_width = 0;
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let read_buffer = 0;
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function read_bit() {
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if (read_width == 0) {
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// this will read beyond end of buffer
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// but (undefined|0) => zero pad
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read_buffer = (read_buffer << 8) | bytes[pos++];
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read_width = 8;
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}
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return (read_buffer >> --read_width) & 1;
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}
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const N = 31;
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const FULL = 2**N;
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const HALF = FULL >>> 1;
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const QRTR = HALF >> 1;
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const MASK = FULL - 1;
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// fill register
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let register = 0;
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for (let i = 0; i < N; i++) register = (register << 1) | read_bit();
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let symbols = [];
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let low = 0;
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let range = FULL; // treat like a float
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while (true) {
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let value = Math.floor((((register - low + 1) * total) - 1) / range);
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let start = 0;
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let end = symbol_count;
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while (end - start > 1) { // binary search
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let mid = (start + end) >>> 1;
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if (value < acc[mid]) {
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end = mid;
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} else {
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start = mid;
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}
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}
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if (start == 0) break; // first symbol is end mark
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symbols.push(start);
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let a = low + Math.floor(range * acc[start] / total);
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let b = low + Math.floor(range * acc[start+1] / total) - 1
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while (((a ^ b) & HALF) == 0) {
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register = (register << 1) & MASK | read_bit();
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a = (a << 1) & MASK;
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b = (b << 1) & MASK | 1;
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}
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while (a & ~b & QRTR) {
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register = (register & HALF) | ((register << 1) & (MASK >>> 1)) | read_bit();
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a = (a << 1) ^ HALF;
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b = ((b ^ HALF) << 1) | HALF | 1;
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}
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low = a;
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range = 1 + b - a;
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}
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let offset = symbol_count - 4;
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return symbols.map(x => { // index into payload
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switch (x - offset) {
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case 3: return offset + 0x10100 + ((bytes[pos_payload++] << 16) | (bytes[pos_payload++] << 8) | bytes[pos_payload++]);
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case 2: return offset + 0x100 + ((bytes[pos_payload++] << 8) | bytes[pos_payload++]);
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case 1: return offset + bytes[pos_payload++];
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default: return x - 1;
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}
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});
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}
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// returns an iterator which returns the next symbol
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export function read_payload(v: Numbers): NextFunc {
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let pos = 0;
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return () => v[pos++];
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}
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export function read_compressed_payload(bytes: Numbers): NextFunc {
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return read_payload(decode_arithmetic(bytes));
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}
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// eg. [0,1,2,3...] => [0,-1,1,-2,...]
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export function signed(i: number): number {
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return (i & 1) ? (~i >> 1) : (i >> 1);
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}
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function read_counts(n: number, next: NextFunc): Array<number> {
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let v = Array(n);
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for (let i = 0; i < n; i++) v[i] = 1 + next();
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return v;
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}
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function read_ascending(n: number, next: NextFunc): Array<number> {
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let v = Array(n);
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for (let i = 0, x = -1; i < n; i++) v[i] = x += 1 + next();
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return v;
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}
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function read_deltas(n: number, next: NextFunc): Array<number> {
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let v = Array(n);
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for (let i = 0, x = 0; i < n; i++) v[i] = x += signed(next());
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return v;
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}
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export function read_member_array(next: NextFunc, lookup?: Record<number, number>) {
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let v = read_ascending(next(), next);
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let n = next();
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let vX = read_ascending(n, next);
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let vN = read_counts(n, next);
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for (let i = 0; i < n; i++) {
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for (let j = 0; j < vN[i]; j++) {
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v.push(vX[i] + j);
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}
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}
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return lookup ? v.map(x => lookup[x]) : v;
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}
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// returns array of
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// [x, ys] => single replacement rule
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// [x, ys, n, dx, dx] => linear map
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export function read_mapped_map(next: NextFunc): Record<number, Array<number>> {
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let ret = [];
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while (true) {
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let w = next();
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if (w == 0) break;
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ret.push(read_linear_table(w, next));
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}
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while (true) {
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let w = next() - 1;
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if (w < 0) break;
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ret.push(read_replacement_table(w, next));
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}
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return fromEntries<number, Array<number>>(flat(ret));
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}
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export function read_zero_terminated_array(next: NextFunc): Array<number> {
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let v = [];
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while (true) {
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let i = next();
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if (i == 0) break;
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v.push(i);
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}
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return v;
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}
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function read_transposed(n: number, w: number, next: NextFunc): Array<Array<number>> {
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let m = Array(n).fill(undefined).map(() => []);
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for (let i = 0; i < w; i++) {
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read_deltas(n, next).forEach((x, j) => m[j].push(x));
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}
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return m;
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}
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function read_linear_table(w: number, next: NextFunc): Array<Array<number | Array<number>>> {
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let dx = 1 + next();
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let dy = next();
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let vN = read_zero_terminated_array(next);
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let m = read_transposed(vN.length, 1+w, next);
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return flat(m.map((v, i) => {
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const x = v[0], ys = v.slice(1);
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//let [x, ...ys] = v;
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//return Array(vN[i]).fill().map((_, j) => {
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return Array(vN[i]).fill(undefined).map((_, j) => {
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let j_dy = j * dy;
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return [x + j * dx, ys.map(y => y + j_dy)];
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});
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}));
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}
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function read_replacement_table(w: number, next: NextFunc): Array<[ number, Array<number> ]> {
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let n = 1 + next();
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let m = read_transposed(n, 1+w, next);
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return m.map(v => [v[0], v.slice(1)]);
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}
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export type Branch = {
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set: Set<number>;
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node: Node;
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};
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export type Node = {
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branches: Array<Branch>;
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valid: number;
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fe0f: boolean;
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save: boolean;
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check: boolean;
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};
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export function read_emoji_trie(next: NextFunc): Node {
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let sorted = read_member_array(next).sort((a, b) => a - b);
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return read();
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function read(): Node {
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let branches = [];
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while (true) {
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let keys = read_member_array(next, sorted);
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if (keys.length == 0) break;
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branches.push({set: new Set(keys), node: read()});
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}
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branches.sort((a, b) => b.set.size - a.set.size); // sort by likelihood
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let temp = next();
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let valid = temp % 3;
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temp = (temp / 3)|0;
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let fe0f = !!(temp & 1);
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temp >>= 1;
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let save = temp == 1;
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let check = temp == 2;
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return {branches, valid, fe0f, save, check};
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}
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}
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