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