mirror of
https://github.com/swc-project/swc.git
synced 2024-11-24 02:06:08 +03:00
108 lines
2.6 KiB
JavaScript
108 lines
2.6 KiB
JavaScript
(function (global, factory) {
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typeof exports === "object" && typeof module !== "undefined"
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? factory(exports)
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: typeof define === "function" && define.amd
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? define(["exports"], factory)
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: ((global =
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typeof globalThis !== "undefined" ? globalThis : global || self),
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factory((global.vlq = {})));
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})(this, function (exports) {
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"use strict";
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/** @type {Record<string, number>} */
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let char_to_integer = {};
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/** @type {Record<number, string>} */
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let integer_to_char = {};
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="
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.split("")
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.forEach(function (char, i) {
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char_to_integer[char] = i;
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integer_to_char[i] = char;
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});
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/** @param {string} string */
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function decode(string) {
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/** @type {number[]} */
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let result = [];
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let shift = 0;
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let value = 0;
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for (let i = 0; i < string.length; i += 1) {
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let integer = char_to_integer[string[i]];
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if (integer === undefined) {
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throw new Error("Invalid character (" + string[i] + ")");
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}
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const has_continuation_bit = integer & 32;
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integer &= 31;
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value += integer << shift;
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if (has_continuation_bit) {
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shift += 5;
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} else {
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const should_negate = value & 1;
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value >>>= 1;
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if (should_negate) {
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result.push(value === 0 ? -0x80000000 : -value);
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} else {
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result.push(value);
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}
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// reset
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value = shift = 0;
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}
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}
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return result;
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}
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/** @param {number | number[]} value */
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function encode(value) {
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if (typeof value === "number") {
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return encode_integer(value);
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}
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let result = "";
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for (let i = 0; i < value.length; i += 1) {
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result += encode_integer(value[i]);
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}
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return result;
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}
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/** @param {number} num */
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function encode_integer(num) {
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let result = "";
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if (num < 0) {
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num = (-num << 1) | 1;
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} else {
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num <<= 1;
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}
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do {
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let clamped = num & 31;
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num >>>= 5;
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if (num > 0) {
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clamped |= 32;
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}
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result += integer_to_char[clamped];
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} while (num > 0);
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return result;
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}
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exports.decode = decode;
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exports.encode = encode;
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Object.defineProperty(exports, "__esModule", { value: true });
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});
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