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- import type { StringReader, StringWriter } from './strings';
- export const comma = ','.charCodeAt(0);
- export const semicolon = ';'.charCodeAt(0);
- const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
- const intToChar = new Uint8Array(64); // 64 possible chars.
- const charToInt = new Uint8Array(128); // z is 122 in ASCII
- for (let i = 0; i < chars.length; i++) {
- const c = chars.charCodeAt(i);
- intToChar[i] = c;
- charToInt[c] = i;
- }
- export function decodeInteger(reader: StringReader): number {
- let value = 0;
- let shift = 0;
- let integer = 0;
- do {
- const c = reader.next();
- integer = charToInt[c];
- value |= (integer & 31) << shift;
- shift += 5;
- } while (integer & 32);
- return value;
- }
- export function decodeSign(num: number): number {
- return num & 1 ? -0x80000000 | -(num >>> 1) : num >>> 1;
- }
- export function encodeInteger(builder: StringWriter, num: number) {
- do {
- let clamped = num & 0b011111;
- num >>>= 5;
- if (num > 0) clamped |= 0b100000;
- builder.write(intToChar[clamped]);
- } while (num > 0);
- }
- export function encodeSign(num: number): number {
- return num < 0 ? (-num << 1) | 1 : num << 1;
- }
- export function hasMoreVlq(reader: StringReader, max: number) {
- if (reader.pos >= max) return false;
- return reader.peek() !== comma;
- }
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