| import type { StringReader, StringWriter } from './strings'; |
|
|
| export const comma = ','.charCodeAt(0); |
| export const semicolon = ';'.charCodeAt(0); |
|
|
| const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'; |
| const intToChar = new Uint8Array(64); |
| const charToInt = new Uint8Array(128); |
|
|
| 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; |
| } |
|
|
