quicvarint

Variable-Length Integer Encoding defined by RFC 9000.

Tables of Content

• Features
• Usage
• Security Considerations
• License

Features

• Decode a 2-MSB varint from a DataView or a Uint8Array
• Encode a 2-MSB varint to a Uint8Array
• Read and write varints in place through a cursor, without per-call allocation
• Support integer between 0 and 2147483647 included
• TypeScript types

Usage

import { encode, decode, MAX } from "quicvarint"

// A number between 0 and MAX
const n = 1234

// Encode it to a Uint8Array
const encN = encode(n)

// Decode it and print it on console
console.log(decode(encN))

Cursor

A cursor is any { buf, p }, so a parser can pass its own state object. readFrom and writeTo advance p and allocate nothing; tryReadFrom returns undefined when the buffer ends mid-varint, for incremental parsing.

import { readFrom, tryReadFrom, writeTo } from "quicvarint"

const buf = new Uint8Array(16)

const w = { buf, p: 0 }
writeTo(w, 1)
writeTo(w, 1234)

const r = { buf, p: 0 }
console.log(readFrom(r), readFrom(r)) // 1 1234

// undefined instead of throwing when more bytes are needed
console.log(tryReadFrom({ buf: new Uint8Array([0x80]), p: 0 })) // undefined

Security Considerations

This software has not been audited. Please use at your sole discretion.

License

This project is under the MIT license.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you shall be MIT licensed as above, without any additional terms or conditions.