pyvint

A pure Python library for encoding and decoding Variable-Sized Integer (VINT) values. VINT is used in EBML (Extensible Binary Meta Language) to encode integers with a variable number of bytes. Detailed information about VINT can be found in the Extensible Binary Meta Language RFC 8794

Installation

The library is available on PyPI and can be installed using pip:

pip install pyvint

Usage

Encoding (Integer to VINT)

import pyvint

vint = pyvint.encode(2)  # just passing an integer returns the minimum length VINT
print(vint)  # b'\x82'
vint2 = pyvint.encode(2, 2)  # passing an integer and the octet length returns a VINT with the specified octet length
print(vint2)  # b'\x40\x02'

Decoding (VINT to Integer)

import pyvint

value = pyvint.decode(b'\x82')
print(value)  # 2
value2 = pyvint.decode(b'\x40\x02')
print(value2)  # 2

pyvint also provides decoding of VINTs from a stream of bytes. This is useful when reading VINTs from a file or a network stream. The decode_stream function returns the integer value of the VINT and advances the buffer to the next byte after the VINT.

from io import BytesIO
import pyvint

data = b'\x82\x40\x02'
buffer = BytesIO(data)
value = pyvint.decode_stream(data)
print(value)  # 2
print(buffer.read())  # b'\x40\x02'