dissect.target.helpers.protobuf

Module Contents

Classes

ProtobufVarint

Implements a protobuf integer type for dissect.cstruct that can span a variable amount of bytes.

Functions

decode_varint	Reads a varint from the provided buffer stream.
encode_varint	Encode a decoded protobuf varint to its original bytes.

class dissect.target.helpers.protobuf.ProtobufVarint(cstruct: BytesInteger.__init__.cstruct, name: str, size: int, signed: bool, alignment: int = None)

Bases: dissect.cstruct.types.bytesinteger.BytesInteger

Implements a protobuf integer type for dissect.cstruct that can span a variable amount of bytes.

Mainly follows the cstruct BytesInteger implementation with minor tweaks to support protobuf’s msb varint implementation.

Resources:

• https://protobuf.dev/programming-guides/encoding/

• https://github.com/protocolbuffers/protobuf/blob/main/python/google/protobuf/internal/decoder.py

dissect.target.helpers.protobuf.decode_varint(stream: BinaryIO) → int

Reads a varint from the provided buffer stream.

If we have not reached the end of a varint, the msb will be 1. We read every byte from our current position until the msb is 0.

dissect.target.helpers.protobuf.encode_varint(number: int) → bytes

Encode a decoded protobuf varint to its original bytes.