pw_varint

Functions for encoding and decoding variable length integers

Stable C C++ Rust

The pw_varint module provides functions for encoding and decoding variable length integers or varints. For smaller values, varints require less memory than a fixed-size encoding. For example, a 32-bit (4-byte) integer requires 1–5 bytes when varint-encoded.

pw_varint supports custom variable-length encodings with different terminator bit values and positions (pw::varint::Format). The basic encoding for unsigned integers is Little Endian Base 128 (LEB128). ZigZag encoding is also supported, which maps negative integers to positive integers to improve encoding density for LEB128.

Protocol Buffers and pw_hdlc use variable-length integer encodings for integers.

Compatibility

• C

• C++

• Rust

API Reference

C/C++

Moved: pw_varint

Rust

pw_varint’s Rust API is documented in our rustdoc API docs.

Zephyr

To enable pw_varint for Zephyr add CONFIG_PIGWEED_VARINT=y to the project’s configuration.