3 releases

0.1.2 Feb 13, 2022
0.1.1 Oct 26, 2020
0.1.0 Apr 16, 2019

#1752 in Procedural macros

22 downloads per month
Used in blynk_io

MIT license

820 lines

Build Status Build status Crates.io Version Docs

restruct is used to interpret binary data stored in files or other sources or convert between C structs and Rust types and when using a parser-generator is considered disproportionate. It is a brainchild of Python's struct-module.

The library uses Format Strings as compact descriptions of the binary data and the intended conversion to/from Rust-types. The Format Strings are interpreted at compile-time to generate a type whose functions can be used to convert between unstructured and structured data.

// Generate a parser in little-endian for two 32bit integers, a float and a bool.
struct FooParser;

// Pack a tuple of two integers, a float and a bool into a [u8; _]-buffer.
let packed = FooParser::pack((1, 2, 3.0, false));
assert_eq!(packed, [1, 0, 0, 0, 2, 0, 0, 0, 0, 0, 64, 64, 0]);
assert_eq!(packed.len(), FooParser::SIZE);

// Packing and unpacking can't fail at runtime.
let unpacked = FooParser::unpack(packed);
assert_eq!(unpacked, (1, 2, 3.0, false));

// Any `io::Read` can be used directly.
let unpacked = FooParser::read_from(&mut &packed[..]).expect("i/o failed");
assert_eq!(unpacked, (1, 2, 3.0, false));

// Any `io::Write` can be used directly.
let mut buffer = Vec::with_capacity(FooParser::SIZE);
FooParser::write_to((1, 2, 3.0, false), &mut buffer).expect("i/o failed");
assert_eq!(&buffer, &packed);
// Because packing and unpacking is const we can use these functions to initialize other consts
const TEAPOT: <Tea as restruct::Struct>::Unpacked = Tea::unpack(*include_bytes!("teapot.bin"));
const TEAPOT_ACTIVE: bool = TEAPOT.3;


~173K SLoC