# Deku

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[![Rust Documentation](https://docs.rs/deku/badge.svg)](https://docs.rs/deku)
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Declarative binary reading and writing

This crate provides bit-level, symmetric, serialization/deserialization implementations for structs and enums

## Why use Deku

**Productivity**: Focus and declare your types that represent the data, Deku will generate symmetric reader/writer functions for your type! Avoid the requirement of writing redundant, error-prone parsing and writing code for binary structs or network headers

## Usage

```toml
[dependencies]
deku = "0.5"
```

no_std:
```toml
[dependencies]
deku = { version = "0.5", default-features = false, features = ["alloc"] }
```

## Example

See [documentation](https://docs.rs/deku) or [examples](https://github.com/sharksforarms/deku/tree/master/examples) folder for more!

Simple example, let's read big-endian data into a struct, with fields containing different sizes, modify a value, and write it back

```rust
use deku::prelude::*;

#[derive(Debug, PartialEq, DekuRead, DekuWrite)]
#[deku(endian = "big")]
struct DekuTest {
    #[deku(bits = "4")]
    field_a: u8,
    #[deku(bits = "4")]
    field_b: u8,
    field_c: u16,
}

let data: Vec<u8> = vec![0b0110_1001, 0xBE, 0xEF];
let (_rest, mut val) = DekuTest::from_bytes((data.as_ref(), 0)).unwrap();
assert_eq!(DekuTest {
    field_a: 0b0110,
    field_b: 0b1001,
    field_c: 0xBEEF,
}, val);

val.field_c = 0xC0FE;

let data_out = val.to_bytes().unwrap();
assert_eq!(vec![0b0110_1001, 0xC0, 0xFE], data_out);
```
