bencodex-rs

The Rust implementation of Bencodex.

• Correctness - Implement Bencodex spec and passed tests with its testsuites.
• Bencodex JSON - Support encoding Bencodex to JSON and decoding JSON to Bencodex.
• Feature flags - Support std, alloc, json, json-cli feature flags to minimize binary size in use.
• no_std support - Can be used in embedded environments with alloc.

Feature Flags

Feature	Default	Description
std	Yes	Enables standard library support
alloc	Yes (via std)	Enables alloc crate for no_std environments
json	No	Enables Bencodex JSON encoding/decoding
json-cli	No	Enables CLI tool for JSON conversion
simd	No	Enables SIMD-accelerated decoding

SIMD Decoding

The simd feature provides SIMD-accelerated decoding for improved performance on large data. This feature requires std and is not available in no_std environments.

Supported architectures:

• x86_64: SSE4.2 and AVX2 (runtime detection)
• AArch64: NEON

[dependencies]
bencodex-rs = { version = "<VERSION>", features = ["simd"] }

use bencodex::{Decode, BencodexValue};

// Using trait method
let data = b"i42e".to_vec();
let value = data.decode_simd().unwrap();

// Or using the function directly
use bencodex::simd::decode_simd;
let value = decode_simd(b"li1ei2ei3ee").unwrap();

no_std Support

This crate supports no_std environments with the alloc crate. To use in a no_std environment:

[dependencies]
bencodex-rs = { version = "<VERSION>", default-features = false, features = ["alloc"] }

Notes:

• no_std support requires Rust 1.81+ (for core::error::Error stabilization).
• The json feature requires std and is not available in no_std environments.

Bencodex JSON feature

bencodex-rs implements Bencodex JSON feature, encoding and decoding both.

To use Bencodex JSON feature, you should enable json feature.

bencodex-rs = { version = "<VERSION>", features = ["json"] }

Encoding to JSON

To encode from Bencodex to JSON, you can use to_json function.

use bencodex::{ BencodexValue, json::to_json };

let json = to_json(&BencodexValue::Null).expect("Failed to encode JSON.");
println!("{}", json);

There are two ways to encode BencodexValue::Binary type, Hex and Base64. You can choose one way with bencodex::json::BinaryEncoding. And you can pass it with bencodex::json::JsonEncodeOptions to bencodex::json::to_json_with_options.

use bencodex::BencodexValue;
use bencodex::json::{ BinaryEncoding, JsonEncodeOptions, to_json_with_options };

let json = to_json_with_options(&BencodexValue::Null, JsonEncodeOptions {
  binary_encoding: BinaryEncoding::Base64,
}).expect("Failed to encode JSON.");
println!("{}", json);

Decoding from JSON

To decode from JSON to Bencodex, you can use from_json_string and from_json function.

// from_json_string
use bencodex::{ BencodexValue, json::from_json_string };

let result = from_json_string("null");
assert!(result.is_ok());
assert_eq!(result.unwrap(), BencodexValue::Null);

// from_json
use serde_json::from_str;
use bencodex::{ BencodexValue, json::from_json };

let json = from_str("null").unwrap();
let result = from_json(&json);
assert!(result.is_ok());
assert_eq!(result.unwrap(), BencodexValue::Null);

CLI Tool

Also, it provides a CLI tool to encode from Bencodex to JSON and to decode from JSON to Bencodex. You can install it with json-cli feature like the below line:

cargo install bencodex-rs --features json-cli

For improved decoding performance, you can also enable SIMD acceleration:

cargo install bencodex-rs --features json-cli,simd

You can use like the below:

# encode
$ echo -n 'n' | bencodex
null
$ echo -n 'i123e' | bencodex
"123"
$ echo -n '1:\x12' | bencodex
"0x12"
$ echo -n '1:\x12' | bencodex --base64
"b64:Eg=="

# decode
$ echo -n '"123"' | bencodex -d
123
$ echo -n 'null' | bencodex -d
n