Crate ssz

Provides encoding (serialization) and decoding (deserialization) in the SimpleSerialize (SSZ) format designed for use in Ethereum 2.0.

Adheres to the Ethereum 2.0 SSZ specification at v0.12.1.

Example

use ssz_derive::{Encode, Decode};
use ssz::{Decode, Encode};

#[derive(PartialEq, Debug, Encode, Decode)]
struct Foo {
    a: u64,
    b: Vec<u16>,
}

fn ssz_encode_decode_example() {
    let foo = Foo {
        a: 42,
        b: vec![1, 3, 3, 7]
    };

    let ssz_bytes: Vec<u8> = foo.as_ssz_bytes();

    let decoded_foo = Foo::from_ssz_bytes(&ssz_bytes).unwrap();

    assert_eq!(foo, decoded_foo);
}

See examples/ for manual implementations of the Encode and Decode traits.

Modules

legacy

Provides a “legacy” version of SSZ encoding for Option<T> where T: Encode + Decode.

Macros

four_byte_option_impl

Structs

SszDecoder

Decodes some slices of SSZ into object instances. Should be instantiated using SszDecoderBuilder.

SszDecoderBuilder

Builds an SszDecoder.

SszEncoder

Allow for encoding an ordered series of distinct or indistinct objects as SSZ bytes.

UnionSelector

Provides the one-byte “selector” from the SSZ union specification:

Enums

DecodeError

Returned when SSZ decoding fails.

Constants

BYTES_PER_LENGTH_OFFSET

The number of bytes used to represent an offset.

BYTES_PER_UNION_SELECTOR

The number of bytes used to indicate the variant of a union.

MAX_LENGTH_VALUE

The maximum value that can be represented using BYTES_PER_LENGTH_OFFSET.

MAX_UNION_SELECTOR

The highest possible union selector value (higher values are reserved for backwards compatible extensions).

Traits

Decode

Provides SSZ decoding (de-serialization) via the from_ssz_bytes(&bytes) method.

Encode

Provides SSZ encoding (serialization) via the as_ssz_bytes(&self) method.

TryFromIter

Partial variant of std::iter::FromIterator.

Functions

decode_list_of_variable_length_items

Decodes bytes as if it were a list of variable-length items.

encode_length

Encode len as a little-endian byte array of BYTES_PER_LENGTH_OFFSET length.

read_offset

Reads a BYTES_PER_LENGTH_OFFSET-byte length from bytes, where bytes.len() >= BYTES_PER_LENGTH_OFFSET.

split_union_bytes

Takes bytes, assuming it is the encoding for a SSZ union, and returns the union-selector and the body (trailing bytes).

ssz_encode

Convenience function to SSZ encode an object supporting ssz::Encode.