Struct scale_bits::dynamic::Format

source · [−]

pub struct Format { /* private fields */ }

Expand description

A description of a format to encode/decode Bits to/from. The format basically defines the “store type” and “order type” that will be used to SCALE encode or decode some Bits. These concepts are the same as in bitvec, but essentially:

The StoreType defines the size of each chunk that’s written (eg u8, u16 etc).
The OrderType determines the order in which we write to the store type; ie do we write to the least significant bit first and work up, or write to the most significant byte first and work down.

Implementations

source

impl Format

source

pub fn new(store: StoreType, order: OrderType) -> Self

Define a new format by providing a store and order.

Example

use scale_bits::dynamic::{ Format, StoreType, OrderType };

let format = Format::new(StoreType::U8, OrderType::Lsb0);

source

pub fn from_metadata(
ty: &TypeDefBitSequence<PortableForm>,
types: &PortableRegistry
) -> Result<Format, BitsDetailsError>

Use metadata to obtain details about the format.

source

pub fn encoded_size(&self, number_of_bits: usize) -> usize

Given some number of bits, how many bytes, in total, would it take to encode that number of bits given the specified format.

Example

use scale_bits::{ Bits, bits, dynamic::{ Format, StoreType, OrderType } };

let bits = bits![1,0,1,1,0,1,0,1,0,0,1];
let format = Format::new(StoreType::U8, OrderType::Lsb0);

// Encode bits with a given format:
let mut out = vec![];
format.encode_bits_to(&bits, &mut out);

// `encoded_size()` returns the same length without needing to allocate/encode:
let expected_len = format.encoded_size(bits.len());
assert_eq!(out.len(), expected_len);

source

pub fn encode_bits(&self, bits: &Bits) -> Vec<u8>

A convenience wrapper around Format::encode_bits_to.

Example

use scale_bits::{ Bits, bits, dynamic::{ Format, StoreType, OrderType } };

let bits = bits![1,0,1,1,0,1,0,1,0,0,1];
let format = Format::new(StoreType::U8, OrderType::Lsb0);

// SCALE encode bits into the chosen format:
let out = format.encode_bits(&bits);

source

pub fn encode_bits_to(&self, bits: &Bits, out: &mut Vec<u8>)

Encode the provided Bits to the output in the given format.

Example

use scale_bits::{ Bits, bits, dynamic::{ Format, StoreType, OrderType } };

let bits = bits![1,0,1,1,0,1,0,1,0,0,1];
let format = Format::new(StoreType::U8, OrderType::Lsb0);

// SCALE encode bits into the chosen format:
let mut out = vec![];
format.encode_bits_to(&bits, &mut out);

source

pub fn decode_bits_from(&self, bytes: &mut &[u8]) -> Result<Bits, CodecError>

Decode the provided bytes into Bits assuming the given format.

Example

use scale_bits::{ Bits, bits, dynamic::{ Format, StoreType, OrderType } };

let bits = bits![1,0,1,1,0,1,0,1,0,0,1];
let format = Format::new(StoreType::U8, OrderType::Lsb0);

// SCALE encode bits into the chosen format:
let mut out = vec![];
format.encode_bits_to(&bits, &mut out);

// Then, we can decode these back given the same format:
let new_bits = format.decode_bits_from(&mut &*out).unwrap();

assert_eq!(bits, new_bits);