Struct Writer 

pub struct Writer { /* private fields */ }

Writes the binary form piece by piece, from data that isn’t a Value — nothing is built or copied on the way. A map or list is given its length, then that many entries (key then a value) or values.

let mut w = substrate_data::binary::Writer::new();
w.map(2).key("id").str("docs/intro").key("count").int(3);
let v = substrate_data::binary::decode(&w.finish()).unwrap();
assert_eq!(v.get("count").and_then(|c| c.as_i64()), Some(3));

Implementations

impl Writer

pub fn new() -> Writer

A writer of a whole document: the header first.

pub fn null(&mut self) -> &mut Writer

Null.

pub fn bool(&mut self, b: bool) -> &mut Writer

A bool.

pub fn int(&mut self, n: i64) -> &mut Writer

An integer.

pub fn float(&mut self, f: f64) -> &mut Writer

A float, eight bytes (Writer::float32 writes four).

pub fn float32(&mut self, f: f32) -> &mut Writer

A 32-bit float: half the bytes of Writer::float.

pub fn floats(&mut self, items: &[f64]) -> &mut Writer

A list of floats, packed, no tag each: four bytes each when every one is an f32 exactly (tag::FLOATS32), else eight.

pub fn floats32(&mut self, items: &[f32]) -> &mut Writer

A list of 32-bit floats, packed: four bytes each, no tag.

pub fn str(&mut self, s: &str) -> &mut Writer

A string: its bytes the first time, its index after.

pub fn bytes(&mut self, b: &[u8]) -> &mut Writer

Bytes as they are.

pub fn list(&mut self, len: usize) -> &mut Writer

A list of len values.

pub fn ints(&mut self, items: impl ExactSizeIterator<Item = i64>) -> &mut Writer

A list of ints, packed (no tag each).

pub fn map(&mut self, len: usize) -> &mut Writer

A map of len entries, each a Writer::key and a value.

pub fn key(&mut self, k: &str) -> &mut Writer

A map’s key.

pub fn value(&mut self, v: &Value) -> &mut Writer

A whole value.

pub fn finish(self) -> Vec<u8>

The bytes.

Trait Implementations

impl Debug for Writer

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for Writer

fn default() -> Writer

Returns the “default value” for a type.