Struct Data 

pub struct Data { /* private fields */ }

The initial contents of a memory are zero bytes. Data segments can be used to initialize a range of memory from a static vector of bytes. Like element segments, data segments have a mode that identifies them as either passive or active. A passive data segment’s contents can be copied into a memory using the 𝗆𝖾𝗆𝗈𝗋𝗒.𝗂𝗇𝗂𝗍 instruction. An active data segment copies its contents into a memory during instantiation, as specified by a memory index and a constant expression defining an offset into that memory. Data segments are referenced through data indices.

See https://webassembly.github.io/spec/core/syntax/modules.html#data-segments

Examples

Passive

use wasm_ast::{Data, DataMode};

let initializer = vec![42];
let data = Data::passive(initializer.clone());

assert_eq!(data, Data::new(DataMode::Passive, initializer.clone()));
assert_eq!(data, initializer.into());
assert_eq!(data.mode(), &DataMode::Passive);
assert_eq!(data.len(), 1);
assert_eq!(data.is_empty(), false);

Active

use wasm_ast::{Data, DataMode, MemoryIndex, Expression};

let initializer = vec![42];
let offset: Expression = vec![1u32.into()].into();
let data = Data::active(0, offset.clone(), initializer.clone());

assert_eq!(data, Data::new(DataMode::Active(0, offset.clone()), initializer.clone()));
assert_eq!(data.mode(), &DataMode::Active(0, offset));
assert_eq!(data.len(), 1);
assert_eq!(data.is_empty(), false);

Implementations

impl Data

pub fn new(mode: DataMode, initializer: Vec<u8>) -> Self

Creates an instance of a data segment.

pub fn passive(initializer: Vec<u8>) -> Self

Creates an instance of a passive data segment.

pub fn active( memory: MemoryIndex, offset: Expression, initializer: Vec<u8>, ) -> Self

Creates an instance of an active data segment.

pub fn mode(&self) -> &DataMode

The mode of the data segment.

pub fn initializer(&self) -> &[u8]

The data to initialize the segment with.

pub fn len(&self) -> usize

The number of bytes in the data segment initializer.

pub fn is_empty(&self) -> bool

True if the data segment’s initializer’s length is zero, false otherwise.

Trait Implementations

impl Clone for Data

fn clone(&self) -> Data

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Data

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

Formats the value using the given formatter.

impl From<Vec<u8>> for Data

fn from(initializer: Vec<u8>) -> Self

Converts to this type from the input type.

impl PartialEq for Data

fn eq(&self, other: &Data) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Data