Struct MemoryView

pub struct MemoryView<'a>(/* private fields */);

A WebAssembly memory view.

A memory view is used to read and write to the linear memory.

After a memory is grown a view must not be used anymore. Views are created using the Memory.view() method.

Implementations

impl<'a> MemoryView<'a>

pub fn data_size(&self) -> u64

Returns the size (in bytes) of the Memory.

pub fn size(&self) -> Pages

Returns the size (in Pages) of the Memory.

Example

let m = Memory::new(&mut store, MemoryType::new(1, None, false)).unwrap();

assert_eq!(m.view(&mut store).size(), Pages(1));

pub fn read(&self, offset: u64, buf: &mut [u8]) -> Result<(), MemoryAccessError>

Safely reads bytes from the memory at the given offset.

The full buffer will be filled, otherwise a MemoryAccessError is returned to indicate an out-of-bounds access.

This method is guaranteed to be safe (from the host side) in the face of concurrent writes.

pub fn read_u8(&self, offset: u64) -> Result<u8, MemoryAccessError>

Safely reads a single byte from memory at the given offset

This method is guaranteed to be safe (from the host side) in the face of concurrent writes.

pub fn read_uninit<'b>( &self, offset: u64, buf: &'b mut [MaybeUninit<u8>], ) -> Result<&'b mut [u8], MemoryAccessError>

Safely reads bytes from the memory at the given offset.

This method is similar to read but allows reading into an uninitialized buffer. An initialized view of the buffer is returned.

The full buffer will be filled, otherwise a MemoryAccessError is returned to indicate an out-of-bounds access.

This method is guaranteed to be safe (from the host side) in the face of concurrent writes.

pub fn write(&self, offset: u64, data: &[u8]) -> Result<(), MemoryAccessError>

Safely writes bytes to the memory at the given offset.

If the write exceeds the bounds of the memory then a MemoryAccessError is returned.

This method is guaranteed to be safe (from the host side) in the face of concurrent reads/writes.

pub fn write_u8(&self, offset: u64, val: u8) -> Result<(), MemoryAccessError>

Safely writes a single byte from memory at the given offset

This method is guaranteed to be safe (from the host side) in the face of concurrent writes.

pub fn copy_to_vec(&self) -> Result<Vec<u8>, MemoryAccessError>

Copies the memory and returns it as a vector of bytes

pub fn copy_range_to_vec( &self, range: Range<u64>, ) -> Result<Vec<u8>, MemoryAccessError>

Copies a range of the memory and returns it as a vector of bytes

pub fn copy_to_memory( &self, amount: u64, new_memory: &Self, ) -> Result<(), MemoryAccessError>

Copies the memory to another new memory object

Trait Implementations

impl<'a> Debug for MemoryView<'a>

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

Formats the value using the given formatter.