Struct ic_cdk::api::stable::StableReader

pub struct StableReader<M: StableMemory = CanisterStableMemory>(_);

Keeps an offset and reads off stable memory consecutively.

Implementations

impl<M: StableMemory> StableReader<M>

pub fn with_memory(memory: M, offset: usize) -> Self

Creates a new StableReader which reads from the selected memory

pub fn offset(&self) -> usize

Returns the offset of the reader

pub fn read(&mut self, buf: &mut [u8]) -> Result<usize, StableMemoryError>

Reads data from the stable memory location specified by an offset.

Note: The stable memory size is cached on creation of the StableReader. Therefore, in following scenario, it will get an OutOfBounds error:

1. Create a StableReader
2. Write some data to the stable memory which causes it grow
3. call read() to read the newly written bytes

Trait Implementations

impl Default for StableReader

fn default() -> Self

Returns the “default value” for a type.

impl<M: StableMemory> From<StableIO<M, u32>> for StableReader<M>

fn from(io: StableIO<M>) -> Self

Converts to this type from the input type.

impl<M: StableMemory> Read for StableReader<M>

fn read(&mut self, buf: &mut [u8]) -> Result<usize, Error>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8, Global>) -> Result<usize, Error>

Read all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Read all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Read the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Read the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Selfwhere
    Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>where
    Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>where
    R: Read,
    Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>where
    Self: Sized,

Creates an adapter which will read at most limit bytes from it.

impl<M: StableMemory> Seek for StableReader<M>

fn seek(&mut self, pos: SeekFrom) -> Result<u64>

Seek to an offset, in bytes, in a stream.

fn rewind(&mut self) -> Result<(), Error>

Rewind to the beginning of a stream.

fn stream_len(&mut self) -> Result<u64, Error>

🔬This is a nightly-only experimental API. (seek_stream_len)

Returns the length of this stream (in bytes).

fn stream_position(&mut self) -> Result<u64, Error>

Returns the current seek position from the start of the stream.