Struct slice::IoSlice

pub struct IoSlice<T> where
    T: Seek,  { /* fields omitted */ }

A slice, subset, or view into some object.

IoSlice impls both std::io::Read and std::io::Write when the source implements them (and only one if the source only implements one).

example usage.

use { std::fs::File, slice::IoSlice };


let source = File::open("/home/annie/data.png")?;
let start  = 10;
let length = 1000;


// create a slice into `home/annie/data.png`, consisting of bytes [10 .. 10 + 1000]
// of that file.
//
// `slice` impls both `std::io::Read` and `std::io::Write` because `source`
// does too.
let slice = IoSlice::new(source, start, length);


// use like any other `std::io::Read` or `std::io::Write`:
//
//     slice.read_to_string(...)?;
//     slice.read_exact(...)?;
//     slice.write_all(...)?;
//
//     writeln!(slice, "hello {}", name)?;
//

Methods

impl<T> IoSlice<T> where     T: Seek,

pub fn new(source: T, begin: u64, length: u64) -> Result<IoSlice<T>, Error>

create a new slice into a specific subset of source.

pub fn len(&self) -> u64

returns the total length of this io slice.

pub fn pos(&self) -> u64

returns the current position of this slice.

pub fn position(&self) -> u64

returns the current position of this slice.

Trait Implementations

impl<T: Debug> Debug for IoSlice<T> where     T: Seek,

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

Formats the value using the given formatter.

impl<T> Seek for IoSlice<T> where     T: Seek,

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

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

impl<T> Read for IoSlice<T> where     T: Read + Seek,

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

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

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

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

unsafe fn initializer(&self) -> Initializer

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

Determines if this Reader can work with buffers of uninitialized memory.

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 by_ref(&mut self) -> &mut Self

Creates a "by reference" adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

Transforms this Read instance to an [Iterator] over its bytes.

fn chars(self) -> Chars<Self>

Deprecated since 1.27.0

: Use str::from_utf8 instead: https://doc.rust-lang.org/nightly/std/str/struct.Utf8Error.html#examples

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

the semantics of a partial read/write of where errors happen is currently unclear and may change

Transforms this Read instance to an [Iterator] over [char]s.

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

Creates an adaptor which will chain this stream with another.

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

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

impl<T> Write for IoSlice<T> where     T: Write + Seek,

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

Write a buffer into this object, returning how many bytes were written.

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

Attempts to write an entire buffer into this write.

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

Flush this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_fmt(&mut self, fmt: Arguments) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

Creates a "by reference" adaptor for this instance of Write.

impl<T> Clone for IoSlice<T> where     T: Clone + Seek,

Important traits for IoSlice<T>

impl<T> Read for IoSlice<T> where
    T: Read + Seek, impl<T> Write for IoSlice<T> where
    T: Write + Seek, 

fn clone(&self) -> IoSlice<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T> TryClone for IoSlice<T> where     T: TryClone + Seek,

fn try_clone(&self) -> Result<IoSlice<T>, Error>