Struct Take

#[non_exhaustive]
pub struct Take<T> { pub inner: T, pub len: u64, pub limit: u64 }

Reader adapter which limits the bytes read from an underlying reader.

This struct is generally created by calling take on a reader. Please see the documentation of take for more details.

Fields

inner: T
len: u64
limit: u64

Implementations

impl<T> Take<T>

fn limit(&self) -> u64

Returns the number of bytes that can be read before this instance will return EOF.

Note

This instance may reach EOF after reading fewer bytes than indicated by this method if the underlying Read instance reaches EOF.

Examples

use std::io;
use std::io::prelude::*;
use std::fs::File;

fn main() -> io::Result<()> {
    let f = File::open("foo.txt")?;

    // read at most five bytes
    let handle = f.take(5);

    println!("limit: {}", handle.limit());
    Ok(())
}
fn position(&self) -> u64

Returns the number of bytes read so far.

fn set_limit(&mut self, limit: u64)

Sets the number of bytes that can be read before this instance will return EOF. This is the same as constructing a new Take instance, so the amount of bytes read and the previous limit value don't matter when calling this method.

Examples

use std::io;
use std::io::prelude::*;
use std::fs::File;

fn main() -> io::Result<()> {
    let f = File::open("foo.txt")?;

    // read at most five bytes
    let mut handle = f.take(5);
    handle.set_limit(10);

    assert_eq!(handle.limit(), 10);
    Ok(())
}
fn into_inner(self) -> T

Consumes the Take, returning the wrapped reader.

Examples

use std::io;
use std::io::prelude::*;
use std::fs::File;

fn main() -> io::Result<()> {
    let mut file = File::open("foo.txt")?;

    let mut buffer = [0; 5];
    let mut handle = file.take(5);
    handle.read(&mut buffer)?;

    let file = handle.into_inner();
    Ok(())
}
fn get_ref(&self) -> &T

Gets a reference to the underlying reader.

Care should be taken to avoid modifying the internal I/O state of the underlying reader as doing so may corrupt the internal limit of this Take.

Examples

use std::io;
use std::io::prelude::*;
use std::fs::File;

fn main() -> io::Result<()> {
    let mut file = File::open("foo.txt")?;

    let mut buffer = [0; 5];
    let mut handle = file.take(5);
    handle.read(&mut buffer)?;

    let file = handle.get_ref();
    Ok(())
}
fn get_mut(&mut self) -> &mut T

Gets a mutable reference to the underlying reader.

Care should be taken to avoid modifying the internal I/O state of the underlying reader as doing so may corrupt the internal limit of this Take.

Examples

use std::io;
use std::io::prelude::*;
use std::fs::File;

fn main() -> io::Result<()> {
    let mut file = File::open("foo.txt")?;

    let mut buffer = [0; 5];
    let mut handle = file.take(5);
    handle.read(&mut buffer)?;

    let file = handle.get_mut();
    Ok(())
}

Trait Implementations

impl<T> SizeHint for Take<T>

fn lower_bound(&self) -> usize
fn upper_bound(&self) -> Option<usize>

impl<T: Debug> Debug for Take<T>

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

impl<T: Seek> Seek for Take<T>

fn seek(&mut self, pos: SeekFrom) -> Result<u64>
fn stream_len(&mut self) -> Result<u64>
fn stream_position(&mut self) -> Result<u64>
fn seek_relative(&mut self, offset: i64) -> Result<()>

Auto Trait Implementations

impl<T> Freeze for Take<T> where T: Freeze,

impl<T> RefUnwindSafe for Take<T> where T: RefUnwindSafe,

impl<T> Send for Take<T> where T: Send,

impl<T> Sync for Take<T> where T: Sync,

impl<T> Unpin for Take<T> where T: Unpin,

impl<T> UnsafeUnpin for Take<T> where T: UnsafeUnpin,

impl<T> UnwindSafe for Take<T> where T: UnwindSafe,

Blanket Implementations

impl<T> Any for Take<T> where T: 'static + ?Sized,

fn type_id(&self) -> TypeId

impl<T> Borrow<T> for Take<T> where T: ?Sized,

fn borrow(&self) -> &T

impl<T> BorrowMut<T> for Take<T> where T: ?Sized,

fn borrow_mut(&mut self) -> &mut T

impl<T> From<T> for Take<T>

fn from(t: T) -> T

Returns the argument unchanged.

impl<T> SizeHint for Take<T> where T: ?Sized,

fn lower_bound(&self) -> usize
fn upper_bound(&self) -> Option<usize>

impl<T> SizedTypeProperties for Take<T>

impl<T, U> Into<U> for Take<T> where U: From<T>,

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of [From]<T> for U chooses to do.

impl<T, U> TryFrom<U> for Take<T> where U: Into<T>,

type Error = Infallible;
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

impl<T, U> TryInto<U> for Take<T> where U: TryFrom<T>,

type Error = <U as TryFrom<T>>::Error;
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>