std::io::Take - Rust
Description: API documentation for the Rust `Take` struct in crate `std`.
Keywords: rust, rustlang, rust-lang, Take

# Struct std::io::Take 1.0.0[−][src]

    pub struct Take<T> { /* fields omitted */ }

Reader adaptor 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.

## Methods

###

`impl<T> Take<T>`

[src]

####

`pub fn limit(&self) -> u64`

[src]

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(())
    }Run

####

`pub fn set_limit(&mut self, limit: u64)`

1.27.0
[src]

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(())
    }Run

####

`pub fn into_inner(self) -> T`

1.15.0
[src]

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(())
    }Run

####
ⓘImportant traits for &'a mut I

### Important traits for &'a mut I

`impl<'a, I> Iterator for &'a mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'a, R: Read + ?Sized> Read for &'a mut Rimpl<'a, W: Write + ?Sized> Write for &'a mut W`

`pub fn get_ref(&self) -> &T`

1.20.0
[src]

Gets a reference to the underlying 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.get_ref();
        Ok(())
    }Run

####
ⓘImportant traits for &'a mut I

### Important traits for &'a mut I

`impl<'a, I> Iterator for &'a mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'a, R: Read + ?Sized> Read for &'a mut Rimpl<'a, W: Write + ?Sized> Write for &'a mut W`

`pub fn get_mut(&mut self) -> &mut T`

1.20.0
[src]

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(())
    }Run

## Trait Implementations

###

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

[src]

####

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

[src]

Formats the value using the given formatter. Read more

###

`impl<T: Read> Read for Take<T>`

[src]

####

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

[src]

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

####

`unsafe fn initializer(&self) -> Initializer`

[src]

🔬 This is a nightly-only experimental API. (`read_initializer` #42788)

Determines if this `Read`er can work with buffers of uninitialized memory. Read more

####

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

[src]

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

####

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

[src]

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

####

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

1.6.0
[src]

Read the exact number of bytes required to fill `buf`. Read more

####
ⓘImportant traits for &'a mut I

### Important traits for &'a mut I

`impl<'a, I> Iterator for &'a mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'a, R: Read + ?Sized> Read for &'a mut Rimpl<'a, W: Write + ?Sized> Write for &'a mut W`

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

[src]

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

####
ⓘImportant traits for Bytes<R>

### Important traits for Bytes<R>

`impl<R: Read> Iterator for Bytes<R> type Item = Result<u8>;`

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

[src]

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

####
ⓘImportant traits for Chars<R>

### Important traits for Chars<R>

`impl<R: Read> Iterator for Chars<R> type Item = Result<char, CharsError>;`

`fn chars(self) -> Chars<Self> where Self: Sized,`

[src]

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` #27802)

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. Read more

####
ⓘImportant traits for Chain<T, U>

### Important traits for Chain<T, U>

`impl<T: Read, U: Read> Read for Chain<T, U>`

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

[src]

Creates an adaptor which will chain this stream with another. Read more

####
ⓘImportant traits for Take<T>

### Important traits for Take<T>

`impl<T: Read> Read for Take<T>`

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

[src]

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

###

`impl<T: BufRead> BufRead for Take<T>`

[src]

####

`fn fill_buf(&mut self) -> Result<&[u8]>`

[src]

Fills the internal buffer of this object, returning the buffer contents. Read more

####

`fn consume(&mut self, amt: usize)`

[src]

Tells this buffer that `amt` bytes have been consumed from the buffer, so they should no longer be returned in calls to `read`. Read more

####

`fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize>`

[src]

Read all bytes into `buf` until the delimiter `byte` or EOF is reached. Read more

####

`fn read_line(&mut self, buf: &mut String) -> Result<usize>`

[src]

Read all bytes until a newline (the 0xA byte) is reached, and append them to the provided buffer. Read more

####
ⓘImportant traits for Split<B>

### Important traits for Split<B>

`impl<B: BufRead> Iterator for Split<B> type Item = Result<Vec<u8>>;`

`fn split(self, byte: u8) -> Split<Self> where Self: Sized,`

[src]

Returns an iterator over the contents of this reader split on the byte `byte`. Read more

####
ⓘImportant traits for Lines<B>

### Important traits for Lines<B>

`impl<B: BufRead> Iterator for Lines<B> type Item = Result<String>;`

`fn lines(self) -> Lines<Self> where Self: Sized,`

[src]

Returns an iterator over the lines of this reader. Read more

## Auto Trait Implementations

###

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

###

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

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