Struct read_restrict::Restrict

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

Reader adaptor which restricts the bytes read from an underlying reader, returning an IO error of the kind ErrorKind::InvalidData when it is exceeded.

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

Implementations

impl<T> Restrict<T>

pub fn restriction(&self) -> u64

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

Examples

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

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

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

    println!("restriction: {}", handle.restriction());
    Ok(())
}

pub fn set_restriction(&mut self, restriction: u64)

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

Examples

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

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

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

    assert_eq!(handle.restriction(), 10);
    Ok(())
}

pub fn into_inner(self) -> T

Consumes the Restrict, returning the wrapped reader.

Examples

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

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

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

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

pub fn get_ref(&self) -> &T

Gets a reference to the underlying reader.

Examples

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

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

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

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

pub 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 Restrict.

Examples

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

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

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

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

Trait Implementations

impl<T: BufRead> BufRead for Restrict<T>

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

Returns the contents of the internal buffer, filling it with more data from the inner reader if it is empty.

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

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

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

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

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

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

pub fn split(self, byte: u8) -> Split<Self>

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

pub fn lines(self) -> Lines<Self>

Returns an iterator over the lines of this reader.

impl<T: Debug> Debug for Restrict<T>

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

Formats the value using the given formatter.

impl<T: Read> Read for Restrict<T>

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

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

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

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

pub 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.

pub 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.

pub 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.

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

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

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

Read the exact number of bytes required to fill buf.

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

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

pub fn bytes(self) -> Bytes<Self>

Transforms this Read instance to an Iterator over its bytes.

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

Creates an adaptor which will chain this stream with another.

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

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