Struct seek_bufread::BufReader

pub struct BufReader<R> { /* private fields */ }

The BufReader struct adds buffering to any reader.

It can be excessively inefficient to work directly with a Read instance. For example, every call to read on TcpStream results in a system call. A BufReader performs large, infrequent reads on the underlying Read and maintains an in-memory buffer of the results.

Examples

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

let mut f = try!(File::open("log.txt"));
let mut reader = BufReader::new(f);

let mut line = String::new();
let len = try!(reader.read_line(&mut line));
println!("First line is {} bytes long", len);

Implementations

impl<R: Read + Seek> BufReader<R>

pub fn new(inner: R) -> BufReader<R>

Creates a new BufReader with a default buffer capacity (8192 bytes).

Examples

use std::fs::File;
use seek_bufread::BufReader;

let mut f = try!(File::open("log.txt"));
let mut reader = BufReader::new(f);

pub fn with_capacity(cap: usize, inner: R) -> BufReader<R>

Creates a new BufReader with the specified buffer capacity.

Examples

Creating a buffer with ten bytes of capacity:

use std::fs::File;
use seek_bufread::BufReader;

let mut f = try!(File::open("log.txt"));
let mut reader = BufReader::with_capacity(10, f);

pub fn position(&self) -> u64

Returns the absolute file pointer position.

pub fn capacity(&self) -> usize

Returns the total buffer capacity.

pub fn available(&self) -> usize

Returns the current number of remaining bytes available in the buffer.

pub fn into_inner(self) -> Result<R>

Consumes self, synchronizes the inner reader position and returns the inner reader.

Trait Implementations

impl<R: Read> BufRead for BufReader<R>

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.

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.

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

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

Check if the underlying Read has any data left to be read.

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.

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. You do not need to clear the buffer before appending.

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

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

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

Returns an iterator over the lines of this reader.

impl<R> Debug for BufReader<R>where
    R: Debug + Read + Seek,

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

Formats the value using the given formatter.

impl<R: Read> Read for BufReader<R>

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

Reads the next available bytes from buffer or inner stream. Doesn’t guarantee the whole buffer is filled. Returns number of read bytes.

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<R: Read + Seek> Seek for BufReader<R>

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

Seek to an offset, in bytes, in the buffer or the underlying reader.

The position used for seeking with SeekFrom::Current(_) is the current position of the underlying reader plus the current position in the internal buffer.

Calling .unwrap() immediately after a seek doesn’t guarantee the underlying reader at the same position!

See std::io::Seek for more details.

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.