Struct 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> BufReader<R>

where R: Read + Seek,

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);

Examples found in repository

examples/ioreg.rs (line 15)

fn main() {
    let ioreg = Command::new("ioreg")
        .arg("-c")
        .arg("IOUSB")
        .arg("-a")
        .output()
        .unwrap();
    let input = BufReader::new(Cursor::new(ioreg.stdout));

    let stdout = OpenOptions::new()
        .write(true)
        .open(Path::new("/dev/stdout"))
        .unwrap();

    let output = BufWriter::new(stdout);

    json::transcode_from_xml_reader(input, output)
}

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, Error>

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

Trait Implementations

impl<R> BufRead for BufReader<R>

where R: Read,

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

Returns the contents of the internal buffer, filling it with more data, via Read methods, if empty.

fn consume(&mut self, amt: usize)

Marks the given amount of additional bytes from the internal buffer as having been read. Subsequent calls to read only return bytes that have not been marked as read.

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

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

Checks if there is any data left to be read.

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

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

fn skip_until(&mut self, byte: u8) -> Result<usize, Error>

Skips all bytes until the delimiter byte or EOF is reached.

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

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

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<(), Error>

Formats the value using the given formatter.

impl<R> Read for BufReader<R>

where R: Read,

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

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>) -> Result<usize, Error>

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

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

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

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

Reads 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)

Reads the exact number of bytes required to fill cursor.

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

where Self: Sized,

Creates a “by reference” adapter 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> Seek for BufReader<R>

where R: Read + Seek,

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

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.

fn seek_relative(&mut self, offset: i64) -> Result<(), Error>

Seeks relative to the current position.