Struct seek_bufread::BufReader
[−]
[src]
pub struct BufReader<R> { /* fields omitted */ }
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);
Methods
impl<R: Read + Seek> BufReader<R>
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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);
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);
fn position(&self) -> u64
Returns the absolute file pointer position.
fn capacity(&self) -> usize
Returns the total buffer capacity.
fn available(&self) -> usize
Returns the current number of remaining bytes available in the buffer.
fn into_inner(self) -> Result<R>
Consumes self
, synchronizes the inner reader position and returns the inner reader.
Trait Implementations
impl<R: Read> Read for BufReader<R>
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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_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>
1.0.0
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, Error>
1.0.0
Read all bytes until EOF in this source, placing them into buf
. Read more
fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>
1.6.0
Read the exact number of bytes required to fill buf
. Read more
fn by_ref(&mut self) -> &mut Self
1.0.0
Creates a "by reference" adaptor for this instance of Read
. Read more
fn bytes(self) -> Bytes<Self>
1.0.0
Transforms this Read
instance to an Iterator
over its bytes. Read more
fn chars(self) -> Chars<Self>
io
): 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
fn chain<R>(self, next: R) -> Chain<Self, R> where R: Read
1.0.0
Creates an adaptor which will chain this stream with another. Read more
fn take(self, limit: u64) -> Take<Self>
1.0.0
Creates an adaptor which will read at most limit
bytes from it. Read more
impl<R: Read> BufRead for BufReader<R>
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fn fill_buf(&mut self) -> Result<&[u8]>
Fills the internal buffer of this object, returning the buffer contents. Read more
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
. Read more
fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize, Error>
1.0.0
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, Error>
1.0.0
Read all bytes until a newline (the 0xA byte) is reached, and append them to the provided buffer. Read more
fn split(self, byte: u8) -> Split<Self>
1.0.0
Returns an iterator over the contents of this reader split on the byte byte
. Read more
fn lines(self) -> Lines<Self>
1.0.0
Returns an iterator over the lines of this reader. Read more
impl<R: Read + Seek> Seek for BufReader<R>
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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.