Struct buf_redux::BufReader

pub struct BufReader<R> {
    // some fields omitted
}

A drop-in replacement for std::io::BufReader with more functionality.

Original method names/signatures and implemented traits are left untouched, making replacement as simple as swapping the import of the type.

Methods

impl<R> BufReader<R>

fn new(inner: R) -> Self

Create a new BufReader wrapping inner, with a buffer of a default capacity.

fn with_capacity(cap: usize, inner: R) -> Self

Create a new BufReader wrapping inner with a capacity of at least cap bytes.

The actual capacity of the buffer may vary based on implementation details of the buffer's allocator.

fn make_room(&mut self)

Move data to the start of the buffer, making room at the end for more reading.

fn grow(&mut self, additional: usize)

Grow the internal buffer by at least additional bytes. May not be quite exact due to implementation details of the buffer's allocator.

Note

This should not be called frequently as each call will incur a reallocation and a zeroing of the new memory.

fn get_buf(&self) -> &[u8]

Get the section of the buffer containing valid data; may be empty.

Call .consume() to remove bytes from the beginning of this section.

fn available(&self) -> usize

Get the current number of bytes available in the buffer.

fn capacity(&self) -> usize

Get the total buffer capacity.

fn get_ref(&self) -> &R

Get an immutable reference to the underlying reader.

fn get_mut(&mut self) -> &mut R

Get a mutable reference to the underlying reader.

Note

Reading directly from the underlying reader is not recommended, as some data has likely already been moved into the buffer.

fn into_inner(self) -> R

Consumes self and returns the inner reader only.

fn into_inner_with_buf(self) -> (R, Vec<u8>)

Consumes self and returns both the underlying reader and the buffer, with the data moved to the beginning and the length truncated to contain only valid data.

See also: BufReader::unbuffer()

fn unbuffer(self) -> Unbuffer<R>

Consumes self and returns an adapter which implements Read and will empty the buffer before reading directly from the underlying reader.

impl<R: Read> BufReader<R>

fn read_into_buf(&mut self) -> Result<usize>

Unconditionally perform a read into the buffer, calling .make_room() if appropriate or necessary, as determined by the implementation.

If the read was successful, returns the number of bytes now available in the buffer.

Trait Implementations

impl<R: Read> Read for BufReader<R>

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.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> 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, placing them into buf.

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

Read the exact number of bytes required to fill buf.

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

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

fn bytes(self) -> Bytes<Self>

Transforms this Read instance to an Iterator over its bytes.

fn chars(self) -> Chars<Self>

Unstable (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 chars.

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

Creates an adaptor which will chain this stream with another.

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

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

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

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

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

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

Read all bytes into buf until the delimiter byte 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.

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

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

fn lines(self) -> Lines<Self>

Returns an iterator over the lines of this reader.

impl<R> Debug for BufReader<R> where R: Debug

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

Formats the value using the given formatter.

impl<R: Seek> Seek for BufReader<R>

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

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

The position used for seeking with SeekFrom::Current(_) is the position the underlying reader would be at if the BufReader had no internal buffer.

Seeking always discards the internal buffer, even if the seek position would otherwise fall within it. This guarantees that calling .unwrap() immediately after a seek yields the underlying reader at the same position.

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

Note: In the edge case where you're seeking with SeekFrom::Current(n) where n minus the internal buffer length underflows an i64, two seeks will be performed instead of one. If the second seek returns Err, the underlying reader will be left at the same position it would have if you seeked to SeekFrom::Current(0).