Struct stack_buffer::StackBufWriter

pub struct StackBufWriter<W: Write, const N: usize = 8192_usize> { /* fields omitted */ }

Wraps a writer and buffers its output.

See BufWriter for more details.

Examples

Let’s write the numbers one through ten to a TcpStream:

use std::io::prelude::*;
use std::net::TcpStream;

let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();

for i in 0..10 {
    stream.write(&[i+1]).unwrap();
}

Because we’re not buffering, we write each one in turn, incurring the overhead of a system call per byte written. We can fix this with a StackBufWriter<W, N>:

use std::io::prelude::*;
use std::net::TcpStream;
use stack_buffer::StackBufWriter;

let mut stream = StackBufWriter::<_, 8192>::new(TcpStream::connect("127.0.0.1:34254").unwrap());

for i in 0..10 {
    stream.write(&[i+1]).unwrap();
}
stream.flush().unwrap();

By wrapping the stream with a StackBufWriter<W, N>, these ten writes are all grouped together by the buffer and will all be written out in one system call when the stream is flushed.

Implementations

impl<W: Write, const N: usize> StackBufWriter<W, N>

pub fn new(inner: W) -> StackBufWriter<W, N>

Creates a new StackBufWriter<W, N>.

Examples

use std::net::TcpStream;
use stack_buffer::StackBufWriter;

let mut buffer = StackBufWriter::<_, 8192>::new(TcpStream::connect("127.0.0.1:34254").unwrap());

pub fn get_ref(&self) -> &W

Gets a reference to the underlying writer.

Examples

use std::net::TcpStream;
use stack_buffer::StackBufWriter;

let mut buffer = StackBufWriter::<_, 8192>::new(TcpStream::connect("127.0.0.1:34254").unwrap());

// we can use reference just like buffer
let reference = buffer.get_ref();

pub fn get_mut(&mut self) -> &mut W

Gets a mutable reference to the underlying writer.

It is inadvisable to directly write to the underlying writer.

Examples

use std::net::TcpStream;
use stack_buffer::StackBufWriter;

let mut buffer = StackBufWriter::<_, 8192>::new(TcpStream::connect("127.0.0.1:34254").unwrap());

// we can use reference just like buffer
let reference = buffer.get_mut();

pub fn buffer(&self) -> &[u8]

Returns a reference to the internally buffered data.

Examples

use std::net::TcpStream;
use stack_buffer::StackBufWriter;

let buf_writer = StackBufWriter::<_, 8192>::new(TcpStream::connect("127.0.0.1:34254").unwrap());

// See how many bytes are currently buffered
let bytes_buffered = buf_writer.buffer().len();

pub fn capacity(&self) -> usize

Returns the number of bytes the internal buffer can hold without flushing.

Examples

use std::net::TcpStream;
use stack_buffer::StackBufWriter;

let buf_writer = StackBufWriter::<_, 8192>::new(TcpStream::connect("127.0.0.1:34254").unwrap());

// Check the capacity of the inner buffer
let capacity = buf_writer.capacity();
// Calculate how many bytes can be written without flushing
let without_flush = capacity - buf_writer.buffer().len();

Trait Implementations

impl<W: Write, const N: usize> Debug for StackBufWriter<W, N> where
    W: Debug, 

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

Formats the value using the given formatter.

impl<W: Write, const N: usize> Drop for StackBufWriter<W, N>

fn drop(&mut self)

Executes the destructor for this type.

impl<W: Write + Seek, const N: usize> Seek for StackBufWriter<W, N>

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

Seek to the offset, in bytes, in the underlying writer.

Seeking always writes out the internal buffer before seeking.

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.

impl<W: Write, const N: usize> Write for StackBufWriter<W, N>

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

Write a buffer into this writer, returning how many bytes were written.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

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

Determines if this Writer has an efficient write_vectored implementation.

fn flush(&mut self) -> Result<()>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination.

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

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

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

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

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

Creates a “by reference” adapter for this instance of Write.