countio

countio

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The wrapper struct to enable byte counting for std::io::{Read, Write, Seek} and its asynchronous variants from futures and tokio crates.

Supports bidirectional I/O objects (like TcpStream or Cursor) that implement both read and write traits, tracking read and write byte counts independently.

Features

• std to enable std::io::{Read, BufRead, Write, Seek}. Enabled by default.
• futures to enable futures_io::{AsyncRead, AsyncBufRead, AsyncWrite, AsyncSeek}.
• tokio to enable tokio::io::{AsyncRead, AsyncBufRead, AsyncWrite, AsyncSeek}.
• full to enable all features (std, futures, and tokio).

Examples

• std::io::Read:

use std::io::{BufRead, BufReader, Result};
use countio::Counter;

fn main() -> Result<()> {
    let reader = "Hello World!".as_bytes();
    let reader = BufReader::new(reader);
    let mut reader = Counter::new(reader);

    let mut buf = String::new();
    let len = reader.read_line(&mut buf)?;

    assert_eq!(len, reader.reader_bytes());
    Ok(())
}

• std::io::Write:

use std::io::{BufWriter, Write, Result};
use countio::Counter;

fn main() -> Result<()> {
    let writer = Vec::new();
    let writer = BufWriter::new(writer);
    let mut writer = Counter::new(writer);

    let buf = "Hello World!".as_bytes();
    let len = writer.write(buf)?;
    writer.flush()?;

    assert_eq!(len, writer.writer_bytes());
    Ok(())
}

• Bidirectional I/O with Progress:

use std::io::{Cursor, Read, Write, Result};
use countio::Progress;

fn main() -> Result<()> {
    let mut data = vec![0u8; 100];
    let cursor = Cursor::new(&mut data);
    let mut progress = Progress::with_expected_bytes(cursor, 50, 50);

    // Write some data
    progress.write_all(b"Hello")?;
    assert_eq!(progress.writer_bytes(), 5);
    assert_eq!(progress.writer_percentage(), Some(0.1));

    // Seek back and read
    progress.get_mut().set_position(0);
    let mut buf = [0u8; 5];
    progress.read_exact(&mut buf)?;
    assert_eq!(progress.reader_bytes(), 5);
    assert_eq!(progress.reader_percentage(), Some(0.1));

    Ok(())
}

Other crates

• SOF3/count-write