Struct IoDecoder

Source

pub struct IoDecoder<R: Read> { /* private fields */ }

Available on crate feature std only.

Expand description

Streaming decoder that reads directly from any Read-shaped source.

Each IoDecoder::read call may issue many small reads against the underlying source. Wrap raw sockets / files in std::io::BufReader first if read-syscall amplification is a concern.

§Examples

use pack_io::{IoEncoder, IoDecoder};
use std::io::Cursor;

let mut buf: Vec<u8> = Vec::new();
{
    let mut enc = IoEncoder::new(&mut buf);
    enc.write(&42_u64).unwrap();
    enc.write(&"hi").unwrap();
}

let mut dec = IoDecoder::new(Cursor::new(buf));
let n: u64 = dec.read().unwrap();
let s: String = dec.read().unwrap();
assert_eq!((n, s.as_str()), (42, "hi"));

Implementations§

Source §

impl<R: Read> IoDecoder<R>

Source

pub fn new(reader: R) -> Self

Wrap reader with the default Config (1 GiB max_alloc).

For tighter allocation caps on untrusted input, use IoDecoder::with_config instead.

§Examples

use std::io::Cursor;
use pack_io::IoDecoder;

let bytes = pack_io::encode(&42_u64).unwrap();
let mut dec = IoDecoder::new(Cursor::new(bytes));
let n: u64 = dec.read().unwrap();
assert_eq!(n, 42);

Source

pub fn with_config(reader: R, config: Config) -> Result<Self>

Wrap reader with the supplied configuration.

§Errors

Returns SerialError::InvalidLength if config.max_alloc == 0.

§Examples

use std::io::Cursor;
use pack_io::{Config, IoDecoder};

let cfg = Config::new().with_max_alloc(16 * 1024);
let bytes = pack_io::encode(&"hello").unwrap();
let mut dec = IoDecoder::with_config(Cursor::new(bytes), cfg).unwrap();
let s: String = dec.read().unwrap();
assert_eq!(s, "hello");

Source

pub fn reader(&self) -> &R

Borrow the underlying reader.

§Examples

use std::io::Cursor;
use pack_io::IoDecoder;

let dec = IoDecoder::new(Cursor::new(vec![0u8; 4]));
assert_eq!(dec.reader().get_ref().len(), 4);

Source

pub fn into_inner(self) -> R

Consume the decoder and return the underlying reader.

Useful when the caller wants to take back ownership of the source (e.g. to drop the reader, return it to a pool, or feed it to a different consumer) after the decoded prefix has been processed.

§Examples

use std::io::Cursor;
use pack_io::IoDecoder;

let bytes = pack_io::encode(&42_u64).unwrap();
let mut dec = IoDecoder::new(Cursor::new(bytes));
let _n: u64 = dec.read().unwrap();
let reader: Cursor<Vec<u8>> = dec.into_inner();
assert_eq!(reader.position(), 1); // one byte consumed for u64=42