Trait bytes::Buf [−] [src]

pub trait Buf {
    fn remaining(&self) -> usize;
    fn bytes(&self) -> &[u8];
    fn advance(&mut self, cnt: usize);

    fn has_remaining(&self) -> bool { ... }
    fn copy_to_slice(&mut self, dst: &mut [u8]) { ... }
    fn get_u8(&mut self) -> u8 { ... }
    fn get_i8(&mut self) -> i8 { ... }
    fn get_u16<T: ByteOrder>(&mut self) -> u16 { ... }
    fn get_i16<T: ByteOrder>(&mut self) -> i16 { ... }
    fn get_u32<T: ByteOrder>(&mut self) -> u32 { ... }
    fn get_i32<T: ByteOrder>(&mut self) -> i32 { ... }
    fn get_u64<T: ByteOrder>(&mut self) -> u64 { ... }
    fn get_i64<T: ByteOrder>(&mut self) -> i64 { ... }
    fn get_uint<T: ByteOrder>(&mut self, nbytes: usize) -> u64 { ... }
    fn get_int<T: ByteOrder>(&mut self, nbytes: usize) -> i64 { ... }
    fn get_f32<T: ByteOrder>(&mut self) -> f32 { ... }
    fn get_f64<T: ByteOrder>(&mut self) -> f64 { ... }
    fn take(self, limit: usize) -> Take<Self> where Self: Sized { ... }
    fn by_ref(&mut self) -> &mut Self where Self: Sized { ... }
    fn reader(self) -> Reader<Self> where Self: Sized { ... }
}

Read bytes from a buffer.

A buffer stores bytes in memory such that read operations are infallible. The underlying storage may or may not be in contiguous memory. A Buf value is a cursor into the buffer. Reading from Buf advances the cursor position.

The simplest Buf is a Cursor wrapping a [u8].

use bytes::Buf;
use std::io::Cursor;

let mut buf = Cursor::new(b"hello world");

assert_eq!(b'h', buf.get_u8());
assert_eq!(b'e', buf.get_u8());
assert_eq!(b'l', buf.get_u8());

let mut rest = [0; 8];
buf.copy_to_slice(&mut rest);

assert_eq!(&rest[..], b"lo world");

Required Methods

`fn remaining(&self) -> usize`

Returns the number of bytes between the current position and the end of the buffer.

This value is greater than or equal to the length of the slice returned by bytes.

Examples

use bytes::Buf;
use std::io::Cursor;

let mut buf = Cursor::new(b"hello world");

assert_eq!(buf.remaining(), 11);

buf.get_u8();

assert_eq!(buf.remaining(), 10);

`fn bytes(&self) -> &[u8]`

Returns a slice starting at the current position and of length between 0 and Buf::remaining().

This is a lower level function. Most operations are done with other functions.

Examples

use bytes::Buf;
use std::io::Cursor;

let mut buf = Cursor::new(b"hello world");

assert_eq!(buf.bytes(), b"hello world");

buf.advance(6);

assert_eq!(buf.bytes(), b"world");

`fn advance(&mut self, cnt: usize)`

Advance the internal cursor of the Buf

The next call to bytes will return a slice starting cnt bytes further into the underlying buffer.

Examples

use bytes::Buf;
use std::io::Cursor;

let mut buf = Cursor::new(b"hello world");

assert_eq!(buf.bytes(), b"hello world");

buf.advance(6);

assert_eq!(buf.bytes(), b"world");

Panics

This function can panic if cnt > self.remaining().

Provided Methods

`fn has_remaining(&self) -> bool`

Returns true if there are any more bytes to consume

This is equivalent to self.remaining() != 0.

Examples

use bytes::Buf;
use std::io::Cursor;

let mut buf = Cursor::new(b"a");

assert!(buf.has_remaining());

buf.get_u8();

assert!(!buf.has_remaining());

`fn copy_to_slice(&mut self, dst: &mut [u8])`

Copies bytes from self into dst.

The cursor is advanced by the number of bytes copied. self must have enough remaining bytes to fill dst.

Examples

use bytes::Buf;
use std::io::Cursor;

let mut buf = Cursor::new(b"hello world");
let mut dst = [0; 5];

buf.copy_to_slice(&mut dst);
assert_eq!(b"hello", &dst);
assert_eq!(6, buf.remaining());

Panics

This function panics if self.remaining() < dst.len()

`fn get_u8(&mut self) -> u8`

Gets an unsigned 8 bit integer from self.

The current position is advanced by 1.

Examples

use bytes::Buf;
use std::io::Cursor;

let mut buf = Cursor::new(b"\x08 hello");
assert_eq!(8, buf.get_u8());

Panics

This function panics if there is no more remaining data in self.

`fn get_i8(&mut self) -> i8`

Gets a signed 8 bit integer from self.

The current position is advanced by 1.

Examples

use bytes::Buf;
use std::io::Cursor;

let mut buf = Cursor::new(b"\x08 hello");
assert_eq!(8, buf.get_i8());

Panics

This function panics if there is no more remaining data in self.

`fn get_u16<T: ByteOrder>(&mut self) -> u16`

Gets an unsigned 16 bit integer from self in the specified byte order.

The current position is advanced by 2.

Examples

use bytes::{Buf, BigEndian};
use std::io::Cursor;

let mut buf = Cursor::new(b"\x08\x09 hello");
assert_eq!(0x0809, buf.get_u16::<BigEndian>());

Panics

This function panics if there is not enough remaining data in self.

`fn get_i16<T: ByteOrder>(&mut self) -> i16`

Gets a signed 16 bit integer from self in the specified byte order.

The current position is advanced by 2.

Examples

use bytes::{Buf, BigEndian};
use std::io::Cursor;

let mut buf = Cursor::new(b"\x08\x09 hello");
assert_eq!(0x0809, buf.get_i16::<BigEndian>());

Panics

This function panics if there is not enough remaining data in self.

`fn get_u32<T: ByteOrder>(&mut self) -> u32`

Gets an unsigned 32 bit integer from self in the specified byte order.

The current position is advanced by 4.

Examples

use bytes::{Buf, BigEndian};
use std::io::Cursor;

let mut buf = Cursor::new(b"\x08\x09\xA0\xA1 hello");
assert_eq!(0x0809A0A1, buf.get_u32::<BigEndian>());

Panics

This function panics if there is not enough remaining data in self.

`fn get_i32<T: ByteOrder>(&mut self) -> i32`

Gets a signed 32 bit integer from self in the specified byte order.

The current position is advanced by 4.

Examples

use bytes::{Buf, BigEndian};
use std::io::Cursor;

let mut buf = Cursor::new(b"\x08\x09\xA0\xA1 hello");
assert_eq!(0x0809A0A1, buf.get_i32::<BigEndian>());

Panics

This function panics if there is not enough remaining data in self.

`fn get_u64<T: ByteOrder>(&mut self) -> u64`

Gets an unsigned 64 bit integer from self in the specified byte order.

The current position is advanced by 8.

Examples

use bytes::{Buf, BigEndian};
use std::io::Cursor;

let mut buf = Cursor::new(b"\x01\x02\x03\x04\x05\x06\x07\x08 hello");
assert_eq!(0x0102030405060708, buf.get_u64::<BigEndian>());

Panics

This function panics if there is not enough remaining data in self.

`fn get_i64<T: ByteOrder>(&mut self) -> i64`

Gets a signed 64 bit integer from self in the specified byte order.

The current position is advanced by 8.

Examples

use bytes::{Buf, BigEndian};
use std::io::Cursor;

let mut buf = Cursor::new(b"\x01\x02\x03\x04\x05\x06\x07\x08 hello");
assert_eq!(0x0102030405060708, buf.get_i64::<BigEndian>());

Panics

This function panics if there is not enough remaining data in self.

`fn get_uint<T: ByteOrder>(&mut self, nbytes: usize) -> u64`

Gets an unsigned n-byte integer from self in the specified byte order.

The current position is advanced by nbytes.

Examples

use bytes::{Buf, BigEndian};
use std::io::Cursor;

let mut buf = Cursor::new(b"\x01\x02\x03 hello");
assert_eq!(0x010203, buf.get_uint::<BigEndian>(3));

Panics

This function panics if there is not enough remaining data in self.

`fn get_int<T: ByteOrder>(&mut self, nbytes: usize) -> i64`

Gets a signed n-byte integer from self in the specified byte order.

The current position is advanced by nbytes.

Examples

use bytes::{Buf, BigEndian};
use std::io::Cursor;

let mut buf = Cursor::new(b"\x01\x02\x03 hello");
assert_eq!(0x010203, buf.get_int::<BigEndian>(3));

Panics

This function panics if there is not enough remaining data in self.

`fn get_f32<T: ByteOrder>(&mut self) -> f32`

Gets an IEEE754 single-precision (4 bytes) floating point number from self in the specified byte order.

The current position is advanced by 4.

Examples

use bytes::{Buf, BigEndian};
use std::io::Cursor;

let mut buf = Cursor::new(b"\x3F\x99\x99\x9A hello");
assert_eq!(1.2f32, buf.get_f32::<BigEndian>());

Panics

This function panics if there is not enough remaining data in self.

`fn get_f64<T: ByteOrder>(&mut self) -> f64`

Gets an IEEE754 double-precision (8 bytes) floating point number from self in the specified byte order.

The current position is advanced by 8.

Examples

use bytes::{Buf, BigEndian};
use std::io::Cursor;

let mut buf = Cursor::new(b"\x3F\xF3\x33\x33\x33\x33\x33\x33 hello");
assert_eq!(1.2f64, buf.get_f64::<BigEndian>());

Panics

This function panics if there is not enough remaining data in self.

`fn take(self, limit: usize) -> Take<Self> where Self: Sized`

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

This function returns a new instance of Buf which will read at most limit bytes.

Examples

use bytes::{Buf, BufMut};
use std::io::Cursor;

let mut buf = Cursor::new("hello world").take(5);
let mut dst = vec![];

dst.put(&mut buf);
assert_eq!(dst, b"hello");

let mut buf = buf.into_inner();
dst.clear();
dst.put(&mut buf);
assert_eq!(dst, b" world");

`fn by_ref(&mut self) -> &mut Self where Self: Sized`

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

The returned adaptor also implements Buf and will simply borrow self.

Examples

use bytes::{Buf, BufMut};
use std::io::Cursor;

let mut buf = Cursor::new("hello world");
let mut dst = vec![];

{
    let mut reference = buf.by_ref();
    dst.put(&mut reference.take(5));
    assert_eq!(dst, b"hello");
} // drop our &mut reference so we can use `buf` again

dst.clear();
dst.put(&mut buf);
assert_eq!(dst, b" world");

`fn reader(self) -> Reader<Self> where Self: Sized`

Creates an adaptor which implements the Read trait for self.

This function returns a new value which implements Read by adapting the Read trait functions to the Buf trait functions. Given that Buf operations are infallible, none of the Read functions will return with Err.

Examples

use bytes::{Buf, IntoBuf, Bytes};
use std::io::Read;

let buf = Bytes::from("hello world").into_buf();

let mut reader = buf.reader();
let mut dst = [0; 1024];

let num = reader.read(&mut dst).unwrap();

assert_eq!(11, num);
assert_eq!(&dst[..11], b"hello world");

Implementors

impl<T: Buf> Buf for Take<T>
impl<'a, T: Buf> Buf for &'a mut T
impl<T: AsRef<[u8]>> Buf for Cursor<T>