Trait bytes::Buf
[−]
[src]
pub trait Buf { fn remaining(&self) -> usize; fn bytes(&self) -> &[u8]; fn advance(&mut self, cnt: usize); fn bytes_vec<'a>(&'a self, dst: &mut [&'a IoVec]) -> 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 collect<B>(self) -> B
where
Self: Sized,
B: FromBuf, { ... } fn take(self, limit: usize) -> Take<Self>
where
Self: Sized, { ... } fn chain<U>(self, next: U) -> Chain<Self, U::Buf>
where
U: IntoBuf,
Self: Sized, { ... } fn by_ref(&mut self) -> &mut Self
where
Self: Sized, { ... } fn reader(self) -> Reader<Self>
where
Self: Sized, { ... } fn iter(self) -> Iter<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. It can be thought of as an efficient Iterator
for collections of
bytes.
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);
Implementer notes
Implementations of remaining
should ensure that the return value does
not change unless a call is made to advance
or any other function that
is documented to change the Buf
's current position.
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");
Implementer notes
This function should never panic. Once the end of the buffer is reached,
i.e., Buf::remaining
returns 0, calls to bytes
should return an
empty slice.
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 may panic if cnt > self.remaining()
.
Implementer notes
It is recommended for implementations of advance
to panic if cnt > self.remaining()
. If the implementation does not panic, the call must
behave as if cnt == self.remaining()
.
A call with cnt == 0
should never panic and be a no-op.
Provided Methods
fn bytes_vec<'a>(&'a self, dst: &mut [&'a IoVec]) -> usize
Fills dst
with potentially multiple slices starting at self
's
current position.
If the Buf
is backed by disjoint slices of bytes, bytes_vec
enables
fetching more than one slice at once. dst
is a slice of IoVec
references, enabling the slice to be directly used with writev
without any further conversion. The sum of the lengths of all the
buffers in dst
will be less than or equal to Buf::remaining()
.
The entries in dst
will be overwritten, but the data contained by
the slices will not be modified. If bytes_vec
does not fill every
entry in dst
, then dst
is guaranteed to contain all remaining slices
in `self.
This is a lower level function. Most operations are done with other functions.
Implementer notes
This function should never panic. Once the end of the buffer is reached,
i.e., Buf::remaining
returns 0, calls to bytes_vec
must return 0
without mutating dst
.
Implementations should also take care to properly handle being called
with dst
being a zero length slice.
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 collect<B>(self) -> B where
Self: Sized,
B: FromBuf,
Self: Sized,
B: FromBuf,
Transforms a Buf
into a concrete buffer.
collect()
can operate on any value that implements Buf
, and turn it
into the relevent concrete buffer type.
Examples
Collecting a buffer and loading the contents into a Vec<u8>
.
use bytes::{Buf, Bytes, IntoBuf}; let buf = Bytes::from(&b"hello world"[..]).into_buf(); let vec: Vec<u8> = buf.collect(); assert_eq!(vec, &b"hello world"[..]);
fn take(self, limit: usize) -> Take<Self> where
Self: Sized,
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 chain<U>(self, next: U) -> Chain<Self, U::Buf> where
U: IntoBuf,
Self: Sized,
U: IntoBuf,
Self: Sized,
Creates an adaptor which will chain this buffer with another.
The returned Buf
instance will first consume all bytes from self
.
Afterwards the output is equivalent to the output of next.
Examples
use bytes::{Bytes, Buf, IntoBuf}; use bytes::buf::Chain; let buf = Bytes::from(&b"hello "[..]).into_buf() .chain(Bytes::from(&b"world"[..])); let full: Bytes = buf.collect(); assert_eq!(full[..], b"hello world"[..]);
fn by_ref(&mut self) -> &mut Self where
Self: Sized,
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,
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");
fn iter(self) -> Iter<Self> where
Self: Sized,
Self: Sized,
Returns an iterator over the bytes contained by the buffer.
Examples
use bytes::{Buf, IntoBuf, Bytes}; let buf = Bytes::from(&b"abc"[..]).into_buf(); let mut iter = buf.iter(); assert_eq!(iter.next(), Some(b'a')); assert_eq!(iter.next(), Some(b'b')); assert_eq!(iter.next(), Some(b'c')); assert_eq!(iter.next(), None);