pub trait Buf {
Show 36 methods
fn remaining(&self) -> usize;
fn chunk(&self) -> &[u8]ⓘNotable traits for &'_ [u8]impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]
;
fn advance(&mut self, cnt: usize);
fn chunks_vectored<'a>(&'a self, dst: &mut [IoSlice<'a>]) -> 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(&mut self) -> u16 { ... }
fn get_u16_le(&mut self) -> u16 { ... }
fn get_i16(&mut self) -> i16 { ... }
fn get_i16_le(&mut self) -> i16 { ... }
fn get_u32(&mut self) -> u32 { ... }
fn get_u32_le(&mut self) -> u32 { ... }
fn get_i32(&mut self) -> i32 { ... }
fn get_i32_le(&mut self) -> i32 { ... }
fn get_u64(&mut self) -> u64 { ... }
fn get_u64_le(&mut self) -> u64 { ... }
fn get_i64(&mut self) -> i64 { ... }
fn get_i64_le(&mut self) -> i64 { ... }
fn get_u128(&mut self) -> u128 { ... }
fn get_u128_le(&mut self) -> u128 { ... }
fn get_i128(&mut self) -> i128 { ... }
fn get_i128_le(&mut self) -> i128 { ... }
fn get_uint(&mut self, nbytes: usize) -> u64 { ... }
fn get_uint_le(&mut self, nbytes: usize) -> u64 { ... }
fn get_int(&mut self, nbytes: usize) -> i64 { ... }
fn get_int_le(&mut self, nbytes: usize) -> i64 { ... }
fn get_f32(&mut self) -> f32 { ... }
fn get_f32_le(&mut self) -> f32 { ... }
fn get_f64(&mut self) -> f64 { ... }
fn get_f64_le(&mut self) -> f64 { ... }
fn copy_to_bytes(&mut self, len: usize) -> Bytes { ... }
fn take(self, limit: usize) -> Take<Self>
where
Self: Sized,
{ ... }
fn chain<U: Buf>(self, next: U) -> Chain<Self, U>
where
Self: Sized,
{ ... }
fn reader(self) -> Reader<Self>ⓘNotable traits for Reader<B>impl<B: Buf + Sized> Read for Reader<B>
where
Self: Sized,
{ ... }
}
Expand description
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 &[u8]
.
use bytes::Buf;
let mut buf = &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
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 chunk()
.
Examples
use bytes::Buf;
let mut buf = &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.
Returns a slice starting at the current position and of length between 0
and Buf::remaining()
. Note that this can return shorter slice (this allows
non-continuous internal representation).
This is a lower level function. Most operations are done with other functions.
Examples
use bytes::Buf;
let mut buf = &b"hello world"[..];
assert_eq!(buf.chunk(), &b"hello world"[..]);
buf.advance(6);
assert_eq!(buf.chunk(), &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 chunk()
should return an
empty slice.
Advance the internal cursor of the Buf
The next call to chunk()
will return a slice starting cnt
bytes
further into the underlying buffer.
Examples
use bytes::Buf;
let mut buf = &b"hello world"[..];
assert_eq!(buf.chunk(), &b"hello world"[..]);
buf.advance(6);
assert_eq!(buf.chunk(), &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
Fills dst
with potentially multiple slices starting at self
’s
current position.
If the Buf
is backed by disjoint slices of bytes, chunk_vectored
enables
fetching more than one slice at once. dst
is a slice of IoSlice
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 chunk_vectored
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 chunk_vectored
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
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;
let mut buf = &b"a"[..];
assert!(buf.has_remaining());
buf.get_u8();
assert!(!buf.has_remaining());
fn copy_to_slice(&mut self, dst: &mut [u8])
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;
let mut buf = &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_u16_le(&mut self) -> u16
fn get_u16_le(&mut self) -> u16
fn get_i16_le(&mut self) -> i16
fn get_i16_le(&mut self) -> i16
fn get_u32_le(&mut self) -> u32
fn get_u32_le(&mut self) -> u32
Gets an unsigned 32 bit integer from self
in the little-endian byte order.
The current position is advanced by 4.
Examples
use bytes::Buf;
let mut buf = &b"\xA1\xA0\x09\x08 hello"[..];
assert_eq!(0x0809A0A1, buf.get_u32_le());
Panics
This function panics if there is not enough remaining data in self
.
fn get_i32_le(&mut self) -> i32
fn get_i32_le(&mut self) -> i32
Gets an unsigned 64 bit integer from self
in big-endian byte order.
The current position is advanced by 8.
Examples
use bytes::Buf;
let mut buf = &b"\x01\x02\x03\x04\x05\x06\x07\x08 hello"[..];
assert_eq!(0x0102030405060708, buf.get_u64());
Panics
This function panics if there is not enough remaining data in self
.
fn get_u64_le(&mut self) -> u64
fn get_u64_le(&mut self) -> u64
Gets an unsigned 64 bit integer from self
in little-endian byte order.
The current position is advanced by 8.
Examples
use bytes::Buf;
let mut buf = &b"\x08\x07\x06\x05\x04\x03\x02\x01 hello"[..];
assert_eq!(0x0102030405060708, buf.get_u64_le());
Panics
This function panics if there is not enough remaining data in self
.
Gets a signed 64 bit integer from self
in big-endian byte order.
The current position is advanced by 8.
Examples
use bytes::Buf;
let mut buf = &b"\x01\x02\x03\x04\x05\x06\x07\x08 hello"[..];
assert_eq!(0x0102030405060708, buf.get_i64());
Panics
This function panics if there is not enough remaining data in self
.
fn get_i64_le(&mut self) -> i64
fn get_i64_le(&mut self) -> i64
Gets a signed 64 bit integer from self
in little-endian byte order.
The current position is advanced by 8.
Examples
use bytes::Buf;
let mut buf = &b"\x08\x07\x06\x05\x04\x03\x02\x01 hello"[..];
assert_eq!(0x0102030405060708, buf.get_i64_le());
Panics
This function panics if there is not enough remaining data in self
.
Gets an unsigned 128 bit integer from self
in big-endian byte order.
The current position is advanced by 16.
Examples
use bytes::Buf;
let mut buf = &b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16 hello"[..];
assert_eq!(0x01020304050607080910111213141516, buf.get_u128());
Panics
This function panics if there is not enough remaining data in self
.
fn get_u128_le(&mut self) -> u128
fn get_u128_le(&mut self) -> u128
Gets an unsigned 128 bit integer from self
in little-endian byte order.
The current position is advanced by 16.
Examples
use bytes::Buf;
let mut buf = &b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01 hello"[..];
assert_eq!(0x01020304050607080910111213141516, buf.get_u128_le());
Panics
This function panics if there is not enough remaining data in self
.
Gets a signed 128 bit integer from self
in big-endian byte order.
The current position is advanced by 16.
Examples
use bytes::Buf;
let mut buf = &b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16 hello"[..];
assert_eq!(0x01020304050607080910111213141516, buf.get_i128());
Panics
This function panics if there is not enough remaining data in self
.
fn get_i128_le(&mut self) -> i128
fn get_i128_le(&mut self) -> i128
Gets a signed 128 bit integer from self
in little-endian byte order.
The current position is advanced by 16.
Examples
use bytes::Buf;
let mut buf = &b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01 hello"[..];
assert_eq!(0x01020304050607080910111213141516, buf.get_i128_le());
Panics
This function panics if there is not enough remaining data in self
.
fn get_uint_le(&mut self, nbytes: usize) -> u64
fn get_uint_le(&mut self, nbytes: usize) -> u64
fn get_int_le(&mut self, nbytes: usize) -> i64
fn get_int_le(&mut self, nbytes: usize) -> i64
Gets an IEEE754 single-precision (4 bytes) floating point number from
self
in big-endian byte order.
The current position is advanced by 4.
Examples
use bytes::Buf;
let mut buf = &b"\x3F\x99\x99\x9A hello"[..];
assert_eq!(1.2f32, buf.get_f32());
Panics
This function panics if there is not enough remaining data in self
.
fn get_f32_le(&mut self) -> f32
fn get_f32_le(&mut self) -> f32
Gets an IEEE754 single-precision (4 bytes) floating point number from
self
in little-endian byte order.
The current position is advanced by 4.
Examples
use bytes::Buf;
let mut buf = &b"\x9A\x99\x99\x3F hello"[..];
assert_eq!(1.2f32, buf.get_f32_le());
Panics
This function panics if there is not enough remaining data in self
.
Gets an IEEE754 double-precision (8 bytes) floating point number from
self
in big-endian byte order.
The current position is advanced by 8.
Examples
use bytes::Buf;
let mut buf = &b"\x3F\xF3\x33\x33\x33\x33\x33\x33 hello"[..];
assert_eq!(1.2f64, buf.get_f64());
Panics
This function panics if there is not enough remaining data in self
.
fn get_f64_le(&mut self) -> f64
fn get_f64_le(&mut self) -> f64
Gets an IEEE754 double-precision (8 bytes) floating point number from
self
in little-endian byte order.
The current position is advanced by 8.
Examples
use bytes::Buf;
let mut buf = &b"\x33\x33\x33\x33\x33\x33\xF3\x3F hello"[..];
assert_eq!(1.2f64, buf.get_f64_le());
Panics
This function panics if there is not enough remaining data in self
.
fn copy_to_bytes(&mut self, len: usize) -> Bytes
fn copy_to_bytes(&mut self, len: usize) -> Bytes
Consumes len
bytes inside self and returns new instance of Bytes
with this data.
This function may be optimized by the underlying type to avoid actual
copies. For example, Bytes
implementation will do a shallow copy
(ref-count increment).
Examples
use bytes::Buf;
let bytes = (&b"hello world"[..]).copy_to_bytes(5);
assert_eq!(&bytes[..], &b"hello"[..]);
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};
let mut buf = b"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");
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::Buf;
let mut chain = b"hello "[..].chain(&b"world"[..]);
let full = chain.copy_to_bytes(11);
assert_eq!(full.chunk(), b"hello world");
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::{Bytes, Buf};
use std::io::Read;
let buf = Bytes::from("hello world");
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"[..]);