pub unsafe trait BufMut {
Show 36 methods
fn remaining_mut(&self) -> usize;
unsafe fn advance_mut(&mut self, cnt: usize);
fn chunk_mut(&mut self) -> &mut UninitSlice;
fn has_remaining_mut(&self) -> bool { ... }
fn put<T: Buf>(&mut self, src: T)
where
Self: Sized,
{ ... }
fn put_slice(&mut self, src: &[u8]) { ... }
fn put_bytes(&mut self, val: u8, cnt: usize) { ... }
fn put_u8(&mut self, n: u8) { ... }
fn put_i8(&mut self, n: i8) { ... }
fn put_u16(&mut self, n: u16) { ... }
fn put_u16_le(&mut self, n: u16) { ... }
fn put_i16(&mut self, n: i16) { ... }
fn put_i16_le(&mut self, n: i16) { ... }
fn put_u32(&mut self, n: u32) { ... }
fn put_u32_le(&mut self, n: u32) { ... }
fn put_i32(&mut self, n: i32) { ... }
fn put_i32_le(&mut self, n: i32) { ... }
fn put_u64(&mut self, n: u64) { ... }
fn put_u64_le(&mut self, n: u64) { ... }
fn put_i64(&mut self, n: i64) { ... }
fn put_i64_le(&mut self, n: i64) { ... }
fn put_u128(&mut self, n: u128) { ... }
fn put_u128_le(&mut self, n: u128) { ... }
fn put_i128(&mut self, n: i128) { ... }
fn put_i128_le(&mut self, n: i128) { ... }
fn put_uint(&mut self, n: u64, nbytes: usize) { ... }
fn put_uint_le(&mut self, n: u64, nbytes: usize) { ... }
fn put_int(&mut self, n: i64, nbytes: usize) { ... }
fn put_int_le(&mut self, n: i64, nbytes: usize) { ... }
fn put_f32(&mut self, n: f32) { ... }
fn put_f32_le(&mut self, n: f32) { ... }
fn put_f64(&mut self, n: f64) { ... }
fn put_f64_le(&mut self, n: f64) { ... }
fn limit(self, limit: usize) -> Limit<Self>
where
Self: Sized,
{ ... }
fn writer(self) -> Writer<Self>ⓘNotable traits for Writer<B>impl<B: BufMut + Sized> Write for Writer<B>
where
Self: Sized,
{ ... }
fn chain_mut<U: BufMut>(self, next: U) -> Chain<Self, U>
where
Self: Sized,
{ ... }
}
Expand description
A trait for values that provide sequential write access to bytes.
Write bytes to a buffer
A buffer stores bytes in memory such that write operations are infallible.
The underlying storage may or may not be in contiguous memory. A BufMut
value is a cursor into the buffer. Writing to BufMut
advances the cursor
position.
The simplest BufMut
is a Vec<u8>
.
use bytes::BufMut;
let mut buf = vec![];
buf.put(&b"hello world"[..]);
assert_eq!(buf, b"hello world");
Required methods
fn remaining_mut(&self) -> usize
fn remaining_mut(&self) -> usize
Returns the number of bytes that can be written from the current position until the end of the buffer is reached.
This value is greater than or equal to the length of the slice returned
by chunk_mut()
.
Writing to a BufMut
may involve allocating more memory on the fly.
Implementations may fail before reaching the number of bytes indicated
by this method if they encounter an allocation failure.
Examples
use bytes::BufMut;
let mut dst = [0; 10];
let mut buf = &mut dst[..];
let original_remaining = buf.remaining_mut();
buf.put(&b"hello"[..]);
assert_eq!(original_remaining - 5, buf.remaining_mut());
Implementer notes
Implementations of remaining_mut
should ensure that the return value
does not change unless a call is made to advance_mut
or any other
function that is documented to change the BufMut
’s current position.
unsafe fn advance_mut(&mut self, cnt: usize)
unsafe fn advance_mut(&mut self, cnt: usize)
Advance the internal cursor of the BufMut
The next call to chunk_mut
will return a slice starting cnt
bytes
further into the underlying buffer.
This function is unsafe because there is no guarantee that the bytes being advanced past have been initialized.
Examples
use bytes::BufMut;
let mut buf = Vec::with_capacity(16);
// Write some data
buf.chunk_mut()[0..2].copy_from_slice(b"he");
unsafe { buf.advance_mut(2) };
// write more bytes
buf.chunk_mut()[0..3].copy_from_slice(b"llo");
unsafe { buf.advance_mut(3); }
assert_eq!(5, buf.len());
assert_eq!(buf, b"hello");
Panics
This function may panic if cnt > self.remaining_mut()
.
Implementer notes
It is recommended for implementations of advance_mut
to panic if
cnt > self.remaining_mut()
. If the implementation does not panic,
the call must behave as if cnt == self.remaining_mut()
.
A call with cnt == 0
should never panic and be a no-op.
fn chunk_mut(&mut self) -> &mut UninitSlice
fn chunk_mut(&mut self) -> &mut UninitSlice
Returns a mutable slice starting at the current BufMut position and of
length between 0 and BufMut::remaining_mut()
. Note that this can be shorter than the
whole remainder of the buffer (this allows non-continuous implementation).
This is a lower level function. Most operations are done with other functions.
The returned byte slice may represent uninitialized memory.
Examples
use bytes::BufMut;
let mut buf = Vec::with_capacity(16);
unsafe {
// MaybeUninit::as_mut_ptr
buf.chunk_mut()[0..].as_mut_ptr().write(b'h');
buf.chunk_mut()[1..].as_mut_ptr().write(b'e');
buf.advance_mut(2);
buf.chunk_mut()[0..].as_mut_ptr().write(b'l');
buf.chunk_mut()[1..].as_mut_ptr().write(b'l');
buf.chunk_mut()[2..].as_mut_ptr().write(b'o');
buf.advance_mut(3);
}
assert_eq!(5, buf.len());
assert_eq!(buf, b"hello");
Implementer notes
This function should never panic. chunk_mut
should return an empty
slice if and only if remaining_mut()
returns 0. In other words,
chunk_mut()
returning an empty slice implies that remaining_mut()
will
return 0 and remaining_mut()
returning 0 implies that chunk_mut()
will
return an empty slice.
This function may trigger an out-of-memory abort if it tries to allocate memory and fails to do so.
Provided methods
fn has_remaining_mut(&self) -> bool
fn has_remaining_mut(&self) -> bool
Returns true if there is space in self
for more bytes.
This is equivalent to self.remaining_mut() != 0
.
Examples
use bytes::BufMut;
let mut dst = [0; 5];
let mut buf = &mut dst[..];
assert!(buf.has_remaining_mut());
buf.put(&b"hello"[..]);
assert!(!buf.has_remaining_mut());
Transfer bytes into self
from src
and advance the cursor by the
number of bytes written.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_u8(b'h');
buf.put(&b"ello"[..]);
buf.put(&b" world"[..]);
assert_eq!(buf, b"hello world");
Panics
Panics if self
does not have enough capacity to contain src
.
Transfer bytes into self
from src
and advance the cursor by the
number of bytes written.
self
must have enough remaining capacity to contain all of src
.
use bytes::BufMut;
let mut dst = [0; 6];
{
let mut buf = &mut dst[..];
buf.put_slice(b"hello");
assert_eq!(1, buf.remaining_mut());
}
assert_eq!(b"hello\0", &dst);
Put cnt
bytes val
into self
.
Logically equivalent to calling self.put_u8(val)
cnt
times, but may work faster.
self
must have at least cnt
remaining capacity.
use bytes::BufMut;
let mut dst = [0; 6];
{
let mut buf = &mut dst[..];
buf.put_bytes(b'a', 4);
assert_eq!(2, buf.remaining_mut());
}
assert_eq!(b"aaaa\0\0", &dst);
Panics
This function panics if there is not enough remaining capacity in
self
.
fn put_u16_le(&mut self, n: u16)
fn put_u16_le(&mut self, n: u16)
fn put_i16_le(&mut self, n: i16)
fn put_i16_le(&mut self, n: i16)
fn put_u32_le(&mut self, n: u32)
fn put_u32_le(&mut self, n: u32)
Writes an unsigned 32 bit integer to self
in little-endian byte order.
The current position is advanced by 4.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_u32_le(0x0809A0A1);
assert_eq!(buf, b"\xA1\xA0\x09\x08");
Panics
This function panics if there is not enough remaining capacity in
self
.
fn put_i32_le(&mut self, n: i32)
fn put_i32_le(&mut self, n: i32)
Writes a signed 32 bit integer to self
in little-endian byte order.
The current position is advanced by 4.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_i32_le(0x0809A0A1);
assert_eq!(buf, b"\xA1\xA0\x09\x08");
Panics
This function panics if there is not enough remaining capacity in
self
.
Writes an unsigned 64 bit integer to self
in the big-endian byte order.
The current position is advanced by 8.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_u64(0x0102030405060708);
assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08");
Panics
This function panics if there is not enough remaining capacity in
self
.
fn put_u64_le(&mut self, n: u64)
fn put_u64_le(&mut self, n: u64)
Writes an unsigned 64 bit integer to self
in little-endian byte order.
The current position is advanced by 8.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_u64_le(0x0102030405060708);
assert_eq!(buf, b"\x08\x07\x06\x05\x04\x03\x02\x01");
Panics
This function panics if there is not enough remaining capacity in
self
.
Writes a signed 64 bit integer to self
in the big-endian byte order.
The current position is advanced by 8.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_i64(0x0102030405060708);
assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08");
Panics
This function panics if there is not enough remaining capacity in
self
.
fn put_i64_le(&mut self, n: i64)
fn put_i64_le(&mut self, n: i64)
Writes a signed 64 bit integer to self
in little-endian byte order.
The current position is advanced by 8.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_i64_le(0x0102030405060708);
assert_eq!(buf, b"\x08\x07\x06\x05\x04\x03\x02\x01");
Panics
This function panics if there is not enough remaining capacity in
self
.
Writes an unsigned 128 bit integer to self
in the big-endian byte order.
The current position is advanced by 16.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_u128(0x01020304050607080910111213141516);
assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16");
Panics
This function panics if there is not enough remaining capacity in
self
.
fn put_u128_le(&mut self, n: u128)
fn put_u128_le(&mut self, n: u128)
Writes an unsigned 128 bit integer to self
in little-endian byte order.
The current position is advanced by 16.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_u128_le(0x01020304050607080910111213141516);
assert_eq!(buf, b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01");
Panics
This function panics if there is not enough remaining capacity in
self
.
Writes a signed 128 bit integer to self
in the big-endian byte order.
The current position is advanced by 16.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_i128(0x01020304050607080910111213141516);
assert_eq!(buf, b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16");
Panics
This function panics if there is not enough remaining capacity in
self
.
fn put_i128_le(&mut self, n: i128)
fn put_i128_le(&mut self, n: i128)
Writes a signed 128 bit integer to self
in little-endian byte order.
The current position is advanced by 16.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_i128_le(0x01020304050607080910111213141516);
assert_eq!(buf, b"\x16\x15\x14\x13\x12\x11\x10\x09\x08\x07\x06\x05\x04\x03\x02\x01");
Panics
This function panics if there is not enough remaining capacity in
self
.
Writes an unsigned n-byte integer to self
in big-endian byte order.
The current position is advanced by nbytes
.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_uint(0x010203, 3);
assert_eq!(buf, b"\x01\x02\x03");
Panics
This function panics if there is not enough remaining capacity in
self
.
fn put_uint_le(&mut self, n: u64, nbytes: usize)
fn put_uint_le(&mut self, n: u64, nbytes: usize)
Writes an unsigned n-byte integer to self
in the little-endian byte order.
The current position is advanced by nbytes
.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_uint_le(0x010203, 3);
assert_eq!(buf, b"\x03\x02\x01");
Panics
This function panics if there is not enough remaining capacity in
self
.
Writes low nbytes
of a signed integer to self
in big-endian byte order.
The current position is advanced by nbytes
.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_int(0x0504010203, 3);
assert_eq!(buf, b"\x01\x02\x03");
Panics
This function panics if there is not enough remaining capacity in
self
or if nbytes
is greater than 8.
fn put_int_le(&mut self, n: i64, nbytes: usize)
fn put_int_le(&mut self, n: i64, nbytes: usize)
Writes low nbytes
of a signed integer to self
in little-endian byte order.
The current position is advanced by nbytes
.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_int_le(0x0504010203, 3);
assert_eq!(buf, b"\x03\x02\x01");
Panics
This function panics if there is not enough remaining capacity in
self
or if nbytes
is greater than 8.
Writes an IEEE754 single-precision (4 bytes) floating point number to
self
in big-endian byte order.
The current position is advanced by 4.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_f32(1.2f32);
assert_eq!(buf, b"\x3F\x99\x99\x9A");
Panics
This function panics if there is not enough remaining capacity in
self
.
fn put_f32_le(&mut self, n: f32)
fn put_f32_le(&mut self, n: f32)
Writes an IEEE754 single-precision (4 bytes) floating point number to
self
in little-endian byte order.
The current position is advanced by 4.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_f32_le(1.2f32);
assert_eq!(buf, b"\x9A\x99\x99\x3F");
Panics
This function panics if there is not enough remaining capacity in
self
.
Writes an IEEE754 double-precision (8 bytes) floating point number to
self
in big-endian byte order.
The current position is advanced by 8.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_f64(1.2f64);
assert_eq!(buf, b"\x3F\xF3\x33\x33\x33\x33\x33\x33");
Panics
This function panics if there is not enough remaining capacity in
self
.
fn put_f64_le(&mut self, n: f64)
fn put_f64_le(&mut self, n: f64)
Writes an IEEE754 double-precision (8 bytes) floating point number to
self
in little-endian byte order.
The current position is advanced by 8.
Examples
use bytes::BufMut;
let mut buf = vec![];
buf.put_f64_le(1.2f64);
assert_eq!(buf, b"\x33\x33\x33\x33\x33\x33\xF3\x3F");
Panics
This function panics if there is not enough remaining capacity in
self
.
Creates an adaptor which can write at most limit
bytes to self
.
Examples
use bytes::BufMut;
let arr = &mut [0u8; 128][..];
assert_eq!(arr.remaining_mut(), 128);
let dst = arr.limit(10);
assert_eq!(dst.remaining_mut(), 10);
Creates an adaptor which implements the Write
trait for self
.
This function returns a new value which implements Write
by adapting
the Write
trait functions to the BufMut
trait functions. Given that
BufMut
operations are infallible, none of the Write
functions will
return with Err
.
Examples
use bytes::BufMut;
use std::io::Write;
let mut buf = vec![].writer();
let num = buf.write(&b"hello world"[..]).unwrap();
assert_eq!(11, num);
let buf = buf.into_inner();
assert_eq!(*buf, b"hello world"[..]);
Creates an adapter which will chain this buffer with another.
The returned BufMut
instance will first write to all bytes from
self
. Afterwards, it will write to next
.
Examples
use bytes::BufMut;
let mut a = [0u8; 5];
let mut b = [0u8; 6];
let mut chain = (&mut a[..]).chain_mut(&mut b[..]);
chain.put_slice(b"hello world");
assert_eq!(&a[..], b"hello");
assert_eq!(&b[..], b" world");