Struct IoBufMut 

pub struct IoBufMut { /* private fields */ }

Mutable byte buffer.

The handle stores the first readable byte, readable length, and writable view capacity directly:

before advance:
[ readable len ][ writable cap-len ]
^
ptr

after advance(n):
[ consumed ][ readable len-n ][ writable cap-len ]
             ^
             ptr

advance moves ptr forward and shrinks both len and cap. BufMut writes always begin at ptr + len.

Capacity

The capacity is fixed at construction: unlike BytesMut, the buffer never grows, and every write past capacity() panics (including through BufMut methods such as put_slice). Self::default and zero-sized constructions own no storage, so any write to them panics. Allocate the full expected size up front. remaining_mut() reports the actual writable tail rather than usize::MAX.

Implementations

impl IoBufMut

pub fn with_capacity(capacity: usize) -> Self

Create a buffer with the given capacity.

The capacity is exact and fixed. Writes past it panic (see the capacity section).

pub fn with_alignment(capacity: usize, alignment: NonZeroUsize) -> Self

Create an untracked aligned buffer with the given capacity and alignment.

The returned buffer is not tracked by a BufferPool, so dropping it deallocates the aligned allocation immediately.

For alignments above the owner header alignment (8 bytes on 64-bit targets) the usable region rounds the request up to the header alignment, so capacity() may exceed the request by up to that alignment minus one.

Panics

Panics if capacity is nonzero and alignment is not a power of two.

pub fn zeroed_with_alignment(len: usize, alignment: NonZeroUsize) -> Self

Create a zero-initialized untracked aligned buffer with the given length and alignment.

For alignments above the owner header alignment (8 bytes on 64-bit targets) the usable region rounds the request up to the header alignment, so capacity() may exceed len by up to that alignment minus one (zero-initialized) bytes.

Panics

Panics if len is nonzero and alignment is not a power of two.

pub fn zeroed(len: usize) -> Self

Create a buffer of len bytes, all initialized to zero.

Unlike Self::with_capacity, the full buffer is immediately readable (len() == capacity() == len), which suits APIs that fill a preallocated buffer such as read_exact.

pub fn is_pooled(&self) -> bool

Returns true if this buffer is tracked by a pool.

pub unsafe fn set_len(&mut self, len: usize)

Sets the length of the buffer.

Safety

Caller must ensure all bytes in 0..len are initialized before any read operations.

Panics

Panics if len > capacity().

pub const fn len(&self) -> usize

Number of readable bytes remaining in the buffer.

pub const fn is_empty(&self) -> bool

Whether the buffer has no readable bytes.

pub fn freeze(self) -> IoBuf

Freeze into immutable IoBuf.

Free: the owner word moves to the immutable handle without a refcount operation (a reserved front heap header is initialized, including its refcount sentinel, before the owner is shared). Freezing an empty buffer releases the allocation immediately so empty immutable views never pin pool memory.

pub const fn capacity(&self) -> usize

Returns the number of bytes the buffer can hold without reallocating.

pub const fn as_mut_ptr(&mut self) -> *mut u8

Returns an unsafe mutable pointer to the first readable byte.

pub fn truncate(&mut self, len: usize)

Truncates the buffer to len readable bytes.

Has no effect when len is greater than the current length.

pub const fn clear(&mut self)

Clears the buffer, removing all readable data. Existing view capacity is preserved.

Trait Implementations

impl AsMut<[u8]> for IoBufMut

fn as_mut(&mut self) -> &mut [u8]

Converts this type into a mutable reference of the (usually inferred) input type.

impl AsRef<[u8]> for IoBufMut

fn as_ref(&self) -> &[u8]

Converts this type into a shared reference of the (usually inferred) input type.

impl Buf for IoBufMut

fn copy_to_bytes(&mut self, len: usize) -> Bytes

Drains len readable bytes into Bytes.

Draining the full readable length consumes the whole handle (mem::take plus freeze) to avoid a copy: unlike BytesMut, the caller’s handle keeps no spare capacity afterwards. A partial drain copies the prefix and preserves the handle’s remaining capacity.

fn remaining(&self) -> usize

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

fn chunk(&self) -> &[u8]

Returns a slice starting at the current position and of length between 0 and Buf::remaining(). Note that this can return a shorter slice (this allows non-continuous internal representation).

fn advance(&mut self, cnt: usize)

Advance the internal cursor of the Buf

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

Copies bytes from self into dst.

fn try_copy_to_slice(&mut self, dst: &mut [u8]) -> Result<(), TryGetError>

Copies bytes from self into dst.

fn chunks_vectored<'a>(&'a self, dst: &mut [IoSlice<'a>]) -> usize

Fills dst with potentially multiple slices starting at self’s current position.

fn has_remaining(&self) -> bool

Returns true if there are any more bytes to consume

fn get_u8(&mut self) -> u8

Gets an unsigned 8 bit integer from self.

fn get_i8(&mut self) -> i8

Gets a signed 8 bit integer from self.

fn get_u16(&mut self) -> u16

Gets an unsigned 16 bit integer from self in big-endian byte order.

fn get_u16_le(&mut self) -> u16

Gets an unsigned 16 bit integer from self in little-endian byte order.

fn get_u16_ne(&mut self) -> u16

Gets an unsigned 16 bit integer from self in native-endian byte order.

fn get_i16(&mut self) -> i16

Gets a signed 16 bit integer from self in big-endian byte order.

fn get_i16_le(&mut self) -> i16

Gets a signed 16 bit integer from self in little-endian byte order.

fn get_i16_ne(&mut self) -> i16

Gets a signed 16 bit integer from self in native-endian byte order.

fn get_u32(&mut self) -> u32

Gets an unsigned 32 bit integer from self in the big-endian byte order.

fn get_u32_le(&mut self) -> u32

Gets an unsigned 32 bit integer from self in the little-endian byte order.

fn get_u32_ne(&mut self) -> u32

Gets an unsigned 32 bit integer from self in native-endian byte order.

fn get_i32(&mut self) -> i32

Gets a signed 32 bit integer from self in big-endian byte order.

fn get_i32_le(&mut self) -> i32

Gets a signed 32 bit integer from self in little-endian byte order.

fn get_i32_ne(&mut self) -> i32

Gets a signed 32 bit integer from self in native-endian byte order.

fn get_u64(&mut self) -> u64

Gets an unsigned 64 bit integer from self in big-endian byte order.

fn get_u64_le(&mut self) -> u64

Gets an unsigned 64 bit integer from self in little-endian byte order.

fn get_u64_ne(&mut self) -> u64

Gets an unsigned 64 bit integer from self in native-endian byte order.

fn get_i64(&mut self) -> i64

Gets a signed 64 bit integer from self in big-endian byte order.

fn get_i64_le(&mut self) -> i64

Gets a signed 64 bit integer from self in little-endian byte order.

fn get_i64_ne(&mut self) -> i64

Gets a signed 64 bit integer from self in native-endian byte order.

fn get_u128(&mut self) -> u128

Gets an unsigned 128 bit integer from self in big-endian byte order.

fn get_u128_le(&mut self) -> u128

Gets an unsigned 128 bit integer from self in little-endian byte order.

fn get_u128_ne(&mut self) -> u128

Gets an unsigned 128 bit integer from self in native-endian byte order.

fn get_i128(&mut self) -> i128

Gets a signed 128 bit integer from self in big-endian byte order.

fn get_i128_le(&mut self) -> i128

Gets a signed 128 bit integer from self in little-endian byte order.

fn get_i128_ne(&mut self) -> i128

Gets a signed 128 bit integer from self in native-endian byte order.

fn get_uint(&mut self, nbytes: usize) -> u64

Gets an unsigned n-byte integer from self in big-endian byte order.

fn get_uint_le(&mut self, nbytes: usize) -> u64

Gets an unsigned n-byte integer from self in little-endian byte order.

fn get_uint_ne(&mut self, nbytes: usize) -> u64

Gets an unsigned n-byte integer from self in native-endian byte order.

fn get_int(&mut self, nbytes: usize) -> i64

Gets a signed n-byte integer from self in big-endian byte order.

fn get_int_le(&mut self, nbytes: usize) -> i64

Gets a signed n-byte integer from self in little-endian byte order.

fn get_int_ne(&mut self, nbytes: usize) -> i64

Gets a signed n-byte integer from self in native-endian byte order.

fn get_f32(&mut self) -> f32

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

fn get_f32_le(&mut self) -> f32

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

fn get_f32_ne(&mut self) -> f32

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

fn get_f64(&mut self) -> f64

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

fn get_f64_le(&mut self) -> f64

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

fn get_f64_ne(&mut self) -> f64

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

fn try_get_u8(&mut self) -> Result<u8, TryGetError>

Gets an unsigned 8 bit integer from self.

fn try_get_i8(&mut self) -> Result<i8, TryGetError>

Gets a signed 8 bit integer from self.

fn try_get_u16(&mut self) -> Result<u16, TryGetError>

Gets an unsigned 16 bit integer from self in big-endian byte order.

fn try_get_u16_le(&mut self) -> Result<u16, TryGetError>

Gets an unsigned 16 bit integer from self in little-endian byte order.

fn try_get_u16_ne(&mut self) -> Result<u16, TryGetError>

Gets an unsigned 16 bit integer from self in native-endian byte order.

fn try_get_i16(&mut self) -> Result<i16, TryGetError>

Gets a signed 16 bit integer from self in big-endian byte order.

fn try_get_i16_le(&mut self) -> Result<i16, TryGetError>

Gets an signed 16 bit integer from self in little-endian byte order.

fn try_get_i16_ne(&mut self) -> Result<i16, TryGetError>

Gets a signed 16 bit integer from self in native-endian byte order.

fn try_get_u32(&mut self) -> Result<u32, TryGetError>

Gets an unsigned 32 bit integer from self in big-endian byte order.

fn try_get_u32_le(&mut self) -> Result<u32, TryGetError>

Gets an unsigned 32 bit integer from self in little-endian byte order.

fn try_get_u32_ne(&mut self) -> Result<u32, TryGetError>

Gets an unsigned 32 bit integer from self in native-endian byte order.

fn try_get_i32(&mut self) -> Result<i32, TryGetError>

Gets a signed 32 bit integer from self in big-endian byte order.

fn try_get_i32_le(&mut self) -> Result<i32, TryGetError>

Gets a signed 32 bit integer from self in little-endian byte order.

fn try_get_i32_ne(&mut self) -> Result<i32, TryGetError>

Gets a signed 32 bit integer from self in native-endian byte order.

fn try_get_u64(&mut self) -> Result<u64, TryGetError>

Gets an unsigned 64 bit integer from self in big-endian byte order.

fn try_get_u64_le(&mut self) -> Result<u64, TryGetError>

Gets an unsigned 64 bit integer from self in little-endian byte order.

fn try_get_u64_ne(&mut self) -> Result<u64, TryGetError>

Gets an unsigned 64 bit integer from self in native-endian byte order.

fn try_get_i64(&mut self) -> Result<i64, TryGetError>

Gets a signed 64 bit integer from self in big-endian byte order.

fn try_get_i64_le(&mut self) -> Result<i64, TryGetError>

Gets a signed 64 bit integer from self in little-endian byte order.

fn try_get_i64_ne(&mut self) -> Result<i64, TryGetError>

Gets a signed 64 bit integer from self in native-endian byte order.

fn try_get_u128(&mut self) -> Result<u128, TryGetError>

Gets an unsigned 128 bit integer from self in big-endian byte order.

fn try_get_u128_le(&mut self) -> Result<u128, TryGetError>

Gets an unsigned 128 bit integer from self in little-endian byte order.

fn try_get_u128_ne(&mut self) -> Result<u128, TryGetError>

Gets an unsigned 128 bit integer from self in native-endian byte order.

fn try_get_i128(&mut self) -> Result<i128, TryGetError>

Gets a signed 128 bit integer from self in big-endian byte order.

fn try_get_i128_le(&mut self) -> Result<i128, TryGetError>

Gets a signed 128 bit integer from self in little-endian byte order.

fn try_get_i128_ne(&mut self) -> Result<i128, TryGetError>

Gets a signed 128 bit integer from self in native-endian byte order.

fn try_get_uint(&mut self, nbytes: usize) -> Result<u64, TryGetError>

Gets an unsigned n-byte integer from self in big-endian byte order.

fn try_get_uint_le(&mut self, nbytes: usize) -> Result<u64, TryGetError>

Gets an unsigned n-byte integer from self in little-endian byte order.

fn try_get_uint_ne(&mut self, nbytes: usize) -> Result<u64, TryGetError>

Gets an unsigned n-byte integer from self in native-endian byte order.

fn try_get_int(&mut self, nbytes: usize) -> Result<i64, TryGetError>

Gets a signed n-byte integer from self in big-endian byte order.

fn try_get_int_le(&mut self, nbytes: usize) -> Result<i64, TryGetError>

Gets a signed n-byte integer from self in little-endian byte order.

fn try_get_int_ne(&mut self, nbytes: usize) -> Result<i64, TryGetError>

Gets a signed n-byte integer from self in native-endian byte order.

fn try_get_f32(&mut self) -> Result<f32, TryGetError>

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

fn try_get_f32_le(&mut self) -> Result<f32, TryGetError>

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

fn try_get_f32_ne(&mut self) -> Result<f32, TryGetError>

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

fn try_get_f64(&mut self) -> Result<f64, TryGetError>

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

fn try_get_f64_le(&mut self) -> Result<f64, TryGetError>

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

fn try_get_f64_ne(&mut self) -> Result<f64, TryGetError>

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

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

where Self: Sized,

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

fn chain<U>(self, next: U) -> Chain<Self, U>

where U: Buf, Self: Sized,

Creates an adaptor which will chain this buffer with another.

fn reader(self) -> Reader<Self>

where Self: Sized,

Creates an adaptor which implements the Read trait for self.

impl BufMut for IoBufMut

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.

unsafe fn advance_mut(&mut self, cnt: usize)

Advance the internal cursor of the BufMut

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).

fn put_slice(&mut self, src: &[u8])

Transfer bytes into self from src and advance the cursor by the number of bytes written.

fn put_bytes(&mut self, val: u8, cnt: usize)

Put cnt bytes val into self.

fn put<T: Buf>(&mut self, src: T)

where Self: Sized,

Transfer bytes into self from src and advance the cursor by the number of bytes written.

fn has_remaining_mut(&self) -> bool

Returns true if there is space in self for more bytes.

fn put_u8(&mut self, n: u8)

Writes an unsigned 8 bit integer to self.

fn put_i8(&mut self, n: i8)

Writes a signed 8 bit integer to self.

fn put_u16(&mut self, n: u16)

Writes an unsigned 16 bit integer to self in big-endian byte order.

fn put_u16_le(&mut self, n: u16)

Writes an unsigned 16 bit integer to self in little-endian byte order.

fn put_u16_ne(&mut self, n: u16)

Writes an unsigned 16 bit integer to self in native-endian byte order.

fn put_i16(&mut self, n: i16)

Writes a signed 16 bit integer to self in big-endian byte order.

fn put_i16_le(&mut self, n: i16)

Writes a signed 16 bit integer to self in little-endian byte order.

fn put_i16_ne(&mut self, n: i16)

Writes a signed 16 bit integer to self in native-endian byte order.

fn put_u32(&mut self, n: u32)

Writes an unsigned 32 bit integer to self in big-endian byte order.

fn put_u32_le(&mut self, n: u32)

Writes an unsigned 32 bit integer to self in little-endian byte order.

fn put_u32_ne(&mut self, n: u32)

Writes an unsigned 32 bit integer to self in native-endian byte order.

fn put_i32(&mut self, n: i32)

Writes a signed 32 bit integer to self in big-endian byte order.

fn put_i32_le(&mut self, n: i32)

Writes a signed 32 bit integer to self in little-endian byte order.

fn put_i32_ne(&mut self, n: i32)

Writes a signed 32 bit integer to self in native-endian byte order.

fn put_u64(&mut self, n: u64)

Writes an unsigned 64 bit integer to self in the big-endian byte order.

fn put_u64_le(&mut self, n: u64)

Writes an unsigned 64 bit integer to self in little-endian byte order.

fn put_u64_ne(&mut self, n: u64)

Writes an unsigned 64 bit integer to self in native-endian byte order.

fn put_i64(&mut self, n: i64)

Writes a signed 64 bit integer to self in the big-endian byte order.

fn put_i64_le(&mut self, n: i64)

Writes a signed 64 bit integer to self in little-endian byte order.

fn put_i64_ne(&mut self, n: i64)

Writes a signed 64 bit integer to self in native-endian byte order.

fn put_u128(&mut self, n: u128)

Writes an unsigned 128 bit integer to self in the big-endian byte order.

fn put_u128_le(&mut self, n: u128)

Writes an unsigned 128 bit integer to self in little-endian byte order.

fn put_u128_ne(&mut self, n: u128)

Writes an unsigned 128 bit integer to self in native-endian byte order.

fn put_i128(&mut self, n: i128)

Writes a signed 128 bit integer to self in the big-endian byte order.

fn put_i128_le(&mut self, n: i128)

Writes a signed 128 bit integer to self in little-endian byte order.

fn put_i128_ne(&mut self, n: i128)

Writes a signed 128 bit integer to self in native-endian byte order.

fn put_uint(&mut self, n: u64, nbytes: usize)

Writes an unsigned n-byte integer to self in big-endian byte order.

fn put_uint_le(&mut self, n: u64, nbytes: usize)

Writes an unsigned n-byte integer to self in the little-endian byte order.

fn put_uint_ne(&mut self, n: u64, nbytes: usize)

Writes an unsigned n-byte integer to self in the native-endian byte order.

fn put_int(&mut self, n: i64, nbytes: usize)

Writes low nbytes of a signed integer to self in big-endian byte order.

fn put_int_le(&mut self, n: i64, nbytes: usize)

Writes low nbytes of a signed integer to self in little-endian byte order.

fn put_int_ne(&mut self, n: i64, nbytes: usize)

Writes low nbytes of a signed integer to self in native-endian byte order.

fn put_f32(&mut self, n: f32)

Writes an IEEE754 single-precision (4 bytes) floating point number to self in big-endian byte order.

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.

fn put_f32_ne(&mut self, n: f32)

Writes an IEEE754 single-precision (4 bytes) floating point number to self in native-endian byte order.

fn put_f64(&mut self, n: f64)

Writes an IEEE754 double-precision (8 bytes) floating point number to self in big-endian byte order.

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.

fn put_f64_ne(&mut self, n: f64)

Writes an IEEE754 double-precision (8 bytes) floating point number to self in native-endian byte order.

fn limit(self, limit: usize) -> Limit<Self>

where Self: Sized,

Creates an adaptor which can write at most limit bytes to self.

fn writer(self) -> Writer<Self>

where Self: Sized,

Creates an adaptor which implements the Write trait for self.

fn chain_mut<U>(self, next: U) -> Chain<Self, U>

where U: BufMut, Self: Sized,

Creates an adapter which will chain this buffer with another.

impl Debug for IoBufMut

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for IoBufMut

fn default() -> Self

Returns the “default value” for a type.

impl Drop for IoBufMut

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.

impl<const N: usize> From<&[u8; N]> for IoBufMut

Create a mutable buffer by copying the array.

fn from(array: &[u8; N]) -> Self

Converts to this type from the input type.

impl From<&[u8]> for IoBufMut

Create a mutable buffer by copying the slice.

fn from(slice: &[u8]) -> Self

Converts to this type from the input type.

impl From<Bytes> for IoBufMut

Create a mutable buffer by copying bytes.

A mutable buffer requires unique ownership of its storage, which shared Bytes cannot provide, so this conversion copies.

fn from(bytes: Bytes) -> Self

Converts to this type from the input type.

impl From<BytesMut> for IoBufMut

Create a mutable buffer by copying bytes.

A mutable buffer requires runtime-owned storage for its owner header, which a BytesMut allocation cannot host, so this conversion copies. The caller’s reserved capacity is preserved.

fn from(bytes: BytesMut) -> Self

Converts to this type from the input type.

impl From<IoBuf> for IoBufMut

Zero-copy when exclusive ownership can be recovered (see IoBuf::try_into_mut), copies otherwise.

fn from(buf: IoBuf) -> Self

Converts to this type from the input type.

impl From<IoBufMut> for IoBufs

Zero-copy: freezes the buffer and wraps it as the single chunk.

fn from(buf: IoBufMut) -> Self

Converts to this type from the input type.

impl From<IoBufMut> for IoBufsMut

Zero-copy: wraps the buffer as the single chunk.

fn from(buf: IoBufMut) -> Self

Converts to this type from the input type.

impl From<Vec<u8>> for IoBufMut

Create a mutable buffer by copying vec.

Zero-copy adoption is not used because it would reserve owner header space inside the vec’s allocation, shrinking the writable capacity below vec.capacity(). Use From<Vec<u8>> for IoBuf for zero-copy immutable conversion (and IoBuf::try_into_mut to recover mutability).

fn from(vec: Vec<u8>) -> Self

Converts to this type from the input type.

impl<const N: usize> From<[u8; N]> for IoBufMut

Create a mutable buffer by copying the array.

fn from(array: [u8; N]) -> Self

Converts to this type from the input type.

impl<const N: usize> PartialEq<&[u8; N]> for IoBufMut

fn eq(&self, other: &&[u8; N]) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialEq<&[u8]> for IoBufMut

fn eq(&self, other: &&[u8]) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<const N: usize> PartialEq<[u8; N]> for IoBufMut

fn eq(&self, other: &[u8; N]) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialEq<[u8]> for IoBufMut

fn eq(&self, other: &[u8]) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Send for IoBufMut

impl Sync for IoBufMut