pub struct ReadBuf<'a> { /* private fields */ }
Expand description
A wrapper around a byte buffer that is incrementally filled and initialized.
This type is a sort of “double cursor”. It tracks three regions in the buffer: a region at the beginning of the buffer that has been logically filled with data, a region that has been initialized at some point but not yet logically filled, and a region at the end that may be uninitialized. The filled region is guaranteed to be a subset of the initialized region.
In summary, the contents of the buffer can be visualized as:
[ capacity ]
[ filled | unfilled ]
[ initialized | uninitialized ]
It is undefined behavior to de-initialize any bytes from the uninitialized region, since it is merely unknown whether this region is uninitialized or not, and if part of it turns out to be initialized, it must stay initialized.
Implementations§
§impl<'a> ReadBuf<'a>
impl<'a> ReadBuf<'a>
pub fn uninit(buf: &'a mut [MaybeUninit<u8>]) -> ReadBuf<'a>
pub fn uninit(buf: &'a mut [MaybeUninit<u8>]) -> ReadBuf<'a>
Creates a new ReadBuf
from a fully uninitialized buffer.
Use assume_init
if part of the buffer is known to be already initialized.
pub fn filled_mut(&mut self) -> &mut [u8] ⓘ
pub fn filled_mut(&mut self) -> &mut [u8] ⓘ
Returns a mutable reference to the filled portion of the buffer.
pub fn take(&mut self, n: usize) -> ReadBuf<'_>
pub fn take(&mut self, n: usize) -> ReadBuf<'_>
Returns a new ReadBuf
comprised of the unfilled section up to n
.
pub fn initialized(&self) -> &[u8] ⓘ
pub fn initialized(&self) -> &[u8] ⓘ
Returns a shared reference to the initialized portion of the buffer.
This includes the filled portion.
pub fn initialized_mut(&mut self) -> &mut [u8] ⓘ
pub fn initialized_mut(&mut self) -> &mut [u8] ⓘ
Returns a mutable reference to the initialized portion of the buffer.
This includes the filled portion.
pub unsafe fn inner_mut(&mut self) -> &mut [MaybeUninit<u8>]
pub unsafe fn inner_mut(&mut self) -> &mut [MaybeUninit<u8>]
Returns a mutable reference to the entire buffer, without ensuring that it has been fully initialized.
The elements between 0 and self.filled().len()
are filled, and those between 0 and
self.initialized().len()
are initialized (and so can be converted to a &mut [u8]
).
The caller of this method must ensure that these invariants are upheld. For example, if the
caller initializes some of the uninitialized section of the buffer, it must call
assume_init
with the number of bytes initialized.
§Safety
The caller must not de-initialize portions of the buffer that have already been initialized.
This includes any bytes in the region marked as uninitialized by ReadBuf
.
pub unsafe fn unfilled_mut(&mut self) -> &mut [MaybeUninit<u8>]
pub unsafe fn unfilled_mut(&mut self) -> &mut [MaybeUninit<u8>]
Returns a mutable reference to the unfilled part of the buffer without ensuring that it has been fully initialized.
§Safety
The caller must not de-initialize portions of the buffer that have already been initialized.
This includes any bytes in the region marked as uninitialized by ReadBuf
.
pub fn initialize_unfilled(&mut self) -> &mut [u8] ⓘ
pub fn initialize_unfilled(&mut self) -> &mut [u8] ⓘ
Returns a mutable reference to the unfilled part of the buffer, ensuring it is fully initialized.
Since ReadBuf
tracks the region of the buffer that has been initialized, this is effectively “free” after
the first use.
pub fn initialize_unfilled_to(&mut self, n: usize) -> &mut [u8] ⓘ
pub fn initialize_unfilled_to(&mut self, n: usize) -> &mut [u8] ⓘ
Returns a mutable reference to the first n
bytes of the unfilled part of the buffer, ensuring it is
fully initialized.
§Panics
Panics if self.remaining()
is less than n
.
pub fn remaining(&self) -> usize
pub fn remaining(&self) -> usize
Returns the number of bytes at the end of the slice that have not yet been filled.
pub fn clear(&mut self)
pub fn clear(&mut self)
Clears the buffer, resetting the filled region to empty.
The number of initialized bytes is not changed, and the contents of the buffer are not modified.
pub fn advance(&mut self, n: usize)
pub fn advance(&mut self, n: usize)
Advances the size of the filled region of the buffer.
The number of initialized bytes is not changed.
§Panics
Panics if the filled region of the buffer would become larger than the initialized region.
pub fn set_filled(&mut self, n: usize)
pub fn set_filled(&mut self, n: usize)
Sets the size of the filled region of the buffer.
The number of initialized bytes is not changed.
Note that this can be used to shrink the filled region of the buffer in addition to growing it (for
example, by a AsyncRead
implementation that compresses data in-place).
§Panics
Panics if the filled region of the buffer would become larger than the initialized region.
pub unsafe fn assume_init(&mut self, n: usize)
pub unsafe fn assume_init(&mut self, n: usize)
Asserts that the first n
unfilled bytes of the buffer are initialized.
ReadBuf
assumes that bytes are never de-initialized, so this method does nothing when called with fewer
bytes than are already known to be initialized.
§Safety
The caller must ensure that n
unfilled bytes of the buffer have already been initialized.
Trait Implementations§
§impl<'a> BufMut for ReadBuf<'a>
Available on crate feature io-util
only.
impl<'a> BufMut for ReadBuf<'a>
io-util
only.§fn remaining_mut(&self) -> usize
fn remaining_mut(&self) -> usize
§unsafe fn advance_mut(&mut self, cnt: usize)
unsafe fn advance_mut(&mut self, cnt: usize)
§fn chunk_mut(&mut self) -> &mut UninitSlice
fn chunk_mut(&mut self) -> &mut UninitSlice
BufMut::remaining_mut()
. Note that this can be shorter than the
whole remainder of the buffer (this allows non-continuous implementation). Read more§fn has_remaining_mut(&self) -> bool
fn has_remaining_mut(&self) -> bool
self
for more bytes. Read more§fn put_u16(&mut self, n: u16)
fn put_u16(&mut self, n: u16)
self
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fn put_u16_le(&mut self, n: u16)
self
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fn put_u16_ne(&mut self, n: u16)
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fn put_i16(&mut self, n: i16)
self
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fn put_i16_le(&mut self, n: i16)
self
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fn put_i16_ne(&mut self, n: i16)
self
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fn put_u32(&mut self, n: u32)
self
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fn put_u32_le(&mut self, n: u32)
self
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self
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fn put_i32(&mut self, n: i32)
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self
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self
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fn put_u64(&mut self, n: u64)
self
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fn put_u64_le(&mut self, n: u64)
self
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fn put_u64_ne(&mut self, n: u64)
self
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fn put_i64(&mut self, n: i64)
self
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self
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fn put_i64_ne(&mut self, n: i64)
self
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fn put_u128(&mut self, n: u128)
self
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fn put_u128_le(&mut self, n: u128)
self
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self
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fn put_i128(&mut self, n: i128)
self
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fn put_i128_le(&mut self, n: i128)
self
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fn put_i128_ne(&mut self, n: i128)
self
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fn put_uint(&mut self, n: u64, nbytes: usize)
self
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fn put_uint_le(&mut self, n: u64, nbytes: usize)
self
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fn put_uint_ne(&mut self, n: u64, nbytes: usize)
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fn put_int_le(&mut self, n: i64, nbytes: usize)
§fn put_int_ne(&mut self, n: i64, nbytes: usize)
fn put_int_ne(&mut self, n: i64, nbytes: usize)
§fn put_f32(&mut self, n: f32)
fn put_f32(&mut self, n: f32)
self
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self
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self
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fn put_f64(&mut self, n: f64)
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self
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self
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