Struct BytePages 

pub struct BytePages { /* private fields */ }

A growable sequence of byte pages.

Data is stored in fixed-capacity pages selected by BytePageSize. This avoids reallocating and copying one large contiguous buffer as data grows.

Implementations

impl BytePages

pub fn new(size: BytePageSize) -> Self

Creates a new BytePages with the specified page size.

Pages are allocated lazily using the specified capacity category.

Panics

Panics if size is BytePageSize::Unset.

pub fn page_size(&self) -> BytePageSize

Returns the capacity category used for new pages.

pub fn set_page_size(&mut self, size: BytePageSize)

Sets the page size for new pages.

Panics

Panics if size is BytePageSize::Unset.

pub fn prepend<T>(&mut self, buf: T) -> bool

where BytePage: From<T>,

Inserts a non-empty page at the front of the collection.

Returns whether a page was inserted.

pub fn append<T>(&mut self, buf: T)

where BytePage: From<T>,

Appends a page to the back of the collection.

Empty pages are ignored. If the current page holds no data and buf is a unique buffer with spare capacity, it becomes the new current page. Data of up to 4 KiB is copied into the current page, and into new pages as needed. Larger data is added as a separate page without copying: the filled part of the current page is split off in front of it, and the spare capacity of the current page stays available for later writes.

pub fn extend_from_slice(&mut self, extend: &[u8])

Appends the given bytes to this page object.

Tries to write the data into the current page first. If there is insufficient space, one or more new pages are allocated as needed, and the remaining data is copied into them.

pub fn len(&self) -> usize

Returns the total number of buffered bytes.

pub fn is_empty(&self) -> bool

Returns true if no bytes are buffered.

pub fn num_pages(&self) -> usize

Returns the number of allocated pages containing buffered data.

pub fn take(&mut self) -> Option<BytePage>

Removes and returns the first page from the collection.

The current writable page is returned last. Returns None if there are no pages with data, an empty current page keeps its spare capacity for later writes.

pub fn iter(&self) -> impl Iterator<Item = &[u8]>

Returns an iterator over the buffered data, one slice per page.

The current writable page is yielded last, if it holds data. The pages are stored on the heap, so their data stays at the same address when self is moved, until self is modified or dropped.

pub fn advance_to(&mut self, cnt: usize)

Advance the internal cursor.

Afterwards self contains elements [cnt, len). Fully consumed pages are dropped, the current writable page keeps its spare capacity.

Panics

Panics if cnt > len.

pub fn copy_to(&self, pages: &mut BytePages)

Appends all buffered data to another BytePages value, self is left unchanged.

Pages are shared with pages rather than copied, unless they are small enough to be copied into the current page of pages, see append.

pub fn move_to(&mut self, pages: &mut BytePages)

Moves all buffered data to the back of another BytePages value, leaving self empty.

Pages are moved as is, without copying or merging. The filled part of the current page of pages is split off in front of the moved data, its spare capacity stays available for later writes. The current page of self is moved as a regular page.

pub fn split_to(&mut self, at: usize) -> BytePages

Splits the buffer into two at the given index.

Afterwards, self contains elements [at, len), and the returned BytePages contains elements [0, at). If at > len, all data is moved.

Depending on the underlying storage, this operation might be O(1) or could involve a memory copy.

pub fn split_into(&mut self, at: usize, to: &mut BytePages)

Splits the buffer, adding the resulting items to the supplied pages object.

Afterwards, self contains elements [at, len), and elements [0, at) are appended to to. If at > len, all data is moved.

Depending on the underlying storage, this operation might be O(1) or could involve a memory copy.

pub fn clear(&mut self)

Clears the buffer, removing all data.

pub fn freeze(&mut self) -> Bytes

Drains all pages into one immutable Bytes value.

pub fn try_get_current_from(&mut self, pages: &mut BytePages)

Moves the current writable page from pages if this value is empty.

Trait Implementations

impl BufMut for BytePages

Pages are allocated on demand, so remaining_mut() reports usize::MAX - len and chunk_mut() is never empty. The chunk covers the spare capacity of the current page only.

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

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

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 has_remaining_mut(&self) -> bool

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

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_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_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_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_u64(&mut self, n: u64)

Writes an unsigned 64 bit integer to self in 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_i64(&mut self, n: i64)

Writes a signed 64 bit integer to self in 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_u128(&mut self, n: u128)

Writes an unsigned 128 bit integer to self in 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_i128(&mut self, n: i128)

Writes a signed 128 bit integer to self in 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_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_int(&mut self, n: i64, nbytes: usize)

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

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

Writes a signed n-byte integer to self in little-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_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.

impl Clone for BytePages

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BytePages

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

Formats the value using the given formatter.

impl Default for BytePages

fn default() -> Self

Returns the “default value” for a type.

impl Drop for BytePages

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 From<BytePages> for Bytes

fn from(pages: BytePages) -> Bytes

A single page is converted without copying.

impl From<BytePages> for BytesMut

fn from(pages: BytePages) -> BytesMut

A single page is converted without copying if nothing else refers to its buffer.

impl Write for BytePages

fn write(&mut self, src: &[u8]) -> Result<usize, Error>

Writes a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<(), Error>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

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

Determines if this Writer has an efficient write_vectored implementation.

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

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

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.