Struct bytes::Bytes

pub struct Bytes { /* fields omitted */ }

A cheaply cloneable and sliceable chunk of contiguous memory.

Bytes is an efficient container for storing and operating on contiguous slices of memory. It is intended for use primarily in networking code, but could have applications elsewhere as well.

Bytes values facilitate zero-copy network programming by allowing multiple Bytes objects to point to the same underlying memory.

Bytes does not have a single implementation. It is an interface, whose exact behavior is implemented through dynamic dispatch in several underlying implementations of Bytes.

All Bytes implementations must fulfill the following requirements:

• They are cheaply cloneable and thereby shareable between an unlimited amount of components, for example by modifying a reference count.
• Instances can be sliced to refer to a subset of the the original buffer.

use bytes::Bytes;

let mut mem = Bytes::from("Hello world");
let a = mem.slice(0..5);

assert_eq!(a, "Hello");

let b = mem.split_to(6);

assert_eq!(mem, "world");
assert_eq!(b, "Hello ");

Memory layout

The Bytes struct itself is fairly small, limited to 4 usize fields used to track information about which segment of the underlying memory the Bytes handle has access to.

Bytes keeps both a pointer to the shared state containing the full memory slice and a pointer to the start of the region visible by the handle. Bytes also tracks the length of its view into the memory.

Sharing

Bytes contains a vtable, which allows implementations of Bytes to define how sharing/cloneing is implemented in detail. When Bytes::clone() is called, Bytes will call the vtable function for cloning the backing storage in order to share it behind between multiple Bytes instances.

For Bytes implementations which refer to constant memory (e.g. created via Bytes::from_static()) the cloning implementation will be a no-op.

For Bytes implementations which point to a reference counted shared storage (e.g. an Arc<[u8]>), sharing will be implemented by increasing the the reference count.

Due to this mechanism, multiple Bytes instances may point to the same shared memory region. Each Bytes instance can point to different sections within that memory region, and Bytes instances may or may not have overlapping views into the memory.

The following diagram visualizes a scenario where 2 Bytes instances make use of an Arc-based backing storage, and provide access to different views:

   Arc ptrs                   +---------+
   ________________________ / | Bytes 2 |
  /                           +---------+
 /          +-----------+     |         |
|_________/ |  Bytes 1  |     |         |
|           +-----------+     |         |
|           |           | ___/ data     | tail
|      data |      tail |/              |
v           v           v               v
+-----+---------------------------------+-----+
| Arc |     |           |               |     |
+-----+---------------------------------+-----+

Implementations

impl Bytes

pub const fn new() -> Bytes

Creates a new empty Bytes.

This will not allocate and the returned Bytes handle will be empty.

Examples

use bytes::Bytes;

let b = Bytes::new();
assert_eq!(&b[..], b"");

pub const fn from_static(bytes: &'static [u8]) -> Bytes

Creates a new Bytes from a static slice.

The returned Bytes will point directly to the static slice. There is no allocating or copying.

Examples

use bytes::Bytes;

let b = Bytes::from_static(b"hello");
assert_eq!(&b[..], b"hello");

pub fn len(&self) -> usize

Returns the number of bytes contained in this Bytes.

Examples

use bytes::Bytes;

let b = Bytes::from(&b"hello"[..]);
assert_eq!(b.len(), 5);

pub fn is_empty(&self) -> bool

Returns true if the Bytes has a length of 0.

Examples

use bytes::Bytes;

let b = Bytes::new();
assert!(b.is_empty());

pub fn copy_from_slice(data: &[u8]) -> Self

Creates Bytes instance from slice, by copying it.

pub fn slice(&self, range: impl RangeBounds<usize>) -> Bytes

Returns a slice of self for the provided range.

This will increment the reference count for the underlying memory and return a new Bytes handle set to the slice.

This operation is O(1).

Examples

use bytes::Bytes;

let a = Bytes::from(&b"hello world"[..]);
let b = a.slice(2..5);

assert_eq!(&b[..], b"llo");

Panics

Requires that begin <= end and end <= self.len(), otherwise slicing will panic.

pub fn slice_ref(&self, subset: &[u8]) -> Bytes

Returns a slice of self that is equivalent to the given subset.

When processing a Bytes buffer with other tools, one often gets a &[u8] which is in fact a slice of the Bytes, i.e. a subset of it. This function turns that &[u8] into another Bytes, as if one had called self.slice() with the offsets that correspond to subset.

This operation is O(1).

Examples

use bytes::Bytes;

let bytes = Bytes::from(&b"012345678"[..]);
let as_slice = bytes.as_ref();
let subset = &as_slice[2..6];
let subslice = bytes.slice_ref(&subset);
assert_eq!(&subslice[..], b"2345");

Panics

Requires that the given sub slice is in fact contained within the Bytes buffer; otherwise this function will panic.

pub fn split_off(&mut self, at: usize) -> Bytes

Splits the bytes into two at the given index.

Afterwards self contains elements [0, at), and the returned Bytes contains elements [at, len).

This is an O(1) operation that just increases the reference count and sets a few indices.

Examples

use bytes::Bytes;

let mut a = Bytes::from(&b"hello world"[..]);
let b = a.split_off(5);

assert_eq!(&a[..], b"hello");
assert_eq!(&b[..], b" world");

Panics

Panics if at > len.

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

Splits the bytes into two at the given index.

Afterwards self contains elements [at, len), and the returned Bytes contains elements [0, at).

This is an O(1) operation that just increases the reference count and sets a few indices.

Examples

use bytes::Bytes;

let mut a = Bytes::from(&b"hello world"[..]);
let b = a.split_to(5);

assert_eq!(&a[..], b" world");
assert_eq!(&b[..], b"hello");

Panics

Panics if at > len.

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

Shortens the buffer, keeping the first len bytes and dropping the rest.

If len is greater than the buffer’s current length, this has no effect.

The split_off method can emulate truncate, but this causes the excess bytes to be returned instead of dropped.

Examples

use bytes::Bytes;

let mut buf = Bytes::from(&b"hello world"[..]);
buf.truncate(5);
assert_eq!(buf, b"hello"[..]);

pub fn clear(&mut self)

Clears the buffer, removing all data.

Examples

use bytes::Bytes;

let mut buf = Bytes::from(&b"hello world"[..]);
buf.clear();
assert!(buf.is_empty());

Trait Implementations

impl AsRef<[u8]> for Bytes

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

Performs the conversion.

impl Borrow<[u8]> for Bytes

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

Immutably borrows from an owned value.

impl Buf for Bytes

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 shorter slice (this allows non-continuous internal representation).

fn advance(&mut self, cnt: usize)

Advance the internal cursor of the Buf

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

Consumes len bytes inside self and returns new instance of Bytes with this data.

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

Copies bytes from self into dst.

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_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_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_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_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_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_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_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_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_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_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_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 take(self, limit: usize) -> Take<Self> where
    Self: Sized, 

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

fn chain<U: Buf>(self, next: U) -> Chain<Self, U> where
    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 Clone for Bytes

fn clone(&self) -> Bytes

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Bytes

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

Formats the value using the given formatter.

impl Default for Bytes

fn default() -> Bytes

Returns the “default value” for a type.

impl Deref for Bytes

type Target = [u8]

The resulting type after dereferencing.

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

Dereferences the value.

impl Drop for Bytes

fn drop(&mut self)

Executes the destructor for this type.

impl From<&'static [u8]> for Bytes

fn from(slice: &'static [u8]) -> Bytes

Performs the conversion.

impl From<&'static str> for Bytes

fn from(slice: &'static str) -> Bytes

Performs the conversion.

impl From<BytesMut> for Bytes

fn from(src: BytesMut) -> Bytes

Performs the conversion.

impl From<String> for Bytes

fn from(s: String) -> Bytes

Performs the conversion.

impl From<Vec<u8, Global>> for Bytes

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

Performs the conversion.

impl FromIterator<u8> for Bytes

fn from_iter<T: IntoIterator<Item = u8>>(into_iter: T) -> Self

Creates a value from an iterator.

impl Hash for Bytes

fn hash<H>(&self, state: &mut H) where
    H: Hasher, 

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl IntoIterator for Bytes

type Item = u8

The type of the elements being iterated over.

type IntoIter = IntoIter<Bytes>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<'a> IntoIterator for &'a Bytes

type Item = &'a u8

The type of the elements being iterated over.

type IntoIter = Iter<'a, u8>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl LowerHex for Bytes

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

Formats the value using the given formatter.

impl Ord for Bytes

fn cmp(&self, other: &Bytes) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

Restrict a value to a certain interval.

impl<'a, T: ?Sized> PartialEq<&'a T> for Bytes where
    Bytes: PartialEq<T>, 

fn eq(&self, other: &&'a T) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<[u8]> for Bytes

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<Bytes> for Bytes

fn eq(&self, other: &Bytes) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<Bytes> for [u8]

fn eq(&self, other: &Bytes) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<Bytes> for str

fn eq(&self, other: &Bytes) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<Bytes> for Vec<u8>

fn eq(&self, other: &Bytes) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<Bytes> for String

fn eq(&self, other: &Bytes) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<Bytes> for &[u8]

fn eq(&self, other: &Bytes) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<Bytes> for &str

fn eq(&self, other: &Bytes) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<Bytes> for BytesMut

fn eq(&self, other: &Bytes) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<BytesMut> for Bytes

fn eq(&self, other: &BytesMut) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<String> for Bytes

fn eq(&self, other: &String) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<Vec<u8, Global>> for Bytes

fn eq(&self, other: &Vec<u8>) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<str> for Bytes

fn eq(&self, other: &str) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl<'a, T: ?Sized> PartialOrd<&'a T> for Bytes where
    Bytes: PartialOrd<T>, 

fn partial_cmp(&self, other: &&'a T) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<[u8]> for Bytes

fn partial_cmp(&self, other: &[u8]) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<Bytes> for Bytes

fn partial_cmp(&self, other: &Bytes) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<Bytes> for [u8]

fn partial_cmp(&self, other: &Bytes) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<Bytes> for str

fn partial_cmp(&self, other: &Bytes) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<Bytes> for Vec<u8>

fn partial_cmp(&self, other: &Bytes) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<Bytes> for String

fn partial_cmp(&self, other: &Bytes) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<Bytes> for &[u8]

fn partial_cmp(&self, other: &Bytes) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<Bytes> for &str

fn partial_cmp(&self, other: &Bytes) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<String> for Bytes

fn partial_cmp(&self, other: &String) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<Vec<u8, Global>> for Bytes

fn partial_cmp(&self, other: &Vec<u8>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<str> for Bytes

fn partial_cmp(&self, other: &str) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl UpperHex for Bytes

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

Formats the value using the given formatter.

impl Eq for Bytes

impl Send for Bytes

impl Sync for Bytes