Struct bytes::Bytes

pub struct Bytes { /* fields omitted */ }

A reference counted contiguous slice of 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. This is managed by using a reference count to track when the memory is no longer needed and can be freed.

use bytes::Bytes;

let mut mem = Bytes::from(&b"Hello world"[..]);
let a = mem.slice(0, 5);

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

let b = mem.split_to(6);

assert_eq!(&mem[..], b"world");
assert_eq!(&b[..], b"Hello ");

Memory layout

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

The memory layout looks like this:

+-------+
| Bytes |
+-------+
 /      \_____
|              \
v               v
+-----+------------------------------------+
| Arc |         |      Data     |          |
+-----+------------------------------------+

Bytes keeps both a pointer to the shared Arc 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

The memory itself is reference counted, and multiple Bytes objects may point to the same region. Each Bytes handle point to different sections within the memory region, and Bytes handle may or may not have overlapping views into the memory.

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

Mutating

While Bytes handles may potentially represent overlapping views of the underlying memory slice and may not be mutated, BytesMut handles are guaranteed to be the only handle able to view that slice of memory. As such, BytesMut handles are able to mutate the underlying memory. Note that holding a unique view to a region of memory does not mean that there are no other Bytes and BytesMut handles with disjoint views of the underlying memory.

Inline bytes

As an optimization, when the slice referenced by a Bytes or BytesMut handle is small enough ¹, with_capacity will avoid the allocation by inlining the slice directly in the handle. In this case, a clone is no longer "shallow" and the data will be copied. Converting from a Vec will never use inlining.

---

1. Small enough: 31 bytes on 64 bit systems, 15 on 32 bit systems. ↩

Methods

impl Bytes

pub fn with_capacity(capacity: usize) -> Bytes

Creates a new Bytes with the specified capacity.

The returned Bytes will be able to hold at least capacity bytes without reallocating. If capacity is under 4 * size_of::<usize>() - 1, then BytesMut will not allocate.

It is important to note that this function does not specify the length of the returned Bytes, but only the capacity.

Examples

use bytes::Bytes;

let mut bytes = Bytes::with_capacity(64);

// `bytes` contains no data, even though there is capacity
assert_eq!(bytes.len(), 0);

bytes.extend_from_slice(&b"hello world"[..]);

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

pub 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 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 slice(&self, begin: usize, end: usize) -> Bytes

Returns a slice of self for the index range [begin..end).

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_from(&self, begin: usize) -> Bytes

Returns a slice of self for the index range [begin..self.len()).

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) and is equivalent to self.slice(begin, self.len()).

Examples

use bytes::Bytes;

let a = Bytes::from(&b"hello world"[..]);
let b = a.slice_from(6);

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

Panics

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

pub fn slice_to(&self, end: usize) -> Bytes

Returns a slice of self for the index range [0..end).

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) and is equivalent to self.slice(0, end).

Examples

use bytes::Bytes;

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

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

Panics

Requires that 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 advance(&mut self, cnt: usize)

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

This is the same function as Buf::advance, and in the next breaking release of bytes, this implementation will be removed in favor of having Bytes implement Buf.

Panics

This function panics if cnt is greater than self.len()

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());

pub fn try_mut(self) -> Result<BytesMut, Bytes>

Attempts to convert into a BytesMut handle.

This will only succeed if there are no other outstanding references to the underlying chunk of memory. Bytes handles that contain inlined bytes will always be convertable to BytesMut.

Examples

use bytes::Bytes;

let a = Bytes::from(&b"Mary had a little lamb, little lamb, little lamb..."[..]);

// Create a shallow clone
let b = a.clone();

// This will fail because `b` shares a reference with `a`
let a = a.try_mut().unwrap_err();

drop(b);

// This will succeed
let mut a = a.try_mut().unwrap();

a[0] = b'b';

assert_eq!(&a[..4], b"bary");

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

Appends given bytes to this object.

If this Bytes object has not enough capacity, it is resized first. If it is shared (refcount > 1), it is copied first.

This operation can be less effective than the similar operation on BytesMut, especially on small additions.

Examples

use bytes::Bytes;

let mut buf = Bytes::from("aabb");
buf.extend_from_slice(b"ccdd");
buf.extend_from_slice(b"eeff");

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

Methods from Deref<Target = [u8]>

pub const fn len(&self) -> usize

Returns the number of elements in the slice.

Examples

let a = [1, 2, 3];
assert_eq!(a.len(), 3);

pub const fn is_empty(&self) -> bool

Returns true if the slice has a length of 0.

Examples

let a = [1, 2, 3];
assert!(!a.is_empty());

pub fn first(&self) -> Option<&T>

Returns the first element of the slice, or None if it is empty.

Examples

let v = [10, 40, 30];
assert_eq!(Some(&10), v.first());

let w: &[i32] = &[];
assert_eq!(None, w.first());

pub fn split_first(&self) -> Option<(&T, &[T])>

Returns the first and all the rest of the elements of the slice, or None if it is empty.

Examples

let x = &[0, 1, 2];

if let Some((first, elements)) = x.split_first() {
    assert_eq!(first, &0);
    assert_eq!(elements, &[1, 2]);
}

pub fn split_last(&self) -> Option<(&T, &[T])>

Returns the last and all the rest of the elements of the slice, or None if it is empty.

Examples

let x = &[0, 1, 2];

if let Some((last, elements)) = x.split_last() {
    assert_eq!(last, &2);
    assert_eq!(elements, &[0, 1]);
}

pub fn last(&self) -> Option<&T>

Returns the last element of the slice, or None if it is empty.

Examples

let v = [10, 40, 30];
assert_eq!(Some(&30), v.last());

let w: &[i32] = &[];
assert_eq!(None, w.last());

pub fn get<I>(&self, index: I) -> Option<&<I as SliceIndex<[T]>>::Output> where     I: SliceIndex<[T]>,

Returns a reference to an element or subslice depending on the type of index.

• If given a position, returns a reference to the element at that position or None if out of bounds.
• If given a range, returns the subslice corresponding to that range, or None if out of bounds.

Examples

let v = [10, 40, 30];
assert_eq!(Some(&40), v.get(1));
assert_eq!(Some(&[10, 40][..]), v.get(0..2));
assert_eq!(None, v.get(3));
assert_eq!(None, v.get(0..4));

pub unsafe fn get_unchecked<I>(     &self,     index: I ) -> &<I as SliceIndex<[T]>>::Output where     I: SliceIndex<[T]>,

Returns a reference to an element or subslice, without doing bounds checking.

This is generally not recommended, use with caution! For a safe alternative see get.

Examples

let x = &[1, 2, 4];

unsafe {
    assert_eq!(x.get_unchecked(1), &2);
}

pub const fn as_ptr(&self) -> *const T

Returns a raw pointer to the slice's buffer.

The caller must ensure that the slice outlives the pointer this function returns, or else it will end up pointing to garbage.

Modifying the container referenced by this slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.

Examples

let x = &[1, 2, 4];
let x_ptr = x.as_ptr();

unsafe {
    for i in 0..x.len() {
        assert_eq!(x.get_unchecked(i), &*x_ptr.offset(i as isize));
    }
}

Important traits for Iter<'a, T>

impl<'a, T> Iterator for Iter<'a, T> type Item = &'a T;

pub fn iter(&self) -> Iter<T>

Returns an iterator over the slice.

Examples

let x = &[1, 2, 4];
let mut iterator = x.iter();

assert_eq!(iterator.next(), Some(&1));
assert_eq!(iterator.next(), Some(&2));
assert_eq!(iterator.next(), Some(&4));
assert_eq!(iterator.next(), None);

Important traits for Windows<'a, T>

impl<'a, T> Iterator for Windows<'a, T> type Item = &'a [T];

pub fn windows(&self, size: usize) -> Windows<T>

Returns an iterator over all contiguous windows of length size. The windows overlap. If the slice is shorter than size, the iterator returns no values.

Panics

Panics if size is 0.

Examples

let slice = ['r', 'u', 's', 't'];
let mut iter = slice.windows(2);
assert_eq!(iter.next().unwrap(), &['r', 'u']);
assert_eq!(iter.next().unwrap(), &['u', 's']);
assert_eq!(iter.next().unwrap(), &['s', 't']);
assert!(iter.next().is_none());

If the slice is shorter than size:

let slice = ['f', 'o', 'o'];
let mut iter = slice.windows(4);
assert!(iter.next().is_none());

Important traits for Chunks<'a, T>

impl<'a, T> Iterator for Chunks<'a, T> type Item = &'a [T];

pub fn chunks(&self, chunk_size: usize) -> Chunks<T>

Returns an iterator over chunk_size elements of the slice at a time. The chunks are slices and do not overlap. If chunk_size does not divide the length of the slice, then the last chunk will not have length chunk_size.

See exact_chunks for a variant of this iterator that returns chunks of always exactly chunk_size elements.

Panics

Panics if chunk_size is 0.

Examples

let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.chunks(2);
assert_eq!(iter.next().unwrap(), &['l', 'o']);
assert_eq!(iter.next().unwrap(), &['r', 'e']);
assert_eq!(iter.next().unwrap(), &['m']);
assert!(iter.next().is_none());

Important traits for ExactChunks<'a, T>

impl<'a, T> Iterator for ExactChunks<'a, T> type Item = &'a [T];

pub fn exact_chunks(&self, chunk_size: usize) -> ExactChunks<T>

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

Returns an iterator over chunk_size elements of the slice at a time. The chunks are slices and do not overlap. If chunk_size does not divide the length of the slice, then the last up to chunk_size-1 elements will be omitted and can be retrieved from the remainder function of the iterator.

Due to each chunk having exactly chunk_size elements, the compiler can often optimize the resulting code better than in the case of chunks.

Panics

Panics if chunk_size is 0.

Examples

#![feature(exact_chunks)]

let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.exact_chunks(2);
assert_eq!(iter.next().unwrap(), &['l', 'o']);
assert_eq!(iter.next().unwrap(), &['r', 'e']);
assert!(iter.next().is_none());

pub fn split_at(&self, mid: usize) -> (&[T], &[T])

Divides one slice into two at an index.

The first will contain all indices from [0, mid) (excluding the index mid itself) and the second will contain all indices from [mid, len) (excluding the index len itself).

Panics

Panics if mid > len.

Examples

let v = [1, 2, 3, 4, 5, 6];

{
   let (left, right) = v.split_at(0);
   assert!(left == []);
   assert!(right == [1, 2, 3, 4, 5, 6]);
}

{
    let (left, right) = v.split_at(2);
    assert!(left == [1, 2]);
    assert!(right == [3, 4, 5, 6]);
}

{
    let (left, right) = v.split_at(6);
    assert!(left == [1, 2, 3, 4, 5, 6]);
    assert!(right == []);
}

Important traits for Split<'a, T, P>

impl<'a, T, P> Iterator for Split<'a, T, P> where
    P: FnMut(&T) -> bool,  type Item = &'a [T];

pub fn split<F>(&self, pred: F) -> Split<T, F> where     F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match pred. The matched element is not contained in the subslices.

Examples

let slice = [10, 40, 33, 20];
let mut iter = slice.split(|num| num % 3 == 0);

assert_eq!(iter.next().unwrap(), &[10, 40]);
assert_eq!(iter.next().unwrap(), &[20]);
assert!(iter.next().is_none());

If the first element is matched, an empty slice will be the first item returned by the iterator. Similarly, if the last element in the slice is matched, an empty slice will be the last item returned by the iterator:

let slice = [10, 40, 33];
let mut iter = slice.split(|num| num % 3 == 0);

assert_eq!(iter.next().unwrap(), &[10, 40]);
assert_eq!(iter.next().unwrap(), &[]);
assert!(iter.next().is_none());

If two matched elements are directly adjacent, an empty slice will be present between them:

let slice = [10, 6, 33, 20];
let mut iter = slice.split(|num| num % 3 == 0);

assert_eq!(iter.next().unwrap(), &[10]);
assert_eq!(iter.next().unwrap(), &[]);
assert_eq!(iter.next().unwrap(), &[20]);
assert!(iter.next().is_none());

Important traits for RSplit<'a, T, P>

impl<'a, T, P> Iterator for RSplit<'a, T, P> where
    P: FnMut(&T) -> bool,  type Item = &'a [T];

pub fn rsplit<F>(&self, pred: F) -> RSplit<T, F> where     F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match pred, starting at the end of the slice and working backwards. The matched element is not contained in the subslices.

Examples

let slice = [11, 22, 33, 0, 44, 55];
let mut iter = slice.rsplit(|num| *num == 0);

assert_eq!(iter.next().unwrap(), &[44, 55]);
assert_eq!(iter.next().unwrap(), &[11, 22, 33]);
assert_eq!(iter.next(), None);

As with split(), if the first or last element is matched, an empty slice will be the first (or last) item returned by the iterator.

let v = &[0, 1, 1, 2, 3, 5, 8];
let mut it = v.rsplit(|n| *n % 2 == 0);
assert_eq!(it.next().unwrap(), &[]);
assert_eq!(it.next().unwrap(), &[3, 5]);
assert_eq!(it.next().unwrap(), &[1, 1]);
assert_eq!(it.next().unwrap(), &[]);
assert_eq!(it.next(), None);

Important traits for SplitN<'a, T, P>

impl<'a, T, P> Iterator for SplitN<'a, T, P> where
    P: FnMut(&T) -> bool,  type Item = &'a [T];

pub fn splitn<F>(&self, n: usize, pred: F) -> SplitN<T, F> where     F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match pred, limited to returning at most n items. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

Examples

Print the slice split once by numbers divisible by 3 (i.e. [10, 40], [20, 60, 50]):

let v = [10, 40, 30, 20, 60, 50];

for group in v.splitn(2, |num| *num % 3 == 0) {
    println!("{:?}", group);
}

Important traits for RSplitN<'a, T, P>

impl<'a, T, P> Iterator for RSplitN<'a, T, P> where
    P: FnMut(&T) -> bool,  type Item = &'a [T];

pub fn rsplitn<F>(&self, n: usize, pred: F) -> RSplitN<T, F> where     F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match pred limited to returning at most n items. This starts at the end of the slice and works backwards. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

Examples

Print the slice split once, starting from the end, by numbers divisible by 3 (i.e. [50], [10, 40, 30, 20]):

let v = [10, 40, 30, 20, 60, 50];

for group in v.rsplitn(2, |num| *num % 3 == 0) {
    println!("{:?}", group);
}

pub fn contains(&self, x: &T) -> bool where     T: PartialEq<T>,

Returns true if the slice contains an element with the given value.

Examples

let v = [10, 40, 30];
assert!(v.contains(&30));
assert!(!v.contains(&50));

pub fn starts_with(&self, needle: &[T]) -> bool where     T: PartialEq<T>,

Returns true if needle is a prefix of the slice.

Examples

let v = [10, 40, 30];
assert!(v.starts_with(&[10]));
assert!(v.starts_with(&[10, 40]));
assert!(!v.starts_with(&[50]));
assert!(!v.starts_with(&[10, 50]));

Always returns true if needle is an empty slice:

let v = &[10, 40, 30];
assert!(v.starts_with(&[]));
let v: &[u8] = &[];
assert!(v.starts_with(&[]));

pub fn ends_with(&self, needle: &[T]) -> bool where     T: PartialEq<T>,

Returns true if needle is a suffix of the slice.

Examples

let v = [10, 40, 30];
assert!(v.ends_with(&[30]));
assert!(v.ends_with(&[40, 30]));
assert!(!v.ends_with(&[50]));
assert!(!v.ends_with(&[50, 30]));

Always returns true if needle is an empty slice:

let v = &[10, 40, 30];
assert!(v.ends_with(&[]));
let v: &[u8] = &[];
assert!(v.ends_with(&[]));

pub fn binary_search(&self, x: &T) -> Result<usize, usize> where     T: Ord,

Binary searches this sorted slice for a given element.

If the value is found then Ok is returned, containing the index of the matching element; if the value is not found then Err is returned, containing the index where a matching element could be inserted while maintaining sorted order.

Examples

Looks up a series of four elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in [1, 4].

let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

assert_eq!(s.binary_search(&13),  Ok(9));
assert_eq!(s.binary_search(&4),   Err(7));
assert_eq!(s.binary_search(&100), Err(13));
let r = s.binary_search(&1);
assert!(match r { Ok(1..=4) => true, _ => false, });

pub fn binary_search_by<'a, F>(&'a self, f: F) -> Result<usize, usize> where     F: FnMut(&'a T) -> Ordering,

Binary searches this sorted slice with a comparator function.

The comparator function should implement an order consistent with the sort order of the underlying slice, returning an order code that indicates whether its argument is Less, Equal or Greater the desired target.

If a matching value is found then returns Ok, containing the index for the matched element; if no match is found then Err is returned, containing the index where a matching element could be inserted while maintaining sorted order.

Examples

Looks up a series of four elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in [1, 4].

let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

let seek = 13;
assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Ok(9));
let seek = 4;
assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(7));
let seek = 100;
assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(13));
let seek = 1;
let r = s.binary_search_by(|probe| probe.cmp(&seek));
assert!(match r { Ok(1..=4) => true, _ => false, });

pub fn binary_search_by_key<'a, B, F>(     &'a self,     b: &B,     f: F ) -> Result<usize, usize> where     B: Ord,     F: FnMut(&'a T) -> B,

Binary searches this sorted slice with a key extraction function.

Assumes that the slice is sorted by the key, for instance with sort_by_key using the same key extraction function.

If a matching value is found then returns Ok, containing the index for the matched element; if no match is found then Err is returned, containing the index where a matching element could be inserted while maintaining sorted order.

Examples

Looks up a series of four elements in a slice of pairs sorted by their second elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in [1, 4].

let s = [(0, 0), (2, 1), (4, 1), (5, 1), (3, 1),
         (1, 2), (2, 3), (4, 5), (5, 8), (3, 13),
         (1, 21), (2, 34), (4, 55)];

assert_eq!(s.binary_search_by_key(&13, |&(a,b)| b),  Ok(9));
assert_eq!(s.binary_search_by_key(&4, |&(a,b)| b),   Err(7));
assert_eq!(s.binary_search_by_key(&100, |&(a,b)| b), Err(13));
let r = s.binary_search_by_key(&1, |&(a,b)| b);
assert!(match r { Ok(1..=4) => true, _ => false, });

pub unsafe fn align_to<U>(&self) -> (&[T], &[U], &[T])

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

Transmute the slice to a slice of another type, ensuring aligment of the types is maintained.

This method splits the slice into three distinct slices: prefix, correctly aligned middle slice of a new type, and the suffix slice. The middle slice will have the greatest length possible for a given type and input slice.

This method has no purpose when either input element T or output element U are zero-sized and will return the original slice without splitting anything.

Unsafety

This method is essentially a transmute with respect to the elements in the returned middle slice, so all the usual caveats pertaining to transmute::<T, U> also apply here.

Examples

Basic usage:

unsafe {
    let bytes: [u8; 7] = [1, 2, 3, 4, 5, 6, 7];
    let (prefix, shorts, suffix) = bytes.align_to::<u16>();
    // less_efficient_algorithm_for_bytes(prefix);
    // more_efficient_algorithm_for_aligned_shorts(shorts);
    // less_efficient_algorithm_for_bytes(suffix);
}

pub fn is_ascii(&self) -> bool

Checks if all bytes in this slice are within the ASCII range.

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

Checks that two slices are an ASCII case-insensitive match.

Same as to_ascii_lowercase(a) == to_ascii_lowercase(b), but without allocating and copying temporaries.

Important traits for Vec<u8>

impl Write for Vec<u8>

pub fn to_vec(&self) -> Vec<T> where     T: Clone,

Copies self into a new Vec.

Examples

let s = [10, 40, 30];
let x = s.to_vec();
// Here, `s` and `x` can be modified independently.

Important traits for Vec<u8>

impl Write for Vec<u8>

pub fn repeat(&self, n: usize) -> Vec<T> where     T: Copy,

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

it's on str, why not on slice?

Creates a vector by repeating a slice n times.

Panics

This function will panic if the capacity would overflow.

Examples

Basic usage:

#![feature(repeat_generic_slice)]

fn main() {
    assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);
}

A panic upon overflow:

#![feature(repeat_generic_slice)]
fn main() {
    // this will panic at runtime
    b"0123456789abcdef".repeat(usize::max_value());
}

Important traits for Vec<u8>

impl Write for Vec<u8>

pub fn to_ascii_uppercase(&self) -> Vec<u8>

Returns a vector containing a copy of this slice where each byte is mapped to its ASCII upper case equivalent.

ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', but non-ASCII letters are unchanged.

To uppercase the value in-place, use make_ascii_uppercase.

Important traits for Vec<u8>

impl Write for Vec<u8>

pub fn to_ascii_lowercase(&self) -> Vec<u8>

Returns a vector containing a copy of this slice where each byte is mapped to its ASCII lower case equivalent.

ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', but non-ASCII letters are unchanged.

To lowercase the value in-place, use make_ascii_lowercase.

Trait Implementations

impl FromBuf for Bytes

fn from_buf<T>(buf: T) -> Self where     T: IntoBuf,

Creates a value from a buffer.

impl IntoBuf for Bytes

type Buf = Cursor<Self>

The Buf type that self is being converted into

fn into_buf(self) -> Self::Buf

Creates a Buf from a value.

impl<'a> IntoBuf for &'a Bytes

type Buf = Cursor<Self>

The Buf type that self is being converted into

fn into_buf(self) -> Self::Buf

Creates a Buf from a value.

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 AsRef<[u8]> for Bytes

Important traits for &'a mut [u8]

impl<'a> Write for &'a mut [u8]impl<'a> Read for &'a [u8]

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

Performs the conversion.

impl Deref for Bytes

type Target = [u8]

The resulting type after dereferencing.

Important traits for &'a mut [u8]

impl<'a> Write for &'a mut [u8]impl<'a> Read for &'a [u8]

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

Dereferences the value.

impl From<BytesMut> for Bytes

fn from(src: BytesMut) -> Bytes

Performs the conversion.

impl From<Vec<u8>> for Bytes

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

Performs the conversion.

impl From<String> for Bytes

fn from(src: String) -> Bytes

Performs the conversion.

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

fn from(src: &'a [u8]) -> Bytes

Performs the conversion.

impl<'a> From<&'a str> for Bytes

fn from(src: &'a str) -> 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 PartialEq for Bytes

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

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

#[must_use] fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl PartialOrd for Bytes

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

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

#[must_use] fn lt(&self, other: &Rhs) -> bool

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

#[must_use] fn le(&self, other: &Rhs) -> bool

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

#[must_use] fn gt(&self, other: &Rhs) -> bool

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

#[must_use] 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 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.

impl Eq for Bytes

impl Default for Bytes

fn default() -> Bytes

Returns the "default value" for a type.

impl Debug for Bytes

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

Formats the value using the given formatter.

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 Borrow<[u8]> for Bytes

Important traits for &'a mut [u8]

impl<'a> Write for &'a mut [u8]impl<'a> Read for &'a [u8]

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

Immutably borrows from an owned value.

impl IntoIterator for Bytes

type Item = u8

The type of the elements being iterated over.

type IntoIter = Iter<Cursor<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 = u8

The type of the elements being iterated over.

type IntoIter = Iter<Cursor<&'a Bytes>>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl Extend<u8> for Bytes

fn extend<T>(&mut self, iter: T) where     T: IntoIterator<Item = u8>,

Extends a collection with the contents of an iterator.

impl<'a> Extend<&'a u8> for Bytes

fn extend<T>(&mut self, iter: T) where     T: IntoIterator<Item = &'a u8>,

Extends a collection with the contents of an iterator.

impl From<Bytes> for BytesMut

fn from(src: Bytes) -> BytesMut

Performs the conversion.

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 ==.

#[must_use] fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

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.

#[must_use] fn lt(&self, other: &Rhs) -> bool

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

#[must_use] fn le(&self, other: &Rhs) -> bool

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

#[must_use] fn gt(&self, other: &Rhs) -> bool

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

#[must_use] 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 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 ==.

#[must_use] fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

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.

#[must_use] fn lt(&self, other: &Rhs) -> bool

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

#[must_use] fn le(&self, other: &Rhs) -> bool

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

#[must_use] fn gt(&self, other: &Rhs) -> bool

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

#[must_use] 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 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 ==.

#[must_use] fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

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.

#[must_use] fn lt(&self, other: &Rhs) -> bool

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

#[must_use] fn le(&self, other: &Rhs) -> bool

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

#[must_use] fn gt(&self, other: &Rhs) -> bool

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

#[must_use] 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 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 ==.

#[must_use] fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

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.

#[must_use] fn lt(&self, other: &Rhs) -> bool

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

#[must_use] fn le(&self, other: &Rhs) -> bool

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

#[must_use] fn gt(&self, other: &Rhs) -> bool

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

#[must_use] 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 PartialEq<Vec<u8>> for Bytes

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

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

#[must_use] fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl PartialOrd<Vec<u8>> for Bytes

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

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

#[must_use] fn lt(&self, other: &Rhs) -> bool

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

#[must_use] fn le(&self, other: &Rhs) -> bool

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

#[must_use] fn gt(&self, other: &Rhs) -> bool

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

#[must_use] 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 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 ==.

#[must_use] fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

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.

#[must_use] fn lt(&self, other: &Rhs) -> bool

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

#[must_use] fn le(&self, other: &Rhs) -> bool

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

#[must_use] fn gt(&self, other: &Rhs) -> bool

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

#[must_use] 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 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 ==.

#[must_use] fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

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.

#[must_use] fn lt(&self, other: &Rhs) -> bool

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

#[must_use] fn le(&self, other: &Rhs) -> bool

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

#[must_use] fn gt(&self, other: &Rhs) -> bool

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

#[must_use] 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 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 ==.

#[must_use] fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

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.

#[must_use] fn lt(&self, other: &Rhs) -> bool

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

#[must_use] fn le(&self, other: &Rhs) -> bool

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

#[must_use] fn gt(&self, other: &Rhs) -> bool

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

#[must_use] 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<'a> PartialEq<Bytes> for &'a [u8]

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

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

#[must_use] fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl<'a> PartialOrd<Bytes> for &'a [u8]

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

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

#[must_use] fn lt(&self, other: &Rhs) -> bool

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

#[must_use] fn le(&self, other: &Rhs) -> bool

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

#[must_use] fn gt(&self, other: &Rhs) -> bool

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

#[must_use] 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<'a> PartialEq<Bytes> for &'a str

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

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

#[must_use] fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl<'a> PartialOrd<Bytes> for &'a str

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

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

#[must_use] fn lt(&self, other: &Rhs) -> bool

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

#[must_use] fn le(&self, other: &Rhs) -> bool

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

#[must_use] fn gt(&self, other: &Rhs) -> bool

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

#[must_use] 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<'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 ==.

#[must_use] 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.

#[must_use] fn lt(&self, other: &Rhs) -> bool

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

#[must_use] fn le(&self, other: &Rhs) -> bool

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

#[must_use] fn gt(&self, other: &Rhs) -> bool

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

#[must_use] 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 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 ==.

#[must_use] 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 ==.

#[must_use] fn ne(&self, other: &Rhs) -> bool

This method tests for !=.