结构体 Bytes 

pub struct Bytes { /* private fields */ }

一段可廉价克隆、可切片访问的连续内存。

Bytes 是一个用于存储和操作连续内存切片的高效容器。 它主要面向网络编程场景，但 在其他场景下也同样适用。

Bytes 通过允许多个 Bytes 对象 指向同一段底层内存来简化零拷贝网络编程。

Bytes 并没有单一的具体实现。它是一个接口， 其具体行为由若干 Bytes 底层实现 通过动态分派来提供。

所有 Bytes 实现都必须满足以下要求：

• 可廉价克隆，从而能在任意数量的组件之间共享（例如通过修改引用计数实现）。
• 可以切片，以引用原缓冲区的一个子集。

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/cloning 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 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 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 │     │           │               │     │
└─────┴─────┴───────────┴───────────────┴─────┘

实现

impl Bytes

pub const fn new() -> Self

创建一个空的 Bytes。

不会分配内存，返回的 Bytes 句柄为空。

示例

use bytes::Bytes;

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

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

从静态切片创建新的 Bytes。

返回的 Bytes 将直接指向静态切片。不进行分配或拷贝。

示例

use bytes::Bytes;

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

pub fn from_owner<T>(owner: T) -> Self

where T: AsRef<[u8]> + Send + 'static,

使用由显式所有者控制生命周期的缓冲区构造 Bytes。

一个常见的用例是从内存映射中零拷贝构造。

use bytes::Bytes;
use memmap2::Mmap;

let file = File::open("upload_bundle.tar.gz")?;
let mmap = unsafe { Mmap::map(&file) }?;
let b = Bytes::from_owner(mmap);

owner 将被转移到已构造的 Bytes 对象中，确保在已构造对象的所有剩余克隆都被丢弃后被释放。然后 owner 将负责释放指定的内存。

请注意，将由 owner 构造的 Bytes 转换为 BytesMut 总会将缓冲区的深度拷贝到新分配的内存中。

pub const fn len(&self) -> usize

返回此 Bytes 所包含的字节数。

示例

use bytes::Bytes;

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

pub const fn is_empty(&self) -> bool

若 Bytes 长度为 0，返回 true。

示例

use bytes::Bytes;

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

pub fn is_unique(&self) -> bool

若这是对数据的唯一引用，且 Into<BytesMut> 转换可避免克隆底层缓冲，则返回 true。

若数据由静态切片或 owner 支持，则始终返回 false。

若在调用此方法时其他线程克隆此值，则该方法的结果可能立即失效。若需确保结果有效（例如出于安全考虑），请先确保你对此值具有唯一访问权限（&mut Bytes）。

示例

use bytes::Bytes;

let a = Bytes::from(vec![1, 2, 3]);
assert!(a.is_unique());
let b = a.clone();
assert!(!a.is_unique());

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

通过复制切片内容创建一个 Bytes 实例。

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

返回 self 中指定范围的切片。

这会增加底层内存的引用计数，并返回一个设置为该切片的新 Bytes 句柄。

此操作为 O(1)。

示例

use bytes::Bytes;

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

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

Panics

要求 begin <= end 且 end <= self.len()，否则切片操作会 panic。

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

返回与给定 subset 等价的 self 切片。

使用其他工具处理 Bytes 缓冲区时，经常会得到 &[u8]，它实际上是 Bytes 的一个切片，即其子集。本函数将该 &[u8] 转换为另一个 Bytes，如同调用 self.slice() 并传入与 subset 对应的偏移量。

此操作为 O(1)。

示例

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

要求给定的 sub 切片确实包含在 Bytes 缓冲区中；否则此函数会 panic。

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

在给定索引处将字节切分为两段。

此后 self 包含元素 [0, at)，返回的 Bytes 包含元素 [at, len)。保证内存不会移动，即 self 的地址不变，且返回切片的地址也不变。

此操作为 O(1)，仅增加引用计数并设置一些索引。

示例

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) -> Self

在给定索引处将字节切分为两段。

此后 self 包含元素 [at, len)，返回的 Bytes 包含元素 [0, at)。

此操作为 O(1)，仅增加引用计数并设置一些索引。

示例

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)

缩短缓冲区，保留前 len 字节，丢弃其余字节。

若 len 大于缓冲区的当前长度，则此操作无效。

split_off 方法可以模拟 truncate，但这会导致多余的字节被返回而不是丢弃。

示例

use bytes::Bytes;

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

pub fn clear(&mut self)

清空缓冲区，移除所有数据。

示例

use bytes::Bytes;

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

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

尝试将 self 转换为 BytesMut。

若 self 在整个原始缓冲区中是唯一的，则此调用成功，并返回包含 self 内容（无拷贝）的 BytesMut。若 self 在整个原始缓冲区中不是唯一的，则此调用失败并返回 self。

若缓冲区是通过 from_owner 或 from_static 构造的，则此调用也总是失败。

示例

use bytes::{Bytes, BytesMut};

let bytes = Bytes::from(b"hello".to_vec());
assert_eq!(bytes.try_into_mut(), Ok(BytesMut::from(&b"hello"[..])));

Methods from Deref<Target = [u8]>

pub fn is_ascii(&self) -> bool

检查本切片中的所有字节是否都在 ASCII 范围内。

An empty slice returns true.

pub fn as_ascii(&self) -> Option<&[AsciiChar]>

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

If this slice is_ascii, returns it as a slice of ASCII characters, otherwise returns None.

pub unsafe fn as_ascii_unchecked(&self) -> &[AsciiChar]

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

Converts this slice of bytes into a slice of ASCII characters, without checking whether they’re valid.

Safety

Every byte in the slice must be in 0..=127, or else this is UB.

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

检查两个切片是否在忽略 ASCII 大小写的情况下相等。

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

pub fn escape_ascii(&self) -> EscapeAscii<'_>

Returns an iterator that produces an escaped version of this slice, treating it as an ASCII string.

示例

let s = b"0\t\r\n'\"\\\x9d";
let escaped = s.escape_ascii().to_string();
assert_eq!(escaped, "0\\t\\r\\n\\'\\\"\\\\\\x9d");

pub fn trim_ascii_start(&self) -> &[u8]

返回一个去除了开头 ASCII 空白字节的字节切片。

‘Whitespace’ refers to the definition used by u8::is_ascii_whitespace.

示例

assert_eq!(b" \t hello world\n".trim_ascii_start(), b"hello world\n");
assert_eq!(b"  ".trim_ascii_start(), b"");
assert_eq!(b"".trim_ascii_start(), b"");

pub fn trim_ascii_end(&self) -> &[u8]

返回一个去除了末尾 ASCII 空白字节的字节切片。

‘Whitespace’ refers to the definition used by u8::is_ascii_whitespace.

示例

assert_eq!(b"\r hello world\n ".trim_ascii_end(), b"\r hello world");
assert_eq!(b"  ".trim_ascii_end(), b"");
assert_eq!(b"".trim_ascii_end(), b"");

pub fn trim_ascii(&self) -> &[u8]

Returns a byte slice with leading and trailing ASCII whitespace bytes removed.

‘Whitespace’ refers to the definition used by u8::is_ascii_whitespace.

示例

assert_eq!(b"\r hello world\n ".trim_ascii(), b"hello world");
assert_eq!(b"  ".trim_ascii(), b"");
assert_eq!(b"".trim_ascii(), b"");

pub fn len(&self) -> usize

返回切片中元素的数量。

示例

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

pub fn is_empty(&self) -> bool

Returns true if the slice has a length of 0.

示例

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

let b: &[i32] = &[];
assert!(b.is_empty());

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

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

示例

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.

示例

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.

示例

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.

示例

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

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

pub fn first_chunk<const N: usize>(&self) -> Option<&[T; N]>

Returns an array reference to the first N items in the slice.

If the slice is not at least N in length, this will return None.

示例

let u = [10, 40, 30];
assert_eq!(Some(&[10, 40]), u.first_chunk::<2>());

let v: &[i32] = &[10];
assert_eq!(None, v.first_chunk::<2>());

let w: &[i32] = &[];
assert_eq!(Some(&[]), w.first_chunk::<0>());

pub fn split_first_chunk<const N: usize>(&self) -> Option<(&[T; N], &[T])>

Returns an array reference to the first N items in the slice and the remaining slice.

If the slice is not at least N in length, this will return None.

示例

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

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

assert_eq!(None, x.split_first_chunk::<4>());

pub fn split_last_chunk<const N: usize>(&self) -> Option<(&[T], &[T; N])>

Returns an array reference to the last N items in the slice and the remaining slice.

If the slice is not at least N in length, this will return None.

示例

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

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

assert_eq!(None, x.split_last_chunk::<4>());

pub fn last_chunk<const N: usize>(&self) -> Option<&[T; N]>

Returns an array reference to the last N items in the slice.

If the slice is not at least N in length, this will return None.

示例

let u = [10, 40, 30];
assert_eq!(Some(&[40, 30]), u.last_chunk::<2>());

let v: &[i32] = &[10];
assert_eq!(None, v.last_chunk::<2>());

let w: &[i32] = &[];
assert_eq!(Some(&[]), w.last_chunk::<0>());

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.

示例

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.

For a safe alternative see get.

Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.

You can think of this like .get(index).unwrap_unchecked(). It’s UB to call .get_unchecked(len), even if you immediately convert to a pointer. And it’s UB to call .get_unchecked(..len + 1), .get_unchecked(..=len), or similar.

示例

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

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

pub 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 dangling.

The caller must also ensure that the memory the pointer (non-transitively) points to is never written to (except inside an UnsafeCell) using this pointer or any pointer derived from it. If you need to mutate the contents of the slice, use as_mut_ptr.

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

示例

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.add(i));
    }
}

pub fn as_ptr_range(&self) -> Range<*const T>

Returns the two raw pointers spanning the slice.

The returned range is half-open, which means that the end pointer points one past the last element of the slice. This way, an empty slice is represented by two equal pointers, and the difference between the two pointers represents the size of the slice.

See as_ptr for warnings on using these pointers. The end pointer requires extra caution, as it does not point to a valid element in the slice.

This function is useful for interacting with foreign interfaces which use two pointers to refer to a range of elements in memory, as is common in C++.

It can also be useful to check if a pointer to an element refers to an element of this slice:

let a = [1, 2, 3];
let x = &a[1] as *const _;
let y = &5 as *const _;

assert!(a.as_ptr_range().contains(&x));
assert!(!a.as_ptr_range().contains(&y));

pub fn as_array<const N: usize>(&self) -> Option<&[T; N]>

Gets a reference to the underlying array.

If N is not exactly equal to the length of self, then this method returns None.

pub fn iter(&self) -> Iter<'_, T>

Returns an iterator over the slice.

迭代器产出从 start 到 end 的全部项。

示例

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);

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 zero.

示例

let slice = ['l', 'o', 'r', 'e', 'm'];
let mut iter = slice.windows(3);
assert_eq!(iter.next().unwrap(), &['l', 'o', 'r']);
assert_eq!(iter.next().unwrap(), &['o', 'r', 'e']);
assert_eq!(iter.next().unwrap(), &['r', 'e', 'm']);
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());

Because the Iterator trait cannot represent the required lifetimes, there is no windows_mut analog to windows; [0,1,2].windows_mut(2).collect() would violate the rules of references (though a LendingIterator analog is possible). You can sometimes use Cell::as_slice_of_cells in conjunction with windows instead:

use std::cell::Cell;

let mut array = ['R', 'u', 's', 't', ' ', '2', '0', '1', '5'];
let slice = &mut array[..];
let slice_of_cells: &[Cell<char>] = Cell::from_mut(slice).as_slice_of_cells();
for w in slice_of_cells.windows(3) {
    Cell::swap(&w[0], &w[2]);
}
assert_eq!(array, ['s', 't', ' ', '2', '0', '1', '5', 'u', 'R']);

pub fn chunks(&self, chunk_size: usize) -> Chunks<'_, T>

Returns an iterator over chunk_size elements of the slice at a time, starting at the beginning of the slice.

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 chunks_exact for a variant of this iterator that returns chunks of always exactly chunk_size elements, and rchunks for the same iterator but starting at the end of the slice.

If your chunk_size is a constant, consider using as_chunks instead, which will give references to arrays of exactly that length, rather than slices.

Panics

Panics if chunk_size is zero.

示例

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());

pub fn chunks_exact(&self, chunk_size: usize) -> ChunksExact<'_, T>

Returns an iterator over chunk_size elements of the slice at a time, starting at the beginning of the slice.

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.

See chunks for a variant of this iterator that also returns the remainder as a smaller chunk, and rchunks_exact for the same iterator but starting at the end of the slice.

If your chunk_size is a constant, consider using as_chunks instead, which will give references to arrays of exactly that length, rather than slices.

Panics

Panics if chunk_size is zero.

示例

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

pub unsafe fn as_chunks_unchecked<const N: usize>(&self) -> &[[T; N]]

Splits the slice into a slice of N-element arrays, assuming that there’s no remainder.

This is the inverse operation to as_flattened.

As this is unsafe, consider whether you could use as_chunks or as_rchunks instead, perhaps via something like if let (chunks, []) = slice.as_chunks() or let (chunks, []) = slice.as_chunks() else { unreachable!() };.

Safety

本方法只能在满足以下条件时调用：

• The slice splits exactly into N-element chunks (aka self.len() % N == 0).
• N != 0.

示例

let slice: &[char] = &['l', 'o', 'r', 'e', 'm', '!'];
let chunks: &[[char; 1]] =
    // SAFETY: 1-element chunks never have remainder
    unsafe { slice.as_chunks_unchecked() };
assert_eq!(chunks, &[['l'], ['o'], ['r'], ['e'], ['m'], ['!']]);
let chunks: &[[char; 3]] =
    // SAFETY: The slice length (6) is a multiple of 3
    unsafe { slice.as_chunks_unchecked() };
assert_eq!(chunks, &[['l', 'o', 'r'], ['e', 'm', '!']]);

// These would be unsound:
// let chunks: &[[_; 5]] = slice.as_chunks_unchecked() // The slice length is not a multiple of 5
// let chunks: &[[_; 0]] = slice.as_chunks_unchecked() // Zero-length chunks are never allowed

pub fn as_chunks<const N: usize>(&self) -> (&[[T; N]], &[T])

Splits the slice into a slice of N-element arrays, starting at the beginning of the slice, and a remainder slice with length strictly less than N.

The remainder is meaningful in the division sense. Given let (chunks, remainder) = slice.as_chunks(), then:

• chunks.len() equals slice.len() / N,
• remainder.len() equals slice.len() % N, and
• slice.len() equals chunks.len() * N + remainder.len().

You can flatten the chunks back into a slice-of-T with as_flattened.

Panics

Panics if N is zero.

Note that this check is against a const generic parameter, not a runtime value, and thus a particular monomorphization will either always panic or it will never panic.

示例

let slice = ['l', 'o', 'r', 'e', 'm'];
let (chunks, remainder) = slice.as_chunks();
assert_eq!(chunks, &[['l', 'o'], ['r', 'e']]);
assert_eq!(remainder, &['m']);

If you expect the slice to be an exact multiple, you can combine let-else with an empty slice pattern:

let slice = ['R', 'u', 's', 't'];
let (chunks, []) = slice.as_chunks::<2>() else {
    panic!("slice didn't have even length")
};
assert_eq!(chunks, &[['R', 'u'], ['s', 't']]);

pub fn as_rchunks<const N: usize>(&self) -> (&[T], &[[T; N]])

Splits the slice into a slice of N-element arrays, starting at the end of the slice, and a remainder slice with length strictly less than N.

The remainder is meaningful in the division sense. Given let (remainder, chunks) = slice.as_rchunks(), then:

• remainder.len() equals slice.len() % N,
• chunks.len() equals slice.len() / N, and
• slice.len() equals chunks.len() * N + remainder.len().

You can flatten the chunks back into a slice-of-T with as_flattened.

Panics

Panics if N is zero.

Note that this check is against a const generic parameter, not a runtime value, and thus a particular monomorphization will either always panic or it will never panic.

示例

let slice = ['l', 'o', 'r', 'e', 'm'];
let (remainder, chunks) = slice.as_rchunks();
assert_eq!(remainder, &['l']);
assert_eq!(chunks, &[['o', 'r'], ['e', 'm']]);

pub fn array_windows<const N: usize>(&self) -> ArrayWindows<'_, T, N>

Returns an iterator over overlapping windows of N elements of a slice, starting at the beginning of the slice.

This is the const generic equivalent of windows.

If N is greater than the size of the slice, it will return no windows.

Panics

Panics if N is zero.

Note that this check is against a const generic parameter, not a runtime value, and thus a particular monomorphization will either always panic or it will never panic.

示例

let slice = [0, 1, 2, 3];
let mut iter = slice.array_windows();
assert_eq!(iter.next().unwrap(), &[0, 1]);
assert_eq!(iter.next().unwrap(), &[1, 2]);
assert_eq!(iter.next().unwrap(), &[2, 3]);
assert!(iter.next().is_none());

pub fn rchunks(&self, chunk_size: usize) -> RChunks<'_, T>

Returns an iterator over chunk_size elements of the slice at a time, starting at the end of the slice.

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 rchunks_exact for a variant of this iterator that returns chunks of always exactly chunk_size elements, and chunks for the same iterator but starting at the beginning of the slice.

If your chunk_size is a constant, consider using as_rchunks instead, which will give references to arrays of exactly that length, rather than slices.

Panics

Panics if chunk_size is zero.

示例

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

pub fn rchunks_exact(&self, chunk_size: usize) -> RChunksExact<'_, T>

Returns an iterator over chunk_size elements of the slice at a time, starting at the end of the slice.

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 rchunks.

See rchunks for a variant of this iterator that also returns the remainder as a smaller chunk, and chunks_exact for the same iterator but starting at the beginning of the slice.

If your chunk_size is a constant, consider using as_rchunks instead, which will give references to arrays of exactly that length, rather than slices.

Panics

Panics if chunk_size is zero.

示例

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

pub fn chunk_by<F>(&self, pred: F) -> ChunkBy<'_, T, F>

where F: FnMut(&T, &T) -> bool,

Returns an iterator over the slice producing non-overlapping runs of elements using the predicate to separate them.

The predicate is called for every pair of consecutive elements, meaning that it is called on slice[0] and slice[1], followed by slice[1] and slice[2], and so on.

示例

let slice = &[1, 1, 1, 3, 3, 2, 2, 2];

let mut iter = slice.chunk_by(|a, b| a == b);

assert_eq!(iter.next(), Some(&[1, 1, 1][..]));
assert_eq!(iter.next(), Some(&[3, 3][..]));
assert_eq!(iter.next(), Some(&[2, 2, 2][..]));
assert_eq!(iter.next(), None);

本方法可用于提取已排序的子切片：

let slice = &[1, 1, 2, 3, 2, 3, 2, 3, 4];

let mut iter = slice.chunk_by(|a, b| a <= b);

assert_eq!(iter.next(), Some(&[1, 1, 2, 3][..]));
assert_eq!(iter.next(), Some(&[2, 3][..]));
assert_eq!(iter.next(), Some(&[2, 3, 4][..]));
assert_eq!(iter.next(), 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. For a non-panicking alternative see split_at_checked.

示例

let v = ['a', 'b', 'c'];

{
   let (left, right) = v.split_at(0);
   assert_eq!(left, []);
   assert_eq!(right, ['a', 'b', 'c']);
}

{
    let (left, right) = v.split_at(2);
    assert_eq!(left, ['a', 'b']);
    assert_eq!(right, ['c']);
}

{
    let (left, right) = v.split_at(3);
    assert_eq!(left, ['a', 'b', 'c']);
    assert_eq!(right, []);
}

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

Divides one slice into two at an index, without doing bounds checking.

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).

For a safe alternative see split_at.

Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used. The caller has to ensure that 0 <= mid <= self.len().

示例

let v = ['a', 'b', 'c'];

unsafe {
   let (left, right) = v.split_at_unchecked(0);
   assert_eq!(left, []);
   assert_eq!(right, ['a', 'b', 'c']);
}

unsafe {
    let (left, right) = v.split_at_unchecked(2);
    assert_eq!(left, ['a', 'b']);
    assert_eq!(right, ['c']);
}

unsafe {
    let (left, right) = v.split_at_unchecked(3);
    assert_eq!(left, ['a', 'b', 'c']);
    assert_eq!(right, []);
}

pub fn split_at_checked(&self, mid: usize) -> Option<(&[T], &[T])>

Divides one slice into two at an index, returning None if the slice is too short.

If mid ≤ len returns a pair of slices where 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).

Otherwise, if mid > len, returns None.

示例

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

{
   let (left, right) = v.split_at_checked(0).unwrap();
   assert_eq!(left, []);
   assert_eq!(right, [1, -2, 3, -4, 5, -6]);
}

{
    let (left, right) = v.split_at_checked(2).unwrap();
    assert_eq!(left, [1, -2]);
    assert_eq!(right, [3, -4, 5, -6]);
}

{
    let (left, right) = v.split_at_checked(6).unwrap();
    assert_eq!(left, [1, -2, 3, -4, 5, -6]);
    assert_eq!(right, []);
}

assert_eq!(None, v.split_at_checked(7));

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.

示例

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());

pub fn split_inclusive<F>(&self, pred: F) -> SplitInclusive<'_, T, F>

where F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match pred. The matched element is contained in the end of the previous subslice as a terminator.

示例

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

assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
assert_eq!(iter.next().unwrap(), &[20]);
assert!(iter.next().is_none());

If the last element of the slice is matched, that element will be considered the terminator of the preceding slice. That slice will be the last item returned by the iterator.

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

assert_eq!(iter.next().unwrap(), &[3]);
assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
assert!(iter.next().is_none());

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.

示例

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);

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.

示例

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:?}");
}

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.

示例

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 split_once<F>(&self, pred: F) -> Option<(&[T], &[T])>

where F: FnMut(&T) -> bool,

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

Splits the slice on the first element that matches the specified predicate.

If any matching elements are present in the slice, returns the prefix before the match and suffix after. The matching element itself is not included. If no elements match, returns None.

示例

#![feature(slice_split_once)]
let s = [1, 2, 3, 2, 4];
assert_eq!(s.split_once(|&x| x == 2), Some((
    &[1][..],
    &[3, 2, 4][..]
)));
assert_eq!(s.split_once(|&x| x == 0), None);

pub fn rsplit_once<F>(&self, pred: F) -> Option<(&[T], &[T])>

where F: FnMut(&T) -> bool,

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

Splits the slice on the last element that matches the specified predicate.

If any matching elements are present in the slice, returns the prefix before the match and suffix after. The matching element itself is not included. If no elements match, returns None.

示例

#![feature(slice_split_once)]
let s = [1, 2, 3, 2, 4];
assert_eq!(s.rsplit_once(|&x| x == 2), Some((
    &[1, 2, 3][..],
    &[4][..]
)));
assert_eq!(s.rsplit_once(|&x| x == 0), None);

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

where T: PartialEq,

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

This operation is O(n).

Note that if you have a sorted slice, binary_search may be faster.

示例

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

If you do not have a &T, but some other value that you can compare with one (for example, String implements PartialEq<str>), you can use iter().any:

let v = [String::from("hello"), String::from("world")]; // slice of `String`
assert!(v.iter().any(|e| e == "hello")); // search with `&str`
assert!(!v.iter().any(|e| e == "hi"));

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

where T: PartialEq,

Returns true if needle is a prefix of the slice or equal to the slice.

示例

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

Returns true if needle is a suffix of the slice or equal to the slice.

示例

let v = [10, 40, 30];
assert!(v.ends_with(&[30]));
assert!(v.ends_with(&[40, 30]));
assert!(v.ends_with(&v));
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 strip_prefix<P>(&self, prefix: &P) -> Option<&[T]>

where P: SlicePattern<Item = T> + ?Sized, T: PartialEq,

Returns a subslice with the prefix removed.

If the slice starts with prefix, returns the subslice after the prefix, wrapped in Some. If prefix is empty, simply returns the original slice. If prefix is equal to the original slice, returns an empty slice.

If the slice does not start with prefix, returns None.

示例

let v = &[10, 40, 30];
assert_eq!(v.strip_prefix(&[10]), Some(&[40, 30][..]));
assert_eq!(v.strip_prefix(&[10, 40]), Some(&[30][..]));
assert_eq!(v.strip_prefix(&[10, 40, 30]), Some(&[][..]));
assert_eq!(v.strip_prefix(&[50]), None);
assert_eq!(v.strip_prefix(&[10, 50]), None);

let prefix : &str = "he";
assert_eq!(b"hello".strip_prefix(prefix.as_bytes()),
           Some(b"llo".as_ref()));

pub fn strip_suffix<P>(&self, suffix: &P) -> Option<&[T]>

where P: SlicePattern<Item = T> + ?Sized, T: PartialEq,

Returns a subslice with the suffix removed.

If the slice ends with suffix, returns the subslice before the suffix, wrapped in Some. If suffix is empty, simply returns the original slice. If suffix is equal to the original slice, returns an empty slice.

If the slice does not end with suffix, returns None.

示例

let v = &[10, 40, 30];
assert_eq!(v.strip_suffix(&[30]), Some(&[10, 40][..]));
assert_eq!(v.strip_suffix(&[40, 30]), Some(&[10][..]));
assert_eq!(v.strip_suffix(&[10, 40, 30]), Some(&[][..]));
assert_eq!(v.strip_suffix(&[50]), None);
assert_eq!(v.strip_suffix(&[50, 30]), None);

pub fn strip_circumfix<S, P>(&self, prefix: &P, suffix: &S) -> Option<&[T]>

where T: PartialEq, S: SlicePattern<Item = T> + ?Sized, P: SlicePattern<Item = T> + ?Sized,

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

Returns a subslice with the prefix and suffix removed.

If the slice starts with prefix and ends with suffix, returns the subslice after the prefix and before the suffix, wrapped in Some.

If the slice does not start with prefix or does not end with suffix, returns None.

示例

#![feature(strip_circumfix)]

let v = &[10, 50, 40, 30];
assert_eq!(v.strip_circumfix(&[10], &[30]), Some(&[50, 40][..]));
assert_eq!(v.strip_circumfix(&[10], &[40, 30]), Some(&[50][..]));
assert_eq!(v.strip_circumfix(&[10, 50], &[40, 30]), Some(&[][..]));
assert_eq!(v.strip_circumfix(&[50], &[30]), None);
assert_eq!(v.strip_circumfix(&[10], &[40]), None);
assert_eq!(v.strip_circumfix(&[], &[40, 30]), Some(&[10, 50][..]));
assert_eq!(v.strip_circumfix(&[10, 50], &[]), Some(&[40, 30][..]));

pub fn trim_prefix<P>(&self, prefix: &P) -> &[T]

where P: SlicePattern<Item = T> + ?Sized, T: PartialEq,

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

Returns a subslice with the optional prefix removed.

If the slice starts with prefix, returns the subslice after the prefix. If prefix is empty or the slice does not start with prefix, simply returns the original slice. If prefix is equal to the original slice, returns an empty slice.

示例

#![feature(trim_prefix_suffix)]

let v = &[10, 40, 30];

// Prefix present - removes it
assert_eq!(v.trim_prefix(&[10]), &[40, 30][..]);
assert_eq!(v.trim_prefix(&[10, 40]), &[30][..]);
assert_eq!(v.trim_prefix(&[10, 40, 30]), &[][..]);

// Prefix absent - returns original slice
assert_eq!(v.trim_prefix(&[50]), &[10, 40, 30][..]);
assert_eq!(v.trim_prefix(&[10, 50]), &[10, 40, 30][..]);

let prefix : &str = "he";
assert_eq!(b"hello".trim_prefix(prefix.as_bytes()), b"llo".as_ref());

pub fn trim_suffix<P>(&self, suffix: &P) -> &[T]

where P: SlicePattern<Item = T> + ?Sized, T: PartialEq,

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

Returns a subslice with the optional suffix removed.

If the slice ends with suffix, returns the subslice before the suffix. If suffix is empty or the slice does not end with suffix, simply returns the original slice. If suffix is equal to the original slice, returns an empty slice.

示例

#![feature(trim_prefix_suffix)]

let v = &[10, 40, 30];

// Suffix present - removes it
assert_eq!(v.trim_suffix(&[30]), &[10, 40][..]);
assert_eq!(v.trim_suffix(&[40, 30]), &[10][..]);
assert_eq!(v.trim_suffix(&[10, 40, 30]), &[][..]);

// Suffix absent - returns original slice
assert_eq!(v.trim_suffix(&[50]), &[10, 40, 30][..]);
assert_eq!(v.trim_suffix(&[50, 30]), &[10, 40, 30][..]);

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

where T: Ord,

Binary searches this slice for a given element. If the slice is not sorted, the returned result is unspecified and meaningless.

If the value is found then Result::Ok is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. The index is chosen deterministically, but is subject to change in future versions of Rust. If the value is not found then Result::Err is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also binary_search_by, binary_search_by_key, and partition_point.

示例

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, });

If you want to find that whole range of matching items, rather than an arbitrary matching one, that can be done using partition_point:

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

let low = s.partition_point(|x| x < &1);
assert_eq!(low, 1);
let high = s.partition_point(|x| x <= &1);
assert_eq!(high, 5);
let r = s.binary_search(&1);
assert!((low..high).contains(&r.unwrap()));

assert!(s[..low].iter().all(|&x| x < 1));
assert!(s[low..high].iter().all(|&x| x == 1));
assert!(s[high..].iter().all(|&x| x > 1));

// For something not found, the "range" of equal items is empty
assert_eq!(s.partition_point(|x| x < &11), 9);
assert_eq!(s.partition_point(|x| x <= &11), 9);
assert_eq!(s.binary_search(&11), Err(9));

If you want to insert an item to a sorted vector, while maintaining sort order, consider using partition_point:

let mut s = vec![0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
let num = 42;
let idx = s.partition_point(|&x| x <= num);
// If `num` is unique, `s.partition_point(|&x| x < num)` (with `<`) is equivalent to
// `s.binary_search(&num).unwrap_or_else(|x| x)`, but using `<=` will allow `insert`
// to shift less elements.
s.insert(idx, num);
assert_eq!(s, [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 42, 55]);

pub fn binary_search_by<'a, F>(&'a self, f: F) -> Result<usize, usize>

where F: FnMut(&'a T) -> Ordering,

Binary searches this slice with a comparator function.

The comparator function should return an order code that indicates whether its argument is Less, Equal or Greater the desired target. If the slice is not sorted or if the comparator function does not implement an order consistent with the sort order of the underlying slice, the returned result is unspecified and meaningless.

If the value is found then Result::Ok is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. The index is chosen deterministically, but is subject to change in future versions of Rust. If the value is not found then Result::Err is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also binary_search, binary_search_by_key, and partition_point.

示例

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 F: FnMut(&'a T) -> B, B: Ord,

Binary searches this 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 the slice is not sorted by the key, the returned result is unspecified and meaningless.

If the value is found then Result::Ok is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. The index is chosen deterministically, but is subject to change in future versions of Rust. If the value is not found then Result::Err is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also binary_search, binary_search_by, and partition_point.

示例

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])

Transmutes the slice to a slice of another type, ensuring alignment 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 part will be as big as possible under the given alignment constraint and element size.

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.

Safety

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.

示例

基本用法：

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 as_simd<const LANES: usize>(&self) -> (&[T], &[Simd<T, LANES>], &[T])

where Simd<T, LANES>: AsRef<[T; LANES]>, T: SimdElement,

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

Splits a slice into a prefix, a middle of aligned SIMD types, and a suffix.

This is a safe wrapper around slice::align_to, so inherits the same guarantees as that method.

Panics

This will panic if the size of the SIMD type is different from LANES times that of the scalar.

At the time of writing, the trait restrictions on Simd<T, LANES> keeps that from ever happening, as only power-of-two numbers of lanes are supported. It’s possible that, in the future, those restrictions might be lifted in a way that would make it possible to see panics from this method for something like LANES == 3.

示例

#![feature(portable_simd)]
use core::simd::prelude::*;

let short = &[1, 2, 3];
let (prefix, middle, suffix) = short.as_simd::<4>();
assert_eq!(middle, []); // Not enough elements for anything in the middle

// They might be split in any possible way between prefix and suffix
let it = prefix.iter().chain(suffix).copied();
assert_eq!(it.collect::<Vec<_>>(), vec![1, 2, 3]);

fn basic_simd_sum(x: &[f32]) -> f32 {
    use std::ops::Add;
    let (prefix, middle, suffix) = x.as_simd();
    let sums = f32x4::from_array([
        prefix.iter().copied().sum(),
        0.0,
        0.0,
        suffix.iter().copied().sum(),
    ]);
    let sums = middle.iter().copied().fold(sums, f32x4::add);
    sums.reduce_sum()
}

let numbers: Vec<f32> = (1..101).map(|x| x as _).collect();
assert_eq!(basic_simd_sum(&numbers[1..99]), 4949.0);

pub fn is_sorted(&self) -> bool

where T: PartialOrd,

Checks if the elements of this slice are sorted.

That is, for each element a and its following element b, a <= b must hold. If the slice yields exactly zero or one element, true is returned.

Note that if Self::Item is only PartialOrd, but not Ord, the above definition implies that this function returns false if any two consecutive items are not comparable.

示例

let empty: [i32; 0] = [];

assert!([1, 2, 2, 9].is_sorted());
assert!(![1, 3, 2, 4].is_sorted());
assert!([0].is_sorted());
assert!(empty.is_sorted());
assert!(![0.0, 1.0, f32::NAN].is_sorted());

pub fn is_sorted_by<'a, F>(&'a self, compare: F) -> bool

where F: FnMut(&'a T, &'a T) -> bool,

Checks if the elements of this slice are sorted using the given comparator function.

Instead of using PartialOrd::partial_cmp, this function uses the given compare function to determine whether two elements are to be considered in sorted order.

示例

assert!([1, 2, 2, 9].is_sorted_by(|a, b| a <= b));
assert!(![1, 2, 2, 9].is_sorted_by(|a, b| a < b));

assert!([0].is_sorted_by(|a, b| true));
assert!([0].is_sorted_by(|a, b| false));

let empty: [i32; 0] = [];
assert!(empty.is_sorted_by(|a, b| false));
assert!(empty.is_sorted_by(|a, b| true));

pub fn is_sorted_by_key<'a, F, K>(&'a self, f: F) -> bool

where F: FnMut(&'a T) -> K, K: PartialOrd,

Checks if the elements of this slice are sorted using the given key extraction function.

Instead of comparing the slice’s elements directly, this function compares the keys of the elements, as determined by f. Apart from that, it’s equivalent to is_sorted; see its documentation for more information.

示例

assert!(["c", "bb", "aaa"].is_sorted_by_key(|s| s.len()));
assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));

pub fn partition_point<P>(&self, pred: P) -> usize

where P: FnMut(&T) -> bool,

Returns the index of the partition point according to the given predicate (the index of the first element of the second partition).

The slice is assumed to be partitioned according to the given predicate. This means that all elements for which the predicate returns true are at the start of the slice and all elements for which the predicate returns false are at the end. For example, [7, 15, 3, 5, 4, 12, 6] is partitioned under the predicate x % 2 != 0 (all odd numbers are at the start, all even at the end).

If this slice is not partitioned, the returned result is unspecified and meaningless, as this method performs a kind of binary search.

See also binary_search, binary_search_by, and binary_search_by_key.

示例

let v = [1, 2, 3, 3, 5, 6, 7];
let i = v.partition_point(|&x| x < 5);

assert_eq!(i, 4);
assert!(v[..i].iter().all(|&x| x < 5));
assert!(v[i..].iter().all(|&x| !(x < 5)));

If all elements of the slice match the predicate, including if the slice is empty, then the length of the slice will be returned:

let a = [2, 4, 8];
assert_eq!(a.partition_point(|x| x < &100), a.len());
let a: [i32; 0] = [];
assert_eq!(a.partition_point(|x| x < &100), 0);

If you want to insert an item to a sorted vector, while maintaining sort order:

let mut s = vec![0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
let num = 42;
let idx = s.partition_point(|&x| x <= num);
s.insert(idx, num);
assert_eq!(s, [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 42, 55]);

pub fn element_offset(&self, element: &T) -> Option<usize>

Returns the index that an element reference points to.

Returns None if element does not point to the start of an element within the slice.

This method is useful for extending slice iterators like slice::split.

Note that this uses pointer arithmetic and does not compare elements. To find the index of an element via comparison, use .iter().position() instead.

Panics

Panics if T is zero-sized.

示例

基本用法：

let nums: &[u32] = &[1, 7, 1, 1];
let num = &nums[2];

assert_eq!(num, &1);
assert_eq!(nums.element_offset(num), Some(2));

Returning None with an unaligned element:

let arr: &[[u32; 2]] = &[[0, 1], [2, 3]];
let flat_arr: &[u32] = arr.as_flattened();

let ok_elm: &[u32; 2] = flat_arr[0..2].try_into().unwrap();
let weird_elm: &[u32; 2] = flat_arr[1..3].try_into().unwrap();

assert_eq!(ok_elm, &[0, 1]);
assert_eq!(weird_elm, &[1, 2]);

assert_eq!(arr.element_offset(ok_elm), Some(0)); // Points to element 0
assert_eq!(arr.element_offset(weird_elm), None); // Points between element 0 and 1

pub fn subslice_range(&self, subslice: &[T]) -> Option<Range<usize>>

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

Returns the range of indices that a subslice points to.

Returns None if subslice does not point within the slice or if it is not aligned with the elements in the slice.

This method does not compare elements. Instead, this method finds the location in the slice that subslice was obtained from. To find the index of a subslice via comparison, instead use .windows().position().

This method is useful for extending slice iterators like slice::split.

Note that this may return a false positive (either Some(0..0) or Some(self.len()..self.len())) if subslice has a length of zero and points to the beginning or end of another, separate, slice.

Panics

Panics if T is zero-sized.

示例

基本用法：

#![feature(substr_range)]

let nums = &[0, 5, 10, 0, 0, 5];

let mut iter = nums
    .split(|t| *t == 0)
    .map(|n| nums.subslice_range(n).unwrap());

assert_eq!(iter.next(), Some(0..0));
assert_eq!(iter.next(), Some(1..3));
assert_eq!(iter.next(), Some(4..4));
assert_eq!(iter.next(), Some(5..6));

pub fn as_slice(&self) -> &[T]

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

Returns the same slice &[T].

This method is redundant when used directly on &[T], but it helps dereferencing other “container” types to slices, for example Box<[T]> or Arc<[T]>.

pub fn utf8_chunks(&self) -> Utf8Chunks<'_>

Creates an iterator over the contiguous valid UTF-8 ranges of this slice, and the non-UTF-8 fragments in between.

See the Utf8Chunk type for documentation of the items yielded by this iterator.

示例

This function formats arbitrary but mostly-UTF-8 bytes into Rust source code in the form of a C-string literal (c"...").

use std::fmt::Write as _;

pub fn cstr_literal(bytes: &[u8]) -> String {
    let mut repr = String::new();
    repr.push_str("c\"");
    for chunk in bytes.utf8_chunks() {
        for ch in chunk.valid().chars() {
            // Escapes \0, \t, \r, \n, \\, \', \", and uses \u{...} for non-printable characters.
            write!(repr, "{}", ch.escape_debug()).unwrap();
        }
        for byte in chunk.invalid() {
            write!(repr, "\\x{:02X}", byte).unwrap();
        }
    }
    repr.push('"');
    repr
}

fn main() {
    let lit = cstr_literal(b"\xferris the \xf0\x9f\xa6\x80\x07");
    let expected = stringify!(c"\xFErris the 🦀\u{7}");
    assert_eq!(lit, expected);
}

pub fn to_vec(&self) -> Vec<T>

where T: Clone,

Copies self into a new Vec.

示例

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

pub fn to_vec_in<A>(&self, alloc: A) -> Vec<T, A>

where A: Allocator, T: Clone,

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

Copies self into a new Vec with an allocator.

示例

#![feature(allocator_api)]

use std::alloc::System;

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

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

where T: Copy,

Creates a vector by copying a slice n times.

Panics

This function will panic if the capacity would overflow.

示例

assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);

A panic upon overflow:

// this will panic at runtime
b"0123456789abcdef".repeat(usize::MAX);

pub fn concat<Item>(&self) -> <[T] as Concat<Item>>::Output

where [T]: Concat<Item>, Item: ?Sized,

Flattens a slice of T into a single value Self::Output.

示例

assert_eq!(["hello", "world"].concat(), "helloworld");
assert_eq!([[1, 2], [3, 4]].concat(), [1, 2, 3, 4]);

pub fn join<Separator>( &self, sep: Separator, ) -> <[T] as Join<Separator>>::Output

where [T]: Join<Separator>,

Flattens a slice of T into a single value Self::Output, placing a given separator between each.

示例

assert_eq!(["hello", "world"].join(" "), "hello world");
assert_eq!([[1, 2], [3, 4]].join(&0), [1, 2, 0, 3, 4]);
assert_eq!([[1, 2], [3, 4]].join(&[0, 0][..]), [1, 2, 0, 0, 3, 4]);

pub fn connect<Separator>( &self, sep: Separator, ) -> <[T] as Join<Separator>>::Output

where [T]: Join<Separator>,

👎Deprecated since 1.3.0: renamed to join

Flattens a slice of T into a single value Self::Output, placing a given separator between each.

示例

assert_eq!(["hello", "world"].connect(" "), "hello world");
assert_eq!([[1, 2], [3, 4]].connect(&0), [1, 2, 0, 3, 4]);

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.

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 实现

impl AsRef<[u8]> for Bytes

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

将此类型转换为输入类型的共享引用（通常自动推导）。

impl Borrow<[u8]> for Bytes

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

Immutably borrows from an owned value. 更多信息

impl Buf for Bytes

fn remaining(&self) -> usize

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

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). 更多信息

fn advance(&mut self, cnt: usize)

Advance the internal cursor of the Buf 更多信息

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

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

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

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

fn has_remaining(&self) -> bool

Returns true if there are any more bytes to consume 更多信息

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

Copies bytes from self into dst. 更多信息

fn get_u8(&mut self) -> u8

Gets an unsigned 8 bit integer from self. 更多信息

fn get_i8(&mut self) -> i8

Gets a signed 8 bit integer from self. 更多信息

fn get_u16(&mut self) -> u16

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

fn get_u16_le(&mut self) -> u16

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

fn get_u16_ne(&mut self) -> u16

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

fn get_i16(&mut self) -> i16

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

fn get_i16_le(&mut self) -> i16

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

fn get_i16_ne(&mut self) -> i16

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

fn get_u32(&mut self) -> u32

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

fn get_u32_le(&mut self) -> u32

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

fn get_u32_ne(&mut self) -> u32

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

fn get_i32(&mut self) -> i32

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

fn get_i32_le(&mut self) -> i32

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

fn get_i32_ne(&mut self) -> i32

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

fn get_u64(&mut self) -> u64

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

fn get_u64_le(&mut self) -> u64

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

fn get_u64_ne(&mut self) -> u64

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

fn get_i64(&mut self) -> i64

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

fn get_i64_le(&mut self) -> i64

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

fn get_i64_ne(&mut self) -> i64

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

fn get_u128(&mut self) -> u128

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

fn get_u128_le(&mut self) -> u128

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

fn get_u128_ne(&mut self) -> u128

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

fn get_i128(&mut self) -> i128

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

fn get_i128_le(&mut self) -> i128

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

fn get_i128_ne(&mut self) -> i128

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

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

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

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

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

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

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

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

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

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

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

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

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

fn get_f32(&mut self) -> f32

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

fn get_f32_le(&mut self) -> f32

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

fn get_f32_ne(&mut self) -> f32

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

fn get_f64(&mut self) -> f64

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

fn get_f64_le(&mut self) -> f64

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

fn get_f64_ne(&mut self) -> f64

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

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

Copies bytes from self into dst. 更多信息

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

Gets an unsigned 8 bit integer from self. 更多信息

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

Gets a signed 8 bit integer from self. 更多信息

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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. 更多信息

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. 更多信息

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

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

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. 更多信息

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. 更多信息

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. 更多信息

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. 更多信息

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. 更多信息

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. 更多信息

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. 更多信息

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. 更多信息

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

where Self: Sized,

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

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

where Self: Sized,

Creates an adaptor which will chain this buffer with another. 更多信息

fn reader(self) -> Reader<Self>

where Self: Sized,

Creates an adaptor which implements the Read trait for self. 更多信息

impl Clone for Bytes

fn clone(&self) -> Bytes

返回值的副本。 更多信息

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

Performs copy-assignment from source. 更多信息

impl Debug for Bytes

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

使用给定的格式化器格式化此值。 更多信息

impl Default for Bytes

fn default() -> Bytes

Returns the “default value” for a type. 更多信息

impl Deref for Bytes

type Target = [u8]

解引用后得到的类型。

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

解引用此值。

impl Drop for Bytes

fn drop(&mut self)

执行此类型的析构函数。 更多信息

impl Extend<Bytes> for BytesMut

fn extend<T>(&mut self, iter: T)

where T: IntoIterator<Item = Bytes>,

Extends a collection with the contents of an iterator. 更多信息

fn extend_one(&mut self, item: A)

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

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

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

Reserves capacity in a collection for the given number of additional elements. 更多信息

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

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

从输入类型转换为此类型。

impl From<&'static str> for Bytes

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

从输入类型转换为此类型。

impl From<Box<[u8]>> for Bytes

fn from(slice: Box<[u8]>) -> Bytes

从输入类型转换为此类型。

impl From<Bytes> for BytesMut

fn from(bytes: Bytes) -> Self

将 self 转换为 BytesMut。

若 bytes 在整个原始缓冲区中是唯一的，则返回包含 bytes 内容（无拷贝）的 BytesMut。若 bytes 在整个原始缓冲区中不是唯一的，则会对原始缓冲区中 bytes 子集进行复制。

示例

use bytes::{Bytes, BytesMut};

let bytes = Bytes::from(b"hello".to_vec());
assert_eq!(BytesMut::from(bytes), BytesMut::from(&b"hello"[..]));

impl From<Bytes> for Vec<u8>

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

从输入类型转换为此类型。

impl From<BytesMut> for Bytes

fn from(src: BytesMut) -> Bytes

从输入类型转换为此类型。

impl From<String> for Bytes

fn from(s: String) -> Bytes

从输入类型转换为此类型。

impl From<Vec<u8>> for Bytes

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

从输入类型转换为此类型。

impl FromIterator<u8> for Bytes

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

Creates a value from an iterator. 更多信息

impl Hash for Bytes

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

where H: Hasher,

Feeds this value into the given Hasher. 更多信息

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

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. 更多信息

impl<'a> IntoIterator for &'a Bytes

type Item = &'a u8

被迭代元素的类型。

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. 更多信息

impl IntoIterator for Bytes

type Item = u8

被迭代元素的类型。

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. 更多信息

impl LowerHex for Bytes

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

使用给定的格式化器格式化此值。 更多信息

impl Ord for Bytes

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

This method returns an Ordering between self and other. 更多信息

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

where Self: Sized,

Compares and returns the maximum of two values. 更多信息

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

where Self: Sized,

Compares and returns the minimum of two values. 更多信息

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

where Self: Sized,

Restrict a value to a certain interval. 更多信息

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

where Bytes: PartialEq<T>,

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

impl PartialEq<[u8]> for Bytes

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

impl PartialEq<Bytes> for &[u8]

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

impl PartialEq<Bytes> for &str

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

impl PartialEq<Bytes> for [u8]

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

impl PartialEq<Bytes> for BytesMut

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

impl PartialEq<Bytes> for String

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

impl PartialEq<Bytes> for Vec<u8>

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

impl PartialEq<Bytes> for str

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

impl PartialEq<BytesMut> for Bytes

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

impl PartialEq<String> for Bytes

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

impl PartialEq<Vec<u8>> for Bytes

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

impl PartialEq<str> for Bytes

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

impl PartialEq for Bytes

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

测试 self 与 other 值是否相等，供 == 运算符使用。

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

测试 != 运算符。默认实现几乎总是够用，除非有非常充分的理由，否则不应被覆盖。

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

where Bytes: PartialOrd<T>,

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

若存在，此方法返回 self 与 other 值之间的排序关系。 更多信息

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

测试小于（针对 self 与 other），供 < 运算符使用。 更多信息

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

Tests less than or equal to (for self and other) and is used by the <= operator. 更多信息

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

Tests greater than (for self and other) and is used by the > operator. 更多信息

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

Tests greater than or equal to (for self and other) and is used by the >= operator. 更多信息

impl PartialOrd<[u8]> for Bytes

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

若存在，此方法返回 self 与 other 值之间的排序关系。 更多信息

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

测试小于（针对 self 与 other），供 < 运算符使用。 更多信息

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

Tests less than or equal to (for self and other) and is used by the <= operator. 更多信息

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

Tests greater than (for self and other) and is used by the > operator. 更多信息

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

Tests greater than or equal to (for self and other) and is used by the >= operator. 更多信息

impl PartialOrd<Bytes> for &[u8]

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

若存在，此方法返回 self 与 other 值之间的排序关系。 更多信息

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

测试小于（针对 self 与 other），供 < 运算符使用。 更多信息

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

Tests less than or equal to (for self and other) and is used by the <= operator. 更多信息

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

Tests greater than (for self and other) and is used by the > operator. 更多信息

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

Tests greater than or equal to (for self and other) and is used by the >= operator. 更多信息

impl PartialOrd<Bytes> for &str

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

若存在，此方法返回 self 与 other 值之间的排序关系。 更多信息

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

测试小于（针对 self 与 other），供 < 运算符使用。 更多信息

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

Tests less than or equal to (for self and other) and is used by the <= operator. 更多信息

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

Tests greater than (for self and other) and is used by the > operator. 更多信息

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

Tests greater than or equal to (for self and other) and is used by the >= operator. 更多信息

impl PartialOrd<Bytes> for [u8]

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

若存在，此方法返回 self 与 other 值之间的排序关系。 更多信息

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

测试小于（针对 self 与 other），供 < 运算符使用。 更多信息

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

Tests less than or equal to (for self and other) and is used by the <= operator. 更多信息

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

Tests greater than (for self and other) and is used by the > operator. 更多信息

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

Tests greater than or equal to (for self and other) and is used by the >= operator. 更多信息

impl PartialOrd<Bytes> for String

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

若存在，此方法返回 self 与 other 值之间的排序关系。 更多信息

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

测试小于（针对 self 与 other），供 < 运算符使用。 更多信息

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

Tests less than or equal to (for self and other) and is used by the <= operator. 更多信息

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

Tests greater than (for self and other) and is used by the > operator. 更多信息

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

Tests greater than or equal to (for self and other) and is used by the >= operator. 更多信息

impl PartialOrd<Bytes> for Vec<u8>

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

若存在，此方法返回 self 与 other 值之间的排序关系。 更多信息

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

测试小于（针对 self 与 other），供 < 运算符使用。 更多信息

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

Tests less than or equal to (for self and other) and is used by the <= operator. 更多信息

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

Tests greater than (for self and other) and is used by the > operator. 更多信息

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

Tests greater than or equal to (for self and other) and is used by the >= operator. 更多信息

impl PartialOrd<Bytes> for str

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

若存在，此方法返回 self 与 other 值之间的排序关系。 更多信息

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

测试小于（针对 self 与 other），供 < 运算符使用。 更多信息

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

Tests less than or equal to (for self and other) and is used by the <= operator. 更多信息

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

Tests greater than (for self and other) and is used by the > operator. 更多信息

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

Tests greater than or equal to (for self and other) and is used by the >= operator. 更多信息

impl PartialOrd<String> for Bytes

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

若存在，此方法返回 self 与 other 值之间的排序关系。 更多信息

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

测试小于（针对 self 与 other），供 < 运算符使用。 更多信息

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

Tests less than or equal to (for self and other) and is used by the <= operator. 更多信息

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

Tests greater than (for self and other) and is used by the > operator. 更多信息

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

Tests greater than or equal to (for self and other) and is used by the >= operator. 更多信息

impl PartialOrd<Vec<u8>> for Bytes

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

若存在，此方法返回 self 与 other 值之间的排序关系。 更多信息

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

测试小于（针对 self 与 other），供 < 运算符使用。 更多信息

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

Tests less than or equal to (for self and other) and is used by the <= operator. 更多信息

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

Tests greater than (for self and other) and is used by the > operator. 更多信息

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

Tests greater than or equal to (for self and other) and is used by the >= operator. 更多信息

impl PartialOrd<str> for Bytes

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

若存在，此方法返回 self 与 other 值之间的排序关系。 更多信息

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

测试小于（针对 self 与 other），供 < 运算符使用。 更多信息

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

Tests less than or equal to (for self and other) and is used by the <= operator. 更多信息

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

Tests greater than (for self and other) and is used by the > operator. 更多信息

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

Tests greater than or equal to (for self and other) and is used by the >= operator. 更多信息

impl PartialOrd for Bytes

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

若存在，此方法返回 self 与 other 值之间的排序关系。 更多信息

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

测试小于（针对 self 与 other），供 < 运算符使用。 更多信息

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

Tests less than or equal to (for self and other) and is used by the <= operator. 更多信息

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

Tests greater than (for self and other) and is used by the > operator. 更多信息

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

Tests greater than or equal to (for self and other) and is used by the >= operator. 更多信息

impl UpperHex for Bytes

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

使用给定的格式化器格式化此值。 更多信息

impl Eq for Bytes

impl Send for Bytes

impl Sync for Bytes