Struct divbuf::DivBuf[−][src]

pub struct DivBuf { /* fields omitted */ }

Provides read-only access to a buffer.

This struct provides a window into a region of a DivBufShared, allowing read-only access. It can be divided into smaller DivBuf using the split_to, split_off, slice, slice_from, and slice_to methods. Adjacent DivBufs can be combined using the unsplit method. Finally, a DivBuf can be upgraded to a writable DivBufMut using the try_mut method, but only if there are no other DivBufs that reference the same DivBufShared.

Examples

let dbs = DivBufShared::from(vec![1, 2, 3, 4, 5, 6]);
let mut db0 : DivBuf = dbs.try().unwrap();
assert_eq!(db0, [1, 2, 3, 4, 5, 6][..]);

Unlike DivBufMut, a DivBuf cannot be used to modify the buffer. The following example will fail.

ⓘThis example deliberately fails to compile
let dbs = DivBufShared::from(vec![1, 2, 3]);
let mut db = dbs.try().unwrap();
db[0] = 9;

Methods

impl DivBuf
[src]

Break the buffer up into equal sized chunks

Returns an interator which will yield equal sized chunks as smaller DivBufs. If the DivBuf is not evenly divisible by size, then the last chunk will be smaller. This method is based on slice::chunks, but with a few key differences:

  • It consumes self
  • Yields smaller DivBufs, not slices
  • Yields owned objects, not references

Examples

let dbs = DivBufShared::from(vec![0, 1, 2, 3, 4, 5, 6, 7]);
let db = dbs.try().unwrap();
let mut iter = db.into_chunks(3);
assert_eq!(&iter.next().unwrap()[..], &[0, 1, 2][..]);
assert_eq!(&iter.next().unwrap()[..], &[3, 4, 5][..]);
assert_eq!(&iter.next().unwrap()[..], &[6, 7][..]);
assert!(&iter.next().is_none())

Returns true if the DivBuf has length 0

Get the length of this DivBuf, not the underlying storage

Create a new DivBuf that spans a subset of this one.

Examples

let dbs = DivBufShared::from(vec![1, 2, 3, 4, 5, 6]);
let db0 = dbs.try().unwrap();
let db1 = db0.slice(1, 4);
assert_eq!(db1, [2, 3, 4][..]);

Creates a new DivBuf that spans a subset of this one, including the end

Examples

let dbs = DivBufShared::from(vec![1, 2, 3, 4, 5, 6]);
let db0 = dbs.try().unwrap();
let db1 = db0.slice_from(3);
assert_eq!(db1, [4, 5, 6][..]);

Creates a new DivBuf that spans a subset of self, including the beginning

Examples

let dbs = DivBufShared::from(vec![1, 2, 3, 4, 5, 6]);
let db0 = dbs.try().unwrap();
let db1 = db0.slice_to(3);
assert_eq!(db1, [1, 2, 3][..]);

Splits the DivBuf into two at the given index.

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

This is an O(1) operation

Examples

let dbs = DivBufShared::from(vec![1, 2, 3, 4, 5, 6]);
let mut db0 = dbs.try().unwrap();
let db1 = db0.split_off(4);
assert_eq!(db0, [1, 2, 3, 4][..]);
assert_eq!(db1, [5, 6][..]);

Splits the DivBuf into two at the given index.

Afterwards self contains elements [at, self.len), and the returned DivBuf contains elements [0, at). This is an O(1) operation.

Examples

let dbs = DivBufShared::from(vec![1, 2, 3, 4, 5, 6]);
let mut db0 = dbs.try().unwrap();
let db1 = db0.split_to(4);
assert_eq!(db0, [5, 6][..]);
assert_eq!(db1, [1, 2, 3, 4][..]);

Attempt to upgrade Self to a writable DivBufMut

This will fail if there are any other living DivBufs for this same DivBufShared

Examples

let dbs = DivBufShared::with_capacity(4096);
let db = dbs.try().unwrap();
db.try_mut().unwrap();

Combine splitted DivBuf objects back into a contiguous single

If DivBuf objects were not contiguous originally, the operation will fail and return other unmodified

Examples

let dbs = DivBufShared::from(vec![1, 2, 3, 4, 5, 6]);
let mut db0 = dbs.try().unwrap();
let db1 = db0.split_off(4);
db0.unsplit(db1);
assert_eq!(db0, [1, 2, 3, 4, 5, 6][..]);

Methods from Deref<Target = [u8]>

Returns the number of elements in the slice.

Examples

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

Returns true if the slice has a length of 0.

Examples

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

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());

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]);
}

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]);
}

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());

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));

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);
}

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));
    }
}

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);

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());

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());

🔬 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.

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());

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 == []);
}

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());

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);

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);
}

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);
}

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));

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(&[]));

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(&[]));

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, });

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, });

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, });

🔬 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);
}

Trait Implementations

impl Debug for DivBuf
[src]

Formats the value using the given formatter. Read more

impl AsRef<[u8]> for DivBuf
[src]

Performs the conversion.

impl Borrow<[u8]> for DivBuf
[src]

Immutably borrows from an owned value. Read more

impl Hash for DivBuf
[src]

Feeds this value into the given [Hasher]. Read more

Feeds a slice of this type into the given [Hasher]. Read more

impl Deref for DivBuf
[src]

The resulting type after dereferencing.

Dereferences the value.

impl Clone for DivBuf
[src]

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

impl Drop for DivBuf
[src]

Executes the destructor for this type. Read more

impl Eq for DivBuf
[src]

impl From<DivBufMut> for DivBuf
[src]

Performs the conversion.

impl Ord for DivBuf
[src]

This method returns an Ordering between self and other. Read more

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

impl PartialEq for DivBuf
[src]

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

This method tests for !=.

impl PartialEq<[u8]> for DivBuf
[src]

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

This method tests for !=.

impl PartialOrd for DivBuf
[src]

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

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

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

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

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

impl Send for DivBuf
[src]

impl Sync for DivBuf
[src]