Trait SliceIndex

pub unsafe trait SliceIndex<T>: Sealed
where
    T: ?Sized,
{
    type Output: ?Sized;

    // Required methods
    fn get(self, slice: &T) -> Option<&Self::Output>;
    fn get_mut(self, slice: &mut T) -> Option<&mut Self::Output>;
    unsafe fn get_unchecked(self, slice: *const T) -> *const Self::Output;
    unsafe fn get_unchecked_mut(self, slice: *mut T) -> *mut Self::Output;
    fn index(self, slice: &T) -> &Self::Output;
    fn index_mut(self, slice: &mut T) -> &mut Self::Output;
}

A helper trait used for indexing operations.

Implementations of this trait have to promise that if the argument to get_unchecked(_mut) is a safe reference, then so is the result.

Required Associated Types

type Output: ?Sized

The output type returned by methods.

Required Methods

fn get(self, slice: &T) -> Option<&Self::Output>

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

Returns a shared reference to the output at this location, if in bounds.

fn get_mut(self, slice: &mut T) -> Option<&mut Self::Output>

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

Returns a mutable reference to the output at this location, if in bounds.

unsafe fn get_unchecked(self, slice: *const T) -> *const Self::Output

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

Returns a pointer to the output at this location, without performing any bounds checking.

Calling this method with an out-of-bounds index or a dangling slice pointer is undefined behavior even if the resulting pointer is not used.

unsafe fn get_unchecked_mut(self, slice: *mut T) -> *mut Self::Output

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

Returns a mutable pointer to the output at this location, without performing any bounds checking.

Calling this method with an out-of-bounds index or a dangling slice pointer is undefined behavior even if the resulting pointer is not used.

fn index(self, slice: &T) -> &Self::Output

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

Returns a shared reference to the output at this location, panicking if out of bounds.

fn index_mut(self, slice: &mut T) -> &mut Self::Output

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

Returns a mutable reference to the output at this location, panicking if out of bounds.

Implementors

impl SliceIndex<str> for (Bound<usize>, Bound<usize>)

Implements substring slicing for arbitrary bounds.

Returns a slice of the given string bounded by the byte indices provided by each bound.

This operation is O(1).

Panics

Panics if begin or end (if it exists and once adjusted for inclusion/exclusion) does not point to the starting byte offset of a character (as defined by is_char_boundary), if begin > end, or if end > len.

type Output = str

impl SliceIndex<str> for core::ops::range::Range<usize>

Implements substring slicing with syntax &self[begin .. end] or &mut self[begin .. end].

Returns a slice of the given string from the byte range [begin, end).

This operation is O(1).

Prior to 1.20.0, these indexing operations were still supported by direct implementation of Index and IndexMut.

Panics

Panics if begin or end does not point to the starting byte offset of a character (as defined by is_char_boundary), if begin > end, or if end > len.

Examples

let s = "Löwe 老虎 Léopard";
assert_eq!(&s[0 .. 1], "L");

assert_eq!(&s[1 .. 9], "öwe 老");

// these will panic:
// byte 2 lies within `ö`:
// &s[2 ..3];

// byte 8 lies within `老`
// &s[1 .. 8];

// byte 100 is outside the string
// &s[3 .. 100];

type Output = str

impl SliceIndex<str> for core::ops::range::RangeFrom<usize>

Implements substring slicing with syntax &self[begin ..] or &mut self[begin ..].

Returns a slice of the given string from the byte range [begin, len). Equivalent to &self[begin .. len] or &mut self[begin .. len].

This operation is O(1).

Prior to 1.20.0, these indexing operations were still supported by direct implementation of Index and IndexMut.

Panics

Panics if begin does not point to the starting byte offset of a character (as defined by is_char_boundary), or if begin > len.

type Output = str

impl SliceIndex<str> for RangeFull

Implements substring slicing with syntax &self[..] or &mut self[..].

Returns a slice of the whole string, i.e., returns &self or &mut self. Equivalent to &self[0 .. len] or &mut self[0 .. len]. Unlike other indexing operations, this can never panic.

This operation is O(1).

Prior to 1.20.0, these indexing operations were still supported by direct implementation of Index and IndexMut.

Equivalent to &self[0 .. len] or &mut self[0 .. len].

type Output = str

impl SliceIndex<str> for core::ops::range::RangeInclusive<usize>

Implements substring slicing with syntax &self[begin ..= end] or &mut self[begin ..= end].

Returns a slice of the given string from the byte range [begin, end]. Equivalent to &self [begin .. end + 1] or &mut self[begin .. end + 1], except if end has the maximum value for usize.

This operation is O(1).

Panics

Panics if begin does not point to the starting byte offset of a character (as defined by is_char_boundary), if end does not point to the ending byte offset of a character (end + 1 is either a starting byte offset or equal to len), if begin > end, or if end >= len.

type Output = str

impl SliceIndex<str> for RangeTo<usize>

Implements substring slicing with syntax &self[.. end] or &mut self[.. end].

Returns a slice of the given string from the byte range [0, end). Equivalent to &self[0 .. end] or &mut self[0 .. end].

This operation is O(1).

Prior to 1.20.0, these indexing operations were still supported by direct implementation of Index and IndexMut.

Panics

Panics if end does not point to the starting byte offset of a character (as defined by is_char_boundary), or if end > len.

type Output = str

impl SliceIndex<str> for RangeToInclusive<usize>

Implements substring slicing with syntax &self[..= end] or &mut self[..= end].

Returns a slice of the given string from the byte range [0, end]. Equivalent to &self [0 .. end + 1], except if end has the maximum value for usize.

This operation is O(1).

Panics

Panics if end does not point to the ending byte offset of a character (end + 1 is either a starting byte offset as defined by is_char_boundary, or equal to len), or if end >= len.

type Output = str

impl SliceIndex<str> for core::range::Range<usize>

type Output = str

impl SliceIndex<str> for core::range::RangeFrom<usize>

type Output = str

impl SliceIndex<str> for core::range::RangeInclusive<usize>

type Output = str

impl<T> SliceIndex<[T]> for (Bound<usize>, Bound<usize>)

type Output = [T]

impl<T> SliceIndex<[T]> for usize

The methods index and index_mut panic if the index is out of bounds.

type Output = T

impl<T> SliceIndex<[T]> for core::ops::range::Range<usize>

The methods index and index_mut panic if:

• the start of the range is greater than the end of the range or
• the end of the range is out of bounds.

type Output = [T]

impl<T> SliceIndex<[T]> for core::ops::range::RangeFrom<usize>

The methods index and index_mut panic if the start of the range is out of bounds.

type Output = [T]

impl<T> SliceIndex<[T]> for RangeFull

type Output = [T]

impl<T> SliceIndex<[T]> for core::ops::range::RangeInclusive<usize>

The methods index and index_mut panic if:

• the end of the range is usize::MAX or
• the start of the range is greater than the end of the range or
• the end of the range is out of bounds.

type Output = [T]

impl<T> SliceIndex<[T]> for RangeTo<usize>

The methods index and index_mut panic if the end of the range is out of bounds.

type Output = [T]

impl<T> SliceIndex<[T]> for RangeToInclusive<usize>

The methods index and index_mut panic if the end of the range is out of bounds.

type Output = [T]

impl<T> SliceIndex<[T]> for core::range::Range<usize>

type Output = [T]

impl<T> SliceIndex<[T]> for core::range::RangeFrom<usize>

type Output = [T]

impl<T> SliceIndex<[T]> for core::range::RangeInclusive<usize>

type Output = [T]