Trait alloc::slice::SliceIndex

1.28.0 · source · 
pub unsafe trait SliceIndex<T>: Sealedwhere
    T: ?Sized,{
    type Output: ?Sized;

    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;
}
Expand description

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§

The output type returned by methods.

Required Methods§

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

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

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

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

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

Returns a shared reference 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 reference is not used.

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

Returns a mutable reference 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 reference is not used.

🔬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.

🔬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§

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];
Run

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.

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].

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.

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.

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.