[−][src]Trait vecdeque_stableix::Offset

pub trait Offset: Clone + Debug + Neg + PartialEq + Eq {
    fn try_increment(&mut self) -> Option<()>;

    fn try_decrement(&mut self) -> Option<()>;

    fn zero() -> Self;

    fn index_input(&self, input: Self) -> Option<usize>;

    fn index_output(&self, inner: usize) -> Option<Self>;
}

Types that can be used as an index for a Deque.

The (fallible) operations required are a very limited subset of arithmetic, combined with conversion between Offset and usize.

The provided generic implementation covers isize, i64, etc.

Required methods

fn try_increment(&mut self) -> Option<()>

Should return None on overflow. Currently, this will cause the library to panic, but that may not always be the case.

fn try_decrement(&mut self) -> Option<()>

Should return None on overflow. Currently, this will cause the library to panic, but that may not always be the case.

fn zero() -> Self

fn index_input(&self, input: Self) -> Option<usize>

Should return Some(input - self), or None on overflow.

Overflows can easily happen with a very old index, if the index type is bigger than usize; this is handled gracefully by the library. So index_input must not panic on overflow.

fn index_output(&self, inner: usize) -> Option<Self>

Should return Some(output + self).

Should return None on overflow; Currently, this will cause the library to panic, but that may not always be the case.

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Implementors

impl<T> Offset for T where
    T: Clone + Debug + Neg + PartialEq + Eq + Zero + One + CheckedAdd + CheckedSub + TryInto<usize> + TryFrom<usize>, [src]

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