Struct obj_pool::invalid_value::OptionInvalidValue

pub struct OptionInvalidValue<T: InvalidValue<T> + PartialEq + Copy + Eq + Hash>(_);

Optimization for Option<T> where T implements an InvalidValue trait and reuses on of the possible values of T to represents None. It's basically the same as NonZero*-types but more powerful as it allows to reuse any value, not just 0 for any type, not just integers. As a downside, it's not an Option, it's a separate type which is needed to be handled explicitly.

use obj_pool::invalid_value::{InvalidValue, OptionInvalidValue};

#[derive(PartialEq, Eq, Hash, Copy, Clone)]
struct A(u32);

impl InvalidValue<A> for A {
  fn invalid_value() -> A {
     A(155) // invalid value in our case
  }
}

let mut v: OptionInvalidValue<A> = A(100).into();
assert!(v.is_some());

v = A(155).into();
assert!(v.is_none());

Methods

impl<T: InvalidValue<T> + PartialEq + Copy + Eq + Hash> OptionInvalidValue<T>

pub fn none() -> OptionInvalidValue<T>

Make a None value

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

Make an Option<&T>

pub fn as_ref_unchecked(&self) -> &T

Get reference to underlying T, panics it it's None.

pub fn as_ref_mut_unchecked(&mut self) -> &mut T

Get mutable reference to underlying T, panics it it's None.

pub fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Option<U>

impl<T: InvalidValue<T> + PartialEq + Copy + Eq + Hash> OptionInvalidValue<T>

pub fn is_some(&self) -> bool

Checks if OptionInvalidValue is Some

pub fn is_none(&self) -> bool

Checks if OptionInvalidValue is None

pub fn unwrap(self) -> T

Unwraps the OptionInvalidValue, panics in case of None.

Trait Implementations

impl<T: PartialEq + InvalidValue<T> + PartialEq + Copy + Eq + Hash> PartialEq for OptionInvalidValue<T>

fn eq(&self, other: &OptionInvalidValue<T>) -> bool

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

fn ne(&self, other: &OptionInvalidValue<T>) -> bool

This method tests for !=.

impl<T: Debug + InvalidValue<T> + PartialEq + Copy + Eq + Hash> Debug for OptionInvalidValue<T>

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

Formats the value using the given formatter.

impl<T: Copy + InvalidValue<T> + PartialEq + Copy + Eq + Hash> Copy for OptionInvalidValue<T>

impl<T: Clone + InvalidValue<T> + PartialEq + Copy + Eq + Hash> Clone for OptionInvalidValue<T>

fn clone(&self) -> OptionInvalidValue<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Eq + InvalidValue<T> + PartialEq + Copy + Eq + Hash> Eq for OptionInvalidValue<T>

impl<T: Hash + InvalidValue<T> + PartialEq + Copy + Eq + Hash> Hash for OptionInvalidValue<T>

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

Feeds this value into the given [Hasher].

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

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

impl<T: InvalidValue<T> + PartialEq + Copy + Eq + Hash> IntoIterator for OptionInvalidValue<T>

type Item = T

The type of the elements being iterated over.

type IntoIter = IntoIter<T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<T: InvalidValue<T> + PartialEq + Copy + Eq + Hash> From<Option<T>> for OptionInvalidValue<T>

fn from(v: Option<T>) -> Self

Performs the conversion.

impl<T: InvalidValue<T> + PartialEq + Copy + Eq + Hash> Into<Option<T>> for OptionInvalidValue<T>

fn into(self) -> Option<T>

Performs the conversion.

impl<T: InvalidValue<T> + PartialEq + Copy + Eq + Hash> From<T> for OptionInvalidValue<T>

Wraps a value in OptionInvalidValue, treats T::invalid_value as None

fn from(v: T) -> Self

Performs the conversion.