Struct compact::COption [−][src]
A wrapper to make an Option
of a nontrivial Compact
possible.
Unfortunately, we can't blanket-impl
that, since that overlaps
(for the compiler) with the impl
for trivial Copy
types...
Methods from Deref<Target = Option<T>>
pub fn is_some(&self) -> bool
1.0.0[src]
pub fn is_some(&self) -> bool
Returns true
if the option is a Some
value.
Examples
let x: Option<u32> = Some(2); assert_eq!(x.is_some(), true); let x: Option<u32> = None; assert_eq!(x.is_some(), false);
pub fn is_none(&self) -> bool
1.0.0[src]
pub fn is_none(&self) -> bool
Returns true
if the option is a None
value.
Examples
let x: Option<u32> = Some(2); assert_eq!(x.is_none(), false); let x: Option<u32> = None; assert_eq!(x.is_none(), true);
pub fn as_ref(&self) -> Option<&T>
1.0.0[src]
pub fn as_ref(&self) -> Option<&T>
Converts from Option<T>
to Option<&T>
.
Examples
Convert an Option<
String
>
into an Option<
usize
>
, preserving the original.
The map
method takes the self
argument by value, consuming the original,
so this technique uses as_ref
to first take an Option
to a reference
to the value inside the original.
let text: Option<String> = Some("Hello, world!".to_string()); // First, cast `Option<String>` to `Option<&String>` with `as_ref`, // then consume *that* with `map`, leaving `text` on the stack. let text_length: Option<usize> = text.as_ref().map(|s| s.len()); println!("still can print text: {:?}", text);
pub fn as_mut(&mut self) -> Option<&mut T>
1.0.0[src]
pub fn as_mut(&mut self) -> Option<&mut T>
Converts from Option<T>
to Option<&mut T>
.
Examples
let mut x = Some(2); match x.as_mut() { Some(v) => *v = 42, None => {}, } assert_eq!(x, Some(42));
pub fn as_pin_mut(self: PinMut<'a, Option<T>>) -> Option<PinMut<'a, T>>
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pub fn as_pin_mut(self: PinMut<'a, Option<T>>) -> Option<PinMut<'a, T>>
pin
)Converts from Option<T>
to Option<PinMut<'_, T>>
ⓘImportant traits for Iter<'a, A>pub fn iter(&self) -> Iter<T>
1.0.0[src]
pub fn iter(&self) -> Iter<T>
Returns an iterator over the possibly contained value.
Examples
let x = Some(4); assert_eq!(x.iter().next(), Some(&4)); let x: Option<u32> = None; assert_eq!(x.iter().next(), None);
ⓘImportant traits for IterMut<'a, A>pub fn iter_mut(&mut self) -> IterMut<T>
1.0.0[src]
pub fn iter_mut(&mut self) -> IterMut<T>
Returns a mutable iterator over the possibly contained value.
Examples
let mut x = Some(4); match x.iter_mut().next() { Some(v) => *v = 42, None => {}, } assert_eq!(x, Some(42)); let mut x: Option<u32> = None; assert_eq!(x.iter_mut().next(), None);
ⓘImportant traits for &'a mut Rpub fn get_or_insert(&mut self, v: T) -> &mut T
1.20.0[src]
pub fn get_or_insert(&mut self, v: T) -> &mut T
Inserts v
into the option if it is None
, then
returns a mutable reference to the contained value.
Examples
let mut x = None; { let y: &mut u32 = x.get_or_insert(5); assert_eq!(y, &5); *y = 7; } assert_eq!(x, Some(7));
ⓘImportant traits for &'a mut Rpub fn get_or_insert_with<F>(&mut self, f: F) -> &mut T where
F: FnOnce() -> T,
1.20.0[src]
pub fn get_or_insert_with<F>(&mut self, f: F) -> &mut T where
F: FnOnce() -> T,
Inserts a value computed from f
into the option if it is None
, then
returns a mutable reference to the contained value.
Examples
let mut x = None; { let y: &mut u32 = x.get_or_insert_with(|| 5); assert_eq!(y, &5); *y = 7; } assert_eq!(x, Some(7));
pub fn take(&mut self) -> Option<T>
1.0.0[src]
pub fn take(&mut self) -> Option<T>
Trait Implementations
impl<T: Clone + Compact + Clone> Clone for CompactOption<T>
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impl<T: Clone + Compact + Clone> Clone for CompactOption<T>
fn clone(&self) -> CompactOption<T>
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fn clone(&self) -> CompactOption<T>
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
1.0.0[src]
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source
. Read more
impl<T: Default + Compact + Clone> Default for CompactOption<T>
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impl<T: Default + Compact + Clone> Default for CompactOption<T>
fn default() -> CompactOption<T>
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fn default() -> CompactOption<T>
Returns the "default value" for a type. Read more
impl<T: Compact + Clone> Deref for CompactOption<T>
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impl<T: Compact + Clone> Deref for CompactOption<T>
type Target = Option<T>
The resulting type after dereferencing.
fn deref(&self) -> &Option<T>
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fn deref(&self) -> &Option<T>
Dereferences the value.
impl<T: Compact + Clone> DerefMut for CompactOption<T>
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impl<T: Compact + Clone> DerefMut for CompactOption<T>
impl<T: Clone + Compact> Compact for CompactOption<T>
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impl<T: Clone + Compact> Compact for CompactOption<T>
fn is_still_compact(&self) -> bool
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fn is_still_compact(&self) -> bool
Is the object's dynamic part stored compactly?
fn dynamic_size_bytes(&self) -> usize
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fn dynamic_size_bytes(&self) -> usize
Size of the dynamic part in bytes
unsafe fn compact(source: *mut Self, dest: *mut Self, new_dynamic_part: *mut u8)
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unsafe fn compact(source: *mut Self, dest: *mut Self, new_dynamic_part: *mut u8)
Copy the static part of source
to dest
and compactly store the dynamic part of source
as the new dynamic part of dest
at new_dynamic_part
. This semantically moves source into dest. Read more
unsafe fn decompact(source: *const Self) -> Self
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unsafe fn decompact(source: *const Self) -> Self
Creates a clone of self with the dynamic part guaranteed to be stored freely. Read more
fn total_size_bytes(&self) -> usize
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fn total_size_bytes(&self) -> usize
Total size of the object (static part + dynamic part)
unsafe fn behind(ptr: *mut Self) -> *mut u8
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unsafe fn behind(ptr: *mut Self) -> *mut u8
Get a pointer to behind the static part of self
(commonly used place for the dynamic part)
unsafe fn compact_behind(source: *mut Self, dest: *mut Self)
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unsafe fn compact_behind(source: *mut Self, dest: *mut Self)
Like compact
with new_dynamic_part
set to dest.behind()