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//! Traits for newtype wrappers.
#[cfg(feature = "alloc")]
use alloc::{
boxed::Box,
rc::Rc,
sync::Arc,
vec::Vec,
};
use std_::mem;
use crate::utils::transmute_ignore_size;
/// Trait for `#[repr(transparent)]` newtypes,
/// which are safe to transmute to/from their contents.
///
/// For additional conversion methods, you can use the [`TransparentNewtypeExt`] extension trait.
///
/// # Safety
///
/// Implementors must only implement this trait for `#[repr(transparent)]` wrappers,
/// with the same alignment as its only non-zero-sized field,
/// and the type of that field must be used as the [`TransparentNewtype::Inner`]
/// associated type.
///
/// This trait can be implemented with any of these macros:
/// - The [`TransparentNewtype`] derive macro (requires the "derive" feature).
/// - The [`impl_transparent_newtype`] macro
/// - The [`delegate_transparent_newtype_impl`] macro.
///
/// # Example
///
/// A totally ordered 32 bit float.
///
/// ```
/// use core_extensions::{TransparentNewtype, TransparentNewtypeExt};
/// # use std::cmp::{Eq,Ord,PartialOrd,PartialEq,Ordering};
///
/// pub struct TotalF32(pub f32);
///
/// // Eq, Ord, PartialEq, PartialOrd impls not shown
/// # impl Eq for TotalF32{}
/// #
/// # impl Ord for TotalF32{
/// # fn cmp(&self, other: &Self) -> Ordering {
/// # self.0.partial_cmp(&other.0).unwrap_or_else(||{
/// # match (self.0.is_nan(),other.0.is_nan()) {
/// # (false,_ )=>Ordering::Less,
/// # (true ,false)=>Ordering::Greater,
/// # (true ,true )=>Ordering::Equal,
/// # }
/// # })
/// # }
/// # }
/// # impl PartialOrd for TotalF32{
/// # fn partial_cmp(&self, other: &Self) -> Option<Ordering>{
/// # Some(self.cmp(other))
/// # }
/// # }
/// # impl PartialEq for TotalF32 {
/// # fn eq(&self, other: &Self) -> bool {
/// # self.cmp(other)==Ordering::Equal
/// # }
/// # }
///
/// unsafe impl TransparentNewtype for TotalF32{
/// type Inner = f32;
/// core_extensions::impl_transparent_newtype!{Self}
/// }
///
/// let mut list = vec![1.0, 0.0, 2.0];
///
/// <[TotalF32]>::from_inner_mut(&mut list).sort();
///
/// assert_eq!(list, vec![0.0, 1.0, 2.0]);
///
/// ```
///
/// [`TransparentNewtype::Inner`]: #associatedtype.Inner
/// [`TransparentNewtypeExt`]: ./trait.TransparentNewtypeExt.html
/// [`TransparentNewtype`]: ../derive.TransparentNewtype.html
/// [`impl_transparent_newtype`]: ../macro.impl_transparent_newtype.html
/// [`delegate_transparent_newtype_impl`]: ../macro.delegate_transparent_newtype_impl.html
///
pub unsafe trait TransparentNewtype {
/// The wrapped type
type Inner: ?Sized;
#[doc(hidden)]
#[allow(non_upper_case_globals)]
const __DUMMY_bCj7dq3Pud: () = ();
/// Converts `*const Self::Inner` to `*const Self`.
fn from_inner_raw(from: *const Self::Inner) -> *const Self;
/// Converts `*mut Self::Inner` to `*mut Self`.
fn from_inner_raw_mut(v: *mut Self::Inner) -> *mut Self;
/// Converts `*const Self` to `*const Self::Inner`.
fn as_inner_raw(from: *const Self) -> *const Self::Inner;
/// Converts `*mut Self` to `*mut Self::Inner`.
fn as_inner_raw_mut(this: *mut Self) -> *mut Self::Inner;
}
/// Extension trait for [`TransparentNewtype`]s
///
/// [`TransparentNewtype`]: ./trait.TransparentNewtype.html
///
///
pub trait TransparentNewtypeExt: TransparentNewtype {
/// Converts `Self::Inner` to `Self`.
///
/// # Example
///
/// ```rust
/// use core_extensions::TransparentNewtypeExt;
///
/// use std::num::Wrapping;
/// use std::mem::ManuallyDrop;
///
/// assert_eq!(Wrapping::from_inner(3), Wrapping(3));
/// assert_eq!(ManuallyDrop::from_inner(5), ManuallyDrop::new(5));
///
/// ```
#[inline(always)]
fn from_inner(v: Self::Inner) -> Self
where
Self: Sized,
Self::Inner: Sized,
{
check_same_size_alignment::<Self::Inner, Self>();
unsafe { transmute_ignore_size::<Self::Inner, Self>(v) }
}
/// Converts `&Self::Inner` to a `&Self`.
///
/// # Example
///
/// ```rust
/// use core_extensions::TransparentNewtypeExt;
///
/// use std::num::Wrapping;
/// use std::mem::ManuallyDrop;
///
/// assert_eq!(Wrapping::from_inner_ref(&3), &Wrapping(3));
/// assert_eq!(ManuallyDrop::from_inner_ref(&5), &ManuallyDrop::new(5));
///
/// ```
#[inline(always)]
fn from_inner_ref(v: &Self::Inner) -> &Self {
unsafe { &*Self::from_inner_raw(v) }
}
/// Converts `&mut Self::Inner` to a `&mut Self`.
///
/// # Example
///
/// ```rust
/// use core_extensions::TransparentNewtypeExt;
///
/// use std::num::Wrapping;
/// use std::mem::ManuallyDrop;
///
/// assert_eq!(Wrapping::from_inner_ref(&mut 3), &mut Wrapping(3));
/// assert_eq!(ManuallyDrop::from_inner_ref(&mut 5), &mut ManuallyDrop::new(5));
///
/// ```
#[inline(always)]
fn from_inner_mut(v: &mut Self::Inner) -> &mut Self {
unsafe { &mut *Self::from_inner_raw_mut(v) }
}
/// Converts `Box<Self::Inner>` to a `Box<Self>` without allocating.
///
/// # Example
///
/// ```rust
/// use core_extensions::TransparentNewtypeExt;
///
/// use std::num::Wrapping;
/// use std::mem::ManuallyDrop as MD;
///
/// assert_eq!(Wrapping::from_inner_box(Box::new(3)), Box::new(Wrapping(3)));
/// assert_eq!(MD::from_inner_box(Box::new(5)), Box::new(MD::new(5)));
///
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
#[inline(always)]
fn from_inner_box(v: Box<Self::Inner>) -> Box<Self> {
unsafe { Box::from_raw(Self::from_inner_raw_mut(Box::into_raw(v))) }
}
/// Converts `Arc<Self::Inner>` to a `Arc<Self>` without allocating.
///
/// # Example
///
/// ```rust
/// use core_extensions::TransparentNewtypeExt;
///
/// use std::num::Wrapping;
/// use std::mem::ManuallyDrop as MD;
/// use std::sync::Arc;
///
/// assert_eq!(Wrapping::from_inner_arc(Arc::new(3)), Arc::new(Wrapping(3)));
/// assert_eq!(MD::from_inner_arc(Arc::new(5)), Arc::new(MD::new(5)));
///
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
#[inline(always)]
fn from_inner_arc(v: Arc<Self::Inner>) -> Arc<Self> {
unsafe { Arc::from_raw(Self::from_inner_raw(Arc::into_raw(v))) }
}
/// Converts `Rc<Self::Inner>` to a `Rc<Self>` without allocating.
///
/// # Example
///
/// ```rust
/// use core_extensions::TransparentNewtypeExt;
///
/// use std::num::Wrapping;
/// use std::mem::ManuallyDrop as MD;
/// use std::rc::Rc;
///
/// assert_eq!(Wrapping::from_inner_rc(Rc::new(3)), Rc::new(Wrapping(3)));
/// assert_eq!(MD::from_inner_rc(Rc::new(5)), Rc::new(MD::new(5)));
///
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
#[inline(always)]
fn from_inner_rc(v: Rc<Self::Inner>) -> Rc<Self> {
unsafe { Rc::from_raw(Self::from_inner_raw(Rc::into_raw(v))) }
}
/// Converts `self` to a `Self::Inner`.
///
/// # Example
///
/// ```rust
/// use core_extensions::TransparentNewtypeExt;
///
/// use std::num::Wrapping;
/// use std::mem::ManuallyDrop;
///
/// assert_eq!(Wrapping(3).into_inner(), 3);
/// assert_eq!(ManuallyDrop::new(5).into_inner(), 5);
///
/// ```
#[inline(always)]
fn into_inner(self) -> Self::Inner
where
Self: Sized,
Self::Inner: Sized,
{
check_same_size_alignment::<Self::Inner, Self>();
unsafe { transmute_ignore_size::<Self, Self::Inner>(self) }
}
/// Converts `self` to a `&Self::Inner`.
///
/// # Example
///
/// ```rust
/// use core_extensions::TransparentNewtypeExt;
///
/// use std::num::Wrapping;
/// use std::mem::ManuallyDrop;
///
/// assert_eq!(Wrapping(3).as_inner(), &3);
/// assert_eq!(ManuallyDrop::new(5).as_inner(), &5);
///
/// ```
#[inline(always)]
fn as_inner(&self) -> &Self::Inner {
unsafe { &*Self::as_inner_raw(self) }
}
/// Converts `self` to a `&mut Self::Inner`.
///
/// # Example
///
/// ```rust
/// use core_extensions::TransparentNewtypeExt;
///
/// use std::num::Wrapping;
/// use std::mem::ManuallyDrop;
///
/// assert_eq!(Wrapping(3).as_inner_mut(), &mut 3);
/// assert_eq!(ManuallyDrop::new(5).as_inner_mut(), &mut 5);
///
/// ```
#[inline(always)]
fn as_inner_mut(&mut self) -> &mut Self::Inner {
unsafe { &mut *Self::as_inner_raw_mut(self) }
}
/// Converts `self` to a `Box<Self::Inner>` without allocating.
///
/// # Example
///
/// ```rust
/// use core_extensions::TransparentNewtypeExt;
///
/// use std::num::Wrapping;
/// use std::mem::ManuallyDrop;
///
/// assert_eq!(Box::new(Wrapping(3)).into_inner_box(), Box::new(3));
/// assert_eq!(Box::new(ManuallyDrop::new(5)).into_inner_box(), Box::new(5));
///
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
#[inline(always)]
fn into_inner_box(self: Box<Self>) -> Box<Self::Inner> {
unsafe { Box::from_raw(Self::as_inner_raw_mut(Box::into_raw(self))) }
}
if_rust_1_46!{
/// Converts `self` to a `Arc<Self::Inner>` without allocating.
///
/// # Self parameter
///
/// Enabling the "rust_1_46" feature changes this method
/// from taking a `this` parameter to taking a `self` parameter,
/// which allows calling it with `.into_inner_arc()`
///
/// # Example
///
/// ```rust
/// use core_extensions::TransparentNewtypeExt;
///
/// use std::num::Wrapping;
/// use std::mem::ManuallyDrop;
/// use std::sync::Arc;
///
/// assert_eq!(
/// Wrapping::into_inner_arc(Arc::new(Wrapping(3))),
/// Arc::new(3)
/// );
/// assert_eq!(
/// ManuallyDrop::into_inner_arc(Arc::new(ManuallyDrop::new(5))),
/// Arc::new(5)
/// );
///
/// // Calling this as a method requires the "rust_1_46" feature
#[cfg_attr(not(feature = "rust_1_46"), doc = "# /*")]
/// assert_eq!(Arc::new(Wrapping(3)).into_inner_arc(), Arc::new(3));
/// assert_eq!(Arc::new(ManuallyDrop::new(5)).into_inner_arc(), Arc::new(5));
#[cfg_attr(not(feature = "rust_1_46"), doc = "# */")]
///
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
#[inline(always)]
=>
(
fn into_inner_arc(this: Arc<Self>) -> Arc<Self::Inner> {
unsafe { Arc::from_raw(Self::as_inner_raw(Arc::into_raw(this))) }
}
)
(
fn into_inner_arc(self: Arc<Self>) -> Arc<Self::Inner> {
unsafe { Arc::from_raw(Self::as_inner_raw(Arc::into_raw(self))) }
}
)
}
if_rust_1_46!{
/// Converts `self` to a `Rc<Self::Inner>` without allocating.
///
/// # Self parameter
///
/// Enabling the "rust_1_46" feature changes this method
/// from taking a `this` parameter to taking a `self` parameter,
/// which allows calling it with `.into_inner_rc()`
///
/// # Example
///
/// ```rust
/// use core_extensions::TransparentNewtypeExt;
///
/// use std::num::Wrapping;
/// use std::mem::ManuallyDrop;
/// use std::rc::Rc;
///
/// assert_eq!(
/// Wrapping::into_inner_rc(Rc::new(Wrapping(3))),
/// Rc::new(3)
/// );
/// assert_eq!(
/// ManuallyDrop::into_inner_rc(Rc::new(ManuallyDrop::new(5))),
/// Rc::new(5)
/// );
///
/// // Calling this as a method requires the "rust_1_46" feature
#[cfg_attr(not(feature = "rust_1_46"), doc = "# /*")]
/// assert_eq!(Rc::new(Wrapping(3)).into_inner_rc(), Rc::new(3));
/// assert_eq!(Rc::new(ManuallyDrop::new(5)).into_inner_rc(), Rc::new(5));
#[cfg_attr(not(feature = "rust_1_46"), doc = "# */")]
///
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
#[inline(always)]
=>
(
fn into_inner_rc(this: Rc<Self>) -> Rc<Self::Inner> {
unsafe { Rc::from_raw(Self::as_inner_raw(Rc::into_raw(this))) }
}
)
(
fn into_inner_rc(self: Rc<Self>) -> Rc<Self::Inner> {
unsafe { Rc::from_raw(Self::as_inner_raw(Rc::into_raw(self))) }
}
)
}
}
impl<T> TransparentNewtypeExt for T
where
T: TransparentNewtype + ?Sized
{}
///////////////////////////////////////////////////////////////////////////////
unsafe impl<T> TransparentNewtype for [T]
where
T: TransparentNewtype,
T::Inner: Sized,
{
type Inner = [T::Inner];
crate::impl_transparent_newtype!{Self}
}
///////////////////////////////////////////////////////////////////////////////
unsafe impl<T> TransparentNewtype for core::num::Wrapping<T> {
type Inner = T;
crate::impl_transparent_newtype!{Self}
}
///////////////////////////////////////////////////////////////////////////////
unsafe impl<T> TransparentNewtype for core::mem::ManuallyDrop<T> {
type Inner = T;
crate::impl_transparent_newtype!{Self}
}
///////////////////////////////////////////////////////////////////////////////
/// Converts a `Vec` of `T` into a `Vec` of the type that `T` wraps.
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
pub fn into_inner_vec<T>(this: Vec<T>) -> Vec<T::Inner>
where
T: TransparentNewtype,
T::Inner: Sized,
{
unsafe{ crate::utils::transmute_vec(this) }
}
/// Converts a `Vec` of some type into a `Vec` of a wrapper around that type.
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
pub fn from_inner_vec<T>(this: Vec<T::Inner>) -> Vec<T>
where
T: TransparentNewtype,
T::Inner: Sized,
{
unsafe{ crate::utils::transmute_vec(this) }
}
///////////////////////////////////////////////////////////////////////////////
#[inline(always)]
fn check_same_size_alignment<T, U>() {
assert_eq!(mem::size_of::<T>(), mem::size_of::<U>());
assert_eq!(mem::align_of::<T>(), mem::align_of::<U>());
}