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//! A contiguous growable array type with heap-allocated contents, written
//! `RelVec<T>`.
use ::core::{alloc::Layout, fmt, ptr};
use ::mischief::{In, Slot};
use ::munge::munge;
use ::ptr_meta::Pointee;
use ::rel_core::{
Basis,
DefaultBasis,
Emplace,
EmplaceExt,
Move,
MoveExt,
Portable,
RelPtr,
};
use ::situ::{
alloc::{RawAllocator, RawRegionalAllocator},
fmt::DebugRaw,
ops::{DerefMutRaw, DerefRaw, IndexMutRaw, IndexRaw},
DropRaw,
Mut,
Ref,
Val,
};
use crate::alloc::RelAllocator;
/// A relative counterpart to `Vec`.
#[derive(Move, Portable)]
#[repr(C)]
pub struct RelVec<T, A: RawRegionalAllocator, B: Basis = DefaultBasis> {
ptr: RelPtr<T, A::Region, B>,
len: B::Usize,
cap: B::Usize,
alloc: A,
}
impl<T, A, B> DropRaw for RelVec<T, A, B>
where
T: DropRaw,
A: RawRegionalAllocator + DropRaw,
B: Basis,
<B as Basis>::Usize: DropRaw,
{
#[inline]
unsafe fn drop_raw(mut this: Mut<'_, Self>) {
let layout = Layout::array::<T>(this.capacity()).unwrap();
let inner = Self::deref_mut_raw(this.as_mut());
let inner_ptr = inner.as_non_null();
// SAFETY: The elements contained in the `RelVec` are always valid for
// dropping. This drop call has the last reference to them, so they will
// never be accessed again.
unsafe {
DropRaw::drop_raw(inner);
}
munge!(let RelVec { ptr, len, cap, alloc } = this);
// SAFETY: `ptr` is never null and always allocated in `alloc` with a
// layout of `layout`.
unsafe {
A::raw_deallocate(alloc.as_ref(), inner_ptr.cast(), layout);
}
// SAFETY: `ptr` and `alloc` are always valid for dropping and are not
// accessed again.
unsafe {
DropRaw::drop_raw(ptr);
DropRaw::drop_raw(len);
DropRaw::drop_raw(cap);
DropRaw::drop_raw(alloc);
}
}
}
impl<T, A: RawRegionalAllocator, B: Basis> RelVec<T, A, B> {
/// Returns `true` if the `RelVec` contains no elements.
#[inline]
pub fn is_empty(&self) -> bool {
self.len() == 0
}
/// Returns the number of elements in the `RelVec`.
#[inline]
pub fn len(&self) -> usize {
B::to_native_usize(self.len).unwrap()
}
/// Returns a raw pointer to the `RelVec`'s buffer, or a dangling raw
/// pointer valid for zero sized reads if the `RelVec` didn't allocate.
#[inline]
pub fn as_ptr(this: Ref<'_, Self>) -> *const T {
munge!(let RelVec { ptr, .. } = this);
// SAFETY: The relative pointer of a `RelVec` is never null.
unsafe { RelPtr::as_ptr_unchecked(ptr) }
}
/// Returns an unsafe mutable pointer to the `RelVec`'s buffer, or a
/// dangling raw pointer valid for zero sized reads if the `RelVec` didn't
/// allocate.
#[inline]
pub fn as_mut_ptr(this: Mut<'_, Self>) -> *mut T {
munge!(let RelVec { ptr, .. } = this);
// SAFETY: The relative pointer of a `RelVec` is never null.
unsafe { RelPtr::as_mut_ptr_unchecked(ptr) }
}
/// Forces the length of the vector to `new_len`.
///
/// # Safety
///
/// - `new_len` must be less than or equal to `capacity()`.
/// - The elements at `old_len..new_len` must be initialized.
pub unsafe fn set_len(this: Mut<'_, Self>, new_len: usize) {
munge!(let RelVec { mut len, .. } = this);
*len = B::from_native_usize(new_len).unwrap();
}
/// Returns the maximum number of elements the `RelVec` can contain before
/// resizing.
#[inline]
pub fn capacity(&self) -> usize {
B::to_native_usize(self.cap).unwrap()
}
/// Returns a reference to the underlying allocator.
#[inline]
pub fn allocator(this: Ref<'_, Self>) -> Ref<'_, A> {
munge!(let RelVec { alloc, .. } = this);
alloc
}
/// Returns a `Ref` to a slice of the elements in the `RelVec`.
#[inline]
pub fn as_slice(this: Ref<'_, Self>) -> Ref<'_, [T]> {
DerefRaw::deref_raw(this)
}
/// # Safety
///
/// `index` must be less than `capacity`.
unsafe fn slot(
this: Mut<'_, Self>,
index: usize,
) -> In<Slot<'_, T>, A::Region> {
munge!(let RelVec { ptr, .. } = this);
// SAFETY: The `ptr` of a `RelVec` is always non-null.
let ptr = unsafe { RelPtr::as_mut_ptr_unchecked(ptr) };
// SAFETY: The `ptr` of a `RelVec` is always non-null, properly aligned,
// and valid for reads and writes. Because `this` is mutably borrowed
// for `'_`, the created reference cannot be aliased for `'_`.
let slot = unsafe { Slot::new_unchecked(ptr.add(index)) };
// SAFETY: All slots of the `RelVec` are allocated in `self.alloc`, and
// since `A` implements `RawRegionalAllocator`, it guarantees that the
// memory it allocates is located in its region.
unsafe { In::new_unchecked(slot) }
}
/// # Safety
///
/// `index` must be less than `len`. The returned `Val` may drop its
/// contained value when it is dropped. Special care must be taken to ensure
/// that this does not cause a dropped element to exist in the initialized
/// section of the `RelVec.
unsafe fn take(
this: Mut<'_, Self>,
index: usize,
) -> In<Val<'_, T>, A::Region>
where
T: DropRaw,
{
// SAFETY: The caller has guaranteed that `index` is less than `len`.
let slot = unsafe { Self::slot(this, index) };
// SAFETY: The slot at `index` is guaranteed to be initialized and valid
// for dropping because `index < len`, and all elements of `RelVec` are
// treated as pinned.
let initialize = |s| unsafe { Val::from_slot_unchecked(s) };
// SAFETY: `initialize` returns a `Val` of the given `Slot`, which is
// always located in the same region as the `Slot` it is derived from.
unsafe { In::map_unchecked(slot, initialize) }
}
/// Reserves capacity for at least `additional` more elements to be inserted
/// in the given `RelVec<T>`. The collection may reserve more space to
/// speculatively avoid frequent reallocations. After calling `reserve`, the
/// capacity will be greater than or equal to `self.len() + additional`.
/// Does nothing if capacity is already sufficient.
///
/// # Panics
///
/// Panics if the new capacity exceeds `isize::MAX` bytes.
pub fn reserve(mut this: Mut<'_, Self>, additional: usize)
where
T: Move<A::Region>,
{
let min_cap = this.len() + additional;
if min_cap > this.capacity() {
let new_cap = min_cap.checked_next_power_of_two().unwrap();
let old_layout = Layout::array::<T>(this.capacity()).unwrap();
let new_layout = Layout::array::<T>(new_cap).unwrap();
let ptr = Self::as_mut_ptr(this.as_mut());
// SAFETY: The pointer of a `RelVec` is always non-null.
let old_ptr = unsafe { ptr::NonNull::new_unchecked(ptr.cast()) };
// SAFETY:
// - `old_ptr` is the memory for the `RelVec`, which was allocated
// with `old_layout`.
// - `new_layout` has a strictly larger size than `old_layout`
// because `new_cap` is greater than `min_cap`, which is greater
// than `this.capacity()`.
let grew_in_place = unsafe {
RawAllocator::raw_grow_in_place(
Self::allocator(this.as_ref()),
old_ptr,
old_layout,
new_layout,
)
.is_ok()
};
if !grew_in_place {
let allocation = RawAllocator::raw_allocate(
Self::allocator(this.as_ref()),
new_layout,
);
let new_ptr = allocation.unwrap().as_ptr().cast::<T>();
for i in 0..this.len() {
// SAFETY:
// - `new_ptr` is the pointer of a `NonNull`, so it must be
// non-null. It is guaranteed to be aligned to
// `new_layout.align()` by the implementation of
// `RawAllocator`, which is at least `align_of::<T>()`. It
// is also guaranteed to be valid for reads and writes of
// at least `new_layout.size()` bytes, which covers every
// element slot in `new_ptr`.
// - `new_ptr` is freshly-allocated, so only we have access
// to it. It is not currently aliased by any other
// pointers.
let out = unsafe { Slot::new_unchecked(new_ptr.add(i)) };
// SAFETY: `new_ptr` is allocated in `this.alloc`, and since
// `A` implements `RawRegionalAllocator`, it guarantees that
// memory it allocates is located in its region.
let out = unsafe { In::new_unchecked(out) };
// SAFETY: `i` is less than `len` and we move out of it then
// free the backing storage so it can't be accessed
// afterward.
let value = unsafe { Self::take(this.as_mut(), i) };
T::r#move(value, out);
}
munge!(let RelVec { ptr, alloc, .. } = this.as_mut());
let new_ptr =
// SAFETY: `new_ptr` is allocated in `this.alloc`, and
// since `A` implements `RawRegionalAllocator` it guarantees
// that memory it allocates is located in its region.
unsafe { In::<_, A::Region>::new_unchecked(new_ptr) };
RelPtr::set(ptr, new_ptr);
// SAFETY:
// - `old_ptr` is currently allocated because it was previously
// allocated and `grow_in_place` failed.
// - `old_layout` was the layout used to allocate `old_ptr`.
unsafe {
RawAllocator::raw_deallocate(
alloc.as_ref(),
old_ptr,
old_layout,
);
}
}
munge!(let RelVec { mut cap, .. } = this);
*cap = B::from_native_usize(new_cap).unwrap();
}
}
/// Appends an element to the back of a collection.
///
/// # Panics
///
/// Panics if the new capacity exceeds `isize::MAX` bytes.
pub fn push<E>(mut this: Mut<'_, Self>, value: E)
where
T: Move<A::Region>,
E: Emplace<T, A::Region>,
{
Self::reserve(this.as_mut(), 1);
let len = this.len();
// SAFETY: `len` is definitely less than `capacity` because we reserved
// one slot at the end of our storage and `len` is equal to the length
// of the `RelVec`.
let slot = unsafe { Self::slot(this.as_mut(), len) };
value.emplace(slot);
// SAFETY: `len + 1` must be less than or equal to `capacity` because we
// reserved space for one additional element. We just initialized that
// element by emplacing to it.
unsafe {
Self::set_len(this, len + 1);
}
}
/// Extends the `RelVec` with the contents of an iterator.
pub fn extend<I>(mut this: Mut<'_, Self>, mut values: I)
where
T: Move<A::Region>,
I: Iterator,
I::Item: Emplace<T, A::Region>,
{
// We can avoid setting our length every time we push a new element by
// reserving the iterator's estimated size and pushing as many as we can
// up to that limit. Then
let reserve = values.size_hint().0;
let mut new_len = this.len();
Self::reserve(this.as_mut(), reserve);
while new_len < this.capacity() {
if let Some(value) = values.next() {
// SAFETY: `len + i` must be less than `capacity` because we
// reserved `reserve` slots at the end of our storage, `len`
// is equal to the length of the `RelVec`, and `i` is less than
// `reserve`.
let slot = unsafe { Self::slot(this.as_mut(), new_len) };
new_len += 1;
value.emplace(slot);
} else {
break;
}
}
// SAFETY: `len + reserve` must be less than or equal to `capacity`
// because we reserved space for `reserve` additional elements. We just
// initialized those element by emplacing to them.
unsafe {
Self::set_len(this.as_mut(), new_len);
}
// The `size_hint` from `values` isn't required to be accurate, so we
// have to slowly push any remaining values.
for value in values {
Self::push(this.as_mut(), value);
}
}
/// Clears the `RelVec`, removing all values.
///
/// Note that this method has no effect on the allocated capacity of the
/// `RelVec`.
pub fn clear(mut this: Mut<'_, Self>)
where
T: DropRaw,
{
for i in 0..this.len() {
// SAFETY: `i` is less than `this.len()` and we set the `len` to 0
// so the removed element won't be accessed again.
let val = unsafe { Self::take(this.as_mut(), i) };
drop(val);
}
// SAFETY: 0 indicates that there are no initialized elements, and must
// be less than or equal to the current capacity because capacity cannot
// be less than 0.
unsafe {
Self::set_len(this, 0);
}
}
}
impl<T, A: RawRegionalAllocator, B: Basis> DerefRaw for RelVec<T, A, B> {
type Target = [T];
fn deref_raw(this: Ref<'_, Self>) -> Ref<'_, [T]> {
let ptr = Self::as_ptr(this);
let slice_ptr = ptr::slice_from_raw_parts(ptr, this.len());
// SAFETY:
// - We already ensured that `ptr` is never null and `slice_ptr` is just
// a copy of `ptr`. `ptr` is additionally always properly aligned and
// valid for reads.
// - `this` is borrowed for `'_` so it cannot alias any other mutable
// references for `'_`.
// - The relative pointer of a `RelVec` is always initialized.
unsafe { Ref::new_unchecked(slice_ptr) }
}
}
impl<T, A: RawRegionalAllocator, B: Basis> DerefMutRaw for RelVec<T, A, B> {
fn deref_mut_raw(mut this: Mut<'_, Self>) -> Mut<'_, [T]> {
let ptr = Self::as_mut_ptr(this.as_mut());
let slice_ptr = ptr::slice_from_raw_parts_mut(ptr, this.len());
// SAFETY:
// - We already ensured that `ptr` is never null and `slice_ptr` is just
// a copy of `ptr`. `ptr` is additionally always properly aligned and
// valid for reads and writes.
// - `this` is borrowed for `'_` so it cannot alias any other accessible
// references for `'_`.
// - The relative pointer of a `RelVec` is always initialized and
// treated as immovable.
unsafe { Mut::new_unchecked(slice_ptr) }
}
}
impl<T, A, B> IndexRaw<usize> for RelVec<T, A, B>
where
A: RawRegionalAllocator,
B: Basis,
{
type Output = T;
fn index_raw(this: Ref<'_, Self>, index: usize) -> Ref<'_, Self::Output> {
IndexRaw::index_raw(DerefRaw::deref_raw(this), index)
}
unsafe fn index_raw_unchecked(
this: Ref<'_, Self>,
index: usize,
) -> Ref<'_, Self::Output> {
// SAFETY: The caller has guaranteed that `index` is in bounds for
// indexing.
unsafe {
IndexRaw::index_raw_unchecked(DerefRaw::deref_raw(this), index)
}
}
}
impl<T, A, B> IndexMutRaw<usize> for RelVec<T, A, B>
where
A: RawRegionalAllocator,
B: Basis,
{
fn index_mut_raw(
this: Mut<'_, Self>,
index: usize,
) -> Mut<'_, Self::Output> {
IndexMutRaw::index_mut_raw(DerefMutRaw::deref_mut_raw(this), index)
}
unsafe fn index_mut_raw_unchecked(
this: Mut<'_, Self>,
index: usize,
) -> Mut<'_, Self::Output> {
// SAFETY: The caller has guaranteed that `index` is in bounds for
// indexing.
unsafe {
IndexMutRaw::index_mut_raw_unchecked(
DerefMutRaw::deref_mut_raw(this),
index,
)
}
}
}
impl<T, A, B> DebugRaw for RelVec<T, A, B>
where
T: DebugRaw,
A: RawRegionalAllocator,
B: Basis,
{
fn fmt_raw(
this: Ref<'_, Self>,
f: &mut fmt::Formatter<'_>,
) -> Result<(), fmt::Error> {
f.debug_list()
.entries((0..this.len()).map(|i| IndexRaw::index_raw(this, i)))
.finish()
}
}
/// An emplacer for a new, empty `RelVec`.
pub struct New<R>(pub R);
// SAFETY:
// - `RelVec` is `Sized` and always has metadata `()`, so `emplaced_meta` always
// returns valid metadata for it.
// - `emplace_unsized_unchecked` initializes its `out` parameter.
unsafe impl<T, A, B, R> Emplace<RelVec<T, A, B>, R::Region> for New<R>
where
T: DropRaw,
A: DropRaw + RawRegionalAllocator<Region = R::Region>,
B: Basis,
<B as Basis>::Usize: DropRaw,
R: RelAllocator<A>,
{
fn emplaced_meta(&self) -> <RelVec<T, A, B> as Pointee>::Metadata {}
unsafe fn emplace_unsized_unchecked(
self,
out: In<Slot<'_, RelVec<T, A, B>>, R::Region>,
) {
WithCapacity(self.0, 0).emplace(out);
}
}
/// An emplacer for a new `RelVec` with an initial capacity.
pub struct WithCapacity<R>(pub R, pub usize);
// SAFETY:
// - `RelVec` is `Sized` and always has metadata `()`, so `emplaced_meta` always
// returns valid metadata for it.
// - `emplace_unsized_unchecked` initializes its `out` parameter by emplacing
// and writing to each field.
unsafe impl<T, A, B, R> Emplace<RelVec<T, A, B>, R::Region> for WithCapacity<R>
where
T: DropRaw,
A: DropRaw + RawRegionalAllocator<Region = R::Region>,
B: Basis,
<B as Basis>::Usize: DropRaw,
R: RelAllocator<A>,
{
fn emplaced_meta(
&self,
) -> <RelVec<T, A, B> as ptr_meta::Pointee>::Metadata {
}
unsafe fn emplace_unsized_unchecked(
self,
out: In<Slot<'_, RelVec<T, A, B>>, R::Region>,
) {
let Self(alloc, cap) = self;
let ptr = alloc
.allocate(Layout::array::<T>(cap).unwrap())
.unwrap()
.cast()
.as_ptr();
// SAFETY: The pointer returned from `allocate` is guaranteed to be in
// the region of `R`.
let ptr = unsafe { In::new_unchecked(ptr) };
munge!(
let RelVec {
ptr: out_ptr,
len: out_len,
cap: out_cap,
alloc: out_alloc,
} = out;
);
ptr.emplace(out_ptr);
In::into_inner(out_len).write(B::from_native_usize(0).unwrap());
In::into_inner(out_cap).write(B::from_native_usize(cap).unwrap());
alloc.emplace(out_alloc);
}
}