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// devela::data::layout::buffer::impls::linear_option
#[doc(hidden)]
#[macro_export]
macro_rules! __buffer_linear_impl_option {
($(#[$impl_attr:meta])* $name:ident, $I:ty, $P:ty) => {
impl<T, const CAP: usize> Default for $name<T, [Option<T>; CAP]> {
fn default() -> Self {
Self::new()
}
}
$(#[$impl_attr])*
///
/// Fully initialized array using `Option<T>` as a drop boundary.
///
/// # Invariants
/// - Slots `0 .. len` are `Some`
/// - Slots `len .. CAP` are logically outside the buffer
/// - No holes are permitted in the active logical range.
///
/// # Notes
/// - `Option<T>` is used to control initialization and dropping, not sparsity
/// - `len` is the number of elements
/// - Methods never access storage past `len`
impl<T, const CAP: usize> $name<T, [Option<T>; CAP]> {
/* construct */
/// Creates a buffer from a fully initialized array with logical length 0.
pub const fn new() -> Self {
Self::_new([const { None }; CAP], Self::_idx_zero())
}
/// Creates a buffer from a fully initialized array of clonable elements.
/// # Panic
/// Panics if `N > CAP`.
pub fn from_array_clone<const N: usize>(src: [T; N]) -> Self where T: Clone {
assert!(N <= CAP); // IMPROVE: Option instead of panic
let mut storage = [const { None }; CAP];
$crate::whilst! { i in 0..N; { storage[i] = Some(src[i].clone()); }}
Self::_new(storage, Self::_usize_to_idx(N))
}
/// Creates a buffer from a fully initialized array of copiable elements.
/// # Panic
/// Panics if `N > CAP`.
pub const fn from_array_copy<const N: usize>(src: [T; N]) -> Self where T: Copy {
assert!(N <= CAP); // IMPROVE: Option instead of panic
let mut storage = [const { None }; CAP];
$crate::whilst! { i in 0..N; { storage[i] = Some(src[i]); }}
Self::_new(storage, Self::_usize_to_idx(N))
}
$crate::_devela_policy! { safe:"safe_data", unsafe:"unsafe_array",
/// Creates a buffer from an array of options and an explicit logical length,
/// without validating the linear invariant.
///
/// # Panics
/// Panics in debug if `len > CAP`.
///
/// # Safety
/// Caller must guarantee:
/// - `len <= CAP`
/// - `storage[0..len]` are `Some`
/// - `storage[len..CAP]` are `None`
pub const unsafe fn from_array_unchecked(array: [Option<T>; CAP], len: $I) -> Self {
debug_assert!(Self::_idx_ge(len, Self::CAP));
Self::_new(array, $crate::MaybeNiche(len))
}
}
/// Creates a buffer from an array of options, validating the linear invariant.
///
/// Returns `None` if:
/// - a `None` appears before a `Some`
/// - any element after the active logical range is `Some`
pub fn from_array_linear(array: [Option<T>; CAP]) -> Option<Self> {
let mut len = 0;
$crate::whilst! { i in 0..CAP; {
if array[i].is_some() { len += 1; } else { break; }
}}
$crate::whilst! { i in len,..CAP; { if array[i].is_some() { return None; } }}
Some(Self::_new(array, Self::_usize_to_idx(len)))
}
/// Creates a buffer from an array of options by taking the prefix of `Some` values.
///
/// The logical length is inferred as the index of the first `None`.
/// Elements after the first `None` are ignored and need not be `None`.
///
/// Returns `None` if a `None` appears before a `Some` in the prefix.
pub fn from_array_prefix(array: [Option<T>; CAP]) -> Option<Self> {
let mut len = 0;
$crate::whilst! { i in 0..CAP; {
if array[i].is_some() { len += 1; } else { break; }
}}
Some(Self::_new(array, Self::_usize_to_idx(len)))
}
/// Creates a new buffer by cloning all the possible elements from `src`.
pub fn from_slice_clone(src: &[T]) -> Option<Self> where T: Clone {
if src.len() > CAP { return None; }
let mut storage = [const { None }; CAP];
$crate::whilst! { i in 0..src.len(); { storage[i] = Some(src[i].clone()); }}
Some(Self::_new(storage, Self::_usize_to_idx(src.len())))
}
/// Creates a new buffer by copying all the possible elements from `src`.
pub const fn from_slice_copy(src: &[T]) -> Option<Self> where T: Copy {
if src.len() > CAP { return None; }
let mut storage = [const { None }; CAP];
$crate::whilst! { i in 0..src.len(); { storage[i] = Some(src[i]); }}
Some(Self::_new(storage, Self::_usize_to_idx(src.len())))
}
/* size & capacity */
$crate::buffer_linear!(%common_static $name, $I, $P);
/* logical range control */
/// Clears the buffer, dropping all elements.
pub fn clear(&mut self) {
$crate::whilst! { i in 0..self._len_usize(); { self.storage[i] = None; }}
self.len = Self::_idx_zero();
}
/// Truncates the buffer to `new_len`, dropping excess elements.
///
/// If `new_len >= len` this is a no-op.
pub fn truncate(&mut self, new_len: $I) {
if new_len >= self.len() { return; }
$crate::whilst! { i in Self::_idx_to_usize(new_len), ..self._len_usize(); {
self.storage[i] = None;
}}
self._set_len(new_len);
}
/* push */
/// Appends a value to the back of the buffer.
///
/// Returns `Err(value)` if the buffer is full.
pub fn push_back(&mut self, value: T) -> Result<(), T> {
if self.is_full() { return Err(value); }
self.storage[self._len_usize()] = Some(value);
self.len = self._len_inc();
Ok(())
}
/// Appends a copy of `value` to the back of the buffer.
///
/// Returns `Err(value)` if the buffer is full.
pub const fn push_back_copy(&mut self, value: T) -> Result<(), T> where T: Copy {
if self.is_full() { return Err(value); }
self.storage[self._len_usize()] = Some(value);
self.len = self._len_inc();
Ok(())
}
/// Appends as many elements cloned from `src` as fit.
///
/// Returns the number of elements appended.
pub fn push_slice(&mut self, src: &[T]) -> usize where T: Clone {
let len = self._len_usize();
let count = $crate::cmp!(min src.len(), CAP - len);
$crate::whilst! { i in 0..count; {
self.storage[len + i] = Some(src[i].clone());
}}
self.len = Self::_usize_to_idx(len + count);
count
}
/// Appends as many copied elements from `src` as fit.
///
/// Returns the number of elements appended.
pub const fn push_slice_copy(&mut self, src: &[T]) -> usize where T: Copy {
let len = self._len_usize();
let count = $crate::cmp!(min src.len(), CAP - len);
$crate::whilst! { i in 0..count; {
self.storage[len + i] = Some(src[i]);
}}
self.len = Self::_usize_to_idx(len + count);
count
}
/// Appends all copied elements from `src`, or none if insufficient capacity.
///
/// Returns `Err(remaining_capacity)` if not enough space is available.
pub const fn push_slice_copy_exact(&mut self, src: &[T]) -> Result<(), usize>
where T: Copy {
let rem = CAP - self._len_usize();
if src.len() > rem { return Err(rem); }
let _ = self.push_slice_copy(src);
Ok(())
}
/* pop */
/// Removes and returns a value from the back of the buffer.
pub const fn pop_back(&mut self) -> Option<T> {
if self.is_empty() { return None; }
self.len = self._len_dec();
self.storage[self._len_usize()].take()
}
/* peek */
/// Returns a reference to the last element without removing it.
pub const fn peek_back(&self) -> Option<&T> {
if self.is_empty() { return None; }
self.storage[self._len_dec().to_usize_saturating()].as_ref()
}
/// Returns a reference to the last element without removing it.
pub const fn peek_mut_back(&mut self) -> Option<&mut T> {
if self.is_empty() { return None; }
self.storage[self._len_dec().to_usize_saturating()].as_mut()
}
/* get */
/// Returns a shared reference to the element at `index`, or `None` if out of bounds.
pub const fn get(&self, index: $I) -> Option<&T> {
if Self::_idx_ge(index, self.len()) { return None; }
self.storage[Self::_idx_to_usize(index)].as_ref()
}
/// Returns an exclusive reference to the element at `index`,
/// or `None` if out of bounds.
pub const fn get_mut(&mut self, index: $I) -> Option<&mut T> {
if Self::_idx_ge(index, self.len()) { return None; }
self.storage[Self::_idx_to_usize(index)].as_mut()
}
/* swap */
/// Removes and returns the value at `index`, filling the gap with the last element.
///
/// Decrements `len`. Does not preserve order.
pub fn swap_remove(&mut self, index: $I) -> Option<T> {
if index >= self.len() { return None; }
let last = self._len_dec().repr();
self._set_len(last);
let last_usize = Self::_idx_to_usize(last);
if index == last {
self.storage[last_usize].take()
} else {
let index_usize = Self::_idx_to_usize(index);
let value = self.storage[index_usize].take();
self.storage[index_usize] = self.storage[last_usize].take();
value
}
}
/// Removes and returns the value at `index`, filling the gap with the last element.
///
/// Decrements `len`. Does not preserve order.
pub const fn swap_remove_copy(&mut self, index: $I) -> Option<T> where T: Copy {
if Self::_idx_ge(index, self.len()) { return None; }
let last = self._len_dec().repr();
self._set_len(last);
let last_usize = Self::_idx_to_usize(last);
if Self::_idx_eq(index, last) {
self.storage[last_usize]
} else {
let index_usize = Self::_idx_to_usize(index);
let value = self.storage[index_usize];
self.storage[index_usize] = self.storage[last_usize];
value
}
}
/* views */
/// Returns the active logical range as a slice.
pub const fn as_slice(&self) -> &[Option<T>] {
$crate::Slice::range_to(&self.storage, self._len_usize())
}
/// Returns the active logical range as a mutable slice.
pub fn as_mut_slice(&mut self) -> &mut [Option<T>] {
let len_usize = self._len_usize();
$crate::Slice::range_to_mut(&mut self.storage, len_usize)
}
/// Iterates over the initialized elements.
pub fn iter(&self) -> impl Iterator<Item = &T> {
let len = self._len_usize();
self.storage[..len].iter().map(|x| x.as_ref().unwrap())
}
/// Iterates mutably over the initialized elements.
pub fn iter_mut(&mut self) -> impl Iterator<Item = &mut T> {
let len = self._len_usize();
self.storage[..len].iter_mut().map(|x| x.as_mut().unwrap())
}
/* visitation */
/// Visits each initialized element without exposing borrow identity.
pub fn visit_each<F>(&self, f: F) where for<'v> F: Fn(&'v T) {
let len = self._len_usize();
self.storage[..len].iter() // SAFETY: prefix elements are all Some(T)
.for_each(|x| f($crate::unwrap![some_guaranteed_or_ub x.as_ref()]));
}
/// Visits each initialized element mutably without exposing borrow identity.
pub fn visit_each_mut<F>(&mut self, f: F) where for<'v> F: Fn(&'v mut T) {
let len = self._len_usize();
self.storage[..len].iter_mut() // SAFETY: prefix elements are all Some(T)
.for_each(|x| f($crate::unwrap![some_guaranteed_or_ub x.as_mut()]));
}
/// Visits the active logical range as a shared slice of `Some(T)`,
/// without exposing borrow identity.
pub fn visit_slice<F, R>(&self, f: F)
-> R where for<'v> F: FnOnce(&'v [Option<T>]) -> R {
let len = self._len_usize(); f(&self.storage[..len])
}
/// Visits the active logical range as an exclusive slice of `Some(T)`,
/// without exposing borrow identity.
pub fn visit_mut_slice<F, R>(&mut self, f: F)
-> R where for<'v> F: FnOnce(&'v mut [Option<T>]) -> R {
let len = self._len_usize(); f(&mut self.storage[..len])
}
}
};
}