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//
//
//!
//
// TOC
use super::super::{check_fat_pointer, list_push_gen, make_fat_ptr};
use super::{DstBuf, DstQueue, DstQueueIter, DstQueueIterMut, DstQueuePopHandle};
use crate::MemAligned;
use ::core::{marker, ptr};
impl<DST: ?Sized, BUF: DstBuf> DstQueue<DST, BUF> {
/// Constructs a new (empty) queue.
#[must_use] #[rustfmt::skip]
pub fn new() -> Self where BUF: Default { Self::with_buffer(BUF::default()) }
/// Constructs a new (empty) queue using the given `buffer`.
#[must_use] #[rustfmt::skip]
pub fn with_buffer(data: BUF) -> Self {
DstQueue { _pd: marker::PhantomData, read_pos: 0, write_pos: 0, data }
}
/// Pushes a value to the end of the queue.
pub fn push_back<VAL, F>(&mut self, value: VAL, f: F) -> Result<(), VAL>
where
F: FnOnce(&VAL) -> &DST,
(VAL, BUF::Inner): MemAligned,
{
<(VAL, BUF::Inner) as MemAligned>::assert_compatibility();
// SAFETY: Destination address is valid.
unsafe {
match self.push_inner(check_fat_pointer(&value, f)) {
Ok(pii) => {
ptr::write(pii.data.as_mut_ptr() as *mut VAL, value);
Ok(())
}
Err(()) => Err(value),
}
}
}
/// Compacts the queue (moving the read position to zero).
pub fn compact(&mut self) {
if self.read_pos != 0 {
self.data.as_mut().rotate_left(self.read_pos);
self.write_pos -= self.read_pos;
self.read_pos = 0;
}
}
/// Returns `true` if the queue is empty.
#[must_use]
pub const fn empty(&self) -> bool {
self.read_pos == self.write_pos
}
/// Removes an item from the front of the queue.
#[must_use]
pub fn pop_front(&mut self) -> Option<DstQueuePopHandle<'_, DST, BUF>> {
if self.read_pos == self.write_pos {
None
} else {
Some(DstQueuePopHandle { parent: self })
}
}
/// Returns an exclusive reference to the front element.
#[must_use]
pub fn front_mut(&mut self) -> Option<&mut DST> {
if self.read_pos == self.write_pos {
None
} else {
// SAFETY: TODO
Some(unsafe { &mut *self.front_raw_mut() })
}
}
/// Returns a shared reference to the front element.
#[must_use]
pub fn front(&self) -> Option<&DST> {
if self.read_pos == self.write_pos {
None
} else {
// SAFETY: TODO
Some(unsafe { &*self.front_raw() })
}
}
/// Returns an immutable iterator
/// (yields references to items, in insertion order).
///
/// # Examples
/// ```
/// # use devela::{DstArray, DstQueue};
/// let mut list = DstQueue::<str, DstArray<usize, 8>>::new();
/// list.push_back_str("Hello");
/// list.push_back_str("world");
/// let mut it = list.iter();
/// assert_eq!(it.next(), Some("Hello"));
/// assert_eq!(it.next(), Some("world"));
/// assert_eq!(it.next(), None);
/// ```
#[must_use]
pub const fn iter(&self) -> DstQueueIter<'_, DST, BUF> {
DstQueueIter(self, self.read_pos)
}
/// Returns a mutable iterator.
///
/// # Examples
/// ```
/// # use devela::{DstArray, DstQueue};
/// let mut list = DstQueue::<[u8], DstArray<usize, 8>>::new();
/// list.push_copied(&[1,2,3]);
/// list.push_copied(&[9]);
/// for v in list.iter_mut() {
/// v[0] -= 1;
/// }
/// let mut it = list.iter();
/// assert_eq!(it.next(), Some(&[0,2,3][..]));
/// assert_eq!(it.next(), Some(&[8][..]));
/// assert_eq!(it.next(), None);
/// ```
#[must_use]
pub fn iter_mut(&mut self) -> DstQueueIterMut<'_, DST, BUF> {
DstQueueIterMut(self, self.read_pos)
}
// NOTE: No into_iter, not possible due to unsized types.
// Could make a `drain` that returns read handles (pops as it goes).
/// Removes any items that don't meet a predicate.
///
/// # Examples
/// ```
/// # use {devela::{DstArray, DstQueue}, core::{any::Any, fmt::Debug}};
/// trait DebugAny: 'static + Any + Debug { fn as_any(&self) -> &dyn Any; }
/// impl<DST: Debug + Any + 'static> DebugAny for DST { fn as_any(&self) -> &dyn Any { self } }
/// let mut list = {
/// let mut list: DstQueue<dyn DebugAny, DstArray<usize, 8>> = DstQueue::new();
/// list.push_back(1234, |v| v);
/// list.push_back(234.5f32, |v| v);
/// list.push_back(5678, |v| v);
/// list.push_back(0.5f32, |v| v);
/// list
/// };
/// list.retain(|v| (*v).as_any().downcast_ref::<f32>().is_some());
/// let mut it = list.iter().map(|v| format!("{:?}", v));
/// assert_eq!(it.next(), Some("234.5".to_owned()));
/// assert_eq!(it.next(), Some("0.5".to_owned()));
/// assert_eq!(it.next(), None);
/// ```
pub fn retain<Cb>(&mut self, mut cb: Cb)
where
Cb: FnMut(&mut DST) -> bool,
{
let orig_write_pos = self.write_pos;
self.write_pos = self.read_pos;
let mut ofs = self.read_pos;
let mut writeback_pos = ofs;
while ofs < orig_write_pos {
// SAFETY: TODO
let v: &mut DST = unsafe {
let meta = &mut self.data.as_mut()[ofs..];
let mw = Self::meta_words();
let (meta, data) = meta.split_at_mut(mw);
&mut *make_fat_ptr(data.as_mut_ptr() as *mut (), meta)
};
let words = Self::meta_words() + BUF::round_to_words(size_of_val(v));
if cb(v) {
if writeback_pos != ofs {
let d = self.data.as_mut();
// writeback is always before `ofs`, so this ordering is correct.
for i in 0..words {
let (a, b) = d.split_at_mut(ofs + i);
a[writeback_pos + i] = b[0];
}
}
writeback_pos += words;
} else {
// Don't update `writeback_pos`.
// SAFETY: Valid pointer, won't be accessed again.
unsafe {
ptr::drop_in_place(v);
}
}
ofs += words;
}
assert!(ofs == orig_write_pos);
self.write_pos = writeback_pos;
}
}
impl<BUF: DstBuf, DST> DstQueue<[DST], BUF>
where
(DST, BUF::Inner): MemAligned,
{
/// Pushes a set of items (cloning out of the input `slice`).
///
/// # Examples
/// ```
/// # use devela::{DstArray, DstQueue};
/// let mut queue = DstQueue::<[String], DstArray<usize, 8>>::new();
/// queue.push_cloned(&["1".to_owned()]);
/// ```
pub fn push_cloned(&mut self, slice: &[DST]) -> Result<(), ()>
where
DST: Clone,
{
<(DST, BUF::Inner) as MemAligned>::assert_compatibility();
self.push_from_iter(slice.iter().cloned())
}
/// Pushes a set of items (copying out of the input `slice`).
///
/// # Examples
/// ```
/// # use devela::{DstArray, DstQueue};
/// let mut queue = DstQueue::<[usize], DstArray<usize, 8>>::new();
/// queue.push_copied(&[1]);
/// ```
pub fn push_copied(&mut self, slice: &[DST]) -> Result<(), ()>
where
DST: Copy,
{
<(DST, BUF::Inner) as MemAligned>::assert_compatibility();
// SAFETY: Carefully constructed to maintain consistency.
unsafe {
self.push_inner(slice).map(|pii| {
ptr::copy(
slice.as_ptr() as *const u8,
pii.data.as_mut_ptr() as *mut u8,
size_of_val(slice),
);
})
}
}
/// Pushes an item, populated from an exact-sized iterator.
///
/// # Examples
/// ```
/// # use devela::{DstArray, DstQueue};
/// let mut stack = DstQueue::<[u8], DstArray<usize, 8>>::new();
/// stack.push_from_iter(0..10);
/// assert_eq!(stack.front().unwrap(), &[0,1,2,3,4,5,6,7,8,9]);
/// ```
pub fn push_from_iter(
&mut self,
mut iter: impl ExactSizeIterator<Item = DST>,
) -> Result<(), ()> {
<(DST, BUF::Inner) as MemAligned>::assert_compatibility();
// SAFETY: API used correctly.
unsafe {
let pii = self.push_inner_raw(iter.len() * size_of::<DST>(), &[0])?;
list_push_gen(
pii.meta,
pii.data,
iter.len(),
|_| iter.next().unwrap(),
pii.reset_slot,
pii.reset_value,
);
Ok(())
}
}
}
impl<BUF: DstBuf> DstQueue<str, BUF> {
/// Pushes the contents of a `string` slice as an item onto the stack.
pub fn push_back_str(&mut self, string: &str) -> Result<(), ()> {
// SAFETY TODO
unsafe {
self.push_inner(string).map(|pii| {
ptr::copy(
string.as_bytes().as_ptr(),
pii.data.as_mut_ptr() as *mut u8,
string.len(),
);
})
}
}
}