use crate::dim::Dim;
use core::{
marker::PhantomData,
slice::{from_raw_parts, from_raw_parts_mut},
};
macro_rules! impl_iter (
($dr_matrix_iter:ident, $data_ptr:ty, $data_type:ty, $from_raw_parts:ident) => (
#[derive(Debug)]
pub struct $dr_matrix_iter<'a, T> {
curr_row: usize,
data: $data_ptr,
dim: Dim<[usize; 2]>,
phantom: PhantomData<&'a T>,
}
impl<'a, T> $dr_matrix_iter<'a, T> {
pub(crate) fn new(
dim: [usize; 2],
data: $data_ptr,
) -> Self {
$dr_matrix_iter {
curr_row: 0,
data,
dim: dim.into(),
phantom: PhantomData,
}
}
pub fn split_at(self, idx: usize) -> (Self, Self) {
let current_len = self.dim.rows() - self.curr_row;
assert!(idx <= current_len);
let slice_point = self.curr_row + idx;
(
$dr_matrix_iter {
curr_row: self.curr_row,
data: self.data,
dim: [slice_point, self.dim.cols()].into(),
phantom: PhantomData,
},
$dr_matrix_iter {
curr_row: slice_point,
data: self.data,
dim: self.dim,
phantom: PhantomData,
}
)
}
}
impl<'a, T> DoubleEndedIterator for $dr_matrix_iter<'a, T> {
fn next_back(&mut self) -> Option<Self::Item> {
if self.curr_row >= self.dim.rows() {
return None;
}
let data: $data_type = unsafe {
let offset = ((self.dim.rows() - 1) * self.dim.cols()) as isize;
let ptr = self.data.offset(offset);
$from_raw_parts(ptr, self.dim.cols())
};
*self.dim.rows_mut() -= 1;
Some(data)
}
}
impl<'a, T> ExactSizeIterator for $dr_matrix_iter<'a, T> {
}
impl<'a, T> Iterator for $dr_matrix_iter<'a, T> {
type Item = $data_type;
fn next(&mut self) -> Option<Self::Item> {
if self.curr_row >= self.dim.rows() {
return None;
}
let data: $data_type = unsafe {
let offset = (self.curr_row * self.dim.cols()) as isize;
let ptr = self.data.offset(offset);
$from_raw_parts(ptr, self.dim.cols())
};
self.curr_row += 1;
Some(data)
}
fn size_hint(&self) -> (usize, Option<usize>) {
(self.dim.rows(), Some(self.dim.rows()))
}
}
unsafe impl<'a, T> Send for $dr_matrix_iter<'a, T> {}
unsafe impl<'a, T> Sync for $dr_matrix_iter<'a, T> {}
);
);
impl_iter!(DrMatrixRowIter, *const T, &'a [T], from_raw_parts);
impl_iter!(DrMatrixRowIterMut, *mut T, &'a mut [T], from_raw_parts_mut);