o3/alloc/raw/
rows.rs

1use std::mem;
2
3use crate::alloc;
4
5/// Equal-length planes with compile-time row bounds.
6/// # Safety
7/// Every plane has exactly `len()` elements.
8pub unsafe trait Rows: alloc::raw::Shape {
9    const ROOT_MAX: usize = match mem::size_of::<Self::Root>() {
10        0 => usize::MAX,
11        size => isize::MAX as usize / size,
12    };
13
14    const MAX: usize = {
15        let root = mem::align_of::<Self::Root>();
16        let tail = mem::align_of::<Self::Tail>();
17        let align = if root > tail { root } else { tail };
18        let bound = (isize::MAX as usize) & !(align - 1);
19        match mem::size_of::<Self::Root>() + mem::size_of::<Self::Tail>() {
20            0 => usize::MAX,
21            size => bound / size,
22        }
23    };
24
25    const EXTRA_MAX: usize = {
26        let mut low = 0;
27        let mut high = Self::MAX;
28        while low < high {
29            let span = high - low;
30            let count = low + span.div_ceil(2);
31            if alloc::raw::Bundle::bounds::<Self>(count, count).fits() {
32                low = count;
33            } else {
34                high = count - 1;
35            }
36        }
37        low
38    };
39}
o3/alloc/raw/rows.rs

o3/alloc/raw/
rows.rs
