4 releases
0.2.1 | Apr 13, 2020 |
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0.2.0 | Apr 13, 2020 |
0.1.1 | Nov 23, 2019 |
0.1.0 | Nov 23, 2019 |
#6 in #mutably
30KB
636 lines
Reusable memory
This Rust crate provides a way to reuse allocated memory for different types.
Basic usage
use reusable_memory::ReusableMemory;
let mut memory: ReusableMemory<u8> = ReusableMemory::new();
{
// The memory can then be borrowed as a different type:
let mut borrowed_memory = memory.borrow_mut_as::<usize>(std::num::NonZeroUsize::new(3).unwrap());
// Now `borrowed_memory` holds a pointer to enough memory to store 3 properly-aligned `usize`s inside the memory allocated in `memory`.
borrowed_memory.push(1).unwrap();
borrowed_memory.push(2).unwrap();
borrowed_memory.push(std::usize::MAX).unwrap();
// `push` will return an `Err` if the pushed value would not fit into the capacity of the borrowed memory.
assert_eq!(borrowed_memory.as_slice(), &[1, 2, std::usize::MAX]);
// values can also be `pop`ed or `drain`ed as with `Vec`:
assert_eq!(borrowed_memory.pop(), Some(std::usize::MAX));
assert_eq!(borrowed_memory.drain(..).collect::<Vec<usize>>().as_slice(), &[1, 2]);
assert_eq!(borrowed_memory.pop(), None);
}
// The borrowed memory is automatically returned when the object is dropped, and the pushed values are dropped as well.
// Now the memory can be reused, even as multiple different types (current limit is 5 because the code is generated by a macro):
{
let (mut borrow_t, mut borrow_u) = memory.borrow_mut_two_as::<usize, u8>(
[
std::num::NonZeroUsize::new(1).unwrap(),
std::num::NonZeroUsize::new(2).unwrap()
]
);
borrow_t.push(0usize).unwrap();
borrow_u.push(1u8).unwrap();
borrow_u.push(2u8).unwrap();
assert_eq!(borrow_t.as_slice(), &[0usize]);
assert_eq!(borrow_u.as_slice(), &[1u8, 2u8]);
}