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use super::compact::Compact;
#[derive(Clone, Default)]
pub struct CompactOption<T: Compact + Clone>(pub Option<T>);
impl<T: Compact + Clone> ::std::ops::Deref for CompactOption<T> {
type Target = Option<T>;
fn deref(&self) -> &Option<T> {
&self.0
}
}
impl<T: Compact + Clone> ::std::ops::DerefMut for CompactOption<T> {
fn deref_mut(&mut self) -> &mut Option<T> {
&mut self.0
}
}
impl<T: Clone + Compact> Compact for CompactOption<T> {
fn is_still_compact(&self) -> bool {
self.0
.as_ref()
.map(|t| t.is_still_compact())
.unwrap_or(true)
}
fn dynamic_size_bytes(&self) -> usize {
self.0.as_ref().map(|t| t.dynamic_size_bytes()).unwrap_or(0)
}
unsafe fn compact(source: *mut Self, dest: *mut Self, new_dynamic_part: *mut u8) {
if let CompactOption(Some(ref mut s)) = *source {
::std::ptr::copy_nonoverlapping(source, dest, 1);
if let CompactOption(Some(ref mut d)) = *dest {
Compact::compact(s, d, new_dynamic_part);
} else {
unreachable!()
}
} else {
::std::ptr::write(dest, CompactOption(None));
}
}
unsafe fn decompact(source: *const Self) -> Self {
if let CompactOption(Some(ref s)) = *source {
CompactOption(Some(Compact::decompact(s)))
} else {
CompactOption(None)
}
}
}
#[test]
fn basic_option() {
use super::compact_vec::CompactVec;
use super::simple_allocator_trait::{Allocator, DefaultHeap};
let mut option: CompactOption<CompactVec<u32>> = CompactOption(Some(CompactVec::new()));
if let Some(ref mut list) = *option {
list.push(1);
list.push(2);
list.push(3);
assert_eq!(&[1, 2, 3], &**list);
} else {
unreachable!()
}
let bytes = option.total_size_bytes();
let storage = DefaultHeap::allocate(bytes);
unsafe {
Compact::compact_behind(&mut option, storage as *mut CompactOption<CompactVec<u32>>);
::std::mem::forget(option);
if let Some(ref list) = **(storage as *mut CompactOption<CompactVec<u32>>) {
assert_eq!(&[1, 2, 3], &**list);
} else {
unreachable!()
}
println!("before decompact!");
if let Some(ref list) = *Compact::decompact(storage as *mut CompactOption<CompactVec<u32>>)
{
assert_eq!(&[1, 2, 3], &**list);
} else {
unreachable!()
}
DefaultHeap::deallocate(storage, bytes);
}
}