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use bumpalo::Bump;
use std::{
self,
fmt::{self, Debug, Formatter},
ops, ptr,
};
pub use bumpalo::collections::{String, Vec};
pub struct Box<'alloc, T: ?Sized>(&'alloc mut T);
impl<'alloc, T> Box<'alloc, T> {
pub fn unbox(self) -> T {
// This pointer read is safe because the reference `self.0` is
// guaranteed to be unique--not just now, but we're guaranteed it's not
// borrowed from some other reference. This in turn is because we never
// construct an alloc::Box with a borrowed reference, only with a fresh
// one just allocated from a Bump.
unsafe { ptr::read(self.0 as *mut T) }
}
}
impl<'alloc, T: ?Sized> ops::Deref for Box<'alloc, T> {
type Target = T;
fn deref(&self) -> &T {
self.0
}
}
impl<'alloc, T: ?Sized> ops::DerefMut for Box<'alloc, T> {
fn deref_mut(&mut self) -> &mut T {
self.0
}
}
impl<'alloc, T: ?Sized> Debug for Box<'alloc, T>
where
T: Debug,
{
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
self.0.fmt(f)
}
}
impl<'alloc, T> PartialEq for Box<'alloc, T>
where
T: PartialEq<T> + ?Sized,
{
fn eq(&self, other: &Box<'alloc, T>) -> bool {
PartialEq::eq(&**self, &**other)
}
fn ne(&self, other: &Box<'alloc, T>) -> bool {
PartialEq::ne(&**self, &**other)
}
}
pub fn alloc<'alloc, T>(allocator: &'alloc Bump, value: T) -> Box<'alloc, T> {
Box(allocator.alloc(value))
}
pub fn alloc_with<'alloc, F, T>(allocator: &'alloc Bump, gen: F) -> Box<'alloc, T>
where
F: FnOnce() -> T,
{
Box(allocator.alloc_with(gen))
}
pub fn alloc_str<'alloc>(allocator: &'alloc Bump, value: &str) -> &'alloc str {
String::from_str_in(value, allocator).into_bump_str()
}
pub fn map_vec<'alloc, A, B>(
source: &mut Vec<A>,
mut map_fn: impl FnMut(&mut A) -> B,
allocator: &'alloc Bump,
) -> Vec<'alloc, B> {
let mut out = Vec::with_capacity_in(source.len(), allocator);
for item in source {
out.push(map_fn(item));
}
out
}