From a205bbb1d286d78efbb325dac1d465c6908e0026 Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Fri, 1 May 2020 22:21:17 +0200
Subject: Use extern type for CStr

---
 safe_libc/src/boxed.rs | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 safe_libc/src/boxed.rs

(limited to 'safe_libc/src/boxed.rs')

diff --git a/safe_libc/src/boxed.rs b/safe_libc/src/boxed.rs
new file mode 100644
index 0000000..a0bbfb4
--- /dev/null
+++ b/safe_libc/src/boxed.rs
@@ -0,0 +1,78 @@
+use core::{marker, mem, ptr};
+use core::ops::{Deref, DerefMut};
+
+pub trait Dealloc<T: ?Sized> {
+	unsafe fn dealloc(p: *mut T);
+}
+
+#[repr(transparent)]
+pub struct BoxLike<T: ?Sized, D: Dealloc<T>> {
+	inner: ptr::NonNull<T>,
+	_phantom: marker::PhantomData<T>,
+	_dropper: marker::PhantomData<D>,
+}
+
+impl<T: ?Sized, D: Dealloc<T>> BoxLike<T, D> {
+	#[inline]
+	pub unsafe fn from_raw_unchecked(p: *mut T) -> Self {
+		BoxLike {
+			inner: ptr::NonNull::new_unchecked(p),
+			_phantom: marker::PhantomData,
+			_dropper: marker::PhantomData,
+		}
+	}
+
+	#[inline]
+	pub unsafe fn from_raw(p: *mut T) -> Option<Self> {
+		if p.is_null() {
+			None
+		} else {
+			Some(Self::from_raw_unchecked(p))
+		}
+	}
+
+	#[inline]
+	pub fn into_raw(self) -> *mut T {
+		let p = self.inner.as_ptr();
+		mem::forget(self);
+		p
+	}
+}
+
+impl<T: ?Sized, D: Dealloc<T>> Drop for BoxLike<T, D> {
+	#[inline]
+	fn drop(&mut self) {
+		let p = self.inner.as_ptr();
+		unsafe {
+			ptr::drop_in_place(p);
+			D::dealloc(p);
+		}
+	}
+}
+
+impl<T: ?Sized, D: Dealloc<T>> Deref for BoxLike<T, D> {
+	type Target = T;
+
+	#[inline]
+	fn deref(&self) -> &T {
+		unsafe { self.inner.as_ref() }
+	}
+}
+
+impl<T: ?Sized, D: Dealloc<T>> DerefMut for BoxLike<T, D> {
+	#[inline]
+	fn deref_mut(&mut self) -> &mut T {
+		unsafe { self.inner.as_mut() }
+	}
+}
+
+pub struct DeallocFree;
+
+impl<T: ?Sized> Dealloc<T> for DeallocFree {
+	#[inline]
+	unsafe fn dealloc(p: *mut T) {
+		libc::free(p as _);
+	}
+}
+
+pub type CBox<T> = BoxLike<T, DeallocFree>;
-- 
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