From 5d2747e26f51cc2344a6bd95f93457248fdfebd8 Mon Sep 17 00:00:00 2001
From: Freya Murphy <freya@freyacat.org>
Date: Thu, 29 Feb 2024 17:04:28 -0500
Subject: fin prob

---
 matrix-lang/src/value/gc.rs | 186 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 186 insertions(+)
 create mode 100644 matrix-lang/src/value/gc.rs

(limited to 'matrix-lang/src/value/gc.rs')

diff --git a/matrix-lang/src/value/gc.rs b/matrix-lang/src/value/gc.rs
new file mode 100644
index 0000000..5ef8b80
--- /dev/null
+++ b/matrix-lang/src/value/gc.rs
@@ -0,0 +1,186 @@
+use std::{ops::{Index, IndexMut, Deref, DerefMut, Add, Sub, Mul}, marker::PhantomData, ptr::NonNull, fmt::{Debug, Display}};
+use crate::prelude::*;
+
+pub struct Gc<T> {
+    ptr: NonNull<GcInner<T>>,
+    phantom: PhantomData<GcInner<T>>
+}
+
+struct GcInner<T> {
+    rc: usize,
+    data: T
+}
+
+impl<T> Gc<T> {
+    pub fn new(data: T) -> Self {
+        let boxed = Box::new(GcInner {
+            rc: 1,
+            data,
+        });
+        Self {
+            ptr: NonNull::new(Box::into_raw(boxed)).unwrap(),
+            phantom: PhantomData
+        }
+    }
+}
+
+impl <T: Clone> Gc<T> {
+    pub fn into_inner(self) -> T {
+        unsafe {
+            self.ptr.as_ref().data.clone()
+        }
+    }
+
+    fn data(&self) -> T {
+        unsafe {
+            self.ptr.as_ref().data.clone()
+        }
+    }
+}
+
+impl <T: ValueClone> ValueClone for Gc<T> {
+    fn deep_clone(&self) -> Self {
+        unsafe {
+            let data = self.ptr.as_ref().data.deep_clone();
+            Self::new(data)
+        }
+    }
+
+    fn shallow_clone(&self) -> Self {
+        unsafe {
+            let data = self.ptr.as_ref().data.shallow_clone();
+            Self::new(data)
+        }
+    }
+}
+
+impl<T> From<T> for Gc<T> {
+    fn from(value: T) -> Self {
+        Gc::new(value)
+    }
+}
+
+impl<T: IndexMut<Idx>, Idx> IndexMut<Idx> for Gc<T> {
+    fn index_mut(&mut self, index: Idx) -> &mut Self::Output {
+        self.deref_mut().index_mut(index)
+    }
+}
+
+impl<T: Index<Idx>, Idx> Index<Idx> for Gc<T> {
+    type Output = T::Output;
+
+    fn index(&self, index: Idx) -> &Self::Output {
+        self.deref().index(index)
+    }
+}
+
+impl<T> DerefMut for Gc<T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        unsafe {
+            &mut self.ptr.as_mut().data
+        }
+    }
+}
+
+impl<T> Deref for Gc<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        unsafe {
+            &self.ptr.as_ref().data
+        }
+    }
+}
+
+impl <T: PartialEq> PartialEq for Gc<T> {
+    fn eq(&self, other: &Self) -> bool {
+        self.deref().eq(other.deref())
+    }
+}
+
+impl <T: Iterator> Iterator for Gc<T> {
+    type Item = T::Item;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.deref_mut().next()
+    }
+}
+
+impl<T: Eq> Eq for Gc<T> {}
+
+impl<T> Clone for Gc<T> {
+    fn clone(&self) -> Self {
+        unsafe {
+            let inner = self.ptr.as_ptr().as_mut().unwrap();
+            inner.rc += 1;
+
+            Self {
+                ptr: self.ptr,
+                phantom: PhantomData
+            }
+        }
+    }
+}
+
+impl<T> Drop for Gc<T> {
+    fn drop(&mut self) {
+        unsafe {
+            let inner = self.ptr.as_mut();
+            if inner.rc > 1 {
+                inner.rc -= 1;
+            } else {
+                let _ = Box::from_raw(self.ptr.as_ptr());
+            }
+        }
+    }
+}
+
+impl<T: Debug> Debug for Gc<T> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        if f.alternate() {
+            write!(f, "{:#?}", self.deref())
+        } else {
+            write!(f, "{:?}", self.deref())
+        }
+    }
+}
+
+impl<T: Display> Display for Gc<T> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        if f.alternate() {
+            write!(f, "{:#}", self.deref())
+        } else {
+            write!(f, "{}", self.deref())
+        }
+    }
+}
+
+impl <T: Add + Clone> Add for Gc<T> {
+    type Output = T::Output;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        let a = self.data();
+        let b = rhs.data();
+        a + b
+    }
+}
+
+impl <T: Sub + Clone> Sub for Gc<T> {
+    type Output = T::Output;
+
+    fn sub(self, rhs: Self) -> Self::Output {
+        let a = self.data();
+        let b = rhs.data();
+        a - b
+    }
+}
+
+impl <T: Mul + Clone> Mul for Gc<T> {
+    type Output = T::Output;
+
+    fn mul(self, rhs: Self) -> Self::Output {
+        let a = self.data();
+        let b = rhs.data();
+        a * b
+    }
+}
-- 
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