Added OwnedRef: References a single slot from an Arc"d Populator.

Fortune for parapop's current commit: Future blessing − 末吉

src/lib.rs

@@ -192,9 +192,15 @@ impl<'a, T> Populator<'a, T>
 	}
     }
 
-    /// Get a reference to an item at `idx` whether it exists or not.
-    #[inline]
-    pub fn get_ref(&self, idx: usize) -> Ref<'_, 'a, T>
+    
+    #[inline(always)]
+    fn bounds_okay(&self, idx: usize) -> bool
+    {
+	idx < self.populates.len()
+    }
+    
+    #[inline(always)]
+    fn bounds_check(&self, idx: usize)
     {
 	#[inline(never)]
 	#[cold]
@@ -205,12 +211,34 @@ impl<'a, T> Populator<'a, T>
 	if idx >= self.populates.len() {
 	    _panic_oob(idx, self.populates.len())
 	}
+    }
+    
+    /// Get a reference to an item at `idx` whether it exists or not.
+    ///
+    /// # Panics
+    /// If the index is out of bounds
+    #[inline]
+    pub fn get_ref(&self, idx: usize) -> Ref<'_, 'a, T>
+    {
+	self.bounds_check(idx);
 	Ref {
 	    pop: self,
 	    idx
 	}
     }
-    //TODO: get_into(Arc<Self>) -> OwnedRef
+
+    /// Consume into a reference to a specific index in the populator, whether it exists or not.
+    ///
+    /// # Panics
+    /// If the index is out of bounds
+    #[inline]
+    pub fn into_ref(self: std::sync::Arc<Self>, idx: usize) -> OwnedRef<'a, T>
+    {
+	OwnedRef {
+	    pop: self,
+	    idx
+	}
+    }
     //TODO: get_excusive -> RefEx
 
     /// Try to get an exclusive, mutable reference to an item at `idx` if an item exists there.

src/refer.rs

@@ -1,5 +1,6 @@
 //! Single-index references.
 use super::*;
+use std::sync::Arc;
 
 #[derive(Debug)] // PartialEq, PartialOrd
 pub struct Ref<'re, 'a, T: 'a>
@@ -10,6 +11,34 @@ pub struct Ref<'re, 'a, T: 'a>
     //TODO:   OR: Hold a reference to the actual AtomicBool at `idx` itself?
 }
 
+#[derive(Debug)]
+pub struct OwnedRef<'a, T: 'a> // PartialEq, PartialOrd
+{
+    pub(super) pop: Arc<Populator<'a, T>>,
+    pub(super) idx: usize,
+}
+
+
+impl<'a, T: 'a> PartialEq for OwnedRef<'a, T>
+{
+    #[inline]
+    fn eq(&self, other: &Self) -> bool
+    {
+	address_eq(self.pop.as_ref(), other.pop.as_ref()) && self.idx == other.idx
+    }
+}
+
+impl<'a, T: 'a> PartialOrd for OwnedRef<'a, T>
+{
+    #[inline]
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+	if address_eq(self.pop.as_ref(), other.pop.as_ref()) {
+	    self.idx.partial_cmp(&other.idx)
+	} else {
+	    None
+	}
+    }
+}
 
 impl<'re, 'a, T: 'a> PartialEq for Ref<'re, 'a, T>
 {
@@ -63,8 +92,65 @@ impl<'re, 'a, T: 'a> Ref<'re, 'a, T>
     {
 	self.pop.insert(self.idx, value)
     }
-    
 }
 
-//TODO: OwnedRef: From Arc<Self> receiver of Arc<Populator<'static, T>>
-//TODO: RefEx: Exclusive reference, holds &'ref mut Populator<'a, T>
+impl<'a,  T:'a> OwnedRef<'a, T>
+{
+    /// The index that this `Ref` refers to.
+    #[inline]
+    pub fn slot(&self) -> usize
+    {
+	self.idx
+    }
+    /// Checks if the references item currently exists.
+    #[inline]
+    pub fn exists(&self) -> bool
+    {
+	self.pop.exists(self.idx)
+    }	
+    /// Try to insert `value` at the referred slot.
+    ///
+    /// If the slot already has a value, then `Err(value)` is returned, otherwise, `value` is inserted into the table and the number of items now populated is returned.
+    #[inline]
+    pub fn try_insert(&self, value: T) -> Result<usize, T>
+    {
+	self.pop.try_insert(self.idx, value)
+    }
+    /// Insert `value` at the referred slot.
+    ///
+    /// # Panics
+    /// If the slot has a value.
+    #[inline]
+    pub fn insert(&self, value: T) -> usize
+    {
+	self.pop.insert(self.idx, value)
+    }
+
+    /// Consume into the inner populator
+    #[inline]
+    pub fn into_inner(self) -> Arc<Populator<'a, T>>
+    {
+	self.pop
+    }
+}
+
+impl<'a, T: 'a> From<(Arc<Populator<'a, T>>, usize)> for OwnedRef<'a, T>
+{
+    #[inline]
+    fn from((pop, idx): (Arc<Populator<'a, T>>, usize)) -> Self
+    {
+	Self { pop, idx }
+    }
+}
+
+
+impl<'a, T: 'a> From<OwnedRef<'a, T>> for (Arc<Populator<'a, T>>, usize)
+{
+    #[inline]
+    fn from(from: OwnedRef<'a, T>) -> Self
+    {
+	(from.pop, from.idx)
+    }
+}
+
+//TODO: RefEx: Exclusive reference, holds &'re mut Populator<'a, T>