Emit slices instead of indices

src/merge.rs

@@ -1,32 +1,38 @@
-use std::ops::Range;
+use std::fmt::Debug;
 
 use diff;
 use diff::Result::*;
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
-struct Chunk(Range<usize>, Range<usize>);
+struct Chunk<'a, Item: 'a + Debug + PartialEq + Eq>(&'a [diff::Result<Item>], &'a [diff::Result<Item>]);
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 enum ChunkKind {
     Stable,
     Unstable,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
-struct ChunkItem {
+struct ChunkItem<'a, Item>
+where
+    Item: 'a + Debug + PartialEq + Eq
+{
     kind: ChunkKind,
-    chunk: Chunk,
+    chunk: Chunk<'a, Item>,
 }
 
-impl ChunkItem {
+impl<'a, Item> ChunkItem<'a, Item>
-    fn stable(chunk: Chunk) -> ChunkItem {
+where
+    Item: 'a + Debug + PartialEq + Eq
+{
+    fn stable(chunk: Chunk<'a, Item>) -> ChunkItem<'a, Item> {
         ChunkItem {
             kind: ChunkKind::Stable,
             chunk: chunk,
         }
     }
 
-    fn unstable(chunk: Chunk) -> ChunkItem {
+    fn unstable(chunk: Chunk<'a, Item>) -> ChunkItem<'a, Item> {
         ChunkItem {
             kind: ChunkKind::Unstable,
             chunk: chunk,
@@ -36,7 +42,7 @@ impl ChunkItem {
 
 struct MergeIterator<'a, Item>
 where
-    Item: 'a
+    Item: 'a + Debug + PartialEq + Eq
 {
     left: &'a [diff::Result<Item>],
     right: &'a [diff::Result<Item>],
@@ -45,7 +51,10 @@ where
     ri: usize,
 }
 
-impl<'a, Item> MergeIterator<'a, Item> {
+impl<'a, Item> MergeIterator<'a, Item>
+where
+    Item: 'a + Debug + PartialEq + Eq
+{
     fn new(left: &'a [diff::Result<Item>], right: &'a [diff::Result<Item>]) -> MergeIterator<'a, Item> {
         MergeIterator {
             left,
@@ -56,8 +65,11 @@ impl<'a, Item> MergeIterator<'a, Item> {
     }
 }
 
-impl<'a, Item> Iterator for MergeIterator<'a, Item> {
+impl<'a, Item> Iterator for MergeIterator<'a, Item>
-    type Item = ChunkItem;
+where
+    Item: 'a + Debug + PartialEq + Eq
+{
+    type Item = ChunkItem<'a, Item>;
 
     fn next(&mut self) -> Option<Self::Item> {
         let mut i = 0;
@@ -65,7 +77,7 @@ impl<'a, Item> Iterator for MergeIterator<'a, Item> {
             i += 1;
         }
         if i > 0 {
-            let chunk = ChunkItem::stable(Chunk(self.li..self.li+i, self.ri..self.ri+i));
+            let chunk = ChunkItem::stable(Chunk(&self.left[self.li..self.li+i], &self.right[self.ri..self.ri+i]));
             self.li += i;
             self.ri += i;
             return Some(chunk);
@@ -90,14 +102,14 @@ impl<'a, Item> Iterator for MergeIterator<'a, Item> {
                     ri += 1;
                 },
                 (Some(&Both(..)), Some(&Both(..))) => {
-                    let chunk = ChunkItem::unstable(Chunk(self.li..li, self.ri..ri));
+                    let chunk = ChunkItem::unstable(Chunk(&self.left[self.li..li], &self.right[self.ri..ri]));
                     self.li = li;
                     self.ri = ri;
                     return Some(chunk);
                 }
                 _ => {
                     if self.li < self.left.len() || self.ri < self.right.len() {
-                        let chunk = ChunkItem::unstable(Chunk(self.li..self.left.len(), self.ri..self.right.len()));
+                        let chunk = ChunkItem::unstable(Chunk(&self.left[self.li..self.left.len()], &self.right[self.ri..self.right.len()]));
                         self.li = self.left.len();
                         self.ri = self.right.len();
                         return Some(chunk);
@@ -124,12 +136,13 @@ mod test {
         let ob = diff::chars(o, b);
 
         let merge = MergeIterator::new(&oa, &ob).collect::<Vec<_>>();
+
         assert_eq!(vec![
-            ChunkItem::stable(Chunk(0..3, 0..3)),
+            ChunkItem::stable  (Chunk(&oa[0.. 3], &ob[0.. 3])),
-            ChunkItem::unstable(Chunk(3..6, 3..3)),
+            ChunkItem::unstable(Chunk(&oa[3.. 6], &ob[3.. 3])),
-            ChunkItem::stable(Chunk(6..9, 3..6)),
+            ChunkItem::stable  (Chunk(&oa[6.. 9], &ob[3.. 6])),
-            ChunkItem::unstable(Chunk(9..9, 6..9)),
+            ChunkItem::unstable(Chunk(&oa[9.. 9], &ob[6.. 9])),
-            ChunkItem::stable(Chunk(9..12, 9..12)),
+            ChunkItem::stable  (Chunk(&oa[9..12], &ob[9..12])),
         ], merge);
     }
 
@@ -144,9 +157,9 @@ mod test {
 
         let merge = MergeIterator::new(&oa, &ob).collect::<Vec<_>>();
         assert_eq!(vec![
-            ChunkItem::stable(Chunk(0..3, 0..3)),
+            ChunkItem::stable  (Chunk(&oa[0.. 3], &ob[0.. 3])),
-            ChunkItem::unstable(Chunk(3..9, 3..9)),
+            ChunkItem::unstable(Chunk(&oa[3.. 9], &ob[3.. 9])),
-            ChunkItem::stable(Chunk(9..12, 9..12)),
+            ChunkItem::stable  (Chunk(&oa[9..12], &ob[9..12])),
         ], merge);
     }
 
@@ -161,8 +174,8 @@ mod test {
 
         let merge = MergeIterator::new(&oa, &ob).collect::<Vec<_>>();
         assert_eq!(vec![
-            ChunkItem::stable(Chunk(0..9, 0..9)),
+            ChunkItem::stable  (Chunk(&oa[0..9], &ob[0.. 9])),
-            ChunkItem::unstable(Chunk(9..9, 9..12)),
+            ChunkItem::unstable(Chunk(&oa[9..9], &ob[9..12])),
         ], merge);
     }
 
@@ -177,8 +190,8 @@ mod test {
 
         let merge = MergeIterator::new(&oa, &ob).collect::<Vec<_>>();
         assert_eq!(vec![
-            ChunkItem::stable(Chunk(0..6, 0..6)),
+            ChunkItem::stable  (Chunk(&oa[0..6], &ob[0.. 6])),
-            ChunkItem::unstable(Chunk(6..9, 6..12)),
+            ChunkItem::unstable(Chunk(&oa[6..9], &ob[6..12])),
         ], merge);
     }
 
@@ -193,7 +206,7 @@ mod test {
 
         let merge = MergeIterator::new(&oa, &ob).collect::<Vec<_>>();
         assert_eq!(vec![
-            ChunkItem::unstable(Chunk(0..6, 0..6)),
+            ChunkItem::unstable(Chunk(&oa[0..6], &ob[0..6])),
         ], merge);
     }
 }