Merge pull request #12 from zenangst/fix/crash-with-only-one-new-matc…

…h-part-deux Fix crash with only one new match
zenangst · Oct 5, 2018 · 6b6ae8c · 6b6ae8c
2 parents 775fbf5 + c286d97
commit 6b6ae8c
Show file tree

Hide file tree

Showing 2 changed files with 26 additions and 19 deletions.
diff --git a/Differific.podspec b/Differific.podspec
@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
   s.name             = "Differific"
   s.summary          = "A fast and convenient diffing framework"
-  s.version          = "0.5.1"
+  s.version          = "0.5.2"
   s.homepage         = "https://github.com/zenangst/Differific"
   s.license          = 'MIT'
   s.author           = { "Christoffer Winterkvist" => "[email protected]" }

diff --git a/Source/Shared/Algorithm.swift b/Source/Shared/Algorithm.swift
@@ -70,27 +70,34 @@ class Algorithm {
 
     // 4th Pass
     offset = 1
-    repeat {
-      if case let .indexInOther(otherIndex) = newArray[offset], otherIndex + 1 < oldArray.count,
-        case let .tableEntry(newEntry) = newArray[offset + 1],
-        case let .tableEntry(oldEntry) = oldArray[otherIndex + 1], newEntry === oldEntry {
-        newArray[offset + 1] = .indexInOther(otherIndex + 1)
-        oldArray[otherIndex + 1] = .indexInOther(offset + 1)
-      }
-      offset += 1
-    } while offset < newArray.count - 1
 
+    if newArray.count > offset {
+      repeat {
+        if case let .indexInOther(otherIndex) = newArray[offset], otherIndex + 1 < oldArray.count,
+          case let .tableEntry(newEntry) = newArray[offset + 1],
+          case let .tableEntry(oldEntry) = oldArray[otherIndex + 1], newEntry === oldEntry {
+          newArray[offset + 1] = .indexInOther(otherIndex + 1)
+          oldArray[otherIndex + 1] = .indexInOther(offset + 1)
+        }
+        offset += 1
+      } while offset < newArray.count - 1
+    }
+
     // 5th Pass
     offset = newArray.count - 1
-    repeat {
-      if case let .indexInOther(otherIndex) = newArray[offset], otherIndex - 1 >= 0,
-        case let .tableEntry(newEntry) = newArray[offset - 1],
-        case let .tableEntry(oldEntry) = oldArray[otherIndex - 1], newEntry === oldEntry {
-        newArray[offset - 1] = .indexInOther(otherIndex - 1)
-        oldArray[otherIndex - 1] = .indexInOther(offset - 1)
-      }
-      offset -= 1
-    } while offset > 0
+
+    if offset > newArray.count {
+      repeat {
+        if case let .indexInOther(otherIndex) = newArray[offset], otherIndex - 1 >= 0,
+          case let .tableEntry(newEntry) = newArray[offset - 1],
+          case let .tableEntry(oldEntry) = oldArray[otherIndex - 1], newEntry === oldEntry {
+          newArray[offset - 1] = .indexInOther(otherIndex - 1)
+          oldArray[otherIndex - 1] = .indexInOther(offset - 1)
+        }
+        offset -= 1
+      } while offset > 0
+    }
+
 
     // Handle deleted objects
     offset = 0