fixed issue #6, prepared release 1.2.1 (#7)

* fixed issue #6

* prepared release 1.2.1

.gitattributes

@@ -0,0 +1 @@
+*.mus filter=lfs diff=lfs merge=lfs -text

src/Diffs.csproj

@@ -11,8 +11,8 @@
     <Copyright>Copyright (c) 2021 Sebastian Fischer</Copyright>
     <RepositoryUrl>https://github.com/spkl/Diffs</RepositoryUrl>
     <AssemblyVersion>1.0.0.0</AssemblyVersion>
-    <FileVersion>1.2.0.0</FileVersion>
-    <Version>1.2.0</Version>
+    <FileVersion>1.2.1.0</FileVersion>
+    <Version>1.2.1</Version>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>..\keys\spkl.Diffs.snk</AssemblyOriginatorKeyFile>
     <DelaySign>false</DelaySign>
@@ -22,8 +22,9 @@
 This project uses Semantic Versioning (https://semver.org/).</Description>
     <PackageTags>diff diffs difference algorithm ses shortest edit script myers</PackageTags>
     <GeneratePackageOnBuild>false</GeneratePackageOnBuild>
-    <PackageReleaseNotes>- Improved performance for .NET standard / Full Framework.
-- Introduced IndexRange class.</PackageReleaseNotes>
+    <PackageReleaseNotes>This is a bugfix release fixing two critical issues:
+- The VArray containing the endpoints of the furthest reaching paths was created too small, leading to an IndexOutOfRangeException in some cases.
+- The result could contain items that indicate they exists on "ResultType.Both" sides, yet they contained two different values as AItem and BItem.</PackageReleaseNotes>
   </PropertyGroup>
 
   <ItemGroup>

src/MyersDiff{T}.cs

@@ -48,7 +48,7 @@ public MyersDiff(T[] aValues, T[] bValues, IEqualityComparer<T> comparer)
             this.aRemoved = new bool[this.aValues.Length];
             this.bAdded = new bool[this.bValues.Length];
 
-            int VMAX = aValues.Length + bValues.Length + 3;
+            int VMAX = (aValues.Length + bValues.Length) * 2;
 
             this.Vf = VArray<int>.CreateFromTo(-VMAX, VMAX);
             this.Vr = VArray<int>.CreateFromTo(-VMAX, VMAX);
@@ -242,13 +242,13 @@ private void LCS(IndexRange A, IndexRange B)
             }
             else
             {
-                (_, int x, int y, int u, int v) = this.SMS(A, B);
+                (int x, int y) = this.SMS(A, B);
                 this.LCS(A.Range(0, x), B.Range(0, y));
-                this.LCS(A.Range(u), B.Range(v));
+                this.LCS(A.Range(x), B.Range(y));
             }
         }
 
-        private (int D, int x, int y, int u, int v) SMS(IndexRange A, IndexRange B)
+        private (int x, int y) SMS(IndexRange A, IndexRange B)
         {
             int N = A.Length;
             int M = B.Length;
@@ -287,10 +287,7 @@ private void LCS(IndexRange A, IndexRange B)
 
                     if (deltaIsOdd && k >= delta - (D - 1) && k <= delta + D - 1 && this.Vf[k] >= this.Vr[k])
                     {
-                        int length = 2 * D - 1;
-                        int u = this.Vr[k];
-                        int v = this.Vr[k] - k;
-                        return (length, x, y, x, y);
+                        return (x, y);
                     }
                 }
 
@@ -318,10 +315,7 @@ private void LCS(IndexRange A, IndexRange B)
 
                     if (deltaIsEven && k >= -D && k <= D && this.Vf[k] >= this.Vr[k])
                     {
-                        int length = 2 * D;
-                        int u = this.Vf[k];
-                        int v = this.Vf[k] - k;
-                        return (length, x, y, u, v);
+                        return (x, y);
                     }
                 }
             }

test/Diffs.Test.csproj

@@ -17,4 +17,13 @@
     <ProjectReference Include="..\src\Diffs.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <None Update="Data\D54ACE32535F00233F43B243D0EF1EDE.mus">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+    <None Update="Data\Smooth_Operator.mus">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
 </Project>

test/MyersDiffClass.cs

@@ -3,6 +3,8 @@
 
 using NUnit.Framework;
 using System;
+using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 
 namespace spkl.Diffs.Test
@@ -70,5 +72,80 @@ public void ReferenceEditScript(ReferenceCase testCase)
         {
             Assert.That(new MyersDiff<string>(testCase.A, testCase.B).GetEditScript().ToArray(), Is.EqualTo(testCase.EditScript));
         }
+
+        [Test]
+        [TestCase("D54ACE32535F00233F43B243D0EF1EDE.mus", "Smooth_Operator.mus")]
+        [TestCase("Smooth_Operator.mus", "D54ACE32535F00233F43B243D0EF1EDE.mus")]
+        public void ApplyDiffResult(string fileA, string fileB)
+        {
+            byte[] a = File.ReadAllBytes(Path.Combine(TestContext.CurrentContext.TestDirectory, "Data", fileA));
+            byte[] b = File.ReadAllBytes(Path.Combine(TestContext.CurrentContext.TestDirectory, "Data", fileB));
+
+            MyersDiff<byte> d = new MyersDiff<byte>(a, b);
+            List<byte> result1 = ApplyEditScript(a, b, d);
+            List<byte> result2 = ApplyResults(d);
+
+            Assert.That(result1, Is.EqualTo(b), "Result constructed from edit script must match original file");
+            Assert.That(result2, Is.EqualTo(b), "Result constructed from result item list must match original file");
+        }
+
+        private static List<byte> ApplyEditScript(byte[] a, byte[] b, MyersDiff<byte> d)
+        {
+            List<byte> result = new List<byte>();
+            Queue<(int LineA, int LineB, int CountA, int CountB)> editScript = new Queue<(int, int, int, int)>(d.GetEditScript());
+            int currentLine = 0;
+            while (currentLine < a.Length)
+            {
+                if (editScript.Count > 0 && editScript.Peek().LineA == currentLine)
+                {
+                    (int lineA, int lineB, int countA, int countB) = editScript.Dequeue();
+                    for (int i = 0; i < countB; i++)
+                    {
+                        result.Add(b[lineB + i]);
+                    }
+
+                    if (countA == 0)
+                    {
+                        result.Add(a[currentLine]);
+                        currentLine++;
+                    }
+                    else
+                    {
+                        currentLine = lineA + countA;
+                    }
+                }
+                else
+                {
+                    result.Add(a[currentLine]);
+                    currentLine++;
+                }
+            }
+
+            return result;
+        }
+
+        private static List<byte> ApplyResults(MyersDiff<byte> d)
+        {
+            List<byte> result = new List<byte>();
+            foreach ((ResultType resultType, byte aItem, byte bItem) in d.GetResult())
+            {
+                switch (resultType)
+                {
+                    case ResultType.A:
+                        break;
+                    case ResultType.B:
+                        result.Add(bItem);
+                        break;
+                    case ResultType.Both:
+                        Assert.That(aItem, Is.EqualTo(bItem), "When ResultType is Both, the AItem and BItem must be equal");
+                        result.Add(aItem);
+                        break;
+                    default:
+                        break;
+                }
+            }
+
+            return result;
+        }
     }
 }