1 files changed, 83 insertions, 0 deletions

diff --git a/src/samples/Dtf/DDiff/FileDiffEngine.cs b/src/samples/Dtf/DDiff/FileDiffEngine.cs
new file mode 100644
index 00000000..20ecd857
--- /dev/null
+++ b/src/samples/Dtf/DDiff/FileDiffEngine.cs
@@ -0,0 +1,83 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+using System;
+using System.IO;
+
+namespace WixToolset.Dtf.Samples.DDiff
+{
+        public class FileDiffEngine : IDiffEngine
+        {
+                public FileDiffEngine()
+                {
+                }
+
+                public virtual float GetDiffQuality(string diffInput1, string diffInput2, string[] options, IDiffEngineFactory diffFactory)
+                {
+                        if(diffInput1 != null && File.Exists(diffInput1) &&
+                           diffInput2 != null && File.Exists(diffInput2))
+                        {
+                                return .10f;
+                        }
+                        else
+                        {
+                                return 0;
+                        }
+                }
+
+                public bool GetDiff(string diffInput1, string diffInput2, string[] options, TextWriter diffOutput, string linePrefix, IDiffEngineFactory diffFactory)
+                {
+                        bool difference = false;
+
+                        FileInfo file1 = new FileInfo(diffInput1);
+                        FileInfo file2 = new FileInfo(diffInput2);
+
+                        if(file1.Length != file2.Length)
+                        {
+                                diffOutput.WriteLine("{0}File size: {1} -> {2}", linePrefix, file1.Length, file2.Length);
+                                difference = true;
+                        }
+                        else
+                        {
+                                FileStream stream1 = file1.Open(FileMode.Open, FileAccess.Read, FileShare.Read);
+                                FileStream stream2 = file2.Open(FileMode.Open, FileAccess.Read, FileShare.Read);
+
+                                byte[] buf1 = new byte[512];
+                                byte[] buf2 = new byte[512];
+
+                                while(!difference)
+                                {
+                                        int count1 = stream1.Read(buf1, 0, buf1.Length);
+                                        int count2 = stream2.Read(buf2, 0, buf2.Length);
+
+                                        for(int i = 0; i < count1; i++)
+                                        {
+                                                if(i == count2 || buf1[i] != buf2[i])
+                                                {
+                                                        difference = true;
+                                                        break;
+                                                }
+                                        }
+                                        if(count1 < buf1.Length) // EOF
+                                        {
+                                                break;
+                                        }
+                                }
+
+                                stream1.Close();
+                                stream2.Close();
+
+                                if(difference)
+                                {
+                                        diffOutput.WriteLine("{0}Files differ.", linePrefix);
+                                }
+                        }
+
+                        return difference;
+                }
+
+                public virtual IDiffEngine Clone()
+                {
+                        return new FileDiffEngine();
+                }
+        }
+}