Minor change to ReadLines method

Source/TailBlazer.Domain/FileHandling/FileInfoEx.cs

@@ -125,7 +125,6 @@ public static IObservable<LineMatches> Match(this IObservable<FileNotification>
                 }).Switch();
         }
 
-
         public static IEnumerable<Line> ReadLines(this FileInfo source, int[] lines, Func<int, bool> isEndOfTail = null)
         {
             using (var stream = File.Open(source.FullName, FileMode.Open, FileAccess.Read, FileShare.Delete | FileShare.ReadWrite))
@@ -145,18 +144,23 @@ public static IEnumerable<Line> ReadLines(this FileInfo source, int[] lines, Fun
             }
         }
 
-        public static IEnumerable<T> ReadLines<T>(this FileInfo source, IEnumerable<LineIndex> lines, Func<LineIndex,string, T>  selector)
+        public static IEnumerable<T> ReadLines<T>(this FileInfo source, IEnumerable<LineIndex> lines, Func<LineIndex,string, T>  selector, Encoding encoding=null)
         {
+            encoding = encoding ?? Encoding.Default;
+
+            //TODO: This assumes a windows file whereas Unix / max have length=1.  
+            //This is accounted for on the LineIndexer but we need to pass the length and current encoding here ()
+            const int delimiterLength = 2;
+
             using (var stream = File.Open(source.FullName, FileMode.Open, FileAccess.Read, FileShare.Delete | FileShare.ReadWrite))
             {
-
                 foreach (var lineIndex in lines.OrderBy(l=>l.Index))
                 {
-                    var data = new byte[lineIndex.Size-2];
+                    var data = new byte[lineIndex.Size- delimiterLength];
                     stream.Seek(lineIndex.Start, SeekOrigin.Begin);
                     stream.Read(data, 0, data.Length);
 
-                    var result = Encoding.Default.GetString(data);
+                    var result = encoding.GetString(data);
                     yield return selector(lineIndex, result);
                 }
             }

Source/TailBlazer.Domain/FileHandling/LineIndexer.cs

@@ -49,6 +49,8 @@ public IEnumerable<int> ReadToEnd()
                 _postion = _postion + line.Length + _delimiterSize;
                 yield return _postion;
             }
+
+
         }
 
         public void Dispose()

Source/TailBlazer.Domain/FileHandling/LineMatcher.cs

@@ -13,9 +13,7 @@ public class LineMatcher: IDisposable
         private readonly StreamReader _reader;
 
         public Encoding Encoding { get; }
-
         public int TotalCount => _index;
-
         public int Count => _matches;
 
         private int _index = -1;
@@ -29,6 +27,9 @@ public LineMatcher(FileInfo info, Func<string,bool> predicate, Encoding encoding
 
             _stream = File.Open(info.FullName, FileMode.Open, FileAccess.Read, FileShare.Delete | FileShare.ReadWrite);
             _reader = new StreamReader(_stream, Encoding, true);
+
+            //TODO 1: Get current encoding from _reader.CurrentEncoding and expose so cusumers can read the lines with the same encoding
+            //TODO 2: Expose line delimiter length so it can be correctly removed from when re-reading a line
         }
 
         public IEnumerable<int> ScanToEnd()
@@ -40,11 +41,9 @@ public IEnumerable<int> ScanToEnd()
             while ((line = _reader.ReadLine()) != null)
             {
                 _index++;
-                if (_predicate(line))
-                {
-                    _matches++;
-                    yield return _index;
-                }
+                if (!_predicate(line)) continue;
+                _matches++;
+                yield return _index;
             }
         }
 

Source/TailBlazer/Views/VirtualScrollPanel.cs

@@ -8,6 +8,11 @@
 
 namespace TailBlazer.Views
 {
+    /// <summary>
+    /// This is adapted (butchered!) from VirtualWrapPanel in https://github.com/samueldjack/VirtualCollection
+    /// 
+    /// See http://blog.hibernatingrhinos.com/12515/implementing-a-virtualizingwrappanel
+    /// </summary>
     public class VirtualScrollPanel : VirtualizingPanel, IScrollInfo
     {
         private const double ScrollLineAmount = 16.0;