Add MarkdownViewer

QuickLook.Plugin/QuickLook.Plugin.HtmlViewer/UrlHelper.cs

@@ -0,0 +1,27 @@
+using System.IO;
+using System.Text;
+
+namespace QuickLook.Plugin.HtmlViewer
+{
+    internal static class UrlHelper
+    {
+        internal static string FilePathToFileUrl(string filePath)
+        {
+            var uri = new StringBuilder();
+            foreach (var v in filePath)
+                if (v >= 'a' && v <= 'z' || v >= 'A' && v <= 'Z' || v >= '0' && v <= '9' ||
+                    v == '+' || v == '/' || v == ':' || v == '.' || v == '-' || v == '_' || v == '~' ||
+                    v > '\xFF')
+                    uri.Append(v);
+                else if (v == Path.DirectorySeparatorChar || v == Path.AltDirectorySeparatorChar)
+                    uri.Append('/');
+                else
+                    uri.Append($"%{(int) v:X2}");
+            if (uri.Length >= 2 && uri[0] == '/' && uri[1] == '/') // UNC path
+                uri.Insert(0, "file:");
+            else
+                uri.Insert(0, "file:///");
+            return uri.ToString();
+        }
+    }
+}