First Public Release.

ROMVault2/Utils/RelativePath.cs

@@ -0,0 +1,95 @@
+/******************************************************
+ *     ROMVault2 is written by Gordon J.              *
+ *     Contact gordon@romvault.com                    *
+ *     Copyright 2014                                 *
+ ******************************************************/
+
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
+
+namespace ROMVault2.Utils
+{
+    public static class RelativePath
+    {
+        /// <summary>
+        /// Creates a relative path from one file
+        /// or folder to another.
+        /// </summary>
+        /// <param name="fromDirectory">
+        /// Contains the directory that defines the
+        /// start of the relative path.
+        /// </param>
+        /// <param name="toPath">
+        /// Contains the path that defines the
+        /// endpoint of the relative path.
+        /// </param>
+        /// <returns>
+        /// The relative path from the start
+        /// directory to the end path.
+        /// </returns>
+        /// <exception cref="ArgumentNullException"></exception>
+        public static string MakeRelative(string fromDirectory, string toPath)
+        {
+            if (fromDirectory == null)
+                throw new ArgumentNullException("fromDirectory");
+
+            if (toPath == null)
+                throw new ArgumentNullException("toPath");
+
+            bool isRooted = (Path.IsPathRooted(fromDirectory) && Path.IsPathRooted(toPath));
+
+            if (isRooted)
+            {
+                bool isDifferentRoot = (String.Compare(Path.GetPathRoot(fromDirectory), Path.GetPathRoot(toPath), StringComparison.OrdinalIgnoreCase) != 0);
+
+                if (isDifferentRoot)
+                    return toPath;
+            }
+
+            List<string> relativePath = new List<string>();
+            string[] fromDirectories = fromDirectory.Split(Path.DirectorySeparatorChar);
+
+            string[] toDirectories = toPath.Split(Path.DirectorySeparatorChar);
+
+            int length = Math.Min(fromDirectories.Length, toDirectories.Length);
+
+            int lastCommonRoot = -1;
+
+            // find common root
+            for (int x = 0; x < length; x++)
+            {
+                if (String.Compare(fromDirectories[x], toDirectories[x], StringComparison.OrdinalIgnoreCase) != 0)
+                    break;
+
+                lastCommonRoot = x;
+            }
+
+            if (lastCommonRoot == -1)
+                return toPath;
+
+            // add relative folders in from path
+            for (int x = lastCommonRoot + 1; x < fromDirectories.Length; x++)
+            {
+                if (fromDirectories[x].Length > 0)
+                    relativePath.Add("..");
+            }
+
+            // add to folders to path
+            for (int x = lastCommonRoot + 1; x < toDirectories.Length; x++)
+            {
+                relativePath.Add(toDirectories[x]);
+            }
+
+            // create relative path
+            string[] relativeParts = new string[relativePath.Count];
+            relativePath.CopyTo(relativeParts, 0);
+
+            string newPath = string.Join(Path.DirectorySeparatorChar.ToString(CultureInfo.InvariantCulture), relativeParts);
+
+            return newPath;
+        }
+
+    }
+}