fileName: Added recursive directory search function

//- Recursively search the given directory for the file
    //  returning the path relative to the directory or
    //  fileName::null if not found
    fileName search(const word& file, const fileName& directory);

src/OpenFOAM/primitives/strings/fileName/fileName.C

@@ -396,4 +396,33 @@ Foam::fileName Foam::operator/(const string& a, const string& b)
 }
 
 
+// * * * * * * * * * * * * * * * Global Functions  * * * * * * * * * * * * * //
+
+Foam::fileName Foam::search(const word& file, const fileName& directory)
+{
+    // Search the current directory for the file
+    fileNameList files(readDir(directory));
+    forAll(files, i)
+    {
+        if (files[i] == file)
+        {
+            return directory/file;
+        }
+    }
+
+    // If not found search each of the sub-directories
+    fileNameList dirs(readDir(directory, fileName::DIRECTORY));
+    forAll(dirs, i)
+    {
+        fileName path = search(file, directory/dirs[i]);
+        if (path != fileName::null)
+        {
+            return path;
+        }
+    }
+
+    return fileName::null;
+}
+
+
 // ************************************************************************* //

src/OpenFOAM/primitives/strings/fileName/fileName.H

@@ -242,6 +242,12 @@ public:
 fileName operator/(const string&, const string&);
 
 
+//- Recursively search the given directory for the file
+//  returning the path relative to the directory or
+//  fileName::null if not found
+fileName search(const word& file, const fileName& directory);
+
+
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 } // End namespace Foam