diff --git a/Makefile.in b/Makefile.in
index 0b47826..7c02a7f 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -31,6 +31,7 @@ SOURCE=\
 	base/endian_utils.cc \
 	base/error_state.cc \
 	base/error_string.cc \
+	base/grid_layout.cc \
 	base/progress_monitor.cc \
 	base/xml_utils.cc \
 	block-cache/block_cache.cc \
diff --git a/base/grid_layout.cc b/base/grid_layout.cc
new file mode 100644
index 0000000..5ba12b4
--- /dev/null
+++ b/base/grid_layout.cc
@@ -0,0 +1,82 @@
+#include "base/grid_layout.h"
+
+#include <stdexcept>
+
+using namespace base;
+using namespace std;
+
+//----------------------------------------------------------------
+
+grid_layout::grid_layout()
+	: nr_fields_(0)
+{
+	new_row();
+}
+
+void
+grid_layout::render(ostream &out) const
+{
+	vector<unsigned> widths;
+	calc_field_widths(widths);
+
+	grid::const_iterator row;
+	for (row = grid_.begin(); row != grid_.end(); ++row) {
+		row::const_iterator col;
+		unsigned i;
+		for (col = row->begin(), i = 0; col != row->end(); ++col, ++i)
+			out << justify(widths[i], *col) << " ";
+		out << "\n";
+	}
+}
+
+void
+grid_layout::new_row()
+{
+	grid_.push_back(row());
+}
+
+grid_layout::row const &
+grid_layout::current_row() const
+{
+	return grid_.back();
+}
+
+grid_layout::row &
+grid_layout::current_row()
+{
+	return grid_.back();
+}
+
+void
+grid_layout::push_field(string const &s)
+{
+	current_row().push_back(s);
+	nr_fields_ = max<unsigned>(nr_fields_, current_row().size());
+}
+
+void
+grid_layout::calc_field_widths(vector<unsigned> &widths) const
+{
+	widths.resize(nr_fields_, 0);
+
+	grid::const_iterator row;
+	for (row = grid_.begin(); row != grid_.end(); ++row) {
+		row::const_iterator col;
+		unsigned i;
+		for (col = row->begin(), i = 0; col != row->end(); ++col, ++i)
+			widths[i] = max<unsigned>(widths[i], col->length());
+	}
+}
+
+string
+grid_layout::justify(unsigned width, string const &txt) const
+{
+	if (txt.length() > width)
+		throw runtime_error("string field too long, internal error");
+
+	string result(width - txt.length(), ' ');
+	result += txt;
+	return result;
+}
+
+//----------------------------------------------------------------
diff --git a/base/grid_layout.h b/base/grid_layout.h
new file mode 100644
index 0000000..7e3ad5b
--- /dev/null
+++ b/base/grid_layout.h
@@ -0,0 +1,41 @@
+#ifndef BASE_GRID_LAYOUT_H
+#define BASE_GRID_LAYOUT_H
+
+#include <boost/lexical_cast.hpp>
+#include <iosfwd>
+#include <list>
+#include <string>
+#include <vector>
+
+//----------------------------------------------------------------
+
+namespace base {
+	class grid_layout {
+	public:
+		typedef std::list<std::string> row;
+		typedef std::list<row> grid;
+
+		grid_layout();
+		void render(std::ostream &out) const;
+		void new_row();
+
+		template <typename T>
+		void field(T const &t) {
+			push_field(boost::lexical_cast<std::string>(t));
+		}
+
+	private:
+		row &current_row();
+		row const &current_row() const;
+		void push_field(std::string const &s);
+		void calc_field_widths(std::vector<unsigned> &widths) const;
+		std::string justify(unsigned width, std::string const &txt) const;
+
+		grid grid_;
+		unsigned nr_fields_;
+	};
+}
+
+//----------------------------------------------------------------
+
+#endif
diff --git a/thin-provisioning/thin_ls.cc b/thin-provisioning/thin_ls.cc
index be34fca..8a104c1 100644
--- a/thin-provisioning/thin_ls.cc
+++ b/thin-provisioning/thin_ls.cc
@@ -22,6 +22,7 @@
 #include <libgen.h>
 
 #include "base/disk_units.h"
+#include "base/grid_layout.h"
 #include "boost/lexical_cast.hpp"
 #include "boost/optional.hpp"
 #include "boost/range.hpp"
@@ -43,77 +44,6 @@ using namespace thin_provisioning;
 //----------------------------------------------------------------
 
 namespace {
-	// FIXME: move to own file
-	class grid_layout {
-	public:
-		typedef list<string> row;
-		typedef list<row> grid;
-
-		grid_layout()
-			: nr_fields_(0) {
-			new_row();
-		}
-
-		void render(ostream &out) {
-			vector<unsigned> widths;
-			calc_field_widths(widths);
-
-			grid::const_iterator row;
-			for (row = grid_.begin(); row != grid_.end(); ++row) {
-				row::const_iterator col;
-				unsigned i;
-				for (col = row->begin(), i = 0; col != row->end(); ++col, ++i)
-					out << justify(widths[i], *col) << " ";
-				out << "\n";
-			}
-		}
-
-		void new_row() {
-			grid_.push_back(row());
-		}
-
-		template <typename T>
-		void field(T const &t) {
-			push_field(lexical_cast<string>(t));
-		}
-
-	private:
-		row &current_row() {
-			return grid_.back();
-		}
-
-		void push_field(string const &s) {
-			current_row().push_back(s);
-			nr_fields_ = max<unsigned>(nr_fields_, current_row().size());
-		}
-
-		void calc_field_widths(vector<unsigned> &widths) const {
-			widths.resize(nr_fields_, 0);
-
-			grid::const_iterator row;
-			for (row = grid_.begin(); row != grid_.end(); ++row) {
-				row::const_iterator col;
-				unsigned i;
-				for (col = row->begin(), i = 0; col != row->end(); ++col, ++i)
-					widths[i] = max<unsigned>(widths[i], col->length());
-			}
-		}
-
-		string justify(unsigned width, string const &txt) const {
-			if (txt.length() > width)
-				throw runtime_error("string field too long, internal error");
-
-			string result(width - txt.length(), ' ');
-			result += txt;
-			return result;
-		}
-
-		grid grid_;
-		unsigned nr_fields_;
-	};
-
-	//------------------------------------------------
-
 	class mapping_set {
 	public:
 		mapping_set(block_address nr_blocks)