Add Variable Packing checks to ANGLE

BUG=373
TEST=unit tests



git-svn-id: https://angleproject.googlecode.com/svn/trunk@1317 736b8ea6-26fd-11df-bfd4-992fa37f6226
diff --git a/src/compiler/VariablePacker.h b/src/compiler/VariablePacker.h
new file mode 100644
index 0000000..8987066
--- /dev/null
+++ b/src/compiler/VariablePacker.h
@@ -0,0 +1,41 @@
+//
+// Copyright (c) 2002-2012 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+
+#ifndef _VARIABLEPACKER_INCLUDED_
+#define _VARIABLEPACKER_INCLUDED_
+
+#include <vector>
+#include "compiler/ShHandle.h"
+
+class VariablePacker {
+ public:
+    // Returns true if the passed in variables pack in maxVectors following
+    // the packing rules from the GLSL 1.017 spec, Appendix A, section 7.
+    bool CheckVariablesWithinPackingLimits(
+        int maxVectors,
+        const TVariableInfoList& in_variables);
+
+    // Gets how many components in a row a data type takes.
+    static int GetNumComponentsPerRow(ShDataType type);
+
+    // Gets how many rows a data type takes.
+    static int GetNumRows(ShDataType type);
+
+ private:
+    static const int kNumColumns = 4;
+    static const unsigned kColumnMask = (1 << kNumColumns) - 1;
+
+    unsigned makeColumnFlags(int column, int numComponentsPerRow);
+    void fillColumns(int topRow, int numRows, int column, int numComponentsPerRow);
+    bool searchColumn(int column, int numRows, int* destRow, int* destSize);
+
+    int topNonFullRow_;
+    int bottomNonFullRow_;
+    int maxRows_;
+    std::vector<unsigned> rows_;
+};
+
+#endif // _VARIABLEPACKER_INCLUDED_