--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/anagram/support/sparse.h	Sat Dec 22 17:52:45 2007 -0500
@@ -0,0 +1,38 @@
+/*
+ * AnaGram, A System for Syntax Directed Programming
+ * Copyright 1993-2002 Parsifal Software. All Rights Reserved.
+ * See the file COPYING for license and usage terms.
+ *
+ * sparse.h
+ */
+
+#ifndef SPARSE_H
+#define SPARSE_H
+
+#include "agbaltree.h"
+
+class AgSparseIntArray {
+public:
+  struct Pair {
+    int key;
+    int value;
+    Pair(int k, int v = 0) : key(k), value(v) {}
+    int operator < (const Pair &p) const { return key < p.key; }
+  };
+
+protected:
+  AgBalancedTree<Pair> tree;
+
+public:
+  AgSparseIntArray() {}
+  ~AgSparseIntArray() {}
+  int &operator [] (int k) {
+    Pair pair(k), *pointer = &pair;
+    tree.identify(pointer);
+    return pointer->value;
+  }
+  void reset() { tree.reset(); }
+};
+
+
+#endif /* SPARSE_H */