--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/utilities/histogram.hpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,91 @@
+/*
+ * Copyright 1998-2000 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+// This class provides a framework for collecting various statistics.
+// The current implementation is oriented towards counting invocations
+// of various types, but that can be easily changed.
+//
+// To use it, you need to declare a Histogram*, and a subtype of
+// HistogramElement:
+//
+//  HistogramElement* MyHistogram;
+//
+//  class MyHistogramElement : public HistogramElement {
+//    public:
+//      MyHistogramElement(char* name);
+//  };
+//
+//  MyHistogramElement::MyHistogramElement(char* elementName) {
+//    _name = elementName;
+//
+//    if(MyHistogram == NULL)
+//      MyHistogram = new Histogram("My Call Counts",100);
+//
+//    MyHistogram->add_element(this);
+//  }
+//
+//  #define MyCountWrapper(arg) static MyHistogramElement* e = new MyHistogramElement(arg); e->increment_count()
+//
+// This gives you a simple way to count invocations of specfic functions:
+//
+// void a_function_that_is_being_counted() {
+//   MyCountWrapper("FunctionName");
+//   ...
+// }
+//
+// To print the results, invoke print() on your Histogram*.
+
+#ifdef ASSERT
+
+class HistogramElement : public CHeapObj {
+ protected:
+  jint _count;
+  const char* _name;
+
+ public:
+  HistogramElement();
+  virtual int count();
+  virtual const char* name();
+  virtual void increment_count();
+  void print_on(outputStream* st) const;
+  virtual int compare(HistogramElement* e1,HistogramElement* e2);
+};
+
+class Histogram : public CHeapObj {
+ protected:
+  GrowableArray<HistogramElement*>* _elements;
+  GrowableArray<HistogramElement*>* elements() { return _elements; }
+  const char* _title;
+  const char* title() { return _title; }
+  static int sort_helper(HistogramElement** e1,HistogramElement** e2);
+  virtual void print_header(outputStream* st);
+  virtual void print_elements(outputStream* st);
+
+ public:
+  Histogram(const char* title,int estimatedSize);
+  virtual void add_element(HistogramElement* element);
+  void print_on(outputStream* st) const;
+};
+
+#endif