ysr@777: /*
mikael@4153:  * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
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ysr@777:  *
ysr@777:  * This code is free software; you can redistribute it and/or modify it
ysr@777:  * under the terms of the GNU General Public License version 2 only, as
ysr@777:  * published by the Free Software Foundation.
ysr@777:  *
ysr@777:  * This code is distributed in the hope that it will be useful, but WITHOUT
ysr@777:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ysr@777:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
ysr@777:  * version 2 for more details (a copy is included in the LICENSE file that
ysr@777:  * accompanied this code).
ysr@777:  *
ysr@777:  * You should have received a copy of the GNU General Public License version
ysr@777:  * 2 along with this work; if not, write to the Free Software Foundation,
ysr@777:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ysr@777:  *
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ysr@777:  */
ysr@777: 
stefank@2314: #ifndef SHARE_VM_UTILITIES_INTHISTO_HPP
stefank@2314: #define SHARE_VM_UTILITIES_INTHISTO_HPP
stefank@2314: 
stefank@2314: #include "memory/allocation.hpp"
stefank@2314: #include "utilities/growableArray.hpp"
stefank@2314: 
ysr@777: // This class implements a simple histogram.
ysr@777: 
ysr@777: // A histogram summarizes a series of "measurements", each of which is
ysr@777: // assumed (required in this implementation) to have an outcome that is a
ysr@777: // non-negative integer.  The histogram efficiently maps measurement outcomes
ysr@777: // to the number of measurements had that outcome.
ysr@777: 
ysr@777: // To print the results, invoke print() on your Histogram*.
ysr@777: 
ysr@777: // Note: there is already an existing "Histogram" class, in file
ysr@777: // histogram.{hpp,cpp}, but to my mind that's not a histogram, it's a table
ysr@777: // mapping strings to counts.  To be a histogram (IMHO) it needs to map
ysr@777: // numbers (in fact, integers) to number of occurrences of that number.
ysr@777: 
ysr@777: // ysr: (i am not sure i agree with the above note.) i suspect we want to have a
ysr@777: // histogram template that will map an arbitrary type (with a defined order
ysr@777: // relation) to a count.
ysr@777: 
ysr@777: 
zgu@3900: class IntHistogram : public CHeapObj<mtInternal> {
ysr@777:  protected:
ysr@777:   int _max;
ysr@777:   int _tot;
ysr@777:   GrowableArray<int>* _elements;
ysr@777: 
ysr@777: public:
ysr@777:   // Create a new, empty table.  "est" is an estimate of the maximum outcome
ysr@777:   // that will be added, and "max" is an outcome such that all outcomes at
ysr@777:   // least that large will be bundled with it.
ysr@777:   IntHistogram(int est, int max);
ysr@777:   // Add a measurement with the given outcome to the sequence.
ysr@777:   void add_entry(int outcome);
ysr@777:   // Return the number of entries recorded so far with the given outcome.
ysr@777:   int  entries_for_outcome(int outcome);
ysr@777:   // Return the total number of entries recorded so far.
ysr@777:   int  total_entries() { return _tot; }
ysr@777:   // Return the number of entries recorded so far with the given outcome as
ysr@777:   // a fraction of the total number recorded so far.
ysr@777:   double fraction_for_outcome(int outcome) {
ysr@777:     return
ysr@777:       (double)entries_for_outcome(outcome)/
ysr@777:       (double)total_entries();
ysr@777:   }
ysr@777:   // Print the histogram on the given output stream.
ysr@777:   void print_on(outputStream* st) const;
ysr@777: };
stefank@2314: 
stefank@2314: #endif // SHARE_VM_UTILITIES_INTHISTO_HPP