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 #ifndef SHARE_VM_UTILITIES_INTHISTO_HPP

 #define SHARE_VM_UTILITIES_INTHISTO_HPP

 #include "memory/allocation.hpp"

 #include "utilities/growableArray.hpp"

 // This class implements a simple histogram.

 // A histogram summarizes a series of "measurements", each of which is

 // assumed (required in this implementation) to have an outcome that is a

 // non-negative integer.  The histogram efficiently maps measurement outcomes

 // to the number of measurements had that outcome.

 // To print the results, invoke print() on your Histogram*.

 // Note: there is already an existing "Histogram" class, in file

 // histogram.{hpp,cpp}, but to my mind that's not a histogram, it's a table

 // mapping strings to counts.  To be a histogram (IMHO) it needs to map

 // numbers (in fact, integers) to number of occurrences of that number.

 // ysr: (i am not sure i agree with the above note.) i suspect we want to have a

 // histogram template that will map an arbitrary type (with a defined order

 // relation) to a count.

 class IntHistogram : public CHeapObj {

  protected:

   int _max;

   int _tot;

   GrowableArray<int>* _elements;

 public:

   // Create a new, empty table.  "est" is an estimate of the maximum outcome

   // that will be added, and "max" is an outcome such that all outcomes at

   // least that large will be bundled with it.

   IntHistogram(int est, int max);

   // Add a measurement with the given outcome to the sequence.

   void add_entry(int outcome);

   // Return the number of entries recorded so far with the given outcome.

   int  entries_for_outcome(int outcome);

   // Return the total number of entries recorded so far.

   int  total_entries() { return _tot; }

   // Return the number of entries recorded so far with the given outcome as

   // a fraction of the total number recorded so far.

   double fraction_for_outcome(int outcome) {

     return

       (double)entries_for_outcome(outcome)/

       (double)total_entries();

   }

   // Print the histogram on the given output stream.

   void print_on(outputStream* st) const;

 };

 #endif // SHARE_VM_UTILITIES_INTHISTO_HPP