1/*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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24
25#ifndef SHARE_VM_UTILITIES_INTHISTO_HPP
26#define SHARE_VM_UTILITIES_INTHISTO_HPP
27
28#include "memory/allocation.hpp"
29#include "utilities/growableArray.hpp"
30
31// This class implements a simple histogram.
32
33// A histogram summarizes a series of "measurements", each of which is
34// assumed (required in this implementation) to have an outcome that is a
35// non-negative integer.  The histogram efficiently maps measurement outcomes
36// to the number of measurements had that outcome.
37
38// To print the results, invoke print() on your Histogram*.
39
40// Note: there is already an existing "Histogram" class, in file
41// histogram.{hpp,cpp}, but to my mind that's not a histogram, it's a table
42// mapping strings to counts.  To be a histogram (IMHO) it needs to map
43// numbers (in fact, integers) to number of occurrences of that number.
44
45// ysr: (i am not sure i agree with the above note.) i suspect we want to have a
46// histogram template that will map an arbitrary type (with a defined order
47// relation) to a count.
48
49
50class IntHistogram : public CHeapObj<mtInternal> {
51 protected:
52  int _max;
53  int _tot;
54  GrowableArray<int>* _elements;
55
56public:
57  // Create a new, empty table.  "est" is an estimate of the maximum outcome
58  // that will be added, and "max" is an outcome such that all outcomes at
59  // least that large will be bundled with it.
60  IntHistogram(int est, int max);
61  // Add a measurement with the given outcome to the sequence.
62  void add_entry(int outcome);
63  // Return the number of entries recorded so far with the given outcome.
64  int  entries_for_outcome(int outcome);
65  // Return the total number of entries recorded so far.
66  int  total_entries() { return _tot; }
67  // Return the number of entries recorded so far with the given outcome as
68  // a fraction of the total number recorded so far.
69  double fraction_for_outcome(int outcome) {
70    return
71      (double)entries_for_outcome(outcome)/
72      (double)total_entries();
73  }
74  // Print the histogram on the given output stream.
75  void print_on(outputStream* st) const;
76};
77
78#endif // SHARE_VM_UTILITIES_INTHISTO_HPP
79