1/* 2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 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