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1 /*
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2 * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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4 *
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5 * This code is free software; you can redistribute it and/or modify it
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6 * under the terms of the GNU General Public License version 2 only, as
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7 * published by the Free Software Foundation.
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8 *
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9 * This code is distributed in the hope that it will be useful, but WITHOUT
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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12 * version 2 for more details (a copy is included in the LICENSE file that
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13 * accompanied this code).
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14 *
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15 * You should have received a copy of the GNU General Public License version
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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18 *
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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20 * CA 95054 USA or visit www.sun.com if you need additional information or
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21 * have any questions.
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22 *
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23 */
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24
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25 // This class implements a simple histogram.
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26
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27 // A histogram summarizes a series of "measurements", each of which is
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28 // assumed (required in this implementation) to have an outcome that is a
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29 // non-negative integer. The histogram efficiently maps measurement outcomes
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30 // to the number of measurements had that outcome.
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31
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32 // To print the results, invoke print() on your Histogram*.
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33
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34 // Note: there is already an existing "Histogram" class, in file
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35 // histogram.{hpp,cpp}, but to my mind that's not a histogram, it's a table
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36 // mapping strings to counts. To be a histogram (IMHO) it needs to map
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37 // numbers (in fact, integers) to number of occurrences of that number.
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38
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39 // ysr: (i am not sure i agree with the above note.) i suspect we want to have a
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40 // histogram template that will map an arbitrary type (with a defined order
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41 // relation) to a count.
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42
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43
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44 class IntHistogram : public CHeapObj {
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45 protected:
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46 int _max;
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47 int _tot;
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48 GrowableArray<int>* _elements;
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49
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50 public:
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51 // Create a new, empty table. "est" is an estimate of the maximum outcome
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52 // that will be added, and "max" is an outcome such that all outcomes at
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53 // least that large will be bundled with it.
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54 IntHistogram(int est, int max);
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55 // Add a measurement with the given outcome to the sequence.
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56 void add_entry(int outcome);
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57 // Return the number of entries recorded so far with the given outcome.
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58 int entries_for_outcome(int outcome);
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59 // Return the total number of entries recorded so far.
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60 int total_entries() { return _tot; }
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61 // Return the number of entries recorded so far with the given outcome as
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62 // a fraction of the total number recorded so far.
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63 double fraction_for_outcome(int outcome) {
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64 return
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65 (double)entries_for_outcome(outcome)/
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66 (double)total_entries();
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67 }
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68 // Print the histogram on the given output stream.
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69 void print_on(outputStream* st) const;
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70 };
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