1 /* |
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2 * Copyright (c) 2001, 2019, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
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22 * |
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23 */ |
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24 |
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25 #ifndef SHARE_UTILITIES_INTHISTO_HPP |
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26 #define SHARE_UTILITIES_INTHISTO_HPP |
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27 |
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28 #include "memory/allocation.hpp" |
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29 #include "utilities/growableArray.hpp" |
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30 |
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31 // This class implements a simple histogram. |
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32 |
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33 // A histogram summarizes a series of "measurements", each of which is |
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34 // assumed (required in this implementation) to have an outcome that is a |
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35 // non-negative integer. The histogram efficiently maps measurement outcomes |
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36 // to the number of measurements had that outcome. |
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37 |
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38 // To print the results, invoke print() on your Histogram*. |
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39 |
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40 // Note: there is already an existing "Histogram" class, in file |
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41 // histogram.{hpp,cpp}, but to my mind that's not a histogram, it's a table |
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42 // mapping strings to counts. To be a histogram (IMHO) it needs to map |
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43 // numbers (in fact, integers) to number of occurrences of that number. |
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44 |
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45 // ysr: (i am not sure i agree with the above note.) i suspect we want to have a |
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46 // histogram template that will map an arbitrary type (with a defined order |
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47 // relation) to a count. |
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48 |
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49 |
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50 class IntHistogram : public CHeapObj<mtInternal> { |
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51 protected: |
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52 int _max; |
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53 int _tot; |
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54 GrowableArray<int>* _elements; |
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55 |
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56 public: |
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57 // Create a new, empty table. "est" is an estimate of the maximum outcome |
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58 // that will be added, and "max" is an outcome such that all outcomes at |
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59 // least that large will be bundled with it. |
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60 IntHistogram(int est, int max); |
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61 // Add a measurement with the given outcome to the sequence. |
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62 void add_entry(int outcome); |
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63 // Return the number of entries recorded so far with the given outcome. |
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64 int entries_for_outcome(int outcome); |
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65 // Return the total number of entries recorded so far. |
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66 int total_entries() { return _tot; } |
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67 // Return the number of entries recorded so far with the given outcome as |
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68 // a fraction of the total number recorded so far. |
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69 double fraction_for_outcome(int outcome) { |
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70 return |
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71 (double)entries_for_outcome(outcome)/ |
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72 (double)total_entries(); |
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73 } |
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74 // Print the histogram on the given output stream. |
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75 void print_on(outputStream* st) const; |
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76 }; |
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77 |
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78 #endif // SHARE_UTILITIES_INTHISTO_HPP |
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