1 | /**************************************************************************
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2 | *
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3 | * mgheap.h -- Heap routines
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4 | * Copyright (C) 1994 Neil Sharman
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5 | *
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6 | * This program is free software; you can redistribute it and/or modify
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7 | * it under the terms of the GNU General Public License as published by
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8 | * the Free Software Foundation; either version 2 of the License, or
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9 | * (at your option) any later version.
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10 | *
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11 | * This program is distributed in the hope that it will be useful,
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12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 | * GNU General Public License for more details.
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15 | *
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16 | * You should have received a copy of the GNU General Public License
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17 | * along with this program; if not, write to the Free Software
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18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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19 | *
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20 | **************************************************************************/
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21 |
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22 | /* Care should be taken when using these routines as NO error checking is
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23 | * done.
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24 | */
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25 |
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26 |
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27 |
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28 | /* The heap comparison routine should return
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29 | * <0 : If a should be before b
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30 | * 0 : If a and b are equal
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31 | * >0 : If a should be after b
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32 | */
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33 | typedef int (*heap_comp) (void *a, void *b);
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34 |
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35 |
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36 | /************************************************************************
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37 | *
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38 | * NOTE: If you choose to change the comparison function the first thing
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39 | * you do after changing the function is call heap_build.
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40 | *
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41 | */
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42 | void heap_build (void *heap, int size, int num, heap_comp hc);
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43 |
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44 |
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45 |
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46 | /************************************************************************
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47 | *
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48 | * NOTE : The heap must be built before heap_sort is called.
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49 | * This has the effect of reversing the order of the array.
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50 | * e.g. if your comparison function is designed to pull the
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51 | * biggest thing off the heap first then the result of
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52 | * sorting with this function will be to put the bigest
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53 | * thing at the end of the array.
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54 | *
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55 | */
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56 | void heap_sort (void *heap, int size, int num, heap_comp hc);
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57 |
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58 | /***********************************************************************
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59 | *
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60 | * NOTE: After deleting the head the heap will be one item shorter.
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61 | * The deleted item will be placed at the end of the heap.
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62 | *
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63 | */
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64 | void heap_deletehead (void *heap, int size, int *num, heap_comp hc);
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65 |
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66 |
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67 | /***********************************************************************
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68 | *
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69 | * If you change the "value" of the root node of the heap then you
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70 | * should call this to re-pritorize the heap.
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71 | *
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72 | */
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73 | void heap_changedhead (void *heap, int size, int num, heap_comp hc);
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74 |
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75 |
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76 | /***********************************************************************
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77 | *
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78 | * This assumes that the item has been added to the end of the
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79 | * array that is the heap. But that num has not been changed.
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80 | *
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81 | */
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82 | void heap_additem (void *heap, int size, int *num, heap_comp hc);
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