1 | /************************************************************************* |
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2 | * * |
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3 | * Open Dynamics Engine, Copyright (C) 2001,2002 Russell L. Smith. * |
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4 | * All rights reserved. Email: russ@q12.org Web: www.q12.org * |
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5 | * * |
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6 | * This library is free software; you can redistribute it and/or * |
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7 | * modify it under the terms of EITHER: * |
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8 | * (1) The GNU Lesser General Public License as published by the Free * |
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9 | * Software Foundation; either version 2.1 of the License, or (at * |
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10 | * your option) any later version. The text of the GNU Lesser * |
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11 | * General Public License is included with this library in the * |
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12 | * file LICENSE.TXT. * |
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13 | * (2) The BSD-style license that is included with this library in * |
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14 | * the file LICENSE-BSD.TXT. * |
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15 | * * |
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16 | * This library is distributed in the hope that it will be useful, * |
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17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of * |
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18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the files * |
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19 | * LICENSE.TXT and LICENSE-BSD.TXT for more details. * |
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20 | * * |
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21 | *************************************************************************/ |
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22 | |
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23 | #ifndef _ODE_OBSTACK_H_ |
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24 | #define _ODE_OBSTACK_H_ |
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25 | |
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26 | #include "objects.h" |
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27 | |
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28 | // each obstack Arena pointer points to a block of this many bytes |
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29 | #define dOBSTACK_ARENA_SIZE 16384 |
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30 | |
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31 | |
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32 | struct dObStack : public dBase { |
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33 | struct Arena { |
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34 | Arena *next; // next arena in linked list |
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35 | size_t used; // total number of bytes used in this arena, counting |
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36 | }; // this header |
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37 | |
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38 | Arena *first; // head of the arena linked list. 0 if no arenas yet |
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39 | Arena *last; // arena where blocks are currently being allocated |
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40 | |
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41 | // used for iterator |
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42 | Arena *current_arena; |
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43 | size_t current_ofs; |
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44 | |
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45 | dObStack(); |
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46 | ~dObStack(); |
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47 | |
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48 | void *alloc (int num_bytes); |
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49 | // allocate a block in the last arena, allocating a new arena if necessary. |
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50 | // it is a runtime error if num_bytes is larger than the arena size. |
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51 | |
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52 | void freeAll(); |
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53 | // free all blocks in all arenas. this does not deallocate the arenas |
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54 | // themselves, so future alloc()s will reuse them. |
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55 | |
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56 | void *rewind(); |
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57 | // rewind the obstack iterator, and return the address of the first |
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58 | // allocated block. return 0 if there are no allocated blocks. |
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59 | |
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60 | void *next (int num_bytes); |
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61 | // return the address of the next allocated block. 'num_bytes' is the size |
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62 | // of the previous block. this returns null if there are no more arenas. |
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63 | // the sequence of 'num_bytes' parameters passed to next() during a |
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64 | // traversal of the list must exactly match the parameters passed to alloc(). |
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65 | }; |
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66 | |
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67 | |
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68 | #endif |
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