158 lines
4.9 KiB
C++
158 lines
4.9 KiB
C++
/*************************************************************************
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* *
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* Open Dynamics Engine, Copyright (C) 2001,2002 Russell L. Smith. *
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* All rights reserved. Email: russ@q12.org Web: www.q12.org *
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* *
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* This library is free software; you can redistribute it and/or *
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* modify it under the terms of EITHER: *
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* (1) The GNU Lesser General Public License as published by the Free *
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* Software Foundation; either version 2.1 of the License, or (at *
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* your option) any later version. The text of the GNU Lesser *
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* General Public License is included with this library in the *
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* file LICENSE.TXT. *
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* (2) The BSD-style license that is included with this library in *
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* the file LICENSE-BSD.TXT. *
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* *
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* This library is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the files *
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* LICENSE.TXT and LICENSE-BSD.TXT for more details. *
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* *
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*************************************************************************/
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#include <ode/common.h>
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#include <ode/error.h>
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#include <ode/memory.h>
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#include "config.h"
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#include "obstack.h"
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//****************************************************************************
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// macros and constants
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#define ROUND_UP_OFFSET_TO_EFFICIENT_SIZE(arena,ofs) \
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ofs = (sizeint) (dEFFICIENT_SIZE( ((sizeint)(arena)) + ofs ) - ((sizeint)(arena)) )
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#define MAX_ALLOC_SIZE \
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((sizeint)(dOBSTACK_ARENA_SIZE - sizeof (Arena) - EFFICIENT_ALIGNMENT + 1))
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//****************************************************************************
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// dObStack
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dObStack::dObStack():
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m_first(NULL), m_last(NULL),
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m_current_arena(NULL), m_current_ofs(0)
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{
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}
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dObStack::~dObStack()
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{
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// free all arenas
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Arena *a,*nexta;
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a = m_first;
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while (a) {
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nexta = a->m_next;
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dFree (a,dOBSTACK_ARENA_SIZE);
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a = nexta;
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}
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}
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void *dObStack::alloc (sizeint num_bytes)
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{
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if (num_bytes > MAX_ALLOC_SIZE) dDebug (0,"num_bytes too large");
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bool last_alloc_needed = false, last_init_needed = false;
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Arena **last_ptr = NULL;
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if (m_last != NULL) {
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if ((m_last->m_used + num_bytes) > dOBSTACK_ARENA_SIZE) {
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if (m_last->m_next != NULL) {
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m_last = m_last->m_next;
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last_init_needed = true;
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} else {
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last_ptr = &m_last->m_next;
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last_alloc_needed = true;
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}
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}
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} else {
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last_ptr = &m_last;
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last_alloc_needed = true;
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}
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if (last_alloc_needed) {
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Arena *new_last = (Arena *) dAlloc (dOBSTACK_ARENA_SIZE);
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new_last->m_next = 0;
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*last_ptr = new_last;
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if (m_first == NULL) {
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m_first = new_last;
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}
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m_last = new_last;
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last_init_needed = true;
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}
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if (last_init_needed) {
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m_last->m_used = sizeof (Arena);
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ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (m_last,m_last->m_used);
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}
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// allocate an area in the arena
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char *c = ((char*) m_last) + m_last->m_used;
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m_last->m_used += num_bytes;
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ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (m_last,m_last->m_used);
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return c;
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}
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void dObStack::freeAll()
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{
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Arena *current = m_first;
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m_last = current;
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// It is necessary to reset used sizes in whole arena chain
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// otherwise enumeration may proceed to remains of old deleted joints in unused arenas
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while (current) {
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current->m_used = sizeof(Arena);
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ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (current,current->m_used);
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current = current->m_next;
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}
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}
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void *dObStack::rewind()
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{
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return switch_to_arena(m_first);
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}
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void *dObStack::next (sizeint num_bytes)
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{
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// this functions like alloc, except that no new storage is ever allocated
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if (!m_current_arena) {
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return 0;
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}
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m_current_ofs += num_bytes;
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ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (m_current_arena,m_current_ofs);
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if (m_current_ofs < m_current_arena->m_used) {
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return ((char*) m_current_arena) + m_current_ofs;
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}
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return switch_to_arena(m_current_arena->m_next);
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}
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void *dObStack::switch_to_arena(Arena *next_arena)
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{
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m_current_arena = next_arena;
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if (!next_arena) {
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return 0;
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}
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m_current_ofs = sizeof (Arena);
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ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (next_arena, m_current_ofs);
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// Check if end of allocation has been reached
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if (m_current_ofs >= next_arena->m_used) {
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return 0;
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}
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return ((char*) next_arena) + m_current_ofs;
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}
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