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