--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ode/src/obstack.cpp	Tue Feb 02 01:00:49 2010 +0200
@@ -0,0 +1,130 @@
+/*************************************************************************
+ *                                                                       *
+ * 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 "obstack.h"
+
+//****************************************************************************
+// macros and constants
+
+#define ROUND_UP_OFFSET_TO_EFFICIENT_SIZE(arena,ofs) \
+  ofs = (size_t) (dEFFICIENT_SIZE( ((intP)(arena)) + ofs ) - ((intP)(arena)) );
+
+#define MAX_ALLOC_SIZE \
+  ((size_t)(dOBSTACK_ARENA_SIZE - sizeof (Arena) - EFFICIENT_ALIGNMENT + 1))
+
+//****************************************************************************
+// dObStack
+
+dObStack::dObStack()
+{
+  first = 0;
+  last = 0;
+  current_arena = 0;
+  current_ofs = 0;
+}
+
+
+dObStack::~dObStack()
+{
+  // free all arenas
+  Arena *a,*nexta;
+  a = first;
+  while (a) {
+    nexta = a->next;
+    dFree (a,dOBSTACK_ARENA_SIZE);
+    a = nexta;
+  }
+}
+
+
+void *dObStack::alloc (int num_bytes)
+{
+
+
+  // allocate or move to a new arena if necessary
+  if (!first) {
+    // allocate the first arena if necessary
+    first = last = (Arena *) dAlloc (dOBSTACK_ARENA_SIZE);
+    first->next = 0;
+    first->used = sizeof (Arena);
+    ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (first,first->used);
+  }
+  else {
+    // we already have one or more arenas, see if a new arena must be used
+    if ((last->used + num_bytes) > dOBSTACK_ARENA_SIZE) {
+      if (!last->next) {
+	last->next = (Arena *) dAlloc (dOBSTACK_ARENA_SIZE);
+	last->next->next = 0;
+      }
+      last = last->next;
+      last->used = sizeof (Arena);
+      ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (last,last->used);
+    }
+  }
+
+  // allocate an area in the arena
+  char *c = ((char*) last) + last->used;
+  last->used += num_bytes;
+  ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (last,last->used);
+  return c;
+}
+
+
+void dObStack::freeAll()
+{
+  last = first;
+  if (first) {
+    first->used = sizeof(Arena);
+    ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (first,first->used);
+  }
+}
+
+
+void *dObStack::rewind()
+{
+  current_arena = first;
+  current_ofs = sizeof (Arena);
+  if (current_arena) {
+    ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (current_arena,current_ofs)
+    return ((char*) current_arena) + current_ofs;
+  }
+  else return 0;
+}
+
+
+void *dObStack::next (int num_bytes)
+{
+  // this functions like alloc, except that no new storage is ever allocated
+  if (!current_arena) return 0;
+  current_ofs += num_bytes;
+  ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (current_arena,current_ofs);
+  if (current_ofs >= current_arena->used) {
+    current_arena = current_arena->next;
+    if (!current_arena) return 0;
+    current_ofs = sizeof (Arena);
+    ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (current_arena,current_ofs);
+  }
+  return ((char*) current_arena) + current_ofs;
+}