From f205de7847da7ae1c10212d82e7042d0100b4ce0 Mon Sep 17 00:00:00 2001
From: dan miller
Date: Fri, 19 Oct 2007 05:24:38 +0000
Subject: from the start... checking in ode-0.9

---
 libraries/ode-0.9/ode/src/stack.h | 138 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 libraries/ode-0.9/ode/src/stack.h

(limited to 'libraries/ode-0.9/ode/src/stack.h')

diff --git a/libraries/ode-0.9/ode/src/stack.h b/libraries/ode-0.9/ode/src/stack.h
new file mode 100644
index 0000000..5afff41
--- /dev/null
+++ b/libraries/ode-0.9/ode/src/stack.h
@@ -0,0 +1,138 @@
+/*************************************************************************
+ *                                                                       *
+ * 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.                     *
+ *                                                                       *
+ *************************************************************************/
+
+/* this comes from the `reuse' library. copy any changes back to the source.
+
+these stack allocation functions are a replacement for alloca(), except that
+they allocate memory from a separate pool.
+
+advantages over alloca():
+  - consecutive allocations are guaranteed to be contiguous with increasing
+    address.
+  - functions can allocate stack memory that is returned to the caller,
+    in other words pushing and popping stack frames is optional.
+
+disadvantages compared to alloca():
+  - less portable
+  - slightly slower, although still orders of magnitude faster than malloc().
+  - longjmp() and exceptions do not deallocate stack memory (but who cares?).
+
+just like alloca():
+  - using too much stack memory does not fail gracefully, it fails with a
+    segfault.
+
+*/
+
+
+#ifndef _ODE_STACK_H_
+#define _ODE_STACK_H_
+
+
+#ifdef WIN32
+#include "windows.h"
+#endif
+
+
+struct dStack {
+  char *base;		// bottom of the stack
+  int size;		// maximum size of the stack
+  char *pointer;	// current top of the stack
+  char *frame;		// linked list of stack frame ptrs
+# ifdef WIN32		// stuff for windows:
+  int pagesize;		//   - page size - this is ASSUMED to be a power of 2
+  int committed;	//   - bytes committed in allocated region
+#endif
+
+  // initialize the stack. `max_size' is the maximum size that the stack can
+  // reach. on unix and windows a `virtual' memory block of this size is
+  // mapped into the address space but does not actually consume physical
+  // memory until it is referenced - so it is safe to set this to a high value.
+
+  void init (int max_size);
+
+
+  // destroy the stack. this unmaps any virtual memory that was allocated.
+
+  void destroy();
+
+
+  // allocate `size' bytes from the stack and return a pointer to the allocated
+  // memory. `size' must be >= 0. the returned pointer will be aligned to the
+  // size of a long int.
+
+  char * alloc (int size)
+  {
+    char *ret = pointer;
+    pointer += ((size-1) | (sizeof(long int)-1) )+1;
+#   ifdef WIN32
+    // for windows we need to commit pages as they are required
+    if ((pointer-base) > committed) {
+      committed = ((pointer-base-1) | (pagesize-1))+1;	// round up to pgsize
+      VirtualAlloc (base,committed,MEM_COMMIT,PAGE_READWRITE);
+    }
+#   endif
+    return ret;
+  }
+
+
+  // return the address that will be returned by the next call to alloc()
+
+  char *nextAlloc()
+  {
+    return pointer;
+  }
+
+
+  // push and pop the current size of the stack. pushFrame() saves the current
+  // frame pointer on the stack, and popFrame() retrieves it. a typical
+  // stack-using function will bracket alloc() calls with pushFrame() and
+  // popFrame(). both functions return the current stack pointer - this should
+  // be the same value for the two bracketing calls. calling popFrame() too
+  // many times will result in a segfault.
+
+  char * pushFrame()
+  {
+    char *newframe = pointer;
+    char **addr = (char**) alloc (sizeof(char*));
+    *addr = frame;
+    frame = newframe;
+    return newframe;
+
+    /* OLD CODE
+	*((char**)pointer) = frame;
+	frame = pointer;
+	char *ret = pointer;
+	pointer += sizeof(char*);
+	return ret;
+    */
+  }
+
+  char * popFrame()
+  {
+    pointer = frame;
+    frame = *((char**)pointer);
+    return pointer;
+  }
+};
+
+
+#endif
-- 
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