--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lwlib/lw_stack.c	Wed Jan 19 22:27:17 2011 -0700
@@ -0,0 +1,78 @@
+/*
+lw_stack.c
+
+Copyright © 2010 William Astle
+
+This file is part of LWTOOLS.
+
+LWTOOLS is free software: you can redistribute it and/or modify it under the
+terms of the GNU General Public License as published by the Free Software
+Foundation, either version 3 of the License, or (at your option) any later
+version.
+
+This program 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 GNU General Public License for
+more details.
+
+You should have received a copy of the GNU General Public License along with
+this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#define ___lw_stack_c_seen___
+#include "lw_stack.h"
+#include "lw_alloc.h"
+
+/* this is technically valid but dubious */
+#define NULL 0
+
+lw_stack_t lw_stack_create(void (*freefn)(void *d))
+{
+	lw_stack_t S;
+	
+	S = lw_alloc(sizeof(lw_stack_t));
+	S -> head = NULL;
+	S -> freefn = freefn;
+	return S;
+}
+
+void *lw_stack_pop(lw_stack_t S)
+{
+	if (S -> head)
+	{
+		void *ret, *r2;
+		
+		ret = S -> head -> data;
+		r2 = S -> head;
+		S -> head = S -> head -> next;
+		lw_free(r2);
+		return ret;
+	}
+	return NULL;
+}
+
+void lw_stack_destroy(lw_stack_t S)
+{
+	void *d;
+	
+	while (d = lw_stack_pop(S))
+		(S->freefn)(d);
+	lw_free(S);
+}
+
+void *lw_stack_top(lw_stack_t S)
+{
+	if (S -> head)
+		return S -> head -> data;
+	return NULL;
+}
+
+void lw_stack_push(lw_stack_t S, void *item)
+{
+	struct lw_stack_node_priv *t;
+	
+	t = lw_alloc(sizeof(struct lw_stack_node_priv));
+	t -> next = S -> head;
+	S -> head = t;
+	t -> data = item;
+}