view lwlib/lw_stack.c @ 273:1409debcb1a0

Fix crash on listing when nested noexpand macros are used Macros flagged noexpand were causing a segfault during listing. The problem was incorrect accounting for nesting levels for noexpand macros causing the listing handler to fall off the end of the program in certain circumstances and in other circumstances it would fail to suppress expansion. Both the segfault in the case of misbehaviour and the misbhaviour itself are corrected with this update. If you do not use nested noexpand macros, this bug has no effect.
author William Astle <lost@l-w.ca>
date Sat, 25 May 2013 13:35:46 -0600
parents 00ddfdc1e1e3
children
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/*
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(struct lw_stack_priv));
	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;
}