view lwlib/lw_stack.c @ 265:6f4c4d59666f

Make lwar use the "b" flag when opening files. Due to the dumbness on Windows systems related to text vs. binary file distinctions, one needs to add 'b' to fopen() calls when dealing with binary files.
author William Astle <lost@l-w.ca>
date Sun, 10 Feb 2013 19:22:24 -0700
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;
}