/*

	Copyright(C) 2016, Red Hat, Inc., Stanislav Kozina

	This program 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/>.

*/

/*

 * A trivial stack implementation.

 */

#include <stdio.h>

#include <stdlib.h>

#include <stdbool.h>

#include <string.h>

#include "utils.h"

#include "stack.h"

#define	INIT_CAPACITY	10

stack_t *stack_init(void)

{

	stack_t *st = safe_zmalloc(sizeof(*st));

	st->st_capacity = INIT_CAPACITY;

	st->st_count = 0;

	st->st_data = safe_zmalloc(st->st_capacity * sizeof(*st->st_data));

	return st;

}

void stack_destroy(stack_t *st)

{

	if (st->st_count > 0)

		fail("Stack not empty!\n");

	free(st->st_data);

	(void) memset(st, 0, sizeof(*st));

	free(st);

}

void stack_push(stack_t *st, void *data)

{

	if (st->st_count == st->st_capacity) {

		st->st_capacity *= 2;

		st->st_data = realloc(st->st_data,

		    st->st_capacity * sizeof(*st->st_data));

	}

	st->st_data[st->st_count] = data;

	st->st_count++;

}

void *stack_pop(stack_t *st)

{

	if (st->st_count == 0)

		return NULL;

	st->st_count--;

	return st->st_data[st->st_count];

}

void *stack_head(stack_t *st)

{

	if (st->st_count == 0)

		return NULL;

	return st->st_data[st->st_count-1];

}

void walk_stack(stack_t *st, void (*cb)(void *, void *), void *arg)

{

	unsigned int i;

	for (i = 0; i < st->st_count; i++)

		cb(st->st_data[i], arg);

}

void walk_stack_backward(stack_t *st, void (*cb)(void *, void *), void *arg)

{

	unsigned int i;

	for (i = st->st_count; i > 0; i--)

		cb(st->st_data[i - 1], arg);

}