/*
   +----------------------------------------------------------------------+
   | Zend Engine                                                          |
   +----------------------------------------------------------------------+
   | Copyright (c) 1998, 1999 Andi Gutmans, Zeev Suraski                  |
   +----------------------------------------------------------------------+
   | This source file is subject to version 0.90 of the Zend license,     |
   | that is bundled with this package in the file LICENSE, and is        | 
   | available at through the world-wide-web at                           |
   | http://www.zend.com/license/0_90.txt.                                |
   | If you did not receive a copy of the Zend license and are unable to  |
   | obtain it through the world-wide-web, please send a note to          |
   | license@zend.com so we can mail you a copy immediately.              |
   +----------------------------------------------------------------------+
   | Authors: Andi Gutmans <andi@zend.com>                                |
   |          Zeev Suraski <zeev@zend.com>                                |
   +----------------------------------------------------------------------+
*/


#include "zend.h"
#include "zend_stack.h"

ZEND_API int zend_stack_init(zend_stack *stack)
{
	stack->top = 0;
	stack->elements = (void **) emalloc(sizeof(void **) * STACK_BLOCK_SIZE);
	if (!stack->elements) {
		return FAILURE;
	} else {
		stack->max = STACK_BLOCK_SIZE;
		return SUCCESS;
	}
}

ZEND_API int zend_stack_push(zend_stack *stack, void *element, int size)
{
	if (stack->top >= stack->max) {		/* we need to allocate more memory */
		stack->elements = (void **) erealloc(stack->elements,
				   (sizeof(void **) * (stack->max += STACK_BLOCK_SIZE)));
		if (!stack->elements) {
			return FAILURE;
		}
	}
	stack->elements[stack->top] = (void *) emalloc(size);
	memcpy(stack->elements[stack->top], element, size);
	return stack->top++;
}


ZEND_API int zend_stack_top(zend_stack *stack, void **element)
{
	if (stack->top > 0) {
		*element = stack->elements[stack->top - 1];
		return SUCCESS;
	} else {
		*element = NULL;
		return FAILURE;
	}
}


ZEND_API int zend_stack_del_top(zend_stack *stack)
{
	if (stack->top > 0) {
		efree(stack->elements[--stack->top]);
	}
	return SUCCESS;
}


ZEND_API int zend_stack_int_top(zend_stack *stack)
{
	int *e;

	if (zend_stack_top(stack, (void **) &e) == FAILURE) {
		return FAILURE;			/* this must be a negative number, since negative numbers can't be address numbers */
	} else {
		return *e;
	}
}


ZEND_API int zend_stack_is_empty(zend_stack *stack)
{
	if (stack->top == 0) {
		return 1;
	} else {
		return 0;
	}
}


ZEND_API int zend_stack_destroy(zend_stack *stack)
{
	register int i;

	for (i = 0; i < stack->top; i++) {
		efree(stack->elements[i]);
	}

	if (stack->elements) {
		efree(stack->elements);
	}
	return SUCCESS;
}


ZEND_API void **zend_stack_base(zend_stack *stack)
{
	return stack->elements;
}


ZEND_API int zend_stack_count(zend_stack *stack)
{
	return stack->top;
}