/* $NetBSD: prop_stack.c,v 1.2 2007/08/30 12:23:54 joerg Exp $ */

/*-
 * Copyright (c) 2007 Joerg Sonnenberger <joerg@NetBSD.org>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "prop_stack.h"
#include "prop_object_impl.h"

void
_prop_stack_init(prop_stack_t stack)
{
        stack->used_intern_elems = 0;
        SLIST_INIT(&stack->extern_elems);
}

bool
_prop_stack_push(prop_stack_t stack, prop_object_t obj, void *data1,
    void *data2, void *data3)
{
        struct _prop_stack_extern_elem *eelem;
        struct _prop_stack_intern_elem *ielem;

        if (stack->used_intern_elems == PROP_STACK_INTERN_ELEMS) {
                eelem = _PROP_MALLOC(sizeof(*eelem), M_TEMP);

                if (eelem == NULL)
                        return false;

                eelem->object = obj;
                eelem->object_data[0] = data1;
                eelem->object_data[1] = data2;
                eelem->object_data[2] = data3;

                SLIST_INSERT_HEAD(&stack->extern_elems, eelem, stack_link);

                return true;
        }

        _PROP_ASSERT(stack->used_intern_elems < PROP_STACK_INTERN_ELEMS);
        _PROP_ASSERT(SLIST_EMPTY(&stack->extern_elems));

        ielem = &stack->intern_elems[stack->used_intern_elems];
        ielem->object = obj;
        ielem->object_data[0] = data1;
        ielem->object_data[1] = data2;
        ielem->object_data[2] = data3;

        ++stack->used_intern_elems;

        return true;
}

bool
_prop_stack_pop(prop_stack_t stack, prop_object_t *obj, void **data1,
    void **data2, void **data3)
{
        struct _prop_stack_extern_elem *eelem;
        struct _prop_stack_intern_elem *ielem;

        if (stack->used_intern_elems == 0)
                return false;

        if ((eelem = SLIST_FIRST(&stack->extern_elems)) != NULL) {
                _PROP_ASSERT(stack->used_intern_elems == PROP_STACK_INTERN_ELEMS);

                SLIST_REMOVE_HEAD(&stack->extern_elems, stack_link);
                if (obj)
                        *obj = eelem->object;
                if (data1)
                        *data1 = eelem->object_data[0];
                if (data2)
                        *data2 = eelem->object_data[1];
                if (data3)
                        *data3 = eelem->object_data[2];
                _PROP_FREE(eelem, M_TEMP);
                return true;
        }

        --stack->used_intern_elems;
        ielem = &stack->intern_elems[stack->used_intern_elems];

        if (obj)
                *obj = ielem->object;
        if (data1)
                *data1 = ielem->object_data[0];
        if (data2)
                *data2 = ielem->object_data[1];
        if (data3)
                *data3 = ielem->object_data[2];

        return true;
}