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prop_stack.c revision 1.1 
      1 /* $NetBSD: prop_stack.c,v 1.1 2007/08/16 21:44:08 joerg Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2007 Joerg Sonnenberger <joerg (at) NetBSD.org>.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  *
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in
     15  *    the documentation and/or other materials provided with the
     16  *    distribution.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     21  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
     22  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     23  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
     24  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     25  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     26  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     27  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     28  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include "prop_stack.h"
     33 #include "prop_object_impl.h"
     34 
     35 void
     36 _prop_stack_init(prop_stack_t stack)
     37 {
     38 	stack->used_intern_elems = 0;
     39 	SLIST_INIT(&stack->extern_elems);
     40 }
     41 
     42 bool
     43 _prop_stack_push(prop_stack_t stack, prop_object_t obj, void *obj_data, void *iter)
     44 {
     45 	struct _prop_stack_extern_elem *eelem;
     46 	struct _prop_stack_intern_elem *ielem;
     47 
     48 	if (stack->used_intern_elems == PROP_STACK_INTERN_ELEMS) {
     49 		eelem = _PROP_MALLOC(sizeof(*eelem), M_TEMP);
     50 
     51 		if (eelem == NULL)
     52 			return false;
     53 
     54 		eelem->object = obj;
     55 		eelem->object_data = obj_data;
     56 		eelem->iterator = iter;
     57 
     58 		SLIST_INSERT_HEAD(&stack->extern_elems, eelem, stack_link);
     59 
     60 		return true;
     61 	}
     62 
     63 	_PROP_ASSERT(stack->used_intern_elems < PROP_STACK_INTERN_ELEMS);
     64 	_PROP_ASSERT(SLIST_EMPTY(&stack->extern_elems));
     65 
     66 	ielem = &stack->intern_elems[stack->used_intern_elems];
     67 	ielem->object = obj;
     68 	ielem->object_data = obj_data;
     69 	ielem->iterator = iter;
     70 
     71 	++stack->used_intern_elems;
     72 
     73 	return true;
     74 }
     75 
     76 bool
     77 _prop_stack_pop(prop_stack_t stack, prop_object_t *obj, void **obj_data, void **iter)
     78 {
     79 	struct _prop_stack_extern_elem *eelem;
     80 	struct _prop_stack_intern_elem *ielem;
     81 
     82 	if (stack->used_intern_elems == 0)
     83 		return false;
     84 
     85 	if ((eelem = SLIST_FIRST(&stack->extern_elems)) != NULL) {
     86 		_PROP_ASSERT(stack->used_intern_elems == PROP_STACK_INTERN_ELEMS);
     87 
     88 		SLIST_REMOVE_HEAD(&stack->extern_elems, stack_link);
     89 		*obj = eelem->object;
     90 		*obj_data = eelem->object_data;
     91 		*iter = eelem->iterator;
     92 		_PROP_FREE(eelem, M_TEMP);
     93 		return true;
     94 	}
     95 
     96 	--stack->used_intern_elems;
     97 	ielem = &stack->intern_elems[stack->used_intern_elems];
     98 
     99 	*obj = ielem->object;
    100 	*obj_data = ielem->object_data;
    101 	*iter = ielem->iterator;
    102 
    103 	return true;
    104 }
    105