/* lv2_atom_helpers.h - Helper functions for the LV2 atoms extension.
 * Copyright (C) 2008-2010 David Robillard <http://drobilla.net>
 *
 * This header is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This header 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 Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this header; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA 01222-1307 USA
 */

#ifndef LV2_ATOM_HELPERS_H
#define LV2_ATOM_HELPERS_H

#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include "lv2/http/lv2plug.in/ns/ext/atom/atom.h"

/** @file
 * Helper functions for the LV2 Atom extension
 * <http://lv2plug.in/ns/ext/atom>.
 *
 * These functions are provided for convenience only, use of them is not
 * required for supporting atoms (i.e. the definition of atoms in memory
 * is described in atom.h and NOT by this API).
 *
 * Note that these functions are all static inline which basically means:
 * do not take the address of these functions.
 */


/** Pad a size to 4 bytes (32 bits) */
static inline uint16_t
lv2_atom_pad_size(uint16_t size)
{
	return (size + 3) & (~3);
}

typedef LV2_Atom_Property* LV2_Atom_Object_Iter;

static inline LV2_Atom_Object_Iter
lv2_atom_object_get_iter(LV2_Atom_Property* prop)
{
	return (LV2_Atom_Object_Iter)prop;
}

static inline bool
lv2_atom_object_iter_is_end(const LV2_Atom* object, LV2_Atom_Object_Iter iter)
{
	return (uint8_t*)iter >= (object->body + object->size);
}

static inline bool
lv2_atom_object_iter_equals(const LV2_Atom_Object_Iter l, const LV2_Atom_Object_Iter r)
{
	return l == r;
}

static inline LV2_Atom_Object_Iter
lv2_atom_object_iter_next(const LV2_Atom_Object_Iter iter)
{
	return (LV2_Atom_Object_Iter)(
		(uint8_t*)iter + sizeof(LV2_Atom_Property) + lv2_atom_pad_size(iter->object.size));
}

static inline LV2_Atom_Property*
lv2_atom_object_iter_get(LV2_Atom_Object_Iter iter)
{
	return (LV2_Atom_Property*)iter;
}

/** Append a Property body to an Atom that contains properties (e.g. atom:Object).
 * This function will write the property body (not including an LV2_Object
 * header) at lv2_atom_pad_size(body + size).  Thus, it can be used with any
 * Atom type that contains headerless 32-bit aligned properties.
 * @param object Pointer to the atom that contains the property to add.  object.size
 *        must be valid, but object.type is ignored.
 * @param size Must point to the size field of the container atom, and will be
 *        padded up to 32 bits then increased by @a value_size.
 * @param body Must point to the body of the container atom.
 * @return a pointer to the new LV2_Atom_Property in @a body.
 */
static inline LV2_Atom_Property*
lv2_atom_append_property(LV2_Atom*   object,
                         uint32_t    key,
                         uint16_t    value_type,
                         uint16_t    value_size,
                         const char* value_body)
{
	object->size = lv2_atom_pad_size(object->size);
	LV2_Atom_Property* prop = (LV2_Atom_Property*)(object->body + object->size);
	prop->predicate = key;
	prop->object.type = value_type;
	prop->object.size = value_size;
	memcpy(prop->object.body, value_body, value_size);
	object->size += sizeof(uint32_t) + sizeof(LV2_Atom_Property) + value_size;
	return prop;
}

static inline bool
lv2_atom_is_null(LV2_Atom* atom)
{
	return !atom || (atom->type == 0 && atom->size == 0);
}

static inline bool
lv2_atom_is_a(LV2_Atom* object,
              uint32_t  rdf_type,
              uint32_t  atom_URIInt,
              uint32_t  atom_Object,
              uint32_t  type)
{
	if (lv2_atom_is_null(object)) {
		printf("is-a null\n");
		return false;
	}
	
	if (object->type == type) {
		printf("is-a exact type\n");
		return true;
	}

	printf("is-a rdf-type: %d int: %d object: %d type: %d\n", rdf_type, atom_URIInt, atom_Object, type);
	
	if (object->type == atom_Object) {
		for (LV2_Atom_Object_Iter i = lv2_atom_object_get_iter((LV2_Atom_Property*)object->body);
		     !lv2_atom_object_iter_is_end(object, i);
		     i = lv2_atom_object_iter_next(i)) {
			LV2_Atom_Property* prop = lv2_atom_object_iter_get(i);
			printf("is-a prop %d\n", prop->predicate);
			if (prop->predicate == rdf_type) {
				printf("is-a rdf:type [ type: %u size: %u ]\n", prop->object.type, prop->object.size);
				if (prop->object.type == atom_URIInt) {
					const uint32_t object_type = *(uint32_t*)prop->object.body;
					printf("rdf:type is-a URIInt type: %u\n", object_type);
					if (object_type == type)
						return true;
				} else {
					fprintf(stderr, "error: rdf:type is not a URIInt\n");
				}

			}
		}
	}

	return false;
}
	
#endif /* LV2_ATOM_HELPERS_H */