/**
 * @file transform_substructure.h
 * 
 * @brief Declaration of the class transform_substructure_t. 
 * 
 * An object of this type represents an IKEv2 TRANSFORM Substructure and contains Attributes.
 * 
 */

/*
 * Copyright (C) 2005 Jan Hutter, Martin Willi
 * Hochschule fuer Technik Rapperswil
 *
 * 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 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * 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.
 */
 
 /* offsetof macro */
#include <stddef.h>

#include "transform_substructure.h"

#include "transform_attribute.h"
#include "encodings.h"
#include "../types.h"
#include "../utils/allocator.h"
#include "../utils/linked_list.h"

/**
 * Private data of an transform_substructure_t' Object
 * 
 */
typedef struct private_transform_substructure_s private_transform_substructure_t;

struct private_transform_substructure_s {
	/**
	 * public transform_substructure_t interface
	 */
	transform_substructure_t public;
	
	/**
	 * next payload type
	 */
	u_int8_t  next_payload;

	
	/**
	 * Length of this payload
	 */
	u_int16_t transform_length;
	
	
	/**
	 * Type of the transform
	 */
	u_int8_t	 transform_type;
	
	/**
	 * Transform ID
	 */
	u_int8_t transform_id;
	
 	/**
 	 * Transforms Attributes are stored in a linked_list_t
 	 */
	linked_list_t * attributes;
};


/**
 * Encoding rules to parse or generate a Transform substructure
 * 
 * The defined offsets are the positions in a object of type 
 * private_transform_substructure_t.
 * 
 */
encoding_rule_t transform_substructure_encodings[] = {
 	/* 1 Byte next payload type, stored in the field next_payload */
	{ U_INT_8,			offsetof(private_transform_substructure_t, next_payload) 		},
	/* Reserved Byte is skipped */
	{ RESERVED_BYTE,		0																},	
	/* Length of the whole transform substructure*/
	{ PAYLOAD_LENGTH,		offsetof(private_transform_substructure_t, transform_length)	},	
	/* transform type is a number of 8 bit */
	{ U_INT_8,				offsetof(private_transform_substructure_t, transform_type) 	},	
	/* Reserved Byte is skipped */
	{ RESERVED_BYTE,		0																},	
	/* tranform ID is a number of 8 bit */
	{ U_INT_8,				offsetof(private_transform_substructure_t, transform_id)		},	
	/* Attributes are stored in a transform attribute, 
	   offset points to a linked_list_t pointer */
	{ TRANSFORM_ATTRIBUTES,	offsetof(private_transform_substructure_t, attributes) 		}
};

/**
 * Implements payload_t's and transform_substructure_t's destroy function.
 * See #payload_s.destroy or transform_substructure_s.destroy for description.
 */
static status_t destroy(private_transform_substructure_t *this)
{
	/* all proposals are getting destroyed */ 
	while (this->attributes->get_count(this->attributes) > 0)
	{
		transform_attribute_t *current_attribute;
		if (this->attributes->remove_last(this->attributes,(void **)&current_attribute) != SUCCESS)
		{
			break;
		}
		current_attribute->destroy(current_attribute);
	}
	this->attributes->destroy(this->attributes);
	
	allocator_free(this);
	
	return SUCCESS;
}

/**
 * Implements payload_t's get_encoding_rules function.
 * See #payload_s.get_encoding_rules for description.
 */
static status_t get_encoding_rules(private_transform_substructure_t *this, encoding_rule_t **rules, size_t *rule_count)
{
	*rules = transform_substructure_encodings;
	*rule_count = sizeof(transform_substructure_encodings) / sizeof(encoding_rule_t);
	
	return SUCCESS;
}

/**
 * Implements payload_t's get_type function.
 * See #payload_s.get_type for description.
 */
static payload_type_t get_type(private_transform_substructure_t *this)
{
	return TRANSFORM_SUBSTRUCTURE;
}

/**
 * Implements payload_t's get_next_type function.
 * See #payload_s.get_next_type for description.
 */
static payload_type_t get_next_type(private_transform_substructure_t *this)
{
	return (this->next_payload);
}

/**
 * Implements payload_t's get_length function.
 * See #payload_s.get_length for description.
 */
static size_t get_length(private_transform_substructure_t *this)
{
	return this->transform_length;
}

/**
 * Implements transform_substructure_t's create_transform_attribute_iterator function.
 * See #transform_substructure_s.create_transform_attribute_iterator for description.
 */
static status_t create_transform_attribute_iterator (private_transform_substructure_t *this,linked_list_iterator_t **iterator,bool forward)
{
	return (this->attributes->create_iterator(this->attributes,iterator,forward));
}

/**
 * Implements transform_substructure_t's add_transform_attribute function.
 * See #transform_substructure_s.add_transform_attribute for description.
 */
static status_t add_transform_attribute (private_transform_substructure_t *this,transform_attribute_t *attribute)
{
	return (this->attributes->insert_last(this->attributes,(void *) attribute));
}


/*
 * Described in header
 */
transform_substructure_t *transform_substructure_create()
{
	private_transform_substructure_t *this = allocator_alloc_thing(private_transform_substructure_t);
	if (this == NULL)
	{
		return NULL;	
	}	
	
	this->public.payload_interface.get_encoding_rules = (status_t (*) (payload_t *, encoding_rule_t **, size_t *) ) get_encoding_rules;
	this->public.payload_interface.get_length = (size_t (*) (payload_t *)) get_length;
	this->public.payload_interface.get_next_type = (payload_type_t (*) (payload_t *)) get_next_type;
	this->public.payload_interface.get_type = (payload_type_t (*) (payload_t *)) get_type;
	this->public.payload_interface.destroy = (status_t (*) (payload_t *))destroy;
	this->public.create_transform_attribute_iterator = (status_t (*) (transform_substructure_t *,linked_list_iterator_t **,bool)) create_transform_attribute_iterator;
	this->public.add_transform_attribute = (status_t (*) (transform_substructure_t *,transform_attribute_t *)) add_transform_attribute;
	this->public.destroy = (status_t (*) (transform_substructure_t *)) destroy;
	
	/* set default values of the fields */
	this->next_payload = NO_PAYLOAD;
	this->transform_length = 0;
	this->transform_id = 0;
	this->transform_type = 0;

	this->attributes = linked_list_create();
	
	if (this->attributes == NULL)
	{
		allocator_free(this);
		return NULL;
	}
	return (&(this->public));
}