/**
 * @file prf_plus.h
 * 
 * @brief Implements the prf+ function described in IKEv2 draft.
 * 
 */

/*
 * 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.
 */

#ifndef PRF_PLUS_H_
#define PRF_PLUS_H_


#include <transforms/prfs/prf.h>


/**
 * Object representing a prf_plus
 */
typedef struct prf_plus_s prf_plus_t;

struct prf_plus_s {
	/**
	 * @brief Get pseudo random bytes.
	 * 
	 * @param this			calling prf_plus
	 * @param length		number of bytes to get
	 * @param [out]buffer	pointer where the generated bytes will be written
	 * @return				
	 * 						- SUCCESS in any case
	 */
	status_t (*get_bytes) (prf_plus_t *this, size_t length, u_int8_t *buffer);
	
	/**
	 * @brief Allocate pseudo random bytes.
	 * 
	 * @param this			calling prf_plus
	 * @param length		number of bytes to get
	 * @param [out]chunk	chunk which will hold generated bytes
	 * @return				
	 * 						- SUCCESS in any case
	 * 						- OUT_OF_RES if space could not be allocated
	 */
	status_t (*allocate_bytes) (prf_plus_t *this, size_t length, chunk_t *chunk);
	
	/**
	 * @brief Destroys a prf_plus object.
	 *
	 * @param this 			prf_plus_t object to destroy
	 * @return 		
	 * 						- SUCCESS in any case
	 */
	status_t (*destroy) (prf_plus_t *this);
};

/**
 * Creates a new prf_plus_t object
 * 
 * Seed will be cloned. prf will
 * not be cloned, must be destroyed outside after
 * prf_plus usage.
 * 
 * @param prf				prf object to use
 * @param seed				input seed for prf
 * @return
 *							- prf_plus_t if successfully
 *							- NULL if out of ressources or hash not supported
 */
prf_plus_t *prf_plus_create(prf_t *prf, chunk_t seed);

#endif /*PRF_PLUS_H_*/