/*
 *  Copyright (c) 2016, The OpenThread Authors.
 *  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.
 *  3. Neither the name of the copyright holder nor the
 *     names of its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  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 HOLDER 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.
 */

/**
 * @file
 * @brief
 *   This file includes the platform abstraction for true random number generation.
 */

#ifndef RANDOM_H_
#define RANDOM_H_

#include <stdint.h>

#include <openthread-types.h>

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @defgroup random Random
 * @ingroup platform
 *
 * @brief
 *   This module includes the platform abstraction to support critical sections.
 *
 * @{
 *
 */

/**
 * Get a 32-bit random value.
 *
 * @returns A 32-bit random value.
 *
 */
uint32_t otPlatRandomGet(void);

/**
 * Get true random stream.
 *
 * @param[in]   aInputLength      The expected size of random values.
 * @param[out]  aOutput           A pointer to the buffer for the generated random stream. The pointer should never be NULL.
 * @param[out]  aOutputLength     A pointer to the generated size of random stream.
 *                                It is supposed to be the same as aInputLength, but maybe less than aInputLength.
 *                                The pointer should never be NULL.
 *
 * @retval kThreadError_None         Generate random successfully.
 * @retval kThreadError_Fail         Generate random fail.
 * @retval kThreadError_InvalidArgs  Invalid args.
 */
ThreadError otPlatRandomSecureGet(uint16_t aInputLength, uint8_t *aOutput, uint16_t *aOutputLength);

/**
 * @}
 *
 */

#ifdef __cplusplus
}  // end of extern "C"
#endif

#endif  // RANDOM_H_