text: /* Copyright (c) 2010 - 2017, Nordic Semiconductor ASA All rights reserved.
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   * Redistribution and use in source and binary forms, with or without
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   * 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 Nordic Semiconductor ASA 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
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  #ifndef NRF_DRV_RNG_H__
  #define NRF_DRV_RNG_H__
  
  #include <stdbool.h>
  #include <stdint.h>
  
  #include "nrf_rng.h"
  #include "sdk_errors.h"
  #include "nrf_drv_config.h"
  
  /**
   * @addtogroup nrf_rng RNG HAL and driver
   * @ingroup nrf_drivers
   * @brief Random number generator (RNG) APIs.
   * @details The RNG HAL provides basic APIs for accessing the registers of the random number generator. 
   * The RNG driver provides APIs on a higher level.
   *
   * @defgroup nrf_drv_rng RNG driver
   * @{
   * @ingroup nrf_rng
   * @brief Driver for managing the random number generator (RNG).
   */
  
  /**@brief Struct for RNG configuration. */
  typedef struct
  {
      bool     error_correction;      /**< Error correction flag. */
      uint8_t  interrupt_priority;    /**< interrupt priority */
  } nrf_drv_rng_config_t;
  
  /**@brief RNG default configuration. */
  #define NRF_DRV_RNG_DEFAULT_CONFIG                                                    \
      {                                                                                 \
          .error_correction   = RNG_CONFIG_ERROR_CORRECTION,                            \
          .interrupt_priority = RNG_CONFIG_IRQ_PRIORITY,                                \
      }
  
  /**
   * @brief Function for initializing the nrf_drv_rng module.
   *
   * @param[in]  p_config                   Initial configuration. Default configuration used if NULL.
   *
   * @retval  NRF_SUCCESS                       Driver was successfully initialized.
   * @retval  NRF_ERROR_INVALID_STATE           Driver was already initialized.
   * @retval  NRF_ERROR_INVALID_LENGTH          Pool size have to be a power of 2.
   * @retval  NRF_ERROR_SOFTDEVICE_NOT_ENABLED  SoftDevice is present, but not enabled.
   */
  ret_code_t nrf_drv_rng_init(nrf_drv_rng_config_t const * p_config);
  
  /**
   * @brief Function for uninitializing the nrf_drv_rng module.
   */
  void nrf_drv_rng_uninit(void);
  
  /**
   * @brief Function for getting the number of currently available random bytes.
   *
   * @param[out] p_bytes_available                    The number of bytes currently available in the pool.
   *
   * @retval     NRF_SUCCESS                          If the number of available random bytes was written to p_bytes_available.
   */
  ret_code_t nrf_drv_rng_bytes_available(uint8_t * p_bytes_available);
  
  /**
   * @brief Function for querying the capacity of the application random pool.
   *
   * @param[out] p_pool_capacity                      The capacity of the pool.
   *
   * @retval     NRF_SUCCESS                          If the capacity of the pool was written to p_pool_capacity.
   */
  ret_code_t nrf_drv_rng_pool_capacity(uint8_t * p_pool_capacity);
  
  /**
   * @brief Function for getting the vector of random numbers.
   *
   * @param[out] p_buff                               Pointer to uint8_t buffer for storing the bytes.
   * @param[in]  length                               Number of bytes to take from the pool and place in p_buff.
   *
   * @retval     NRF_SUCCESS                          If the requested bytes were written to p_buff.
   * @retval     NRF_ERROR_NO_MEM                     If no bytes were written to the buffer
   *                                                  because there were not enough bytes available in p_buff.
   * @retval     NRF_ERROR_SOC_RAND_NOT_ENOUGH_VALUES If no bytes were written to the buffer
   *                                                  because there were not enough bytes available in the pool.
   */
  ret_code_t nrf_drv_rng_rand(uint8_t * p_buff, uint8_t length);
  
  /**
   * @brief Blocking function for getting an arbitrary array of random numbers.
   *
   * @note This function may execute for a substantial amount of time depending on the length of the buffer
   *       required and on the state of the current internal pool of random numbers.
   *
   * @param[out] p_buff                               Pointer to uint8_t buffer for storing the bytes.
   * @param[in]  length                               Number of bytes place in p_buff.
   *
   * @retval     NRF_SUCCESS                          If the requested bytes were written to p_buff.
   */
  ret_code_t nrf_drv_rng_block_rand(uint8_t * p_buff, uint32_t length);
  
  /**
   *@}
   **/
  #endif // NRF_DRV_RNG_H__
  