text: /**
   * Copyright (c) 2013 - 2020, Nordic Semiconductor ASA
   *
   * 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, except as embedded into a Nordic
   *    Semiconductor ASA integrated circuit in a product or a software update for
   *    such product, 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.
   *
   * 4. This software, with or without modification, must only be used with a
   *    Nordic Semiconductor ASA integrated circuit.
   *
   * 5. Any software provided in binary form under this license must not be reverse
   *    engineered, decompiled, modified and/or disassembled.
   *
   * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
   * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA 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.
   *
   */
  #include "sdk_common.h"
  #if NRF_MODULE_ENABLED(APP_FIFO)
  #include "app_fifo.h"
  
  static __INLINE uint32_t fifo_length(app_fifo_t * p_fifo)
  {
      uint32_t tmp = p_fifo->read_pos;
      return p_fifo->write_pos - tmp;
  }
  
  
  #define FIFO_LENGTH() fifo_length(p_fifo)  /**< Macro for calculating the FIFO length. */
  
  
  /**@brief Put one byte to the FIFO. */
  static __INLINE void fifo_put(app_fifo_t * p_fifo, uint8_t byte)
  {
      p_fifo->p_buf[p_fifo->write_pos & p_fifo->buf_size_mask] = byte;
      p_fifo->write_pos++;
  }
  
  
  /**@brief Look at one byte in the FIFO. */
  static __INLINE void fifo_peek(app_fifo_t * p_fifo, uint16_t index, uint8_t * p_byte)
  {
      *p_byte = p_fifo->p_buf[(p_fifo->read_pos + index) & p_fifo->buf_size_mask];
  }
  
  
  /**@brief Get one byte from the FIFO. */
  static __INLINE void fifo_get(app_fifo_t * p_fifo, uint8_t * p_byte)
  {
      fifo_peek(p_fifo, 0, p_byte);
      p_fifo->read_pos++;
  }
  
  
  uint32_t app_fifo_init(app_fifo_t * p_fifo, uint8_t * p_buf, uint16_t buf_size)
  {
      // Check buffer for null pointer.
      if (p_buf == NULL)
      {
          return NRF_ERROR_NULL;
      }
  
      // Check that the buffer size is a power of two.
      if (!IS_POWER_OF_TWO(buf_size))
      {
          return NRF_ERROR_INVALID_LENGTH;
      }
  
      p_fifo->p_buf         = p_buf;
      p_fifo->buf_size_mask = buf_size - 1;
      p_fifo->read_pos      = 0;
      p_fifo->write_pos     = 0;
  
      return NRF_SUCCESS;
  }
  
  
  uint32_t app_fifo_put(app_fifo_t * p_fifo, uint8_t byte)
  {
      if (FIFO_LENGTH() <= p_fifo->buf_size_mask)
      {
          fifo_put(p_fifo, byte);
          return NRF_SUCCESS;
      }
  
      return NRF_ERROR_NO_MEM;
  }
  
  
  uint32_t app_fifo_get(app_fifo_t * p_fifo, uint8_t * p_byte)
  {
      if (FIFO_LENGTH() != 0)
      {
          fifo_get(p_fifo, p_byte);
          return NRF_SUCCESS;
      }
  
      return NRF_ERROR_NOT_FOUND;
  
  }
  
  
  uint32_t app_fifo_peek(app_fifo_t * p_fifo, uint16_t index, uint8_t * p_byte)
  {
      if (FIFO_LENGTH() > index)
      {
          fifo_peek(p_fifo, index, p_byte);
          return NRF_SUCCESS;
      }
  
      return NRF_ERROR_NOT_FOUND;
  }
  
  
  uint32_t app_fifo_flush(app_fifo_t * p_fifo)
  {
      p_fifo->read_pos = p_fifo->write_pos;
      return NRF_SUCCESS;
  }
  
  
  uint32_t app_fifo_read(app_fifo_t * p_fifo, uint8_t * p_byte_array, uint32_t * p_size)
  {
      VERIFY_PARAM_NOT_NULL(p_fifo);
      VERIFY_PARAM_NOT_NULL(p_size);
  
      const uint32_t byte_count    = fifo_length(p_fifo);
      const uint32_t requested_len = (*p_size);
      uint32_t       index         = 0;
      uint32_t       read_size     = MIN(requested_len, byte_count);
  
      (*p_size) = byte_count;
  
      // Check if the FIFO is empty.
      if (byte_count == 0)
      {
          return NRF_ERROR_NOT_FOUND;
      }
  
      // Check if application has requested only the size.
      if (p_byte_array == NULL)
      {
          return NRF_SUCCESS;
      }
  
      // Fetch bytes from the FIFO.
      while (index < read_size)
      {
          fifo_get(p_fifo, &p_byte_array[index++]);
      }
  
      (*p_size) = read_size;
  
      return NRF_SUCCESS;
  }
  
  
  uint32_t app_fifo_write(app_fifo_t * p_fifo, uint8_t const * p_byte_array, uint32_t * p_size)
  {
      VERIFY_PARAM_NOT_NULL(p_fifo);
      VERIFY_PARAM_NOT_NULL(p_size);
  
      const uint32_t available_count = p_fifo->buf_size_mask - fifo_length(p_fifo) + 1;
      const uint32_t requested_len   = (*p_size);
      uint32_t       index           = 0;
      uint32_t       write_size      = MIN(requested_len, available_count);
  
      (*p_size) = available_count;
  
      // Check if the FIFO is FULL.
      if (available_count == 0)
      {
          return NRF_ERROR_NO_MEM;
      }
  
      // Check if application has requested only the size.
      if (p_byte_array == NULL)
      {
          return NRF_SUCCESS;
      }
  
      //Fetch bytes from the FIFO.
      while (index < write_size)
      {
          fifo_put(p_fifo, p_byte_array[index++]);
      }
  
      (*p_size) = write_size;
  
      return NRF_SUCCESS;
  }
  #endif //NRF_MODULE_ENABLED(APP_FIFO)
  