text: /**
   * Copyright (c) 2015 - 2018, 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(PEER_MANAGER)
  #include "peer_id.h"
  
  #include <stdint.h>
  #include <string.h>
  #include "sdk_errors.h"
  #include "peer_manager_types.h"
  #include "nrf_atflags.h"
  
  
  typedef struct
  {
      NRF_ATFLAGS_DEF_MEMBER(used_peer_ids,    PM_PEER_ID_N_AVAILABLE_IDS); /**< Bitmap designating which peer IDs are in use. */
      NRF_ATFLAGS_DEF_MEMBER(deleted_peer_ids, PM_PEER_ID_N_AVAILABLE_IDS); /**< Bitmap designating which peer IDs are marked for deletion. */
  } pi_t;
  
  
  static pi_t m_pi = {{0}, {0}};
  
  
  static void internal_state_reset(pi_t * p_pi)
  {
      memset(p_pi, 0, sizeof(pi_t));
  }
  
  
  void peer_id_init(void)
  {
      internal_state_reset(&m_pi);
  }
  
  
  static pm_peer_id_t claim(pm_peer_id_t peer_id, nrf_atflags_t * p_peer_id_flags)
  {
      pm_peer_id_t allocated_peer_id = PM_PEER_ID_INVALID;
      if (peer_id == PM_PEER_ID_INVALID)
      {
          allocated_peer_id = nrf_atflags_find_and_set_flag(p_peer_id_flags, PM_PEER_ID_N_AVAILABLE_IDS);
          if (allocated_peer_id == PM_PEER_ID_N_AVAILABLE_IDS)
          {
              allocated_peer_id = PM_PEER_ID_INVALID;
          }
      }
      else if (peer_id < PM_PEER_ID_N_AVAILABLE_IDS)
      {
          bool lock_success = !nrf_atflags_fetch_set(p_peer_id_flags, peer_id);
          allocated_peer_id = lock_success ? peer_id : PM_PEER_ID_INVALID;
      }
      return allocated_peer_id;
  }
  
  
  static void release(pm_peer_id_t peer_id, nrf_atflags_t * p_peer_id_flags)
  {
      if (peer_id < PM_PEER_ID_N_AVAILABLE_IDS)
      {
          nrf_atflags_clear(p_peer_id_flags, peer_id);
      }
  }
  
  
  pm_peer_id_t peer_id_allocate(pm_peer_id_t peer_id)
  {
      return claim(peer_id, m_pi.used_peer_ids);
  }
  
  
  bool peer_id_delete(pm_peer_id_t peer_id)
  {
      pm_peer_id_t deleted_peer_id;
  
      if (peer_id == PM_PEER_ID_INVALID)
      {
          return false;
      }
  
      deleted_peer_id = claim(peer_id, m_pi.deleted_peer_ids);
  
      return (deleted_peer_id == peer_id);
  }
  
  
  void peer_id_free(pm_peer_id_t peer_id)
  {
      release(peer_id, m_pi.used_peer_ids);
      release(peer_id, m_pi.deleted_peer_ids);
  }
  
  
  bool peer_id_is_allocated(pm_peer_id_t peer_id)
  {
      if (peer_id < PM_PEER_ID_N_AVAILABLE_IDS)
      {
          return nrf_atflags_get(m_pi.used_peer_ids, peer_id);
      }
      return false;
  }
  
  
  bool peer_id_is_deleted(pm_peer_id_t peer_id)
  {
      if (peer_id < PM_PEER_ID_N_AVAILABLE_IDS)
      {
          return nrf_atflags_get(m_pi.deleted_peer_ids, peer_id);
      }
      return false;
  }
  
  
  pm_peer_id_t next_id_get(pm_peer_id_t prev_peer_id, nrf_atflags_t * p_peer_id_flags)
  {
      pm_peer_id_t i = (prev_peer_id == PM_PEER_ID_INVALID) ? 0 : (prev_peer_id + 1);
      for (; i < PM_PEER_ID_N_AVAILABLE_IDS; i++)
      {
          if (nrf_atflags_get(p_peer_id_flags, i))
          {
              return i;
          }
      }
  
      return PM_PEER_ID_INVALID;
  }
  
  
  pm_peer_id_t peer_id_get_next_used(pm_peer_id_t peer_id)
  {
      peer_id = next_id_get(peer_id, m_pi.used_peer_ids);
  
      while (peer_id != PM_PEER_ID_INVALID)
      {
          if (!peer_id_is_deleted(peer_id))
          {
              return peer_id;
          }
  
          peer_id = next_id_get(peer_id, m_pi.used_peer_ids);
      }
  
      return peer_id;
  }
  
  
  pm_peer_id_t peer_id_get_next_deleted(pm_peer_id_t prev_peer_id)
  {
      return next_id_get(prev_peer_id, m_pi.deleted_peer_ids);
  }
  
  
  uint32_t peer_id_n_ids(void)
  {
      uint32_t n_ids = 0;
  
      for (pm_peer_id_t i = 0; i < PM_PEER_ID_N_AVAILABLE_IDS; i++)
      {
          n_ids += nrf_atflags_get(m_pi.used_peer_ids, i);
      }
  
      return n_ids;
  }
  #endif // NRF_MODULE_ENABLED(PEER_MANAGER)
  