text: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *  http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  #include <stddef.h>
  
  #include "fcb/fcb.h"
  #include "fcb_priv.h"
  
  static struct flash_area *
  fcb_new_area(struct fcb *fcb, int cnt)
  {
      struct flash_area *fa;
      struct flash_area *rfa;
      int i;
  
      rfa = NULL;
      i = 0;
      fa = fcb->f_active.fe_area;
      do {
          fa = fcb_getnext_area(fcb, fa);
          if (!rfa) {
              rfa = fa;
          }
          if (fa == fcb->f_oldest) {
              return NULL;
          }
      } while (i++ < cnt);
      return rfa;
  }
  
  /*
   * Take one of the scratch blocks into use, if at all possible.
   */
  int
  fcb_append_to_scratch(struct fcb *fcb)
  {
      struct flash_area *fa;
      int rc;
  
      fa = fcb_new_area(fcb, 0);
      if (!fa) {
          return FCB_ERR_NOSPACE;
      }
      rc = fcb_sector_hdr_init(fcb, fa, fcb->f_active_id + 1);
      if (rc) {
          return rc;
      }
      fcb->f_active.fe_area = fa;
      fcb->f_active.fe_elem_off = sizeof(struct fcb_disk_area);
      fcb->f_active_id++;
      return FCB_OK;
  }
  
  int
  fcb_append(struct fcb *fcb, uint16_t len, struct fcb_entry *append_loc)
  {
      struct fcb_entry *active;
      struct flash_area *fa;
      uint8_t tmp_str[2];
      int cnt;
      int rc;
  
      cnt = fcb_put_len(tmp_str, len);
      if (cnt < 0) {
          return cnt;
      }
      cnt = fcb_len_in_flash(fcb, cnt);
      len = fcb_len_in_flash(fcb, len) + fcb_len_in_flash(fcb, FCB_CRC_SZ);
  
      rc = os_mutex_pend(&fcb->f_mtx, OS_WAIT_FOREVER);
      if (rc && rc != OS_NOT_STARTED) {
          return FCB_ERR_ARGS;
      }
      active = &fcb->f_active;
      if (active->fe_elem_off + len + cnt > active->fe_area->fa_size) {
          fa = fcb_new_area(fcb, fcb->f_scratch_cnt);
          if (!fa || (fa->fa_size <
              sizeof(struct fcb_disk_area) + len + cnt)) {
              rc = FCB_ERR_NOSPACE;
              goto err;
          }
          rc = fcb_sector_hdr_init(fcb, fa, fcb->f_active_id + 1);
          if (rc) {
              goto err;
          }
          fcb->f_active.fe_area = fa;
          fcb->f_active.fe_elem_off = sizeof(struct fcb_disk_area);
          fcb->f_active_id++;
      }
  
      rc = flash_area_write(active->fe_area, active->fe_elem_off, tmp_str, cnt);
      if (rc) {
          rc = FCB_ERR_FLASH;
          goto err;
      }
      append_loc->fe_area = active->fe_area;
      append_loc->fe_elem_off = active->fe_elem_off;
      append_loc->fe_data_off = active->fe_elem_off + cnt;
  
      active->fe_elem_off = append_loc->fe_data_off + len;
      active->fe_data_off = append_loc->fe_data_off;
  
      os_mutex_release(&fcb->f_mtx);
  
      return FCB_OK;
  err:
      os_mutex_release(&fcb->f_mtx);
      return rc;
  }
  
  int
  fcb_append_finish(struct fcb *fcb, struct fcb_entry *loc)
  {
      int rc;
      uint8_t crc8;
      uint32_t off;
  
      rc = fcb_elem_crc8(fcb, loc, &crc8);
      if (rc) {
          return rc;
      }
      off = loc->fe_data_off + fcb_len_in_flash(fcb, loc->fe_data_len);
  
      rc = flash_area_write(loc->fe_area, off, &crc8, sizeof(crc8));
      if (rc) {
          return FCB_ERR_FLASH;
      }
      return 0;
  }
  