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RIOT/core/lifo.c 1.35 KB
a752c7ab   elopes   add first test an...
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  /*
   * Copyright (C) 2013 Freie Universitรคt Berlin
   *
   * This file is subject to the terms and conditions of the GNU Lesser
   * General Public License v2.1. See the file LICENSE in the top level
   * directory for more details.
   */
  
  /**
   * @ingroup     core_util
   * @{
   * @file
   * @brief       LIFO buffer implementation
   *
   * @author      Heiko Will <hwill@inf.fu-berlin.de>
   * @}
   */
  
  #include "lifo.h"
  #include "log.h"
  
  #define ENABLE_DEBUG (0)
  #include "debug.h"
  
  int lifo_empty(int *array)
  {
      return array[0] == -1;
  }
  
  void lifo_init(int *array, int n)
  {
      DEBUG("lifo_init(%i)\n", n);
      for (int i = 0; i <= n; i++) {
          array[i] = -1;
      }
  }
  
  void lifo_insert(int *array, int i)
  {
      DEBUG("lifo_insert(%i)\n", i);
  
      int index = i + 1;
  
  #ifdef DEVELHELP
      if ((array[index] != -1) && (array[0] != -1)) {
          LOG_WARNING("lifo_insert: overwriting array[%i] == %i with %i\n\n\n\t\tThe lifo is broken now.\n\n\n", index, array[index], array[0]);
      }
  #endif
  
      array[index] = array[0];
      array[0] = i;
  }
  
  int lifo_get(int *array)
  {
      DEBUG("lifo_get\n");
      int head = array[0];
  
      if (head != -1) {
          array[0] = array[head + 1];
      }
  
  #ifdef DEVELHELP
      /* make sure a double insert does not result in an infinite
       * resource of values */
      array[head+1] = -1;
  #endif
  
      DEBUG("lifo_get: returning %i\n", head);
      return head;
  }