text: /*
   * BSD 2-Clause License
   *
   * Copyright (c) 2019, Andrea Giacomo Baldan All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   * * Redistributions of source code must retain the above copyright notice,
   * this list of conditions and the following disclaimer.
   *
   * * 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.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER 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.
   */
  
  #ifndef ITERATOR_H
  #define ITERATOR_H
  
  /*
   * Generic iterator strucuture, have the following fields
   * - unsigned long index: The index of the last visited item in the iterable
   * - void *ptr: The pointer to the current visited item
   * - void *iterable: The iterable data structure to iterate on
   * - void (*next)(struct iterator *): Function pointer used to update the ptr
   *   value, it has to be defined for each different data structure
   */
  struct iterator {
      unsigned long index;
      void *ptr;
      void *iterable;
      void (*next)(struct iterator *);
  };
  
  struct iterator *iter_new(void *, void (*next)(struct iterator *));
  struct iterator *iter_next(struct iterator *);
  void iter_destroy(struct iterator *);
  
  #endif
  