gdb/unittests/int-array-iterator.h

/* An iterator class that iterates on integer arrays.

   Copyright (C) 2019-2026 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#ifndef GDB_UNITTESTS_INT_ARRAY_ITERATOR_H
#define GDB_UNITTESTS_INT_ARRAY_ITERATOR_H

#include "gdbsupport/selftest.h"

#include <iterator>

namespace selftests {

struct int_array_iterator
{
  using value_type = int;
  using reference = int &;
  using pointer = int *;
  using iterator_category = std::forward_iterator_tag;
  using difference_type = int;

  /* Create an iterator that points at the first element of an integer
     array at ARRAY of size SIZE.  */
  int_array_iterator (int *array, size_t size)
    : m_array (array), m_size (size)
  {}

  /* Create a past-the-end iterator.  */
  int_array_iterator ()
    : m_array (nullptr), m_size (0)
  {}

  bool operator== (const int_array_iterator &other) const
  {
    /* If both are past-the-end, they are equal.  */
    if (m_array == nullptr && other.m_array == nullptr)
      return true;

    /* If just one of them is past-the-end, they are not equal.  */
    if (m_array == nullptr || other.m_array == nullptr)
      return false;

    /* If they are both not past-the-end, make sure they iterate on the
       same array (we shouldn't compare iterators that iterate on different
       things).  */
    SELF_CHECK (m_array == other.m_array);

    /* They are equal if they have the same current index.  */
    return m_cur_idx == other.m_cur_idx;
  }

  bool operator!= (const int_array_iterator &other) const
  {
    return !(*this == other);
  }

  void operator++ ()
  {
    /* Make sure nothing tries to increment a past the end iterator.  */
    SELF_CHECK (m_cur_idx < m_size);

    m_cur_idx++;

    /* Mark the iterator as "past-the-end" if we have reached the end.  */
    if (m_cur_idx == m_size)
      m_array = nullptr;
  }

  int operator* () const
  {
    /* Make sure nothing tries to dereference a past the end iterator.  */
    SELF_CHECK (m_cur_idx < m_size);

    return m_array[m_cur_idx];
  }

private:
  /* A nullptr value in M_ARRAY indicates a past-the-end iterator.  */
  int *m_array;
  size_t m_size;
  size_t m_cur_idx = 0;
};

} /* namespace selftests */

#endif /* GDB_UNITTESTS_INT_ARRAY_ITERATOR_H */