gdbsupport/next-iterator.h

   1 /* A "next" iterator for GDB, the GNU debugger.
   2    Copyright (C) 2019-2023 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef COMMON_NEXT_ITERATOR_H
  20 #define COMMON_NEXT_ITERATOR_H
  21
  22 #include "gdbsupport/iterator-range.h"
  23
  24 /* An iterator that uses the 'next' field of a type to iterate.  This
  25    can be used with various GDB types that are stored as linked
  26    lists.  */
  27
  28 template<typename T>
  29 struct next_iterator
  30 {
  31   typedef next_iterator self_type;
  32   typedef T *value_type;
  33   typedef T *&reference;
  34   typedef T **pointer;
  35   typedef std::forward_iterator_tag iterator_category;
  36   typedef int difference_type;
  37
  38   explicit next_iterator (T *item)
  39     : m_item (item)
  40   {
  41   }
  42
  43   /* Create a one-past-the-end iterator.  */
  44   next_iterator ()
  45     : m_item (nullptr)
  46   {
  47   }
  48
  49   value_type operator* () const
  50   {
  51     return m_item;
  52   }
  53
  54   bool operator== (const self_type &other) const
  55   {
  56     return m_item == other.m_item;
  57   }
  58
  59   bool operator!= (const self_type &other) const
  60   {
  61     return m_item != other.m_item;
  62   }
  63
  64   self_type &operator++ ()
  65   {
  66     m_item = m_item->next;
  67     return *this;
  68   }
  69
  70 private:
  71
  72   T *m_item;
  73 };
  74
  75 /* A convenience wrapper to make a range type around a next_iterator.  */
  76
  77 template <typename T>
  78 using next_range = iterator_range<next_iterator<T>>;
  79
  80 #endif /* COMMON_NEXT_ITERATOR_H */