wibble 0.1.28
empty.h
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00001 // -*- C++ -*-
00002 #ifndef WIBBLE_EMPTY_H
00003 #define WIBBLE_EMPTY_H
00004 
00005 /*
00006  * Degenerated container to hold a single value
00007  *
00008  * Copyright (C) 2006  Enrico Zini <enrico@debian.org>
00009  *
00010  * This library is free software; you can redistribute it and/or
00011  * modify it under the terms of the GNU Lesser General Public
00012  * License as published by the Free Software Foundation; either
00013  * version 2.1 of the License, or (at your option) any later version.
00014  *
00015  * This library is distributed in the hope that it will be useful,
00016  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00017  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00018  * Lesser General Public License for more details.
00019  *
00020  * You should have received a copy of the GNU Lesser General Public
00021  * License along with this library; if not, write to the Free Software
00022  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
00023  */
00024 
00025 #include <cstddef>
00026 #include <iterator>
00027 
00028 namespace wibble {
00029 
00030 template<typename T>
00031 class Empty
00032 {
00033 public:
00034     typedef T value_type;
00035 
00036     class const_iterator : public std::iterator<std::forward_iterator_tag, const T, void, const T*, const T&>
00037     {
00038     public:
00039         const T& operator*() const { return *(T*)0; }
00040         const T* operator->() const { return 0; }
00041         const_iterator& operator++() { return *this; }
00042         bool operator==(const const_iterator&) const { return true; }
00043         bool operator!=(const const_iterator&) const { return false; }
00044     };
00045 
00046     class iterator : public std::iterator<std::forward_iterator_tag, T, void, T*, T&>
00047     {
00048     public:
00049         T& operator*() const { return *(T*)0; }
00050         T* operator->() const { return 0; }
00051         iterator& operator++() { return *this; }
00052         bool operator==(const iterator&) const { return true; }
00053         bool operator!=(const iterator&) const { return false; }
00054     };
00055 
00056     bool empty() const { return true; }
00057     size_t size() const { return 0; }
00058 
00059     iterator begin() { return iterator(); }
00060     iterator end() { return iterator(); }
00061     const_iterator begin() const { return const_iterator(); }
00062     const_iterator end() const { return const_iterator(); }
00063 };
00064 
00065 }
00066 
00067 // vim:set ts=4 sw=4:
00068 #endif