Osmium  0.1
include/osmium/utils/delta.hpp
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00001 #ifndef OSMIUM_UTILS_DELTA_HPP
00002 #define OSMIUM_UTILS_DELTA_HPP
00003 
00004 /*
00005 
00006 Copyright 2011 Jochen Topf <jochen@topf.org> and others (see README).
00007 
00008 This file is part of Osmium (https://github.com/joto/osmium).
00009 
00010 Osmium is free software: you can redistribute it and/or modify it under the
00011 terms of the GNU Lesser General Public License or (at your option) the GNU
00012 General Public License as published by the Free Software Foundation, either
00013 version 3 of the Licenses, or (at your option) any later version.
00014 
00015 Osmium is distributed in the hope that it will be useful, but WITHOUT ANY
00016 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
00017 PARTICULAR PURPOSE. See the GNU Lesser General Public License and the GNU
00018 General Public License for more details.
00019 
00020 You should have received a copy of the Licenses along with Osmium. If not, see
00021 <http://www.gnu.org/licenses/>.
00022 
00023 */
00024 
00025 #include <algorithm>
00026 
00027 namespace Osmium {
00028 
00034     template<typename T>
00035     class Delta {
00036 
00037     public:
00038 
00039         Delta() : m_value(0) {
00040         }
00041 
00042         void clear() {
00043             m_value = 0;
00044         }
00045 
00046         T update(T new_value) {
00047             std::swap(m_value, new_value);
00048             return m_value - new_value;
00049         }
00050 
00051     private:
00052 
00053         T m_value;
00054 
00055     };
00056 
00057 }
00058 
00059 #endif // OSMIUM_UTILS_DELTA_HPP
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