// [License] // The Ariba-Underlay Copyright // // Copyright (c) 2008-2009, Institute of Telematics, Universität Karlsruhe (TH) // // Institute of Telematics // Universität Karlsruhe (TH) // Zirkel 2, 76128 Karlsruhe // Germany // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // 1. Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // 2. 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 INSTITUTE OF TELEMATICS ``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 INSTITUTE OF TELEMATICS 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. // // The views and conclusions contained in the software and documentation // are those of the authors and should not be interpreted as representing // official policies, either expressed or implied, of the Institute of // Telematics. // [License] #ifndef DISTANCES_HPP_ #define DISTANCES_HPP_ /** * TODO: Doc * * @author Sebastian Mies */ namespace distances { /// returns the maximum value of a type template T max_value() { return ~(T)0; } /// returns the maximum value of a type template T min_value() { return 0; } /// euclidean distance between two points (metric) struct default_distance { template T operator ()(const T& x, const T& y) { return abs(x - y); } }; /// xor distance (metric) struct xor_distance { template T operator()(const T& x, const T& y) { return x ^ y; } }; /// distance between two points on a ring (metric) struct ring_distance { template T operator()(const T& x, const T& y) { const T m = max_value(); T d_nor = (x >= y) ? (x-y) : (y-x); T d_inv = m - d_nor; return d_nor < d_inv ? d_nor : d_inv; } }; /// distance from x to a predecessor y on a ring (not a metric!) struct ring_pred_distance { template T operator ()(const T& x, const T& y) { const T m = max_value(); if (x >= y) return x - y; else return m - y + x; } }; /// distance from x to a successor y on a ring (not a metric!) struct ring_succ_distance { template T operator ()(const T& y, const T& x) { const T m = max_value(); if (x >= y) return x - y; else return m - y + x; } }; } #endif /* DISTANCES_HPP_ */