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div.hpp

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00001 /* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
00002 /*
00003  *  Main authors:
00004  *     Christian Schulte <schulte@gecode.org>
00005  *
00006  *  Copyright:
00007  *     Christian Schulte, 2013
00008  *
00009  *  This file is part of Gecode, the generic constraint
00010  *  development environment:
00011  *     http://www.gecode.org
00012  *
00013  *  Permission is hereby granted, free of charge, to any person obtaining
00014  *  a copy of this software and associated documentation files (the
00015  *  "Software"), to deal in the Software without restriction, including
00016  *  without limitation the rights to use, copy, modify, merge, publish,
00017  *  distribute, sublicense, and/or sell copies of the Software, and to
00018  *  permit persons to whom the Software is furnished to do so, subject to
00019  *  the following conditions:
00020  *
00021  *  The above copyright notice and this permission notice shall be
00022  *  included in all copies or substantial portions of the Software.
00023  *
00024  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
00025  *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
00026  *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00027  *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
00028  *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
00029  *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
00030  *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00031  *
00032  */
00033 
00034 namespace Gecode { namespace Int {
00035 
00036   template<class IntType>
00037   forceinline IntType
00038   ceil_div_pp(IntType x, IntType y) {
00039     assert((x >= 0) && (y >= 0));
00040     /*
00041      * This is smarter than it looks: for many cpus, % and / are
00042      * implemented by the same instruction and an optimizing compiler
00043      * will generate the instruction only once.
00044      */
00045     return ((x % y) == 0) ? x/y : (x/y + 1);
00046   }
00047   template<class IntType>
00048   forceinline IntType
00049   floor_div_pp(IntType x, IntType y) {
00050     assert((x >= 0) && (y >= 0));
00051     return x / y;
00052   }
00053 
00054   template<class IntType>
00055   forceinline IntType
00056   ceil_div_px(IntType x, IntType y) {
00057     assert(x >= 0);
00058     return (y >= 0) ? ceil_div_pp(x,y) : -floor_div_pp(x,-y);
00059   }
00060   template<class IntType>
00061   forceinline IntType
00062   floor_div_px(IntType x, IntType y) {
00063     assert(x >= 0);
00064     return (y >= 0) ? floor_div_pp(x,y) : -ceil_div_pp(x,-y);
00065   }
00066 
00067   template<class IntType>
00068   forceinline IntType
00069   ceil_div_xp(IntType x, IntType y) {
00070     assert(y >= 0);
00071     return (x >= 0) ? ceil_div_pp(x,y) : -floor_div_pp(-x,y);
00072   }
00073   template<class IntType>
00074   forceinline IntType
00075   floor_div_xp(IntType x, IntType y) {
00076     assert(y >= 0);
00077     return (x >= 0) ? floor_div_pp(x,y) : -ceil_div_pp(-x,y);
00078   }
00079 
00080   template<class IntType>
00081   forceinline IntType
00082   ceil_div_xx(IntType x, IntType y) {
00083     return (x >= 0) ? ceil_div_px(x,y) : -floor_div_px(-x,y);
00084   }
00085   template<class IntType>
00086   forceinline IntType
00087   floor_div_xx(IntType x, IntType y) {
00088     return (x >= 0) ? floor_div_px(x,y) : -ceil_div_px(-x,y);
00089   }
00090 
00091 }}
00092 
00093 // STATISTICS: int-prop
00094