cmd_helper.h

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00001 /* $Id$ */
00002 
00003 /*
00004  * This file is part of OpenTTD.
00005  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
00006  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
00007  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
00008  */
00009 
00012 #ifndef CMD_HELPER_H
00013 #define CMD_HELPER_H
00014 
00015 #include "core/enum_type.hpp"
00016 #include "core/bitmath_func.hpp"
00017 
00026 template<typename T, uint S, uint N, typename U> static inline T Extract(U v)
00027 {
00028   /* Check if there are enough bits in v */
00029   assert_tcompile(N == EnumPropsT<T>::num_bits);
00030   assert_tcompile(S + N <= sizeof(U) * 8);
00031   assert_tcompile(EnumPropsT<T>::end <= (1 << N));
00032   U masked = GB(v, S, N);
00033   return IsInsideMM(masked, EnumPropsT<T>::begin, EnumPropsT<T>::end) ? (T)masked : EnumPropsT<T>::invalid;
00034 }
00035 
00036 #endif /* CMD_HELPER_H */