# cmd_helper.h

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    00001 /* $Id: cmd_helper.h 19665 2010-04-17 22:27:49Z rubidium $ */
    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
    00017 template<typename T, uint S, uint N, typename U> static inline T Extract(U v)
    00018 {
    00019   /* Check if there are enough bits in v */
    00020   assert_tcompile(N == EnumPropsT<T>::num_bits);
    00021   assert_tcompile(S + N <= sizeof(U) * 8);
    00022   assert_tcompile(EnumPropsT<T>::end <= (1 << N));
    00023   U masked = GB(v, S, N);
    00024   return IsInsideMM(masked, EnumPropsT<T>::begin, EnumPropsT<T>::end) ? (T)masked : EnumPropsT<T>::invalid;
    00025 }
    00026
    00027 #endif