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Diffstat (limited to 'src/core')
| -rw-r--r-- | src/core/enum_type.hpp | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/src/core/enum_type.hpp b/src/core/enum_type.hpp new file mode 100644 index 000000000..725d3985f --- /dev/null +++ b/src/core/enum_type.hpp @@ -0,0 +1,115 @@ +/* $Id$ */ + +/** @file enum_type.hpp Type (helpers) for enums */ + +#ifndef ENUM_TYPE_HPP +#define ENUM_TYPE_HPP + +/** Some enums need to have allowed incrementing (i.e. StationClassID) */ +#define DECLARE_POSTFIX_INCREMENT(type) \ + FORCEINLINE type operator ++(type& e, int) \ + { \ + type e_org = e; \ + e = (type)((int)e + 1); \ + return e_org; \ + } \ + FORCEINLINE type operator --(type& e, int) \ + { \ + type e_org = e; \ + e = (type)((int)e - 1); \ + return e_org; \ + } + + + +/** Operators to allow to work with enum as with type safe bit set in C++ */ +# define DECLARE_ENUM_AS_BIT_SET(mask_t) \ + FORCEINLINE mask_t operator | (mask_t m1, mask_t m2) {return (mask_t)((int)m1 | m2);} \ + FORCEINLINE mask_t operator & (mask_t m1, mask_t m2) {return (mask_t)((int)m1 & m2);} \ + FORCEINLINE mask_t operator ^ (mask_t m1, mask_t m2) {return (mask_t)((int)m1 ^ m2);} \ + FORCEINLINE mask_t& operator |= (mask_t& m1, mask_t m2) {m1 = m1 | m2; return m1;} \ + FORCEINLINE mask_t& operator &= (mask_t& m1, mask_t m2) {m1 = m1 & m2; return m1;} \ + FORCEINLINE mask_t& operator ^= (mask_t& m1, mask_t m2) {m1 = m1 ^ m2; return m1;} \ + FORCEINLINE mask_t operator ~(mask_t m) {return (mask_t)(~(int)m);} + + +/** Informative template class exposing basic enumeration properties used by several + * other templates below. Here we have only forward declaration. For each enum type + * we will create specialization derived from MakeEnumPropsT<>. + * i.e.: + * template <> struct EnumPropsT<Track> : MakeEnumPropsT<Track, byte, TRACK_BEGIN, TRACK_END, INVALID_TRACK> {}; + * followed by: + * typedef TinyEnumT<Track> TrackByte; + */ +template <typename Tenum_t> struct EnumPropsT; + +/** Helper template class that makes basic properties of given enumeration type visible + * from outsize. It is used as base class of several EnumPropsT specializations each + * dedicated to one of commonly used enumeration types. + * @param Tenum_t enumeration type that you want to describe + * @param Tstorage_t what storage type would be sufficient (i.e. byte) + * @param Tbegin first valid value from the contiguous range (i.e. TRACK_BEGIN) + * @param Tend one past the last valid value from the contiguous range (i.e. TRACK_END) + * @param Tinvalid value used as invalid value marker (i.e. INVALID_TRACK) + */ +template <typename Tenum_t, typename Tstorage_t, Tenum_t Tbegin, Tenum_t Tend, Tenum_t Tinvalid> +struct MakeEnumPropsT { + typedef Tenum_t type; ///< enum type (i.e. Trackdir) + typedef Tstorage_t storage; ///< storage type (i.e. byte) + static const Tenum_t begin = Tbegin; ///< lowest valid value (i.e. TRACKDIR_BEGIN) + static const Tenum_t end = Tend; ///< one after the last valid value (i.e. TRACKDIR_END) + static const Tenum_t invalid = Tinvalid; ///< what value is used as invalid value (i.e. INVALID_TRACKDIR) +}; + + + +/** In some cases we use byte or uint16 to store values that are defined as enum. It is + * necessary in order to control the sizeof() such values. Some compilers make enum + * the same size as int (4 or 8 bytes instead of 1 or 2). As a consequence the strict + * compiler type-checking causes errors like: + * 'HasPowerOnRail' : cannot convert parameter 1 from 'byte' to 'RailType' when + * u->u.rail.railtype is passed as argument or type RailType. In such cases it is better + * to teach the compiler that u->u.rail.railtype is to be treated as RailType. */ +template <typename Tenum_t> struct TinyEnumT; + +/** The general declaration of TinyEnumT<> (above) */ +template <typename Tenum_t> struct TinyEnumT +{ + typedef Tenum_t enum_type; ///< expose our enumeration type (i.e. Trackdir) to outside + typedef EnumPropsT<Tenum_t> Props; ///< make easier access to our enumeration propeties + typedef typename Props::storage storage_type; ///< small storage type + static const enum_type begin = Props::begin; ///< enum beginning (i.e. TRACKDIR_BEGIN) + static const enum_type end = Props::end; ///< enum end (i.e. TRACKDIR_END) + static const enum_type invalid = Props::invalid;///< invalid value (i.e. INVALID_TRACKDIR) + + storage_type m_val; ///< here we hold the actual value in small (i.e. byte) form + + /** Cast operator - invoked then the value is assigned to the Tenum_t type */ + FORCEINLINE operator enum_type () const + { + return (enum_type)m_val; + } + + /** Assignment operator (from Tenum_t type) */ + FORCEINLINE TinyEnumT& operator = (enum_type e) + { + m_val = (storage_type)e; return *this; + } + + /** postfix ++ operator on tiny type */ + FORCEINLINE TinyEnumT operator ++ (int) + { + TinyEnumT org = *this; + if (++m_val >= end) m_val -= (storage_type)(end - begin); + return org; + } + + /** prefix ++ operator on tiny type */ + FORCEINLINE TinyEnumT& operator ++ () + { + if (++m_val >= end) m_val -= (storage_type)(end - begin); + return *this; + } +}; + +#endif /* HELPERS_HPP */ |