/* $Id$ */
/** @file helpers.hpp */
#ifndef HELPERS_HPP
#define HELPERS_HPP
#include "macros.h"
/** When allocating using malloc/calloc in C++ it is usually needed to cast the return value
* from void* to the proper pointer type. Another alternative would be MallocT<> as follows */
template <typename T> FORCEINLINE T* MallocT(size_t num_elements)
{
T *t_ptr = (T*)malloc(num_elements * sizeof(T));
return t_ptr;
}
/** When allocating using malloc/calloc in C++ it is usually needed to cast the return value
* from void* to the proper pointer type. Another alternative would be MallocT<> as follows */
template <typename T> FORCEINLINE T* CallocT(size_t num_elements)
{
T *t_ptr = (T*)calloc(num_elements, sizeof(T));
return t_ptr;
}
/** When allocating using malloc/calloc in C++ it is usually needed to cast the return value
* from void* to the proper pointer type. Another alternative would be MallocT<> as follows */
template <typename T> FORCEINLINE T* ReallocT(T* t_ptr, size_t num_elements)
{
t_ptr = (T*)realloc(t_ptr, num_elements * sizeof(T));
return t_ptr;
}
/** type safe swap operation */
template<typename T> void Swap(T& a, T& b)
{
T t = a;
a = b;
b = t;
}
/** returns the absolute value of (scalar) variable. @note assumes variable to be signed */
template <typename T> static inline T myabs(T a) { return a < (T)0 ? -a : a; }
/** returns the (absolute) difference between two (scalar) variables */
template <typename T> static inline T delta(T a, T b) { return a < b ? b - a : a - b; }
/** 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)
{
if (++m_val >= end) m_val -= (storage_type)(end - begin);
return *this;
}
};
template <typename T> void ClrBitT(T &t, int bit_index)
{
t = (T)(t & ~((T)1 << bit_index));
}
template <typename T> void SetBitT(T &t, int bit_index)
{
t = (T)(t | ((T)1 << bit_index));
}
template <typename T> void ToggleBitT(T &t, int bit_index)
{
t = (T)(t ^ ((T)1 << bit_index));
}
/**
* Zero initialization end marker.
* @see ZeroInitBegin for usage.
*/
struct ZeroInitEnd {
};
/**
* Zero initialization begin marker. When you need to initialize struct/class members by
* memset(&m_first_member, 0, ((byte*)&m_last_member) - ((byte*)&m_first_member + sizeof(m_last_member));
* place ZeroInitBegin before m_first_member, place ZeroInitEnd after m_last_member, call ZeroInitBegin
* constructor give him ZeroInitEnd& as parameter. This will clear whole area between them using memset.
* @see ZeroInitEnd
*/
struct ZeroInitBegin {
ZeroInitBegin(const ZeroInitEnd &end)
{
memset(this, 0, ((byte*)&end) - ((byte*)this));
}
};
#endif /* HELPERS_HPP */