1

/* $Id$ */

     2

     3

#ifndef HELPERS_HPP

     4

#define HELPERS_HPP

     5

     6

/** @file helpers.hpp */

     7

#include "macros.h"

     8

     9

#ifdef __cplusplus

    10

    11

/** When allocating using malloc/calloc in C++ it is usually needed to cast the return value

    12

*  from void* to the proper pointer type. Another alternative would be MallocT<> as follows */

    13

template <typename T> FORCEINLINE bool MallocT(T** t_ptr, size_t num_elements)

    14

{

    15

	*t_ptr = (T*)malloc(num_elements * sizeof(T));

    16

	return (*t_ptr != NULL);

    17

}

    18

/** When allocating using malloc/calloc in C++ it is usually needed to cast the return value

    19

*  from void* to the proper pointer type. Another alternative would be MallocT<> as follows */

    20

template <typename T> FORCEINLINE bool CallocT(T** t_ptr, size_t num_elements)

    21

{

    22

	*t_ptr = (T*)calloc(num_elements, sizeof(T));

    23

	return (*t_ptr != NULL);

    24

}

    25

/** When allocating using malloc/calloc in C++ it is usually needed to cast the return value

    26

*  from void* to the proper pointer type. Another alternative would be MallocT<> as follows */

    27

template <typename T> FORCEINLINE bool ReallocT(T** t_ptr, size_t num_elements)

    28

{

    29

	*t_ptr = (T*)realloc(*t_ptr, num_elements * sizeof(T));

    30

	return (*t_ptr != NULL);

    31

}

    32

    33

/** type safe swap operation */

    34

template <typename T> void SwapT(T *a, T *b);

    35

    36

template <typename T> FORCEINLINE void SwapT(T *a, T *b)

    37

{

    38

	T t = *a;

    39

	*a = *b;

    40

	*b = t;

    41

}

    42

    43

    44

/** returns the absolute value of (scalar) variable. @note assumes variable to be signed */

    45

template <typename T> static inline T myabs(T a) { return a < (T)0 ? -a : a; }

    46

/** returns the (absolute) difference between two (scalar) variables */

    47

template <typename T> static inline T delta(T a, T b) { return a < b ? b - a : a - b; }

    48

    49

/** Some enums need to have allowed incrementing (i.e. StationClassID) */

    50

#define DECLARE_POSTFIX_INCREMENT(type) \

    51

	FORCEINLINE type operator ++(type& e, int) \

    52

	{ \

    53

		type e_org = e; \

    54

		e = (type)((int)e + 1); \

    55

		return e_org; \

    56

	} \

    57

	FORCEINLINE type operator --(type& e, int) \

    58

	{ \

    59

		type e_org = e; \

    60

		e = (type)((int)e - 1); \

    61

		return e_org; \

    62

	}

    63

    64

    65

    66

/** Operators to allow to work with enum as with type safe bit set in C++ */

    67

# define DECLARE_ENUM_AS_BIT_SET(mask_t) \

    68

	FORCEINLINE mask_t operator | (mask_t m1, mask_t m2) {return (mask_t)((int)m1 | m2);} \

    69

	FORCEINLINE mask_t operator & (mask_t m1, mask_t m2) {return (mask_t)((int)m1 & m2);} \

    70

	FORCEINLINE mask_t operator ^ (mask_t m1, mask_t m2) {return (mask_t)((int)m1 ^ m2);} \

    71

	FORCEINLINE mask_t& operator |= (mask_t& m1, mask_t m2) {m1 = m1 | m2; return m1;} \

    72

	FORCEINLINE mask_t& operator &= (mask_t& m1, mask_t m2) {m1 = m1 & m2; return m1;} \

    73

	FORCEINLINE mask_t& operator ^= (mask_t& m1, mask_t m2) {m1 = m1 ^ m2; return m1;} \

    74

	FORCEINLINE mask_t operator ~(mask_t m) {return (mask_t)(~(int)m);}

    75

    76

/** probably redundant enum combining operators (as we have conversion functions)

    77

 *  but the old code is full of such arithmetics */

    78

# define DECLARE_ENUM_AS_BIT_INDEX(idx_t, mask_t) \

    79

	FORCEINLINE mask_t operator << (int m, idx_t i) {return (mask_t)(m << (int)i);} \

    80

	FORCEINLINE mask_t operator << (mask_t m, int i) {return (mask_t)(((int)m) << i);} \

    81

	FORCEINLINE mask_t operator >> (mask_t m, int i) {return (mask_t)(((int)m) >> i);}

    82

    83

    84

/** Informative template class exposing basic enumeration properties used by several

    85

 *  other templates below. Here we have only forward declaration. For each enum type

    86

 *  we will create specialization derived from MakeEnumPropsT<>. */

    87

template <typename Tenum_t> struct EnumPropsT;

    88

    89

/** Helper template class that makes basic properties of given enumeration type visible

    90

 *  from outsize. It is used as base class of several EnumPropsT specializations each

    91

 *  dedicated to one of commonly used enumeration types. */

    92

template <typename Tenum_t, typename Tstorage_t, Tenum_t Tbegin, Tenum_t Tend, Tenum_t Tinvalid>

    93

struct MakeEnumPropsT {

    94

	typedef Tenum_t type;                     ///< enum type (i.e. Trackdir)

    95

	typedef Tstorage_t storage;               ///< storage type (i.e. byte)

    96

	static const Tenum_t begin = Tbegin;      ///< lowest valid value (i.e. TRACKDIR_BEGIN)

    97

	static const Tenum_t end = Tend;          ///< one after the last valid value (i.e. TRACKDIR_END)

    98

	static const Tenum_t invalid = Tinvalid;  ///< what value is used as invalid value (i.e. INVALID_TRACKDIR)

    99

};

   100

   101

   102

   103

/** In some cases we use byte or uint16 to store values that are defined as enum. It is

   104

	*  necessary in order to control the sizeof() such values. Some compilers make enum

   105

	*  the same size as int (4 or 8 bytes instead of 1 or 2). As a consequence the strict

   106

	*  compiler type-checking causes errors like:

   107

	*     'HasPowerOnRail' : cannot convert parameter 1 from 'byte' to 'RailType' when

   108

	*  u->u.rail.railtype is passed as argument or type RailType. In such cases it is better

   109

	*  to teach the compiler that u->u.rail.railtype is to be treated as RailType. */

   110

template <typename Tenum_t> struct TinyEnumT;

   111

   112

/** The general declaration of TinyEnumT<> (above) */

   113

template <typename Tenum_t> struct TinyEnumT

   114

{

   115

	typedef Tenum_t enum_type;                      ///< expose our enumeration type (i.e. Trackdir) to outside

   116

	typedef EnumPropsT<Tenum_t> Props;              ///< make easier access to our enumeration propeties

   117

	typedef typename Props::storage storage_type;   ///< small storage type

   118

	static const enum_type begin = Props::begin;    ///< enum beginning (i.e. TRACKDIR_BEGIN)

   119

	static const enum_type end = Props::end;        ///< enum end (i.e. TRACKDIR_END)

   120

	static const enum_type invalid = Props::invalid;///< invalid value (i.e. INVALID_TRACKDIR)

   121

   122

	storage_type m_val;  ///< here we hold the actual value in small (i.e. byte) form

   123

   124

	/** Cast operator - invoked then the value is assigned to the Tenum_t type */

   125

	FORCEINLINE operator enum_type () const

   126

	{

   127

		return (enum_type)m_val;

   128

	}

   129

   130

	/** Assignment operator (from Tenum_t type) */

   131

	FORCEINLINE TinyEnumT& operator = (enum_type e)

   132

	{

   133

		m_val = (storage_type)e; return *this;

   134

	}

   135

   136

	/** postfix ++ operator on tiny type */

   137

	FORCEINLINE TinyEnumT& operator ++ (int)

   138

	{

   139

		if (++m_val >= end) m_val -= (storage_type)(end - begin);

   140

		return *this;

   141

	}

   142

};

   143

   144

template <typename Tenum_t> FORCEINLINE void SwapT(TinyEnumT<Tenum_t> *a, TinyEnumT<Tenum_t> *b)

   145

{

   146

	SwapT(&a->m_val, &b->m_val);

   147

}

   148

   149

template <typename T> FORCEINLINE T ClrBitT(T t, int bit_index)

   150

{

   151

	int val = t;

   152

	CLRBIT(val, bit_index);

   153

	return (T)val;

   154

}

   155

   156

template <typename T> FORCEINLINE T SetBitT(T t, int bit_index)

   157

{

   158

	int val = t;

   159

	SETBIT(val, bit_index);

   160

	return (T)val;

   161

}

   162

   163

template <typename T> FORCEINLINE T ToggleBitT(T t, int bit_index)

   164

{

   165

	int val = t;

   166

	TOGGLEBIT(val, bit_index);

   167

	return (T)val;

   168

}

   169

   170

#else // __cplusplus

   171

   172

#define DECLARE_POSTFIX_INCREMENT(E)

   173

#define DECLARE_ENUM_AS_BIT_SET(E)

   174

#define DECLARE_ENUM_AS_BIT_INDEX(E1,E2)

   175

   176

#endif  // __cplusplus

   177

   178

#endif /* HELPERS_HPP */