summaryrefslogtreecommitdiff
path: root/src/helpers.hpp
blob: 9f4cf0c827b0ffcf90a0b0171996c469af665295 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
/* $Id$ */

#ifndef HELPERS_HPP
#define HELPERS_HPP

/** @file 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));
}

#endif /* HELPERS_HPP */