(svn r8038) -Merge: the cpp branch. Effort of KUDr, Celestar, glx, Smoovius, stillunknown and pv2b.

1 files changed, 178 insertions, 0 deletions

diff --git a/src/helpers.hpp b/src/helpers.hpp
new file mode 100644
index 000000000..b13fc25d4
--- /dev/null
+++ b/src/helpers.hpp
@@ -0,0 +1,178 @@
+/* $Id$ */
+
+#ifndef HELPERS_HPP
+#define HELPERS_HPP
+
+/** @file helpers.hpp */
+#include "macros.h"
+
+#ifdef __cplusplus
+
+/** 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 bool MallocT(T** t_ptr, size_t num_elements)
+{
+	*t_ptr = (T*)malloc(num_elements * sizeof(T));
+	return (*t_ptr != NULL);
+}
+/** 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 bool CallocT(T** t_ptr, size_t num_elements)
+{
+	*t_ptr = (T*)calloc(num_elements, sizeof(T));
+	return (*t_ptr != NULL);
+}
+/** 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 bool ReallocT(T** t_ptr, size_t num_elements)
+{
+	*t_ptr = (T*)realloc(*t_ptr, num_elements * sizeof(T));
+	return (*t_ptr != NULL);
+}
+
+/** type safe swap operation */
+template <typename T> void SwapT(T *a, T *b);
+
+template <typename T> FORCEINLINE void SwapT(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);}
+
+/** probably redundant enum combining operators (as we have conversion functions)
+ *  but the old code is full of such arithmetics */
+# define DECLARE_ENUM_AS_BIT_INDEX(idx_t, mask_t) \
+	FORCEINLINE mask_t operator << (int m, idx_t i) {return (mask_t)(m << (int)i);} \
+	FORCEINLINE mask_t operator << (mask_t m, int i) {return (mask_t)(((int)m) << i);} \
+	FORCEINLINE mask_t operator >> (mask_t m, int i) {return (mask_t)(((int)m) >> i);}
+
+
+/** 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<>. */
+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. */
+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 Tenum_t> FORCEINLINE void SwapT(TinyEnumT<Tenum_t> *a, TinyEnumT<Tenum_t> *b)
+{
+	SwapT(&a->m_val, &b->m_val);
+}
+
+template <typename T> FORCEINLINE T ClrBitT(T t, int bit_index)
+{
+	int val = t;
+	CLRBIT(val, bit_index);
+	return (T)val;
+}
+
+template <typename T> FORCEINLINE T SetBitT(T t, int bit_index)
+{
+	int val = t;
+	SETBIT(val, bit_index);
+	return (T)val;
+}
+
+template <typename T> FORCEINLINE T ToggleBitT(T t, int bit_index)
+{
+	int val = t;
+	TOGGLEBIT(val, bit_index);
+	return (T)val;
+}
+
+#else // __cplusplus
+
+#define DECLARE_POSTFIX_INCREMENT(E)
+#define DECLARE_ENUM_AS_BIT_SET(E)
+#define DECLARE_ENUM_AS_BIT_INDEX(E1,E2)
+
+#endif  // __cplusplus
+
+#endif /* HELPERS_HPP */