diff options
Diffstat (limited to 'common/func.h')
-rw-r--r-- | common/func.h | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/common/func.h b/common/func.h index 95df96123a..fdb55b43c2 100644 --- a/common/func.h +++ b/common/func.h @@ -29,12 +29,18 @@ namespace Common { +/** + * Generic unary function. + */ template<class Arg, class Result> struct UnaryFunction { typedef Arg ArgumenType; typedef Result ResultType; }; +/** + * Generic binary function. + */ template<class Arg1, class Arg2, class Result> struct BinaryFunction { typedef Arg1 FirstArgumentType; @@ -42,16 +48,25 @@ struct BinaryFunction { typedef Result ResultType; }; +/** + * Predicate to check for equallity of two data elements. + */ template<class T> struct EqualTo : public BinaryFunction<T, T, bool> { bool operator()(const T &x, const T &y) const { return x == y; } }; +/** + * Predicate to check for x being less than y. + */ template<class T> struct Less : public BinaryFunction<T, T, bool> { bool operator()(const T &x, const T &y) const { return x < y; } }; +/** + * Predicate to check for x being greater than y. + */ template<class T> struct Greater : public BinaryFunction<T, T, bool> { bool operator()(const T &x, const T &y) const { return x > y; } @@ -70,6 +85,10 @@ public: } }; +/** + * Transforms a binary function object into an unary function object. + * To achieve that the first parameter is bound to the passed value t. + */ template<class Op, class T> inline Binder1st<Op> bind1st(const Op &op, const T &t) { return Binder1st<Op>(op, t); @@ -88,6 +107,10 @@ public: } }; +/** + * Transforms a binary function object into an unary function object. + * To achieve that the second parameter is bound to the passed value t. + */ template<class Op, class T> inline Binder2nd<Op> bind2nd(const Op &op, const T &t) { return Binder2nd<Op>(op, t); @@ -119,11 +142,17 @@ public: } }; +/** + * Creates an unary function object from a function pointer. + */ template<class Arg, class Result> inline PointerToUnaryFunc<Arg, Result> ptr_fun(Result (*func)(Arg)) { return PointerToUnaryFunc<Arg, Result>(func); } +/** + * Creates an binary function object from a function pointer. + */ template<class Arg1, class Arg2, class Result> inline PointerToBinaryFunc<Arg1, Arg2, Result> ptr_fun(Result (*func)(Arg1, Arg2)) { return PointerToBinaryFunc<Arg1, Arg2, Result>(func); @@ -181,21 +210,43 @@ public: } }; +/** + * Creates a unary function object from a class member function pointer. + * The parameter passed to the function object is the 'this' pointer to + * be used for the function call. + */ template<class Result, class T> inline MemFunc0<Result, T> mem_fun(Result (T::*f)()) { return MemFunc0<Result, T>(f); } +/** + * Creates a unary function object from a class member function pointer. + * The parameter passed to the function object is the 'this' pointer to + * be used for the function call. + */ template<class Result, class T> inline ConstMemFunc0<Result, T> mem_fun(Result (T::*f)() const) { return ConstMemFunc0<Result, T>(f); } +/** + * Creates a binary function object from a class member function pointer. + * The first parameter passed to the function object is the 'this' pointer to + * be used for the function call. + * The second one is the parameter passed to the member function. + */ template<class Result, class Arg, class T> inline MemFunc1<Result, Arg, T> mem_fun(Result (T::*f)(Arg)) { return MemFunc1<Result, Arg, T>(f); } +/** + * Creates a binary function object from a class member function pointer. + * The first parameter passed to the function object is the 'this' pointer to + * be used for the function call. + * The second one is the parameter passed to the member function. + */ template<class Result, class Arg, class T> inline ConstMemFunc1<Result, Arg, T> mem_fun(Result (T::*f)(Arg) const) { return ConstMemFunc1<Result, Arg, T>(f); @@ -203,6 +254,11 @@ inline ConstMemFunc1<Result, Arg, T> mem_fun(Result (T::*f)(Arg) const) { // functor code +/** + * Generic functor object for function objects without parameters. + * + * @see Functor1 + */ template<class Res> struct Functor0 { virtual ~Functor0() {} @@ -211,6 +267,18 @@ struct Functor0 { virtual Res operator()() const = 0; }; +/** + * Functor object for a class member function without parameter. + * + * Example creation: + * + * Foo bar; + * Functor0Men<void, Foo> myFunctor(&bar, &Foo::myFunc); + * + * Example usage: + * + * myFunctor(); + */ template<class Res, class T> class Functor0Mem : public Functor0<Res> { public: @@ -227,6 +295,38 @@ private: const FuncType _func; }; +/** + * Generic functor object for unary function objects. + * + * A typical usage for an unary function object is for executing opcodes + * in a script interpreter. To achieve that one can create an Common::Array + * object with 'Functor1<Arg, Res> *' as type. Now after the right engine version + * has been determined and the opcode table to use is found one could easily + * add the opcode implementations like this: + * + * Common::Array<Functor1<ScriptState, void> *> opcodeTable; + * opcodeTable[0] = new Functor1Mem<ScriptState, void, MyEngine>(&myEngine, &MyEngine_v1::o1_foo); + * opcodeTable[1] = new Functor1Mem<ScriptState, void, MyEngine>(&myEngine, &MyEngine_v2::o2_foo); + * // unimplemented/unused opcode + * opcodeTable[2] = 0; + * etc. + * + * This makes it easy to add member functions of different classes as + * opcode functions to the function table. Since with the generic + * Functor1<ScriptState, void> object the only requirement for an + * function to be used is 'ScriptState' as argument and 'void' as return + * value. + * + * Now for calling the opcodes one has simple to do: + * if (opcodeTable[opcodeNum] && opcodeTable[opcodeNum]->isValid()) + * (*opcodeTable[opcodeNum])(scriptState); + * else + * warning("Unimplemented opcode %d", opcodeNum); + * + * If you want to see an real world example check the kyra engine. + * Files: engines/kyra/script.cpp and .h and engine/kyra/script_*.cpp + * are interesting for that matter. + */ template<class Arg, class Res> struct Functor1 : public Common::UnaryFunction<Arg, Res> { virtual ~Functor1() {} @@ -235,6 +335,13 @@ struct Functor1 : public Common::UnaryFunction<Arg, Res> { virtual Res operator()(Arg) const = 0; }; +/** + * Functor object for an unary class member function. + * Usage is like with Functor0Mem. The resulting functor object + * will take one parameter though. + * + * @see Functor0Men + */ template<class Arg, class Res, class T> class Functor1Mem : public Functor1<Arg, Res> { public: @@ -251,6 +358,11 @@ private: const FuncType _func; }; +/** + * Generic functor object for binary function objects. + * + * @see Functor1 + */ template<class Arg1, class Arg2, class Res> struct Functor2 : public Common::BinaryFunction<Arg1, Arg2, Res> { virtual ~Functor2() {} @@ -259,6 +371,13 @@ struct Functor2 : public Common::BinaryFunction<Arg1, Arg2, Res> { virtual Res operator()(Arg1, Arg2) const = 0; }; +/** + * Functor object for a binary class member function. + * Usage is like with Functor0Mem. The resulting functor object + * will take two parameter though. + * + * @see Functor0Men + */ template<class Arg1, class Arg2, class Res, class T> class Functor2Mem : public Functor2<Arg1, Arg2, Res> { public: |