A preliminary study of COM Technology (III): a real com

First, implement Ismiplemath,iadvancedmath interface and DllGetClassObject ()

1.1 Implement Ismiplemath and Iadvancedmath interface

Let's change the original Cmath class (Cmath is actually "COM technology (ii) COM basics" of that Cmath Class) to implement Ismiplemath interface and Iadvancedmath interface.

The modifications are as follows:

1) Math.h File/*@**#---2003-10-29 21:33:44 (tulip)---#**@
#include "interface.h"*/
#include "MathCOM.h"//新增加的，以替换上面的东东
class CMath : public ISimpleMath,
　　　　　　　public IAdvancedMath
{
private:
　　ULONG m_cRef;
private:
　　int calcFactorial(int nOp);
　　int calcFabonacci(int nOp);
public:
　　CMath();
　　//IUnknown Method
　　STDMETHOD(QueryInterface)(REFIID riid, void **ppv);
　　STDMETHOD_(ULONG, AddRef)();
　　STDMETHOD_(ULONG, Release)();
　　//　　ISimpleMath Method
　　STDMETHOD (Add)(int nOp1, int nOp2,int * pret);
　　STDMETHOD (Subtract)(int nOp1, int nOp2,int *pret);
　　STDMETHOD (Multiply)(int nOp1, int nOp2,int *pret);
　　STDMETHOD (Divide)(int nOp1, int nOp2,int * pret);
　　//　　IAdvancedMath Method
　　STDMETHOD (Factorial)(int nOp,int *pret);
　　STDMETHOD (Fabonacci)(int nOp,int *pret);
};2) Math.cpp file/*@**#---2003-10-29 21:32:35 (tulip)---#**@
#include "math.h"
STDMETHODIMP Cmath::queryinterface (REFIID riid, void **PPV)
{//Here This is the functionality to implement dynamic_cast, but because dynamic_cast is related to the compiler.
if (riid = = Iid_isimplemath)
*PPV = Static_cast<isimplemath *> (this);
else if (riid = = Iid_iadvancedmath)
*PPV = Static_cast<iadvancedmath *> (this);
else if (riid = = IID_IUnknown)
*PPV = Static_cast<isimplemath *> (this);
else {
*PPV = 0;
return e_nointerface;
}
This is because the reference count is for the component
Reinterpret_cast<iunknown *> (*PPV)->addref ();
return S_OK;
}
Stdmethodimp_ (ULONG) cmath::addref ()
{
return ++m_cref;
}
Stdmethodimp_ (ULONG) cmath::release ()
{
Use a temporary variable to cache the modified reference count value
ULONG res =--m_cref;
Because it is illegal to refer to the object's data after the object has been destroyed.
if (res = 0)
Delete this;
return res;
}
STDMETHODIMP Cmath::add (int nOp1, int nop2,int * pret)
{
*PRET=NOP1+NOP2;
return S_OK;
}
STDMETHODIMP cmath::subtract (int nOp1, int nop2,int * pret)
{
*pret= Nop1-nop2;
return S_OK;
}
STDMETHODIMP cmath::multiply (int nOp1, int nop2,int * pret)
{
*PRET=NOP1 * NOP2;
return S_OK;
}
STDMETHODIMP Cmath::D ivide (int nOp1, int nop2,int * pret)
{
*pret= Nop1/nop2;
return S_OK;
}
int cmath::calcfactorial (int nOp)
{
if (nOp <= 1)
return 1;
Return nOp * calcfactorial (NOP-1);
}
STDMETHODIMP cmath::factorial (int nop,int * pret)
{
*pret=calcfactorial (NOP);
return S_OK;
}
int Cmath::calcfabonacci (int nOp)
{
if (nOp <= 1)
return 1;
Return Calcfabonacci (nOp-1) + Calcfabonacci (nOp-2);
}
STDMETHODIMP Cmath::fabonacci (int nop,int * pret)
{
*pret=calcfabonacci (NOP);
return S_OK;
}
Cmath::cmath ()
{
m_cref=0;
}