Mfc rtti.
先放上分析后，并且简化后的源代码，有时间在说 1
#include <stdio.h>
2#define LPCSTR char *
3#define BOOL bool
4#define TRUE true
5#define FALSE false
6#define NULL 0
7
8struct CRuntimeClass
9
{
10
// Attributes
11 LPCSTR m_lpszClassName;
12 int m_nObjectSize;
13
14 BOOL IsDerivedFrom(const CRuntimeClass* pBaseClass) const
15
{
16 // simple SI case
17 const CRuntimeClass* pClassThis = this;
18 while (pClassThis != NULL)
19 {
20 if (pClassThis == pBaseClass)
21 return TRUE;
22 pClassThis = pClassThis->m_pBaseClass;
23
}
24 return FALSE; // walked to the top, no match
25 }
26
27 void PrintAll()
28 {
29 for(CRuntimeClass * pc=this; pc; pc=pc->m_pBaseClass)
30 {
31 printf("->%s", pc->m_lpszClassName);
32 }
33 printf("\n");
34 }
35 CRuntimeClass* m_pBaseClass; // linked list of registered classes
36
};
37
38
39#define RUNTIME_CLASS(class_name) ((CRuntimeClass*)(&class_name::class##class_name))
40
41class CObject
42{
43public:
44 static CRuntimeClass classCObject;
45
46 virtual CRuntimeClass * GetRuntimeClass() const //must be virtual
47 {
48 return &CObject::classCObject;
49 }
50
51 BOOL IsKindOf(const CRuntimeClass* pClass) const
52 {
53 CRuntimeClass* pClassThis = GetRuntimeClass();
54
55 return pClassThis->IsDerivedFrom(pClass);
56 }
57
58};
59
60__declspec(selectany) CRuntimeClass CObject::classCObject =
61{
62 "CObject", sizeof(class CObject), NULL
63};
64
65class A:public CObject
66{
67 public:
68 static const CRuntimeClass classA;
69 virtual CRuntimeClass* GetRuntimeClass() const;
70};
71
72__declspec(selectany) const CRuntimeClass A::classA =
73{
74 "A", sizeof(class A), &CObject::classCObject
75};
76CRuntimeClass* A::GetRuntimeClass() const
77{ return ((CRuntimeClass*)(&A::classA)); }
78
79void main()
80{
81 A a;
82 printf("%d\n", a.IsKindOf(RUNTIME_CLASS(CObject)));
83 printf("%d\n", a.IsKindOf(RUNTIME_CLASS(A)));
84 //printf("%d\n", a.IsKindOf(RUNTIME_CLASS(int))); //Compile Fail
85
86 RUNTIME_CLASS(CObject)->PrintAll();
87 RUNTIME_CLASS(A)->PrintAll();
88}
#include <stdio.h>2
#define LPCSTR char *3
#define BOOL bool4
#define TRUE true5
#define FALSE false6
#define NULL 07
8
struct CRuntimeClass9
{
10
// Attributes11
LPCSTR m_lpszClassName;12
int m_nObjectSize;13
14
BOOL IsDerivedFrom(const CRuntimeClass* pBaseClass) const15
{
16
// simple SI case17
const CRuntimeClass* pClassThis = this;18
while (pClassThis != NULL)19
{20
if (pClassThis == pBaseClass)21
return TRUE;22
pClassThis = pClassThis->m_pBaseClass;23
}24
return FALSE; // walked to the top, no match25
}26
27
void PrintAll()28
{29
for(CRuntimeClass * pc=this; pc; pc=pc->m_pBaseClass)30
{31
printf("->%s", pc->m_lpszClassName);32
}33
printf("\n");34
}35
CRuntimeClass* m_pBaseClass; // linked list of registered classes36
};37
38
39
#define RUNTIME_CLASS(class_name) ((CRuntimeClass*)(&class_name::class##class_name))40
41
class CObject42
{43
public:44
static CRuntimeClass classCObject; 45
46
virtual CRuntimeClass * GetRuntimeClass() const //must be virtual47
{48
return &CObject::classCObject;49
}50
51
BOOL IsKindOf(const CRuntimeClass* pClass) const52
{53
CRuntimeClass* pClassThis = GetRuntimeClass();54
55
return pClassThis->IsDerivedFrom(pClass);56
}57
58
};59
60
__declspec(selectany) CRuntimeClass CObject::classCObject = 61
{ 62
"CObject", sizeof(class CObject), NULL 63
}; 64
65
class A:public CObject66
{67
public: 68
static const CRuntimeClass classA; 69
virtual CRuntimeClass* GetRuntimeClass() const; 70
};71
72
__declspec(selectany) const CRuntimeClass A::classA = 73
{ 74
"A", sizeof(class A), &CObject::classCObject 75
}; 76
CRuntimeClass* A::GetRuntimeClass() const 77
{ return ((CRuntimeClass*)(&A::classA)); } 78
79
void main()80
{81
A a;82
printf("%d\n", a.IsKindOf(RUNTIME_CLASS(CObject)));83
printf("%d\n", a.IsKindOf(RUNTIME_CLASS(A)));84
//printf("%d\n", a.IsKindOf(RUNTIME_CLASS(int))); //Compile Fail85
86
RUNTIME_CLASS(CObject)->PrintAll();87
RUNTIME_CLASS(A)->PrintAll();88
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