MSTAR虚函数表（以IBitmap为例），以及快速查找函数实现的方法
2011-10-13 19:16
MSTAR的EMMI中跟BREW类似，采用虚函数表的方式定义各种对象及其接口，这有点面向对象的思想。
而其实现方法，全是用C语言，通过宏定义来实现的。将各种宏带入还原一下，其结构就很清新了，下面以以IBitmap为例：
Mmi_mae_bitmap.h (proj\sc\application\mmi\mae\pub):
DEFINE_INTERFACE(IBitmap);
Mmi_mae_interface_def.h (proj\sc\application\mmi\mae\pub):
#define DEFINE_INTERFACE(IName) \
typedef struct IName##_tag IName; \
DEFINE_FUNCTBL(IName) \
{ INHERIT_##IName(IName); }; \
struct IName##_tag \
{ DECLARE_FUNCTBL(IName); }
----------------------------->
typedef struct IBitmap_tag IBitmap; \
DEFINE_FUNCTBL(IBitmap) \
{ INHERIT_IBitmap(IBitmap); }; \
struct IBitmap_tag \
{ DECLARE_FUNCTBL(IBitmap); };
#define DEFINE_FUNCTBL(IName) \
typedef struct IName##_Vtbl_tag FUNCTBL(IName); \
struct IName##_Vtbl_tag
----------------------------->
typedef struct IBitmap_tag IBitmap; \
typedef struct IBitmap_Vtbl_tag FUNCTBL(IBitmap); \
struct IBitmap_Vtbl_tag \
{ INHERIT_IBitmap(IBitmap); }; \
struct IBitmap_tag \
{ DECLARE_FUNCTBL(IBitmap); };
#define DECLARE_FUNCTBL(IName) const IName##_Vtbl *Vtbl_Ptr
----------------------------->
typedef struct IBitmap_tag IBitmap; \
typedef struct IBitmap_Vtbl_tag FUNCTBL(IBitmap); \
struct IBitmap_Vtbl_tag \
{ INHERIT_IBitmap(IBitmap); }; \
struct IBitmap_tag \
{ const IBitmap_Vtbl *Vtbl_Ptr; }
#define FUNCTBL(IName) IName##_Vtbl
----------------------------->
typedef struct IBitmap_tag IBitmap; \
typedef struct IBitmap_Vtbl_tag IBitmap_Vtbl; \
struct IBitmap_Vtbl_tag \
{ INHERIT_IBitmap(IBitmap); }; \
struct IBitmap_tag \
{ const IBitmap_Vtbl *Vtbl_Ptr; };
Mmi_mae_bitmap.h (proj\sc\application\mmi\mae\pub):
#define INHERIT_IBitmap(IName) \
INHERIT_IBase(IName); \
MAE_Ret (*GetInfo) (IName*, BitmapInfo_t*); \
MAE_Ret (*GetPixel) (IName*, u32, u32, RGBColor_t*); \
MAE_Ret (*SetPixel) (IName*, u32, u32, RGBColor_t, RasterOp_t); \
MAE_Ret (*SetPixels) (IName*, u32, Point_t*, RGBColor_t, RasterOp_t); \
MAE_Ret (*GetTransInfo) (IName*, TransparentInfo_t*); \
MAE_Ret (*SetTransInfo) (IName*, TransparentInfo_t*); \
MAE_Ret (*GetTransType) (IName*, u32*); \
MAE_Ret (*SetTransType) (IName*, u32); \
MAE_Ret (*GetTransColor) (IName*, RGBColor_t*); \
MAE_Ret (*SetTransColor) (IName*, RGBColor_t*); \
MAE_Ret (*GetTransMask) (IName*, u8**, u32*); \
MAE_Ret (*SetTransMask) (IName*, u32, u8*, u32); \
MAE_Ret (*GetTransparency) (IName*, u8*); \
MAE_Ret (*SetTransparency) (IName*, u8); \
MAE_Ret (*DrawHLine) (IName*, u32, u32, u32, RGBColor_t, RasterOp_t); \
MAE_Ret (*DrawVLine) (IName*, u32, u32, u32, RGBColor_t, RasterOp_t); \
MAE_Ret (*FillRect) (IName*, const Rect_t*, RGBColor_t, RasterOp_t); \
MAE_Ret (*BltIn) (IName*, const Rect_t*, IBitmap*, const Rect_t*, RasterOp_t); \
MAE_Ret (*GetDib) (IName*, void**);\
MAE_Ret (*StretchBlt) (IName*, const Rect_t*, IBitmap*, const Rect_t*, RasterOp_t, u32);\
MAE_Ret (*PerspectiveBlt) (IName*, const Rect_t*, IBitmap*, const Rect_t*, RasterOp_t, u32, u16)
----------------------------->
typedef struct IBitmap_tag IBitmap; \
typedef struct IBitmap_Vtbl_tag IBitmap_Vtbl; \
struct IBitmap_Vtbl_tag \
{ INHERIT_IBase(IBitmap); \
MAE_Ret (*GetInfo) (IBitmap*, BitmapInfo_t*); \
MAE_Ret (*GetPixel) (IBitmap*, u32, u32, RGBColor_t*); \
MAE_Ret (*SetPixel) (IBitmap*, u32, u32, RGBColor_t, RasterOp_t); \
MAE_Ret (*SetPixels) (IBitmap*, u32, Point_t*, RGBColor_t, RasterOp_t); \
MAE_Ret (*GetTransInfo) (IBitmap*, TransparentInfo_t*); \
MAE_Ret (*SetTransInfo) (IBitmap*, TransparentInfo_t*); \
MAE_Ret (*GetTransType) (IBitmap*, u32*); \
MAE_Ret (*SetTransType) (IBitmap*, u32); \
MAE_Ret (*GetTransColor) (IBitmap*, RGBColor_t*); \
MAE_Ret (*SetTransColor) (IBitmap*, RGBColor_t*); \
MAE_Ret (*GetTransMask) (IBitmap*, u8**, u32*); \
MAE_Ret (*SetTransMask) (IBitmap*, u32, u8*, u32); \
MAE_Ret (*GetTransparency) (IBitmap*, u8*); \
MAE_Ret (*SetTransparency) (IBitmap*, u8); \
MAE_Ret (*DrawHLine) (IBitmap*, u32, u32, u32, RGBColor_t, RasterOp_t); \
MAE_Ret (*DrawVLine) (IBitmap*, u32, u32, u32, RGBColor_t, RasterOp_t); \
MAE_Ret (*FillRect) (IBitmap*, const Rect_t*, RGBColor_t, RasterOp_t); \
MAE_Ret (*BltIn) (IBitmap*, const Rect_t*, IBitmap*, const Rect_t*, RasterOp_t); \
MAE_Ret (*GetDib) (IBitmap*, void**);\
MAE_Ret (*StretchBlt) (IBitmap*, const Rect_t*, IBitmap*, const Rect_t*, RasterOp_t, u32);\
MAE_Ret (*PerspectiveBlt) (IBitmap*, const Rect_t*, IBitmap*, const Rect_t*, RasterOp_t, u32, u16); }; \
struct IBitmap_tag \
{ const IBitmap_Vtbl *Vtbl_Ptr; };
Mmi_mae_interface_def.h (proj\sc\application\mmi\mae\pub):
#define INHERIT_IBase(IName) \
u32 (*AddRef)(IName*); \
u32 (*Release)(IName*); \
MAERet_t (*QueryInterface)(IName*, MAEIId_t, void**, IBase*)
----------------------------->
typedef struct IBitmap_tag IBitmap; \
typedef struct IBitmap_Vtbl_tag IBitmap_Vtbl; \
struct IBitmap_Vtbl_tag \
{ u32 (*AddRef)(IBitmap*); \
u32 (*Release)(IBitmap*); \
MAERet_t (*QueryInterface)(IBitmap*, MAEIId_t, void**, IBase*); \
MAE_Ret (*GetInfo) (IBitmap*, BitmapInfo_t*); \
MAE_Ret (*GetPixel) (IBitmap*, u32, u32, RGBColor_t*); \
MAE_Ret (*SetPixel) (IBitmap*, u32, u32, RGBColor_t, RasterOp_t); \
MAE_Ret (*SetPixels) (IBitmap*, u32, Point_t*, RGBColor_t, RasterOp_t); \
MAE_Ret (*GetTransInfo) (IBitmap*, TransparentInfo_t*); \
MAE_Ret (*SetTransInfo) (IBitmap*, TransparentInfo_t*); \
MAE_Ret (*GetTransType) (IBitmap*, u32*); \
MAE_Ret (*SetTransType) (IBitmap*, u32); \
MAE_Ret (*GetTransColor) (IBitmap*, RGBColor_t*); \
MAE_Ret (*SetTransColor) (IBitmap*, RGBColor_t*); \
MAE_Ret (*GetTransMask) (IBitmap*, u8**, u32*); \
MAE_Ret (*SetTransMask) (IBitmap*, u32, u8*, u32); \
MAE_Ret (*GetTransparency) (IBitmap*, u8*); \
MAE_Ret (*SetTransparency) (IBitmap*, u8); \
MAE_Ret (*DrawHLine) (IBitmap*, u32, u32, u32, RGBColor_t, RasterOp_t); \
MAE_Ret (*DrawVLine) (IBitmap*, u32, u32, u32, RGBColor_t, RasterOp_t); \
MAE_Ret (*FillRect) (IBitmap*, const Rect_t*, RGBColor_t, RasterOp_t); \
MAE_Ret (*BltIn) (IBitmap*, const Rect_t*, IBitmap*, const Rect_t*, RasterOp_t); \
MAE_Ret (*GetDib) (IBitmap*, void**);\
MAE_Ret (*StretchBlt) (IBitmap*, const Rect_t*, IBitmap*, const Rect_t*, RasterOp_t, u32);\
MAE_Ret (*PerspectiveBlt) (IBitmap*, const Rect_t*, IBitmap*, const Rect_t*, RasterOp_t, u32, u16); }; \
struct IBitmap_tag \
{ const IBitmap_Vtbl *Vtbl_Ptr; };
由上可知，IBitmap就是一个成员只有一个虚函数表IBitmap_Vtbl的结构体。
在这个虚函数表中，可以看到类IBitmap所提供的各种接口。
给用户使用的接口，在头文件Mmi_mae_bitmap.h (proj\sc\application\mmi\mae\pub)中，如下定义：
#define IBITMAP_SetTransparency(pIbmp,t) GET_FUNCTBL(pIbmp,IBitmap)->SetTransparency(pIbmp,t)
要想找到IBITMAP_xxx的实现，可以搜索：FUNCTBL(IBitmap，比如IBitmap虚函数表的定义在这里：
Mae_bitmap.c (proj\sc\application\mmi\mae\src)
而用DECLARE_FUNCTBL(IBitmap)可以查到该虚函数表的声明，比如IBitmap虚函数表的声明在这里：
Mae_bitmap_priv.h (proj\sc\application\mmi\mae\src):