typedef struct gifheader   {      BYTE bySignature[3];      BYTE byVersion[3];   }  GIFHEADER;typedef struct gifscrdesc   {      WORD wWidth;      WORD wDepth;      struct globalflag         {            BYTE PalBits   : 3;            BYTE SortFlag  : 1;            BYTE ColorRes  : 3;            BYTE GlobalPal : 1;         }  GlobalFlag;      BYTE byBackground;      BYTE byAspect;   }  GIFSCRDESC;typedef struct gifimage   {      WORD wLeft;      WORD wTop;      WORD wWidth;      WORD wDepth;      struct localflag         {            BYTE PalBits   : 3;            BYTE Reserved  : 2;            BYTE SortFlag  : 1;            BYTE Interlace : 1;            BYTE LocalPal  : 1;         }  LocalFlag;   }  GIFIMAGE;typedef struct gifcontrol   {      BYTE byBlockSize;      struct flag         {            BYTE Transparency   : 1;            BYTE UserInput      : 1;            BYTE DisposalMethod : 3;            BYTE Reserved       : 3;         }  Flag;      WORD wDelayTime;      BYTE byTransparencyIndex;      BYTE byTerminator;   }  GIFCONTROL;typedef struct gifplaintext   {      BYTE byBlockSize;      WORD wTextGridLeft;      WORD wTextGridTop;      WORD wTextGridWidth;      WORD wTextGridDepth;      BYTE byCharCellWidth;      BYTE byCharCellDepth;      BYTE byForeColorIndex;      BYTE byBackColorIndex;   }  GIFPLAINTEXT;typedef struct gifapplication   {      BYTE byBlockSize;      BYTE byIdentifier[8];      BYTE byAuthentication[3];   }  GIFAPPLICATION;typedef struct gifd_var   {      LPSTR lpDataBuff;      LPSTR lpBgnBuff;      LPSTR lpEndBuff;      DWORD dwDataLen;      WORD  wMemLen;      WORD  wWidth;      WORD  wDepth;      WORD  wLineBytes;      WORD  wBits;      BOOL  bEOF;      BOOL  bInterlace;   }  GIFD_VAR;typedef GIFD_VAR FAR *LPGIFD_VAR;typedef struct gifc_var   {      LPSTR lpDataBuff;      LPSTR lpEndBuff;      DWORD dwTempCode;      WORD  wWidth;      WORD  wDepth;      WORD  wLineBytes;      WORD  wBits;      WORD  wByteCnt;      WORD  wBlockNdx;      BYTE  byLeftBits;   }  GIFC_VAR;typedef GIFC_VAR FAR *LPGIFC_VAR;// 宏運算#define DWORD_WBYTES(x)         ( (((x) + 31UL) >> 5) << 2 )#define WORD_WBYTES(x)          ( (((x) + 15UL) >> 4) << 1 )#define BYTE_WBYTES(x)          (  ((x) +  7UL) >> 3       )//常量#define MAX_BUFF_SIZE           32768 /* 32K */#define MAX_HASH_SIZE            5051#define MAX_TABLE_SIZE           4096 /* 12-bit */#define MAX_SUBBLOCK_SIZE         255// 函數原型BOOL WINAPI DIBToGIF(LPSTR lpDIB, CFile& file, BOOL bInterlace);void WINAPI EncodeGIF_LZW(LPSTR lpDIBBits, CFile& file, 						  LPGIFC_VAR lpGIFCVar,WORD wWidthBytes, BOOL bInterlace);void WINAPI GIF_LZW_WriteCode(CFile& file, WORD wCode, LPSTR lpSubBlock,							  LPBYTE lpbyCurrentBits,LPGIFC_VAR lpGIFCVar);HDIB WINAPI ReadGIF(CFile& file);void WINAPI ReadSrcData(CFile& file, LPWORD lpwMemLen, LPDWORD lpdwDataLen,                        LPSTR lpSrcBuff, LPBOOL lpbEOF);void WINAPI DecodeGIF_LZW(CFile& file, LPSTR lpDIBBits,						  LPGIFD_VAR lpGIFDVar,WORD wWidthBytes);