gif_lib_private.h

支持各种栅格图像和矢量图像读取的库

#ifndef GIF_LIB_PRIVATE_H
#define GIF_LIB_PRIVATE_H

#include "gif_lib.h"

#define PROGRAM_NAME	"GIFLIB"

#define LZ_MAX_CODE	4095		/* Biggest code possible in 12 bits. */
#define LZ_BITS		12

#define FLUSH_OUTPUT		4096    /* Impossible code, to signal flush. */
#define FIRST_CODE		4097    /* Impossible code, to signal first. */
#define NO_SUCH_CODE		4098    /* Impossible code, to signal empty. */

#define FILE_STATE_WRITE    0x01
#define FILE_STATE_SCREEN   0x02
#define FILE_STATE_IMAGE    0x04
#define FILE_STATE_READ     0x08

#define IS_READABLE(Private)    (Private->FileState & FILE_STATE_READ)
#define IS_WRITEABLE(Private)   (Private->FileState & FILE_STATE_WRITE)


typedef struct GifFilePrivateType {
    int FileState,
	FileHandle,			     /* Where all this data goes to! */
	BitsPerPixel,	    /* Bits per pixel (Codes uses at least this + 1). */
	ClearCode,				       /* The CLEAR LZ code. */
	EOFCode,				         /* The EOF LZ code. */
	RunningCode,		    /* The next code algorithm can generate. */
	RunningBits,/* The number of bits required to represent RunningCode. */
	MaxCode1,  /* 1 bigger than max. possible code, in RunningBits bits. */
	LastCode,		        /* The code before the current code. */
	CrntCode,				  /* Current algorithm code. */
	StackPtr,		         /* For character stack (see below). */
	CrntShiftState;		        /* Number of bits in CrntShiftDWord. */
    unsigned long CrntShiftDWord;     /* For bytes decomposition into codes. */
    unsigned long PixelCount;		       /* Number of pixels in image. */
    FILE *File;						  /* File as stream. */
    InputFunc Read;                 /* function to read gif input (TVT) */
    OutputFunc Write;               /* function to write gif output (MRB) */
    GifByteType Buf[256];	       /* Compressed input is buffered here. */
    GifByteType Stack[LZ_MAX_CODE];	 /* Decoded pixels are stacked here. */
    GifByteType Suffix[LZ_MAX_CODE+1];	       /* So we can trace the codes. */
    unsigned int Prefix[LZ_MAX_CODE+1];
} GifFilePrivateType;

extern int _GifError;

#endif /* GIF_LIB_PRIVATE_H */