/* Copyright 1990 by Christopher A. Wichura.
   See file GIFMachine.doc for full description of rights.
*/

#include <exec/types.h>
#include <exec/lists.h>
#include <exec/nodes.h>
#include <proto/dos.h>
#include <proto/exec.h>
#include <string.h>
#include <stdlib.h>

/* some structures to make parsing the gif files a bit easier */
struct GIFdescriptor {
	UWORD gd_Width;
	UWORD gd_Height;
	UBYTE gd_ColInfo;
	UBYTE gd_BackGround;
	UBYTE gd_PixelAspect;	/* Aspect Ratio = (Pixel Aspect + 15) / 64 */
};

struct ImageDesc {
	UWORD id_Left;
	UWORD id_Top;
	UWORD id_Width;
	UWORD id_Height;
	UBYTE id_Info;
};

struct RGB {
	UBYTE rgb_Red;
	UBYTE rgb_Green;
	UBYTE rgb_Blue;
};

#define GIF_IMAGE      0x2C
#define GIF_EXTENSION  0x21
#define GIF_TERMINATOR 0x3B

#define GIF_COMMENT_EXT 0xFE

#define MAXCOLOURS 4096

/* these next macros are used to get the r, g, and b values of a given
   index */
#define GetRed(a)	(UBYTE)(a >> 8)
#define GetGreen(a)	(UBYTE)((a >> 4) & 0xF)
#define GetBlue(a)	(UBYTE)(a & 0xF)

/* whenever we want to abort we will return this as our error code */
#define ABORTEXITVAL 1

/* this struct is used to hold the linked list of comments found in the GIF
   file so that each can be written as a seperate ANNO chunk. */
struct CommentNode {
	struct MinNode cn_Node;
	char *cn_Comment;
	ULONG cn_CommentLength;
};

/* function prototypes we use */
extern int __regargs main(char *cmdptr, int cmdlen, struct WBStartup *WBMsg);
extern void	WarnMustUseCLI(void);
extern void	DoPattern(char *);
extern void	Convert(char *);
extern BOOL	IsDir(char *);
extern void	FlipWord(UWORD *);
extern BOOL	DoImage(BPTR);
extern BOOL	DoExtension(BPTR);
extern BOOL	WriteIFF(char *, BOOL);
extern void	PutValue(UWORD, UWORD, UWORD);
extern UWORD	GetValue(UWORD, UWORD);
extern int	ReadCode(BPTR);
extern void	AddPixel(UBYTE);
extern void	StripBorder(void);
extern BOOL	BorderCheck(UWORD, UWORD);
extern void	DoXComp(void);
extern void	GIFtoSHAM(void);
extern void	InitDiff(void);
extern ULONG	RGBdiff(UBYTE, UBYTE, UBYTE, UBYTE, UBYTE, UBYTE);
extern void	OutDump(int);
extern void	OutRun(int, int);
extern void	InitMemory(void);
extern char *	MyAlloc(ULONG);
extern void	MyFree(char *);
extern void	FreeAll(UWORD);
extern void	MyExit(ULONG);
extern void	DoXFlip(void);
extern void	DoYFlip(void);
extern void	ReduceTo12(void);
extern void	DitherTo12(void);
extern UWORD	AddColour(struct RGB *);
extern void __stdargs MyPrintf(char *, ...);
extern void __stdargs MySPrintf(char *, char *, ...);

/* modules that want to use the Get/PutValue macros should include this
   next macro to externally reference the picture storage array */
#define EXTERNBITPLANE extern struct RGB **BitPlane

/* for use once colour palette has been reduced to 12 bits */
#define GetValue(a, b) *((UWORD *)&BitPlane[b][a])
#define PutValue(a, b, c) *((UWORD *)&BitPlane[b][a]) = c