// GIF File Format Header
// Gif.h

struct SGifHeader
{
	// Header
	BYTE signature[3];		// Header Signature (always "GIF")
	BYTE version[3];		// GIF format version ("87a" or "89a")

	// Logical Screen Descriptor
	WORD width;				// Width of Display Screen in Pixels
	WORD height;			// Height of Display Screen in Pixels
	BYTE packed;			// Screen and Color Map Information
	BYTE bgColor;			// Background Color Index
	BYTE aspectRatio;		// Pixel Aspect Ratio
};
struct SGifColorTable
{
	BYTE red;
	BYTE green;
	BYTE blue;
};
struct SGifImageDesc
{
//	BYTE separator;			// Image Descriptor identifier (always 2Ch)
	WORD left;				// X position of image on the display
	WORD top;				// Y position of image on the display
	WORD width;				// Width of the image in pixels
	WORD height;			// Height of the image in pixels
	BYTE packed;			// Image and Color Table Data Information
};
struct SGifGraphicControlExt
{
//	BYTE introducer;		// Extension Introducer (always 21h)
//	BYTE label;				// Graphic Control label (always F9h)
//	BYTE blockSize;			// Size of remaining fields (always 04h)

	BYTE packed;			// Method of graphics disposal to use
	WORD delayTime;			// Hundredths of seconds to wait
	BYTE colorIndex;		// Transparent Color Index
//	BYTE terminator;		// Block Terminator (always 0)

	struct SGifGraphicControlExt *next;
};
struct SGifPlainTextExt
{
//	BYTE introducer;		// Extension Introducer (always 21h)
//	BYTE label;				// Extension Label (always 01h)
//	BYTE blockSize;			// Size of Extension Block (always 0Ch)

	WORD left;				// X position of text grid in pixels
	WORD top;				// Y position of text grid in pixels
	WORD width;				// Width of the text grid in pixels
	WORD height;			// Height of the text grid in pixels
	BYTE cellWidth;			// Width of a grid cell in pixels
	BYTE cellHeight;		// Height of a grid cell in pixels
	BYTE fgColor;			// Text foreground color index value
	BYTE bgColor;			// Text background color index value

	BYTE dataSize;
	BYTE *plainTextData;	// The Plain Text Data
//	BYTE terminator;		// Block Terminator (always 0)

	struct SGifPlainTextExt *next;
};
struct SGifApplicationExt
{
//	BYTE introducer;		// Extension Introducer (always 21h)
//	BYTE label;				// Extension Label (always FFh)
//	BYTE blockSize;			// Size of Extension Block (always 0Bh)

	char identifier[8];		// Application Identifier
	BYTE authentCode[3];	// Application Authentication Code

	BYTE dataSize;
	BYTE *applicationData;	// Pointer to Application Data sub-blocks
//	BYTE terminator;		// Block Terminator (always 0)

	struct SGifApplicationExt *next;
};
struct SGifCommentExt
{
//	BYTE introducer;		// Extension Introducer (always 21h)
//	BYTE label;				// Comment Label (always FEh)

	BYTE dataSize;
	BYTE *commentData;		// Pointer to comment Data sub-blocks
//	BYTE terminator;		// Block Terminator (always 0)

	struct SGifCommentExt *next;
};

struct SGifImage
{
	SGifImageDesc info;
	SGifColorTable *localColorTable;
	BYTE *image;
	unsigned long size;
	
	struct SGifImage *next;
};

struct SLzwTable
{
	BYTE bits;

	WORD previous;
	WORD next;
};