////////////////////////////////////////////////////////////////////////////////
//
//      File: GIFLoad.h
//
//      Date: December 1999
//
//      Author: Daniel Switkin
//
//      Copyright 2003 (c) by Daniel Switkin. This file is made publically available
//      under the BSD license, with the stipulations that this complete header must
//      remain at the top of the file indefinitely, and credit must be given to the
//      original author in any about box using this software.
//
////////////////////////////////////////////////////////////////////////////////

// Additional authors:  John Scipione, <jscipione@gmail.com>

#ifndef GIF_LOAD_H
#define GIF_LOAD_H


#include <DataIO.h>
#include "LoadPalette.h"


#define GIF_INTERLACED          0x40
#define GIF_LOCALCOLORMAP       0x80

#define ENTRY_COUNT                     4354
        // 4354 = 4096 + 256 + 1 + 1
        // 4096 for the image data, 256 for the color codes,
        // 1 for the clear code, 1 for the end code


typedef struct Memblock {
        unsigned char   data[ENTRY_COUNT];
        int                             offset;
        Memblock*               next;
} Memblock;


const int gl_pass_starts_at[]           = { 0, 4, 2, 1, 0 };
const int gl_increment_pass_by[]        = { 8, 8, 4, 2, 0 };


class GIFLoad {
public:
                                                                GIFLoad(BPositionIO* input,
                                                                        BPositionIO* output);
        virtual                                         ~GIFLoad();

                        bool                            fatalerror;

private:
                        bool                            ReadGIFHeader();
                        bool                            ReadGIFLoopBlock();
                        bool                            ReadGIFControlBlock();
                        bool                            ReadGIFImageHeader();
                        bool                            ReadGIFImageData();
                        bool                            ReadGIFCommentBlock();
                        bool                            ReadGIFUnknownBlock(unsigned char c);

                        bool                            InitFrame(int codeSize);
                        short                           NextCode();
                        void                            ResetTable();

                        unsigned char*          MemblockAllocate(int size);
                        void                            MemblockDeleteAll();

                        inline  bool            OutputColor(unsigned char* string, int size);

                        BPositionIO*            fInput;
                        BPositionIO*            fOutput;
                        LoadPalette*            fPalette;

                        bool                            fInterlaced;

                        int                                     fPass;
                        int                                     fRow;

                        int                                     fWidth;
                        int                                     fHeight;

                        unsigned char           fOldCode[ENTRY_COUNT];
                        unsigned int            fOldCodeLength;

                        short                           fNewCode;
                        int                                     fBits;
                        int                                     fMaxCode;
                        int                                     fCodeSize;

                        short                           fClearCode;
                        short                           fEndCode;
                        short                           fNextCode;

                        unsigned char*          fTable[ENTRY_COUNT];
                        short                           fEntrySize[ENTRY_COUNT];
                        Memblock*                       fHeadMemblock;

                        int                                     fBitCount;
                        unsigned int            fBitBuffer;
                        unsigned char           fByteCount;
                        unsigned char           fByteBuffer[255];

                        uint32*                         fScanLine;
                        int                                     fScanlinePosition;
};


#endif  // GIF_LOAD_H