#pragma warn -use
static char 	*sccsid = "@(#)TIFF/tif_fax4.c 1.05, Copyright (c) Sam Leffler, Dieter Linde, "__DATE__;
#pragma warn .use
/*
 * Copyright (c) 1988, 1990 by Sam Leffler, Oct 8 1990
 * All rights reserved.
 *
 * This file is provided for unrestricted use provided that this legend is included on all tape media and as a part of the
 * software program in whole or part.  Users may copy, modify or distribute this file at will.
 *
 * TIFF Library.
 *
 * CCITT Group 4 Facsimile-compatible Compression Scheme Support.
 */
#include "tiffio.h"
#include "tif_fax3.h"

/****************************************************************************
 * Decode the requested amount of data.
 */
static int
Fax4Decode(
        TIFF 	*tif,
        u_char 	*buf,
        int 	occ
        )
{
        int 		scanline = tif->tif_scanlinesize;
        int 		imagewidth = tif->tif_dir.td_imagewidth;
        Fax3BaseState 	*sp = (Fax3BaseState *)tif->tif_data;

        bzero(buf, occ);               	/* decoding only sets non-zero bits */
        while (occ > 0) {
                if (!Fax3Decode2DRow(tif, (u_char *)buf, imagewidth))
                        return(0);
                bcopy(buf, sp->refline, scanline);
                buf += scanline;
                occ -= scanline;
        }
        return(1);
}

/****************************************************************************
 * Encode the requested amount of data.
 */
static int
Fax4Encode(
        TIFF 	*tif,
        u_char	*buf,
        int 	cc
        )
{
        u_char 	*refline = ((Fax3BaseState *)tif->tif_data)->refline;
        int 	scanline = tif->tif_scanlinesize;
        int 	imagewidth = tif->tif_dir.td_imagewidth;

        while (cc > 0) {
                if (!Fax3Encode2DRow(tif, (u_char *)buf, refline, imagewidth))
                        return(0);
                bcopy(buf, refline, scanline);
                buf += scanline;
                cc -= scanline;
        }
        return(1);
}

/****************************************************************************
 *
 */
static void
Fax4Close(
        TIFF 	*tif
        )
{
        if (tif->tif_data) {           	/* append EOFB */
                Fax3PutEOL(tif);
                Fax3PutEOL(tif);
                (*tif->tif_encodestrip)(tif);
        }
}

/****************************************************************************
 *
 */
int
TIFFInitCCITTFax4(
        TIFF	*tif
        )
{
        TIFFInitCCITTFax3(tif);        	/* reuse G3 compression */
        tif->tif_decoderow = Fax4Decode;
        tif->tif_encoderow = Fax4Encode;
        tif->tif_close = Fax4Close;

        /*
         * This magic causes the regular G3 decompression code to not skip to the EOL mark at the end of
         * a row (during normal decoding).
         */
        tif->tif_options |= TIFF_OPT1;
        return(1);
}