/*

 * Copyright (c) 1988-1997 Sam Leffler

 * Copyright (c) 1991-1997 Silicon Graphics, Inc.

 *

 * Permission to use, copy, modify, distribute, and sell this software and

 * its documentation for any purpose is hereby granted without fee, provided

 * that (i) the above copyright notices and this permission notice appear in

 * all copies of the software and related documentation, and (ii) the names of

 * Sam Leffler and Silicon Graphics may not be used in any advertising or

 * publicity relating to the software without the specific, prior written

 * permission of Sam Leffler and Silicon Graphics.

 *

 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,

 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY

 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

 *

 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR

 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,

 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,

 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF

 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE

 * OF THIS SOFTWARE.

 */

#include "tiffiop.h"

#ifdef NEXT_SUPPORT

/*

 * TIFF Library.

 *

 * NeXT 2-bit Grey Scale Compression Algorithm Support

 */

#define SETPIXEL(op, v)                                                        \

    {                                                                          \

        switch (npixels++ & 3)                                                 \

        {                                                                      \

            case 0:                                                            \

                op[0] = (unsigned char)((v) << 6);                             \

                break;                                                         \

            case 1:                                                            \

                op[0] |= (unsigned char)((v) << 4);                            \

                break;                                                         \

            case 2:                                                            \

                op[0] |= (unsigned char)((v) << 2);                            \

                break;                                                         \

            case 3:                                                            \

                *op++ |= (unsigned char)(v);                                   \

                op_offset++;                                                   \

                break;                                                         \

            default:                                                           \

                break;                                                         \

        }                                                                      \

    }

#define LITERALROW 0x00

#define LITERALSPAN 0x40

static int NeXTDecode(TIFF *tif, uint8_t *buf, tmsize_t occ, uint16_t s)

{

    static const char module[] = "NeXTDecode";

    unsigned char *bp, *op;

    tmsize_t cc;

    uint8_t *row;

    tmsize_t scanline, n;

    (void)s;

    /*

     * Each scanline is assumed to start off as all

     * white (we assume a PhotometricInterpretation

     * of ``min-is-black'').

     */

    for (op = (unsigned char *)buf, cc = occ; cc-- > 0;)

        *op++ = 0xff;

    bp = (unsigned char *)tif->tif_rawcp;

    cc = tif->tif_rawcc;

    scanline = tif->tif_dir.td_scanlinesize;

    if (occ % scanline)

    {

        TIFFErrorExtR(tif, module, "Fractional scanlines cannot be read");

        return (0);

    }

    for (row = buf; cc > 0 && occ > 0; occ -= scanline, row += scanline)

    {

        n = *bp++;

        cc--;

        switch (n)

        {

            case LITERALROW:

                /*

                 * The entire scanline is given as literal values.

                 */

                if (cc < scanline)

                    goto bad;

                _TIFFmemcpy(row, bp, scanline);

                bp += scanline;

                cc -= scanline;

                break;

            case LITERALSPAN:

            {

                tmsize_t off;

                /*

                 * The scanline has a literal span that begins at some

                 * offset.

                 */

                if (cc < 4)

                    goto bad;

                off = (bp[0] * 256) + bp[1];

                n = (bp[2] * 256) + bp[3];

                if (cc < 4 + n || off + n > scanline)

                    goto bad;

                _TIFFmemcpy(row + off, bp + 4, n);

                bp += 4 + n;

                cc -= 4 + n;

                break;

            }

            default:

            {

                uint32_t npixels = 0, grey;

                tmsize_t op_offset = 0;

                uint32_t imagewidth = tif->tif_dir.td_imagewidth;

                if (isTiled(tif))

                    imagewidth = tif->tif_dir.td_tilewidth;

                /*

                 * The scanline is composed of a sequence of constant

                 * color ``runs''.  We shift into ``run mode'' and

                 * interpret bytes as codes of the form

                 * <color><npixels> until we've filled the scanline.

                 */

                op = row;

                for (;;)

                {

                    grey = (uint32_t)((n >> 6) & 0x3);

                    n &= 0x3f;

                    /*

                     * Ensure the run does not exceed the scanline

                     * bounds, potentially resulting in a security

                     * issue.

                     */

                    while (n-- > 0 && npixels < imagewidth &&

                           op_offset < scanline)

                        SETPIXEL(op, grey);

                    if (npixels >= imagewidth)

                        break;

                    if (op_offset >= scanline)

                    {

                        TIFFErrorExtR(tif, module,

                                      "Invalid data for scanline %" PRIu32,

                                      tif->tif_dir.td_row);

                        return (0);

                    }

                    if (cc == 0)

                        goto bad;

                    n = *bp++;

                    cc--;

                }

                break;

            }

        }

    }

    tif->tif_rawcp = (uint8_t *)bp;

    tif->tif_rawcc = cc;

    return (1);

bad:

    TIFFErrorExtR(tif, module, "Not enough data for scanline %" PRIu32,

                  tif->tif_dir.td_row);

    return (0);

}

static int NeXTPreDecode(TIFF *tif, uint16_t s)

{

    static const char module[] = "NeXTPreDecode";

    TIFFDirectory *td = &tif->tif_dir;

    (void)s;

    if (td->td_bitspersample != 2)

    {

        TIFFErrorExtR(tif, module, "Unsupported BitsPerSample = %" PRIu16,

                      td->td_bitspersample);

        return (0);

    }

    return (1);

}

int TIFFInitNeXT(TIFF *tif, int scheme)

{

    (void)scheme;

    tif->tif_predecode = NeXTPreDecode;

    tif->tif_decoderow = NeXTDecode;

    tif->tif_decodestrip = NeXTDecode;

    tif->tif_decodetile = NeXTDecode;

    return (1);

}

#endif /* NEXT_SUPPORT */