/*

 * 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 PACKBITS_SUPPORT

/*

 * TIFF Library.

 *

 * PackBits Compression Algorithm Support

 */

#include <stdio.h>

#ifndef PACKBITS_READ_ONLY

static int PackBitsPreEncode(TIFF *tif, uint16_t s)

{

    (void)s;

    tif->tif_data = (uint8_t *)_TIFFmallocExt(tif, sizeof(tmsize_t));

    if (tif->tif_data == NULL)

        return (0);

    /*

     * Calculate the scanline/tile-width size in bytes.

     */

    if (isTiled(tif))

        *(tmsize_t *)tif->tif_data = TIFFTileRowSize(tif);

    else

        *(tmsize_t *)tif->tif_data = TIFFScanlineSize(tif);

    return (1);

}

static int PackBitsPostEncode(TIFF *tif)

{

    if (tif->tif_data)

        _TIFFfreeExt(tif, tif->tif_data);

    return (1);

}

/*

 * Encode a run of pixels.

 */

static int PackBitsEncode(TIFF *tif, uint8_t *buf, tmsize_t cc, uint16_t s)

{

    unsigned char *bp = (unsigned char *)buf;

    uint8_t *op;

    uint8_t *ep;

    uint8_t *lastliteral;

    long n, slop;

    int b;

    enum

    {

        BASE,

        LITERAL,

        RUN,

        LITERAL_RUN

    } state;

    (void)s;

    op = tif->tif_rawcp;

    ep = tif->tif_rawdata + tif->tif_rawdatasize;

    state = BASE;

    lastliteral = NULL;

    while (cc > 0)

    {

        /*

         * Find the longest string of identical bytes.

         */

        b = *bp++;

        cc--;

        n = 1;

        for (; cc > 0 && b == *bp; cc--, bp++)

            n++;

    again:

        if (op + 2 >= ep)

        { /* insure space for new data */

            /*

             * Be careful about writing the last

             * literal.  Must write up to that point

             * and then copy the remainder to the

             * front of the buffer.

             */

            if (state == LITERAL || state == LITERAL_RUN)

            {

                slop = (long)(op - lastliteral);

                tif->tif_rawcc += (tmsize_t)(lastliteral - tif->tif_rawcp);

                if (!TIFFFlushData1(tif))

                    return (0);

                op = tif->tif_rawcp;

                while (slop-- > 0)

                    *op++ = *lastliteral++;

                lastliteral = tif->tif_rawcp;

            }

            else

            {

                tif->tif_rawcc += (tmsize_t)(op - tif->tif_rawcp);

                if (!TIFFFlushData1(tif))

                    return (0);

                op = tif->tif_rawcp;

            }

        }

        switch (state)

        {

            case BASE: /* initial state, set run/literal */

                if (n > 1)

                {

                    state = RUN;

                    if (n > 128)

                    {

                        *op++ = (uint8_t)-127;

                        *op++ = (uint8_t)b;

                        n -= 128;

                        goto again;

                    }

                    *op++ = (uint8_t)(-(n - 1));

                    *op++ = (uint8_t)b;

                }

                else

                {

                    lastliteral = op;

                    *op++ = 0;

                    *op++ = (uint8_t)b;

                    state = LITERAL;

                }

                break;

            case LITERAL: /* last object was literal string */

                if (n > 1)

                {

                    state = LITERAL_RUN;

                    if (n > 128)

                    {

                        *op++ = (uint8_t)-127;

                        *op++ = (uint8_t)b;

                        n -= 128;

                        goto again;

                    }

                    *op++ = (uint8_t)(-(n - 1)); /* encode run */

                    *op++ = (uint8_t)b;

                }

                else

                { /* extend literal */

                    if (++(*lastliteral) == 127)

                        state = BASE;

                    *op++ = (uint8_t)b;

                }

                break;

            case RUN: /* last object was run */

                if (n > 1)

                {

                    if (n > 128)

                    {

                        *op++ = (uint8_t)-127;

                        *op++ = (uint8_t)b;

                        n -= 128;

                        goto again;

                    }

                    *op++ = (uint8_t)(-(n - 1));

                    *op++ = (uint8_t)b;

                }

                else

                {

                    lastliteral = op;

                    *op++ = 0;

                    *op++ = (uint8_t)b;

                    state = LITERAL;

                }

                break;

            case LITERAL_RUN: /* literal followed by a run */

                /*

                 * Check to see if previous run should

                 * be converted to a literal, in which

                 * case we convert literal-run-literal

                 * to a single literal.

                 */

                if (n == 1 && op[-2] == (uint8_t)-1 && *lastliteral < 126)

                {

                    state =

                        (((*lastliteral) = (uint8_t)(*lastliteral + 2)) == 127

                             ? BASE

                             : LITERAL);

                    op[-2] = op[-1]; /* replicate */

                }

                else

                    state = RUN;

                goto again;

            default:

                break;

        }

    }

    tif->tif_rawcc += (tmsize_t)(op - tif->tif_rawcp);

    tif->tif_rawcp = op;

    return (1);

}

/*

 * Encode a rectangular chunk of pixels.  We break it up

 * into row-sized pieces to insure that encoded runs do

 * not span rows.  Otherwise, there can be problems with

 * the decoder if data is read, for example, by scanlines

 * when it was encoded by strips.

 */

static int PackBitsEncodeChunk(TIFF *tif, uint8_t *bp, tmsize_t cc, uint16_t s)

{

    tmsize_t rowsize = *(tmsize_t *)tif->tif_data;

    while (cc > 0)

    {

        tmsize_t chunk = rowsize;

        if (cc < chunk)

            chunk = cc;

        if (PackBitsEncode(tif, bp, chunk, s) < 0)

            return (-1);

        bp += chunk;

        cc -= chunk;

    }

    return (1);

}

#endif

static int PackBitsDecode(TIFF *tif, uint8_t *op, tmsize_t occ, uint16_t s)

{

    static const char module[] = "PackBitsDecode";

    int8_t *bp;

    tmsize_t cc;

    long n;

    int b;

    (void)s;

    bp = (int8_t *)tif->tif_rawcp;

    cc = tif->tif_rawcc;

    while (cc > 0 && occ > 0)

    {

        n = (long)*bp++;

        cc--;

        if (n < 0)

        {                  /* replicate next byte -n+1 times */

            if (n == -128) /* nop */

                continue;

            n = -n + 1;

            if (occ < (tmsize_t)n)

            {

                TIFFWarningExtR(tif, module,

                                "Discarding %" TIFF_SSIZE_FORMAT

                                " bytes to avoid buffer overrun",

                                (tmsize_t)n - occ);

                n = (long)occ;

            }

            if (cc == 0)

            {

                TIFFWarningExtR(

                    tif, module,

                    "Terminating PackBitsDecode due to lack of data.");

                break;

            }

            occ -= n;

            b = *bp++;

            cc--;

            while (n-- > 0)

                *op++ = (uint8_t)b;

        }

        else

        { /* copy next n+1 bytes literally */

            if (occ < (tmsize_t)(n + 1))

            {

                TIFFWarningExtR(tif, module,

                                "Discarding %" TIFF_SSIZE_FORMAT

                                " bytes to avoid buffer overrun",

                                (tmsize_t)n - occ + 1);

                n = (long)occ - 1;

            }

            if (cc < (tmsize_t)(n + 1))

            {

                TIFFWarningExtR(

                    tif, module,

                    "Terminating PackBitsDecode due to lack of data.");

                break;

            }

            _TIFFmemcpy(op, bp, ++n);

            op += n;

            occ -= n;

            bp += n;

            cc -= n;

        }

    }

    tif->tif_rawcp = (uint8_t *)bp;

    tif->tif_rawcc = cc;

    if (occ > 0)

    {

        memset(op, 0, (size_t)occ);

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

                      tif->tif_dir.td_row);

        return (0);

    }

    return (1);

}

static uint64_t PackBitsGetMaxCompressionRatio(TIFF *tif)

{

    (void)tif;

    /* See README_for_libtiff_developpers.md for raw data used to estimate

     * the maximum compression rate. */

    return 64;

}

int TIFFInitPackBits(TIFF *tif, int scheme)

{

    (void)scheme;

    tif->tif_decoderow = PackBitsDecode;

    tif->tif_decodestrip = PackBitsDecode;

    tif->tif_decodetile = PackBitsDecode;

#ifndef PACKBITS_READ_ONLY

    tif->tif_preencode = PackBitsPreEncode;

    tif->tif_postencode = PackBitsPostEncode;

    tif->tif_encoderow = PackBitsEncode;

    tif->tif_encodestrip = PackBitsEncodeChunk;

    tif->tif_encodetile = PackBitsEncodeChunk;

#endif

    tif->tif_getmaxcompressionratio = PackBitsGetMaxCompressionRatio;

    return (1);

}

#endif /* PACKBITS_SUPPORT */