tif_predict.c

/* $Id: tif_predict.c,v 1.32 2010-03-10 18:56:49 bfriesen Exp $ */

/*
 * 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.
 */

/*
 * TIFF Library.
 *
 * Predictor Tag Support (used by multiple codecs).
 */
#include "tiffiop.h"
#include "tif_predict.h"

#define	PredictorState(tif)	((TIFFPredictorState*) (tif)->tif_data)

static void horAcc8(TIFF* tif, uint8* cp0, tmsize_t cc);
static void horAcc16(TIFF* tif, uint8* cp0, tmsize_t cc);
static void horAcc32(TIFF* tif, uint8* cp0, tmsize_t cc);
static void swabHorAcc16(TIFF* tif, uint8* cp0, tmsize_t cc);
static void swabHorAcc32(TIFF* tif, uint8* cp0, tmsize_t cc);
static void horDiff8(TIFF* tif, uint8* cp0, tmsize_t cc);
static void horDiff16(TIFF* tif, uint8* cp0, tmsize_t cc);
static void horDiff32(TIFF* tif, uint8* cp0, tmsize_t cc);
static void fpAcc(TIFF* tif, uint8* cp0, tmsize_t cc);
static void fpDiff(TIFF* tif, uint8* cp0, tmsize_t cc);
static int PredictorDecodeRow(TIFF* tif, uint8* op0, tmsize_t occ0, uint16 s);
static int PredictorDecodeTile(TIFF* tif, uint8* op0, tmsize_t occ0, uint16 s);
static int PredictorEncodeRow(TIFF* tif, uint8* bp, tmsize_t cc, uint16 s);
static int PredictorEncodeTile(TIFF* tif, uint8* bp0, tmsize_t cc0, uint16 s);

static int
PredictorSetup(TIFF* tif)
{
    static const char module[] = "PredictorSetup";

    TIFFPredictorState* sp = PredictorState(tif);
    TIFFDirectory* td = &tif->tif_dir;

    switch (sp->predictor)		/* no differencing */
    {
        case PREDICTOR_NONE:
            return 1;
        case PREDICTOR_HORIZONTAL:
            if (td->td_bitspersample != 8
                && td->td_bitspersample != 16
                && td->td_bitspersample != 32) {
                TIFFErrorExt(tif->tif_clientdata, module,
                    "Horizontal differencing \"Predictor\" not supported with %d-bit samples",
                    td->td_bitspersample);
                return 0;
            }
            break;
        case PREDICTOR_FLOATINGPOINT:
            if (td->td_sampleformat != SAMPLEFORMAT_IEEEFP) {
                TIFFErrorExt(tif->tif_clientdata, module,
                    "Floating point \"Predictor\" not supported with %d data format",
                    td->td_sampleformat);
                return 0;
            }
            break;
        default:
            TIFFErrorExt(tif->tif_clientdata, module,
                "\"Predictor\" value %d not supported",
                sp->predictor);
            return 0;
    }
    sp->stride = (td->td_planarconfig == PLANARCONFIG_CONTIG ?
        td->td_samplesperpixel : 1);
    /*
     * Calculate the scanline/tile-width size in bytes.
     */
    if (isTiled(tif))
        sp->rowsize = TIFFTileRowSize(tif);
    else
        sp->rowsize = TIFFScanlineSize(tif);
    if (sp->rowsize == 0)
        return 0;

    return 1;
}

static int
PredictorSetupDecode(TIFF* tif)
{
    TIFFPredictorState* sp = PredictorState(tif);
    TIFFDirectory* td = &tif->tif_dir;

    if (!(*sp->setupdecode)(tif) || !PredictorSetup(tif))
        return 0;

    if (sp->predictor == 2) {
        switch (td->td_bitspersample) {
            case 8:  sp->decodepfunc = horAcc8; break;
            case 16: sp->decodepfunc = horAcc16; break;
            case 32: sp->decodepfunc = horAcc32; break;
        }
        /*
         * Override default decoding method with one that does the
         * predictor stuff.
         */
                if( tif->tif_decoderow != PredictorDecodeRow )
                {
                    sp->decoderow = tif->tif_decoderow;
                    tif->tif_decoderow = PredictorDecodeRow;
                    sp->decodestrip = tif->tif_decodestrip;
                    tif->tif_decodestrip = PredictorDecodeTile;
                    sp->decodetile = tif->tif_decodetile;
                    tif->tif_decodetile = PredictorDecodeTile;
                }

        /*
         * If the data is horizontally differenced 16-bit data that
         * requires byte-swapping, then it must be byte swapped before
         * the accumulation step.  We do this with a special-purpose
         * routine and override the normal post decoding logic that
         * the library setup when the directory was read.
         */
        if (tif->tif_flags & TIFF_SWAB) {
            if (sp->decodepfunc == horAcc16) {
                sp->decodepfunc = swabHorAcc16;
                tif->tif_postdecode = _TIFFNoPostDecode;
            } else if (sp->decodepfunc == horAcc32) {
                sp->decodepfunc = swabHorAcc32;
                tif->tif_postdecode = _TIFFNoPostDecode;
            }
        }
    }

    else if (sp->predictor == 3) {
        sp->decodepfunc = fpAcc;
        /*
         * Override default decoding method with one that does the
         * predictor stuff.
         */
                if( tif->tif_decoderow != PredictorDecodeRow )
                {
                    sp->decoderow = tif->tif_decoderow;
                    tif->tif_decoderow = PredictorDecodeRow;
                    sp->decodestrip = tif->tif_decodestrip;
                    tif->tif_decodestrip = PredictorDecodeTile;
                    sp->decodetile = tif->tif_decodetile;
                    tif->tif_decodetile = PredictorDecodeTile;
                }
        /*
         * The data should not be swapped outside of the floating
         * point predictor, the accumulation routine should return
         * byres in the native order.
         */
        if (tif->tif_flags & TIFF_SWAB) {
            tif->tif_postdecode = _TIFFNoPostDecode;
        }
        /*
         * Allocate buffer to keep the decoded bytes before
         * rearranging in the ight order
         */
    }

    return 1;
}

static int
PredictorSetupEncode(TIFF* tif)
{
    TIFFPredictorState* sp = PredictorState(tif);
    TIFFDirectory* td = &tif->tif_dir;

    if (!(*sp->setupencode)(tif) || !PredictorSetup(tif))
        return 0;

    if (sp->predictor == 2) {
        switch (td->td_bitspersample) {
            case 8:  sp->encodepfunc = horDiff8; break;
            case 16: sp->encodepfunc = horDiff16; break;
            case 32: sp->encodepfunc = horDiff32; break;
        }
        /*
         * Override default encoding method with one that does the
         * predictor stuff.
         */
                if( tif->tif_encoderow != PredictorEncodeRow )
                {
                    sp->encoderow = tif->tif_encoderow;
                    tif->tif_encoderow = PredictorEncodeRow;
                    sp->encodestrip = tif->tif_encodestrip;
                    tif->tif_encodestrip = PredictorEncodeTile;
                    sp->encodetile = tif->tif_encodetile;
                    tif->tif_encodetile = PredictorEncodeTile;
                }
    }

    else if (sp->predictor == 3) {
        sp->encodepfunc = fpDiff;
        /*
         * Override default encoding method with one that does the
         * predictor stuff.
         */
                if( tif->tif_encoderow != PredictorEncodeRow )
                {
                    sp->encoderow = tif->tif_encoderow;
                    tif->tif_encoderow = PredictorEncodeRow;
                    sp->encodestrip = tif->tif_encodestrip;
                    tif->tif_encodestrip = PredictorEncodeTile;
                    sp->encodetile = tif->tif_encodetile;
                    tif->tif_encodetile = PredictorEncodeTile;
                }
    }

    return 1;
}

#define REPEAT4(n, op)		\
    switch (n) {		\
    default: { tmsize_t i; for (i = n-4; i > 0; i--) { op; } } \
    case 4:  op;		\
    case 3:  op;		\
    case 2:  op;		\
    case 1:  op;		\
    case 0:  ;			\
    }

static void
horAcc8(TIFF* tif, uint8* cp0, tmsize_t cc)
{
    tmsize_t stride = PredictorState(tif)->stride;

    char* cp = (char*) cp0;
    assert((cc%stride)==0);
    if (cc > stride) {
        /*
         * Pipeline the most common cases.
         */
        if (stride == 3)  {
            unsigned int cr = cp[0];
            unsigned int cg = cp[1];
            unsigned int cb = cp[2];
            cc -= 3;
            cp += 3;
            while (cc>0) {
                cp[0] = (char) (cr += cp[0]);
                cp[1] = (char) (cg += cp[1]);
                cp[2] = (char) (cb += cp[2]);
                cc -= 3;
                cp += 3;
            }
        } else if (stride == 4)  {
            unsigned int cr = cp[0];
            unsigned int cg = cp[1];
            unsigned int cb = cp[2];
            unsigned int ca = cp[3];
            cc -= 4;
            cp += 4;
            while (cc>0) {
                cp[0] = (char) (cr += cp[0]);
                cp[1] = (char) (cg += cp[1]);
                cp[2] = (char) (cb += cp[2]);
                cp[3] = (char) (ca += cp[3]);
                cc -= 4;
                cp += 4;
            }
        } else  {
            cc -= stride;
            do {
                REPEAT4(stride, cp[stride] =
                    (char) (cp[stride] + *cp); cp++)
                cc -= stride;
            } while (cc>0);
        }
    }
}

static void
swabHorAcc16(TIFF* tif, uint8* cp0, tmsize_t cc)
{
    tmsize_t stride = PredictorState(tif)->stride;
    uint16* wp = (uint16*) cp0;
    tmsize_t wc = cc / 2;

    assert((cc%(2*stride))==0);

    if (wc > stride) {
        TIFFSwabArrayOfShort(wp, wc);
        wc -= stride;
        do {
            REPEAT4(stride, wp[stride] += wp[0]; wp++)
            wc -= stride;
        } while (wc > 0);
    }
}

static void
horAcc16(TIFF* tif, uint8* cp0, tmsize_t cc)
{
    tmsize_t stride = PredictorState(tif)->stride;
    uint16* wp = (uint16*) cp0;
    tmsize_t wc = cc / 2;

    assert((cc%(2*stride))==0);

    if (wc > stride) {
        wc -= stride;
        do {
            REPEAT4(stride, wp[stride] += wp[0]; wp++)
            wc -= stride;
        } while (wc > 0);
    }
}

static void
swabHorAcc32(TIFF* tif, uint8* cp0, tmsize_t cc)
{
    tmsize_t stride = PredictorState(tif)->stride;
    uint32* wp = (uint32*) cp0;
    tmsize_t wc = cc / 4;

    assert((cc%(4*stride))==0);

    if (wc > stride) {
        TIFFSwabArrayOfLong(wp, wc);
        wc -= stride;
        do {
            REPEAT4(stride, wp[stride] += wp[0]; wp++)
            wc -= stride;
        } while (wc > 0);
    }
}

static void
horAcc32(TIFF* tif, uint8* cp0, tmsize_t cc)
{
    tmsize_t stride = PredictorState(tif)->stride;
    uint32* wp = (uint32*) cp0;
    tmsize_t wc = cc / 4;

    assert((cc%(4*stride))==0);

    if (wc > stride) {
        wc -= stride;
        do {
            REPEAT4(stride, wp[stride] += wp[0]; wp++)
            wc -= stride;
        } while (wc > 0);
    }
}

/*
 * Floating point predictor accumulation routine.
 */
static void
fpAcc(TIFF* tif, uint8* cp0, tmsize_t cc)
{
    tmsize_t stride = PredictorState(tif)->stride;
    uint32 bps = tif->tif_dir.td_bitspersample / 8;
    tmsize_t wc = cc / bps;
    tmsize_t count = cc;
    uint8 *cp = (uint8 *) cp0;
    uint8 *tmp = (uint8 *)_TIFFmalloc(cc);

    assert((cc%(bps*stride))==0);

    if (!tmp)
        return;

    while (count > stride) {
        REPEAT4(stride, cp[stride] += cp[0]; cp++)
        count -= stride;
    }

    _TIFFmemcpy(tmp, cp0, cc);
    cp = (uint8 *) cp0;
    for (count = 0; count < wc; count++) {
        uint32 byte;
        for (byte = 0; byte < bps; byte++) {
            #if WORDS_BIGENDIAN
            cp[bps * count + byte] = tmp[byte * wc + count];
            #else
            cp[bps * count + byte] =
                tmp[(bps - byte - 1) * wc + count];
            #endif
        }
    }
    _TIFFfree(tmp);
}

/*
 * Decode a scanline and apply the predictor routine.
 */
static int
PredictorDecodeRow(TIFF* tif, uint8* op0, tmsize_t occ0, uint16 s)
{
    TIFFPredictorState *sp = PredictorState(tif);

    assert(sp != NULL);
    assert(sp->decoderow != NULL);
    assert(sp->decodepfunc != NULL);

    if ((*sp->decoderow)(tif, op0, occ0, s)) {
        (*sp->decodepfunc)(tif, op0, occ0);
        return 1;
    } else
        return 0;
}

/*
 * Decode a tile/strip and apply the predictor routine.
 * Note that horizontal differencing must be done on a
 * row-by-row basis.  The width of a "row" has already
 * been calculated at pre-decode time according to the
 * strip/tile dimensions.
 */
static int
PredictorDecodeTile(TIFF* tif, uint8* op0, tmsize_t occ0, uint16 s)
{
    TIFFPredictorState *sp = PredictorState(tif);

    assert(sp != NULL);
    assert(sp->decodetile != NULL);

    if ((*sp->decodetile)(tif, op0, occ0, s)) {
        tmsize_t rowsize = sp->rowsize;
        assert(rowsize > 0);
        assert((occ0%rowsize)==0);
        assert(sp->decodepfunc != NULL);
        while (occ0 > 0) {
            (*sp->decodepfunc)(tif, op0, rowsize);
            occ0 -= rowsize;
            op0 += rowsize;
        }
        return 1;
    } else
        return 0;
}

static void
horDiff8(TIFF* tif, uint8* cp0, tmsize_t cc)
{
    TIFFPredictorState* sp = PredictorState(tif);
    tmsize_t stride = sp->stride;
    char* cp = (char*) cp0;

    assert((cc%stride)==0);

    if (cc > stride) {
        cc -= stride;
        /*
         * Pipeline the most common cases.
         */
        if (stride == 3) {
            int r1, g1, b1;
            int r2 = cp[0];
            int g2 = cp[1];
            int b2 = cp[2];
            do {
                r1 = cp[3]; cp[3] = r1-r2; r2 = r1;
                g1 = cp[4]; cp[4] = g1-g2; g2 = g1;
                b1 = cp[5]; cp[5] = b1-b2; b2 = b1;
                cp += 3;
            } while ((cc -= 3) > 0);
        } else if (stride == 4) {
            int r1, g1, b1, a1;
            int r2 = cp[0];
            int g2 = cp[1];
            int b2 = cp[2];
            int a2 = cp[3];
            do {
                r1 = cp[4]; cp[4] = r1-r2; r2 = r1;
                g1 = cp[5]; cp[5] = g1-g2; g2 = g1;
                b1 = cp[6]; cp[6] = b1-b2; b2 = b1;
                a1 = cp[7]; cp[7] = a1-a2; a2 = a1;
                cp += 4;
            } while ((cc -= 4) > 0);
        } else {
            cp += cc - 1;
            do {
                REPEAT4(stride, cp[stride] -= cp[0]; cp--)
            } while ((cc -= stride) > 0);
        }
    }
}

static void
horDiff16(TIFF* tif, uint8* cp0, tmsize_t cc)
{
    TIFFPredictorState* sp = PredictorState(tif);
    tmsize_t stride = sp->stride;
    int16 *wp = (int16*) cp0;
    tmsize_t wc = cc/2;

    assert((cc%(2*stride))==0);

    if (wc > stride) {
        wc -= stride;
        wp += wc - 1;
        do {
            REPEAT4(stride, wp[stride] -= wp[0]; wp--)
            wc -= stride;
        } while (wc > 0);
    }
}

static void
horDiff32(TIFF* tif, uint8* cp0, tmsize_t cc)
{
    TIFFPredictorState* sp = PredictorState(tif);
    tmsize_t stride = sp->stride;
    int32 *wp = (int32*) cp0;
    tmsize_t wc = cc/4;

    assert((cc%(4*stride))==0);

    if (wc > stride) {
        wc -= stride;
        wp += wc - 1;
        do {
            REPEAT4(stride, wp[stride] -= wp[0]; wp--)
            wc -= stride;
        } while (wc > 0);
    }
}

/*
 * Floating point predictor differencing routine.
 */
static void
fpDiff(TIFF* tif, uint8* cp0, tmsize_t cc)
{
    tmsize_t stride = PredictorState(tif)->stride;
    uint32 bps = tif->tif_dir.td_bitspersample / 8;
    tmsize_t wc = cc / bps;
    tmsize_t count;
    uint8 *cp = (uint8 *) cp0;
    uint8 *tmp = (uint8 *)_TIFFmalloc(cc);

    assert((cc%(bps*stride))==0);

    if (!tmp)
        return;

    _TIFFmemcpy(tmp, cp0, cc);
    for (count = 0; count < wc; count++) {
        uint32 byte;
        for (byte = 0; byte < bps; byte++) {
            #if WORDS_BIGENDIAN
            cp[byte * wc + count] = tmp[bps * count + byte];
            #else
            cp[(bps - byte - 1) * wc + count] =
                tmp[bps * count + byte];
            #endif
        }
    }
    _TIFFfree(tmp);

    cp = (uint8 *) cp0;
    cp += cc - stride - 1;
    for (count = cc; count > stride; count -= stride)
        REPEAT4(stride, cp[stride] -= cp[0]; cp--)
}

static int
PredictorEncodeRow(TIFF* tif, uint8* bp, tmsize_t cc, uint16 s)
{
    TIFFPredictorState *sp = PredictorState(tif);

    assert(sp != NULL);
    assert(sp->encodepfunc != NULL);
    assert(sp->encoderow != NULL);

    /* XXX horizontal differencing alters user's data XXX */
    (*sp->encodepfunc)(tif, bp, cc);
    return (*sp->encoderow)(tif, bp, cc, s);
}

static int
PredictorEncodeTile(TIFF* tif, uint8* bp0, tmsize_t cc0, uint16 s)
{
    static const char module[] = "PredictorEncodeTile";
    TIFFPredictorState *sp = PredictorState(tif);
        uint8 *working_copy;
    tmsize_t cc = cc0, rowsize;
    unsigned char* bp;
        int result_code;

    assert(sp != NULL);
    assert(sp->encodepfunc != NULL);
    assert(sp->encodetile != NULL);

        /*
         * Do predictor manipulation in a working buffer to avoid altering
         * the callers buffer. http://trac.osgeo.org/gdal/ticket/1965
         */
        working_copy = (uint8*) _TIFFmalloc(cc0);
        if( working_copy == NULL )
        {
            TIFFErrorExt(tif->tif_clientdata, module,
                         "Out of memory allocating " TIFF_SSIZE_FORMAT " byte temp buffer.",
                         cc0 );
            return 0;
        }
        memcpy( working_copy, bp0, cc0 );
        bp = working_copy;

    rowsize = sp->rowsize;
    assert(rowsize > 0);
    assert((cc0%rowsize)==0);
    while (cc > 0) {
        (*sp->encodepfunc)(tif, bp, rowsize);
        cc -= rowsize;
        bp += rowsize;
    }
    result_code = (*sp->encodetile)(tif, working_copy, cc0, s);

        _TIFFfree( working_copy );

        return result_code;
}

#define	FIELD_PREDICTOR	(FIELD_CODEC+0)		/* XXX */

static const TIFFField predictFields[] = {
    { TIFFTAG_PREDICTOR, 1, 1, TIFF_SHORT, 0, TIFF_SETGET_UINT16, TIFF_SETGET_UINT16, FIELD_PREDICTOR, FALSE, FALSE, "Predictor", NULL },
};

static int
PredictorVSetField(TIFF* tif, uint32 tag, va_list ap)
{
    TIFFPredictorState *sp = PredictorState(tif);

    assert(sp != NULL);
    assert(sp->vsetparent != NULL);

    switch (tag) {
    case TIFFTAG_PREDICTOR:
        sp->predictor = (uint16) va_arg(ap, uint16_vap);
        TIFFSetFieldBit(tif, FIELD_PREDICTOR);
        break;
    default:
        return (*sp->vsetparent)(tif, tag, ap);
    }
    tif->tif_flags |= TIFF_DIRTYDIRECT;
    return 1;
}

static int
PredictorVGetField(TIFF* tif, uint32 tag, va_list ap)
{
    TIFFPredictorState *sp = PredictorState(tif);

    assert(sp != NULL);
    assert(sp->vgetparent != NULL);

    switch (tag) {
    case TIFFTAG_PREDICTOR:
        *va_arg(ap, uint16*) = sp->predictor;
        break;
    default:
        return (*sp->vgetparent)(tif, tag, ap);
    }
    return 1;
}

static void
PredictorPrintDir(TIFF* tif, FILE* fd, long flags)
{
    TIFFPredictorState* sp = PredictorState(tif);

    (void) flags;
    if (TIFFFieldSet(tif,FIELD_PREDICTOR)) {
        fprintf(fd, "  Predictor: ");
        switch (sp->predictor) {
            case 1: fprintf(fd, "none "); break;
            case 2: fprintf(fd, "horizontal differencing "); break;
            case 3: fprintf(fd, "floating point predictor "); break;
        }
        fprintf(fd, "%u (0x%x)\n", sp->predictor, sp->predictor);
    }
    if (sp->printdir)
        (*sp->printdir)(tif, fd, flags);
}

int
TIFFPredictorInit(TIFF* tif)
{
    TIFFPredictorState* sp = PredictorState(tif);

    assert(sp != 0);

    /*
     * Merge codec-specific tag information.
     */
    if (!_TIFFMergeFields(tif, predictFields,
                  TIFFArrayCount(predictFields))) {
        TIFFErrorExt(tif->tif_clientdata, "TIFFPredictorInit",
            "Merging Predictor codec-specific tags failed");
        return 0;
    }

    /*
     * Override parent get/set field methods.
     */
    sp->vgetparent = tif->tif_tagmethods.vgetfield;
    tif->tif_tagmethods.vgetfield =
            PredictorVGetField;/* hook for predictor tag */
    sp->vsetparent = tif->tif_tagmethods.vsetfield;
    tif->tif_tagmethods.vsetfield =
        PredictorVSetField;/* hook for predictor tag */
    sp->printdir = tif->tif_tagmethods.printdir;
    tif->tif_tagmethods.printdir =
            PredictorPrintDir;	/* hook for predictor tag */

    sp->setupdecode = tif->tif_setupdecode;
    tif->tif_setupdecode = PredictorSetupDecode;
    sp->setupencode = tif->tif_setupencode;
    tif->tif_setupencode = PredictorSetupEncode;

    sp->predictor = 1;			/* default value */
    sp->encodepfunc = NULL;			/* no predictor routine */
    sp->decodepfunc = NULL;			/* no predictor routine */
    return 1;
}

int
TIFFPredictorCleanup(TIFF* tif)
{
    TIFFPredictorState* sp = PredictorState(tif);

    assert(sp != 0);

    tif->tif_tagmethods.vgetfield = sp->vgetparent;
    tif->tif_tagmethods.vsetfield = sp->vsetparent;
    tif->tif_tagmethods.printdir = sp->printdir;
    tif->tif_setupdecode = sp->setupdecode;
    tif->tif_setupencode = sp->setupencode;

    return 1;
}

/* vim: set ts=8 sts=8 sw=8 noet: */
/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 8
 * fill-column: 78
 * End:
 */