/* Header */

/*
 * 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"

#include <assert.h>

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

static  void horAcc8(TIFF*, tidata_t, tsize_t);
static  void horAcc16(TIFF*, tidata_t, tsize_t);
static  void swabHorAcc16(TIFF*, tidata_t, tsize_t);
static  void horDiff8(TIFF*, tidata_t, tsize_t);
static  void horDiff16(TIFF*, tidata_t, tsize_t);
static  int PredictorDecodeRow(TIFF*, tidata_t, tsize_t, tsample_t);
static  int PredictorDecodeTile(TIFF*, tidata_t, tsize_t, tsample_t);
static  int PredictorEncodeRow(TIFF*, tidata_t, tsize_t, tsample_t);
static  int PredictorEncodeTile(TIFF*, tidata_t, tsize_t, tsample_t);

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

        if (sp->predictor == 1)         /* no differencing */
                return (1);
        if (sp->predictor != 2) {
                TIFFError(tif->tif_name, "\"Predictor\" value %d not supported",
                    sp->predictor);
                return (0);
        }
        if (td->td_bitspersample != 8 && td->td_bitspersample != 16) {
                TIFFError(tif->tif_name,
    "Horizontal differencing \"Predictor\" not supported with %d-bit samples",
                    td->td_bitspersample);
                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);
        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->pfunc = horAcc8; break;
                case 16: sp->pfunc = horAcc16; break;
                }
                /*
                 * Override default decoding method with
                 * one that does the predictor stuff.
                 */
                sp->coderow = tif->tif_decoderow;
                tif->tif_decoderow = PredictorDecodeRow;
                sp->codestrip = tif->tif_decodestrip;
                tif->tif_decodestrip = PredictorDecodeTile;
                sp->codetile = 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->pfunc == horAcc16) {
                                sp->pfunc = swabHorAcc16;
                                tif->tif_postdecode = _TIFFNoPostDecode;
                        } /* else handle 32-bit case... */
                }
        }
        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->pfunc = horDiff8; break;
                case 16: sp->pfunc = horDiff16; break;
                }
                /*
                 * Override default encoding method with
                 * one that does the predictor stuff.
                 */
                sp->coderow = tif->tif_encoderow;
                tif->tif_encoderow = PredictorEncodeRow;
                sp->codestrip = tif->tif_encodestrip;
                tif->tif_encodestrip = PredictorEncodeTile;
                sp->codetile = tif->tif_encodetile;
                tif->tif_encodetile = PredictorEncodeTile;
        }
        return (1);
}

#define REPEAT4(n, op)          \
    switch (n) {                \
    default: { int 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, tidata_t cp0, tsize_t cc)
{
        TIFFPredictorState* sp = PredictorState(tif);
        tsize_t stride = sp->stride;

        char* cp = (char*) cp0;
        if (cc > stride) {
                cc -= stride;
                /*
                 * Pipeline the most common cases.
                 */
                if (stride == 3)  {
                        u_int cr = cp[0];
                        u_int cg = cp[1];
                        u_int cb = cp[2];
                        do {
                                cc -= 3, cp += 3;
                                cp[0] = (cr += cp[0]);
                                cp[1] = (cg += cp[1]);
                                cp[2] = (cb += cp[2]);
                        } while ((int32) cc > 0);
                } else if (stride == 4)  {
                        u_int cr = cp[0];
                        u_int cg = cp[1];
                        u_int cb = cp[2];
                        u_int ca = cp[3];
                        do {
                                cc -= 4, cp += 4;
                                cp[0] = (cr += cp[0]);
                                cp[1] = (cg += cp[1]);
                                cp[2] = (cb += cp[2]);
                                cp[3] = (ca += cp[3]);
                        } while ((int32) cc > 0);
                } else  {
                        do {
                                REPEAT4(stride, cp[stride] += *cp; cp++)
                                cc -= stride;
                        } while ((int32) cc > 0);
                }
        }
}

static void
swabHorAcc16(TIFF* tif, tidata_t cp0, tsize_t cc)
{
        TIFFPredictorState* sp = PredictorState(tif);
        tsize_t stride = sp->stride;
        uint16* wp = (uint16*) cp0;
        tsize_t wc = cc / 2;

        if (wc > stride) {
                TIFFSwabArrayOfShort(wp, wc);
                wc -= stride;
                do {
                        REPEAT4(stride, wp[stride] += wp[0]; wp++)
                        wc -= stride;
                } while ((int32) wc > 0);
        }
}

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

        if (wc > stride) {
                wc -= stride;
                do {
                        REPEAT4(stride, wp[stride] += wp[0]; wp++)
                        wc -= stride;
                } while ((int32) wc > 0);
        }
}

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

        assert(sp != NULL);
        assert(sp->coderow != NULL);
        assert(sp->pfunc != NULL);
        if ((*sp->coderow)(tif, op0, occ0, s)) {
                (*sp->pfunc)(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, tidata_t op0, tsize_t occ0, tsample_t s)
{
        TIFFPredictorState *sp = PredictorState(tif);

        assert(sp != NULL);
        assert(sp->codetile != NULL);
        if ((*sp->codetile)(tif, op0, occ0, s)) {
                tsize_t rowsize = sp->rowsize;
                assert(rowsize > 0);
                assert(sp->pfunc != NULL);
                while ((long)occ0 > 0) {
                        (*sp->pfunc)(tif, op0, (tsize_t) rowsize);
                        occ0 -= rowsize;
                        op0 += rowsize;
                }
                return (1);
        } else
                return (0);
}

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

        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 ((int32)(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 ((int32)(cc -= 4) > 0);
                } else {
                        cp += cc - 1;
                        do {
                                REPEAT4(stride, cp[stride] -= cp[0]; cp--)
                        } while ((int32)(cc -= stride) > 0);
                }
        }
}

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

        if (wc > stride) {
                wc -= stride;
                wp += wc - 1;
                do {
                        REPEAT4(stride, wp[stride] -= wp[0]; wp--)
                        wc -= stride;
                } while ((int32) wc > 0);
        }
}

static int
PredictorEncodeRow(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
        TIFFPredictorState *sp = PredictorState(tif);

        assert(sp != NULL);
        assert(sp->pfunc != NULL);
        assert(sp->coderow != NULL);
/* XXX horizontal differencing alters user's data XXX */
        (*sp->pfunc)(tif, bp, cc);
        return ((*sp->coderow)(tif, bp, cc, s));
}

static int
PredictorEncodeTile(TIFF* tif, tidata_t bp0, tsize_t cc0, tsample_t s)
{
        TIFFPredictorState *sp = PredictorState(tif);
        tsize_t cc = cc0, rowsize;
        u_char* bp = bp0;

        assert(sp != NULL);
        assert(sp->pfunc != NULL);
        assert(sp->codetile != NULL);
        rowsize = sp->rowsize;
        assert(rowsize > 0);
        while ((long)cc > 0) {
                (*sp->pfunc)(tif, bp, (tsize_t) rowsize);
                cc -= rowsize;
                bp += rowsize;
        }
        return ((*sp->codetile)(tif, bp0, cc0, s));
}

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

static const TIFFFieldInfo predictFieldInfo[] = {
    { TIFFTAG_PREDICTOR,         1, 1, TIFF_SHORT,      FIELD_PREDICTOR,
      FALSE,    FALSE,  "Predictor" },
};
#define N(a)    (sizeof (a) / sizeof (a[0]))

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

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

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

        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;
                }
                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);

        /*
         * Merge codec-specific tag information and
         * override parent get/set field methods.
         */
        _TIFFMergeFieldInfo(tif, predictFieldInfo, N(predictFieldInfo));
        sp->vgetparent = tif->tif_vgetfield;
        tif->tif_vgetfield = PredictorVGetField;/* hook for predictor tag */
        sp->vsetparent = tif->tif_vsetfield;
        tif->tif_vsetfield = PredictorVSetField;/* hook for predictor tag */
        sp->printdir = tif->tif_printdir;
        tif->tif_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->pfunc = NULL;                       /* no predictor routine */
        return (1);
}
