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[wxWidgets.git] / src / tiff / libtiff / tif_pixarlog.c

/* $Id$ */

/*
 * Copyright (c) 1996-1997 Sam Leffler
 * Copyright (c) 1996 Pixar
 *
 * 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
 * Pixar, 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 Pixar, 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 PIXAR, 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 PIXARLOG_SUPPORT

/*
 * TIFF Library.
 * PixarLog Compression Support
 *
 * Contributed by Dan McCoy.
 *
 * PixarLog film support uses the TIFF library to store companded
 * 11 bit values into a tiff file, which are compressed using the 
 * zip compressor.  
 *
 * The codec can take as input and produce as output 32-bit IEEE float values 
 * as well as 16-bit or 8-bit unsigned integer values.
 *
 * On writing any of the above are converted into the internal
 * 11-bit log format.   In the case of  8 and 16 bit values, the
 * input is assumed to be unsigned linear color values that represent
 * the range 0-1.  In the case of IEEE values, the 0-1 range is assumed to
 * be the normal linear color range, in addition over 1 values are
 * accepted up to a value of about 25.0 to encode "hot" hightlights and such.
 * The encoding is lossless for 8-bit values, slightly lossy for the
 * other bit depths.  The actual color precision should be better
 * than the human eye can perceive with extra room to allow for
 * error introduced by further image computation.  As with any quantized
 * color format, it is possible to perform image calculations which
 * expose the quantization error. This format should certainly be less 
 * susceptable to such errors than standard 8-bit encodings, but more
 * susceptable than straight 16-bit or 32-bit encodings.
 *
 * On reading the internal format is converted to the desired output format.
 * The program can request which format it desires by setting the internal
 * pseudo tag TIFFTAG_PIXARLOGDATAFMT to one of these possible values:
 *  PIXARLOGDATAFMT_FLOAT     = provide IEEE float values.
 *  PIXARLOGDATAFMT_16BIT     = provide unsigned 16-bit integer values
 *  PIXARLOGDATAFMT_8BIT      = provide unsigned 8-bit integer values
 *
 * alternately PIXARLOGDATAFMT_8BITABGR provides unsigned 8-bit integer
 * values with the difference that if there are exactly three or four channels
 * (rgb or rgba) it swaps the channel order (bgr or abgr).
 *
 * PIXARLOGDATAFMT_11BITLOG provides the internal encoding directly
 * packed in 16-bit values.   However no tools are supplied for interpreting
 * these values.
 *
 * "hot" (over 1.0) areas written in floating point get clamped to
 * 1.0 in the integer data types.
 *
 * When the file is closed after writing, the bit depth and sample format
 * are set always to appear as if 8-bit data has been written into it.
 * That way a naive program unaware of the particulars of the encoding
 * gets the format it is most likely able to handle.
 *
 * The codec does it's own horizontal differencing step on the coded
 * values so the libraries predictor stuff should be turned off.
 * The codec also handle byte swapping the encoded values as necessary
 * since the library does not have the information necessary
 * to know the bit depth of the raw unencoded buffer.
 *
 * NOTE: This decoder does not appear to update tif_rawcp, and tif_rawcc.
 * This can cause problems with the implementation of CHUNKY_STRIP_READ_SUPPORT
 * as noted in http://trac.osgeo.org/gdal/ticket/3894.   FrankW - Jan'11
 */

#include "tif_predict.h"
#include "zlib.h"

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

/* Tables for converting to/from 11 bit coded values */

#define  TSIZE   2048           /* decode table size (11-bit tokens) */
#define  TSIZEP1 2049           /* Plus one for slop */
#define  ONE     1250           /* token value of 1.0 exactly */
#define  RATIO   1.004          /* nominal ratio for log part */

#define CODE_MASK 0x7ff         /* 11 bits. */

static float  Fltsize;
static float  LogK1, LogK2;

#define REPEAT(n, op)   { int i; i=n; do { i--; op; } while (i>0); }

static void
horizontalAccumulateF(uint16 *wp, int n, int stride, float *op,
        float *ToLinearF)
{
    register unsigned int  cr, cg, cb, ca, mask;
    register float  t0, t1, t2, t3;

    if (n >= stride) {
        mask = CODE_MASK;
        if (stride == 3) {
            t0 = ToLinearF[cr = (wp[0] & mask)];
            t1 = ToLinearF[cg = (wp[1] & mask)];
            t2 = ToLinearF[cb = (wp[2] & mask)];
            op[0] = t0;
            op[1] = t1;
            op[2] = t2;
            n -= 3;
            while (n > 0) {
                wp += 3;
                op += 3;
                n -= 3;
                t0 = ToLinearF[(cr += wp[0]) & mask];
                t1 = ToLinearF[(cg += wp[1]) & mask];
                t2 = ToLinearF[(cb += wp[2]) & mask];
                op[0] = t0;
                op[1] = t1;
                op[2] = t2;
            }
        } else if (stride == 4) {
            t0 = ToLinearF[cr = (wp[0] & mask)];
            t1 = ToLinearF[cg = (wp[1] & mask)];
            t2 = ToLinearF[cb = (wp[2] & mask)];
            t3 = ToLinearF[ca = (wp[3] & mask)];
            op[0] = t0;
            op[1] = t1;
            op[2] = t2;
            op[3] = t3;
            n -= 4;
            while (n > 0) {
                wp += 4;
                op += 4;
                n -= 4;
                t0 = ToLinearF[(cr += wp[0]) & mask];
                t1 = ToLinearF[(cg += wp[1]) & mask];
                t2 = ToLinearF[(cb += wp[2]) & mask];
                t3 = ToLinearF[(ca += wp[3]) & mask];
                op[0] = t0;
                op[1] = t1;
                op[2] = t2;
                op[3] = t3;
            }
        } else {
            REPEAT(stride, *op = ToLinearF[*wp&mask]; wp++; op++)
            n -= stride;
            while (n > 0) {
                REPEAT(stride,
                    wp[stride] += *wp; *op = ToLinearF[*wp&mask]; wp++; op++)
                n -= stride;
            }
        }
    }
}

static void
horizontalAccumulate12(uint16 *wp, int n, int stride, int16 *op,
        float *ToLinearF)
{
    register unsigned int  cr, cg, cb, ca, mask;
    register float  t0, t1, t2, t3;

#define SCALE12 2048.0F
#define CLAMP12(t) (((t) < 3071) ? (uint16) (t) : 3071)

    if (n >= stride) {
        mask = CODE_MASK;
        if (stride == 3) {
            t0 = ToLinearF[cr = (wp[0] & mask)] * SCALE12;
            t1 = ToLinearF[cg = (wp[1] & mask)] * SCALE12;
            t2 = ToLinearF[cb = (wp[2] & mask)] * SCALE12;
            op[0] = CLAMP12(t0);
            op[1] = CLAMP12(t1);
            op[2] = CLAMP12(t2);
            n -= 3;
            while (n > 0) {
                wp += 3;
                op += 3;
                n -= 3;
                t0 = ToLinearF[(cr += wp[0]) & mask] * SCALE12;
                t1 = ToLinearF[(cg += wp[1]) & mask] * SCALE12;
                t2 = ToLinearF[(cb += wp[2]) & mask] * SCALE12;
                op[0] = CLAMP12(t0);
                op[1] = CLAMP12(t1);
                op[2] = CLAMP12(t2);
            }
        } else if (stride == 4) {
            t0 = ToLinearF[cr = (wp[0] & mask)] * SCALE12;
            t1 = ToLinearF[cg = (wp[1] & mask)] * SCALE12;
            t2 = ToLinearF[cb = (wp[2] & mask)] * SCALE12;
            t3 = ToLinearF[ca = (wp[3] & mask)] * SCALE12;
            op[0] = CLAMP12(t0);
            op[1] = CLAMP12(t1);
            op[2] = CLAMP12(t2);
            op[3] = CLAMP12(t3);
            n -= 4;
            while (n > 0) {
                wp += 4;
                op += 4;
                n -= 4;
                t0 = ToLinearF[(cr += wp[0]) & mask] * SCALE12;
                t1 = ToLinearF[(cg += wp[1]) & mask] * SCALE12;
                t2 = ToLinearF[(cb += wp[2]) & mask] * SCALE12;
                t3 = ToLinearF[(ca += wp[3]) & mask] * SCALE12;
                op[0] = CLAMP12(t0);
                op[1] = CLAMP12(t1);
                op[2] = CLAMP12(t2);
                op[3] = CLAMP12(t3);
            }
        } else {
            REPEAT(stride, t0 = ToLinearF[*wp&mask] * SCALE12;
                           *op = CLAMP12(t0); wp++; op++)
            n -= stride;
            while (n > 0) {
                REPEAT(stride,
                    wp[stride] += *wp; t0 = ToLinearF[wp[stride]&mask]*SCALE12;
                    *op = CLAMP12(t0);  wp++; op++)
                n -= stride;
            }
        }
    }
}

static void
horizontalAccumulate16(uint16 *wp, int n, int stride, uint16 *op,
        uint16 *ToLinear16)
{
    register unsigned int  cr, cg, cb, ca, mask;

    if (n >= stride) {
        mask = CODE_MASK;
        if (stride == 3) {
            op[0] = ToLinear16[cr = (wp[0] & mask)];
            op[1] = ToLinear16[cg = (wp[1] & mask)];
            op[2] = ToLinear16[cb = (wp[2] & mask)];
            n -= 3;
            while (n > 0) {
                wp += 3;
                op += 3;
                n -= 3;
                op[0] = ToLinear16[(cr += wp[0]) & mask];
                op[1] = ToLinear16[(cg += wp[1]) & mask];
                op[2] = ToLinear16[(cb += wp[2]) & mask];
            }
        } else if (stride == 4) {
            op[0] = ToLinear16[cr = (wp[0] & mask)];
            op[1] = ToLinear16[cg = (wp[1] & mask)];
            op[2] = ToLinear16[cb = (wp[2] & mask)];
            op[3] = ToLinear16[ca = (wp[3] & mask)];
            n -= 4;
            while (n > 0) {
                wp += 4;
                op += 4;
                n -= 4;
                op[0] = ToLinear16[(cr += wp[0]) & mask];
                op[1] = ToLinear16[(cg += wp[1]) & mask];
                op[2] = ToLinear16[(cb += wp[2]) & mask];
                op[3] = ToLinear16[(ca += wp[3]) & mask];
            }
        } else {
            REPEAT(stride, *op = ToLinear16[*wp&mask]; wp++; op++)
            n -= stride;
            while (n > 0) {
                REPEAT(stride,
                    wp[stride] += *wp; *op = ToLinear16[*wp&mask]; wp++; op++)
                n -= stride;
            }
        }
    }
}

/* 
 * Returns the log encoded 11-bit values with the horizontal
 * differencing undone.
 */
static void
horizontalAccumulate11(uint16 *wp, int n, int stride, uint16 *op)
{
    register unsigned int  cr, cg, cb, ca, mask;

    if (n >= stride) {
        mask = CODE_MASK;
        if (stride == 3) {
            op[0] = cr = wp[0];  op[1] = cg = wp[1];  op[2] = cb = wp[2];
            n -= 3;
            while (n > 0) {
                wp += 3;
                op += 3;
                n -= 3;
                op[0] = (cr += wp[0]) & mask;
                op[1] = (cg += wp[1]) & mask;
                op[2] = (cb += wp[2]) & mask;
            }
        } else if (stride == 4) {
            op[0] = cr = wp[0];  op[1] = cg = wp[1];
            op[2] = cb = wp[2];  op[3] = ca = wp[3];
            n -= 4;
            while (n > 0) {
                wp += 4;
                op += 4;
                n -= 4;
                op[0] = (cr += wp[0]) & mask;
                op[1] = (cg += wp[1]) & mask;
                op[2] = (cb += wp[2]) & mask;
                op[3] = (ca += wp[3]) & mask;
            } 
        } else {
            REPEAT(stride, *op = *wp&mask; wp++; op++)
            n -= stride;
            while (n > 0) {
                REPEAT(stride,
                    wp[stride] += *wp; *op = *wp&mask; wp++; op++)
                n -= stride;
            }
        }
    }
}

static void
horizontalAccumulate8(uint16 *wp, int n, int stride, unsigned char *op,
        unsigned char *ToLinear8)
{
    register unsigned int  cr, cg, cb, ca, mask;

    if (n >= stride) {
        mask = CODE_MASK;
        if (stride == 3) {
            op[0] = ToLinear8[cr = (wp[0] & mask)];
            op[1] = ToLinear8[cg = (wp[1] & mask)];
            op[2] = ToLinear8[cb = (wp[2] & mask)];
            n -= 3;
            while (n > 0) {
                n -= 3;
                wp += 3;
                op += 3;
                op[0] = ToLinear8[(cr += wp[0]) & mask];
                op[1] = ToLinear8[(cg += wp[1]) & mask];
                op[2] = ToLinear8[(cb += wp[2]) & mask];
            }
        } else if (stride == 4) {
            op[0] = ToLinear8[cr = (wp[0] & mask)];
            op[1] = ToLinear8[cg = (wp[1] & mask)];
            op[2] = ToLinear8[cb = (wp[2] & mask)];
            op[3] = ToLinear8[ca = (wp[3] & mask)];
            n -= 4;
            while (n > 0) {
                n -= 4;
                wp += 4;
                op += 4;
                op[0] = ToLinear8[(cr += wp[0]) & mask];
                op[1] = ToLinear8[(cg += wp[1]) & mask];
                op[2] = ToLinear8[(cb += wp[2]) & mask];
                op[3] = ToLinear8[(ca += wp[3]) & mask];
            }
        } else {
            REPEAT(stride, *op = ToLinear8[*wp&mask]; wp++; op++)
            n -= stride;
            while (n > 0) {
                REPEAT(stride,
                    wp[stride] += *wp; *op = ToLinear8[*wp&mask]; wp++; op++)
                n -= stride;
            }
        }
    }
}


static void
horizontalAccumulate8abgr(uint16 *wp, int n, int stride, unsigned char *op,
        unsigned char *ToLinear8)
{
    register unsigned int  cr, cg, cb, ca, mask;
    register unsigned char  t0, t1, t2, t3;

    if (n >= stride) {
        mask = CODE_MASK;
        if (stride == 3) {
            op[0] = 0;
            t1 = ToLinear8[cb = (wp[2] & mask)];
            t2 = ToLinear8[cg = (wp[1] & mask)];
            t3 = ToLinear8[cr = (wp[0] & mask)];
            op[1] = t1;
            op[2] = t2;
            op[3] = t3;
            n -= 3;
            while (n > 0) {
                n -= 3;
                wp += 3;
                op += 4;
                op[0] = 0;
                t1 = ToLinear8[(cb += wp[2]) & mask];
                t2 = ToLinear8[(cg += wp[1]) & mask];
                t3 = ToLinear8[(cr += wp[0]) & mask];
                op[1] = t1;
                op[2] = t2;
                op[3] = t3;
            }
        } else if (stride == 4) {
            t0 = ToLinear8[ca = (wp[3] & mask)];
            t1 = ToLinear8[cb = (wp[2] & mask)];
            t2 = ToLinear8[cg = (wp[1] & mask)];
            t3 = ToLinear8[cr = (wp[0] & mask)];
            op[0] = t0;
            op[1] = t1;
            op[2] = t2;
            op[3] = t3;
            n -= 4;
            while (n > 0) {
                n -= 4;
                wp += 4;
                op += 4;
                t0 = ToLinear8[(ca += wp[3]) & mask];
                t1 = ToLinear8[(cb += wp[2]) & mask];
                t2 = ToLinear8[(cg += wp[1]) & mask];
                t3 = ToLinear8[(cr += wp[0]) & mask];
                op[0] = t0;
                op[1] = t1;
                op[2] = t2;
                op[3] = t3;
            }
        } else {
            REPEAT(stride, *op = ToLinear8[*wp&mask]; wp++; op++)
            n -= stride;
            while (n > 0) {
                REPEAT(stride,
                    wp[stride] += *wp; *op = ToLinear8[*wp&mask]; wp++; op++)
                n -= stride;
            }
        }
    }
}

/*
 * State block for each open TIFF
 * file using PixarLog compression/decompression.
 */
typedef struct {
        TIFFPredictorState      predict;
        z_stream                stream;
        uint16                  *tbuf; 
        uint16                  stride;
        int                     state;
        int                     user_datafmt;
        int                     quality;
#define PLSTATE_INIT 1

        TIFFVSetMethod          vgetparent;     /* super-class method */
        TIFFVSetMethod          vsetparent;     /* super-class method */

        float *ToLinearF;
        uint16 *ToLinear16;
        unsigned char *ToLinear8;
        uint16  *FromLT2;
        uint16  *From14; /* Really for 16-bit data, but we shift down 2 */
        uint16  *From8;
        
} PixarLogState;

static int
PixarLogMakeTables(PixarLogState *sp)
{

/*
 *    We make several tables here to convert between various external
 *    representations (float, 16-bit, and 8-bit) and the internal
 *    11-bit companded representation.  The 11-bit representation has two
 *    distinct regions.  A linear bottom end up through .018316 in steps
 *    of about .000073, and a region of constant ratio up to about 25.
 *    These floating point numbers are stored in the main table ToLinearF. 
 *    All other tables are derived from this one.  The tables (and the
 *    ratios) are continuous at the internal seam.
 */

    int  nlin, lt2size;
    int  i, j;
    double  b, c, linstep, v;
    float *ToLinearF;
    uint16 *ToLinear16;
    unsigned char *ToLinear8;
    uint16  *FromLT2;
    uint16  *From14; /* Really for 16-bit data, but we shift down 2 */
    uint16  *From8;

    c = log(RATIO);     
    nlin = (int)(1./c); /* nlin must be an integer */
    c = 1./nlin;
    b = exp(-c*ONE);    /* multiplicative scale factor [b*exp(c*ONE) = 1] */
    linstep = b*c*exp(1.);

    LogK1 = (float)(1./c);      /* if (v >= 2)  token = k1*log(v*k2) */
    LogK2 = (float)(1./b);
    lt2size = (int)(2./linstep) + 1;
    FromLT2 = (uint16 *)_TIFFmalloc(lt2size*sizeof(uint16));
    From14 = (uint16 *)_TIFFmalloc(16384*sizeof(uint16));
    From8 = (uint16 *)_TIFFmalloc(256*sizeof(uint16));
    ToLinearF = (float *)_TIFFmalloc(TSIZEP1 * sizeof(float));
    ToLinear16 = (uint16 *)_TIFFmalloc(TSIZEP1 * sizeof(uint16));
    ToLinear8 = (unsigned char *)_TIFFmalloc(TSIZEP1 * sizeof(unsigned char));
    if (FromLT2 == NULL || From14  == NULL || From8   == NULL ||
         ToLinearF == NULL || ToLinear16 == NULL || ToLinear8 == NULL) {
        if (FromLT2) _TIFFfree(FromLT2);
        if (From14) _TIFFfree(From14);
        if (From8) _TIFFfree(From8);
        if (ToLinearF) _TIFFfree(ToLinearF);
        if (ToLinear16) _TIFFfree(ToLinear16);
        if (ToLinear8) _TIFFfree(ToLinear8);
        sp->FromLT2 = NULL;
        sp->From14 = NULL;
        sp->From8 = NULL;
        sp->ToLinearF = NULL;
        sp->ToLinear16 = NULL;
        sp->ToLinear8 = NULL;
        return 0;
    }

    j = 0;

    for (i = 0; i < nlin; i++)  {
        v = i * linstep;
        ToLinearF[j++] = (float)v;
    }

    for (i = nlin; i < TSIZE; i++)
        ToLinearF[j++] = (float)(b*exp(c*i));

    ToLinearF[2048] = ToLinearF[2047];

    for (i = 0; i < TSIZEP1; i++)  {
        v = ToLinearF[i]*65535.0 + 0.5;
        ToLinear16[i] = (v > 65535.0) ? 65535 : (uint16)v;
        v = ToLinearF[i]*255.0  + 0.5;
        ToLinear8[i]  = (v > 255.0) ? 255 : (unsigned char)v;
    }

    j = 0;
    for (i = 0; i < lt2size; i++)  {
        if ((i*linstep)*(i*linstep) > ToLinearF[j]*ToLinearF[j+1])
            j++;
        FromLT2[i] = j;
    }

    /*
     * Since we lose info anyway on 16-bit data, we set up a 14-bit
     * table and shift 16-bit values down two bits on input.
     * saves a little table space.
     */
    j = 0;
    for (i = 0; i < 16384; i++)  {
        while ((i/16383.)*(i/16383.) > ToLinearF[j]*ToLinearF[j+1])
            j++;
        From14[i] = j;
    }

    j = 0;
    for (i = 0; i < 256; i++)  {
        while ((i/255.)*(i/255.) > ToLinearF[j]*ToLinearF[j+1])
            j++;
        From8[i] = j;
    }

    Fltsize = (float)(lt2size/2);

    sp->ToLinearF = ToLinearF;
    sp->ToLinear16 = ToLinear16;
    sp->ToLinear8 = ToLinear8;
    sp->FromLT2 = FromLT2;
    sp->From14 = From14;
    sp->From8 = From8;

    return 1;
}

#define DecoderState(tif)       ((PixarLogState*) (tif)->tif_data)
#define EncoderState(tif)       ((PixarLogState*) (tif)->tif_data)

static int PixarLogEncode(TIFF* tif, uint8* bp, tmsize_t cc, uint16 s);
static int PixarLogDecode(TIFF* tif, uint8* op, tmsize_t occ, uint16 s);

#define PIXARLOGDATAFMT_UNKNOWN -1

static int
PixarLogGuessDataFmt(TIFFDirectory *td)
{
        int guess = PIXARLOGDATAFMT_UNKNOWN;
        int format = td->td_sampleformat;

        /* If the user didn't tell us his datafmt,
         * take our best guess from the bitspersample.
         */
        switch (td->td_bitspersample) {
         case 32:
                if (format == SAMPLEFORMAT_IEEEFP)
                        guess = PIXARLOGDATAFMT_FLOAT;
                break;
         case 16:
                if (format == SAMPLEFORMAT_VOID || format == SAMPLEFORMAT_UINT)
                        guess = PIXARLOGDATAFMT_16BIT;
                break;
         case 12:
                if (format == SAMPLEFORMAT_VOID || format == SAMPLEFORMAT_INT)
                        guess = PIXARLOGDATAFMT_12BITPICIO;
                break;
         case 11:
                if (format == SAMPLEFORMAT_VOID || format == SAMPLEFORMAT_UINT)
                        guess = PIXARLOGDATAFMT_11BITLOG;
                break;
         case 8:
                if (format == SAMPLEFORMAT_VOID || format == SAMPLEFORMAT_UINT)
                        guess = PIXARLOGDATAFMT_8BIT;
                break;
        }

        return guess;
}

static tmsize_t
multiply_ms(tmsize_t m1, tmsize_t m2)
{
        tmsize_t bytes = m1 * m2;

        if (m1 && bytes / m1 != m2)
                bytes = 0;

        return bytes;
}

static int
PixarLogFixupTags(TIFF* tif)
{
        (void) tif;
        return (1);
}

static int
PixarLogSetupDecode(TIFF* tif)
{
        static const char module[] = "PixarLogSetupDecode";
        TIFFDirectory *td = &tif->tif_dir;
        PixarLogState* sp = DecoderState(tif);
        tmsize_t tbuf_size;

        assert(sp != NULL);

        /* Make sure no byte swapping happens on the data
         * after decompression. */
        tif->tif_postdecode = _TIFFNoPostDecode;  

        /* for some reason, we can't do this in TIFFInitPixarLog */

        sp->stride = (td->td_planarconfig == PLANARCONFIG_CONTIG ?
            td->td_samplesperpixel : 1);
        tbuf_size = multiply_ms(multiply_ms(multiply_ms(sp->stride, td->td_imagewidth),
                                      td->td_rowsperstrip), sizeof(uint16));
        if (tbuf_size == 0)
                return (0);   /* TODO: this is an error return without error report through TIFFErrorExt */
        sp->tbuf = (uint16 *) _TIFFmalloc(tbuf_size+sizeof(uint16)*sp->stride);
        if (sp->tbuf == NULL)
                return (0);
        if (sp->user_datafmt == PIXARLOGDATAFMT_UNKNOWN)
                sp->user_datafmt = PixarLogGuessDataFmt(td);
        if (sp->user_datafmt == PIXARLOGDATAFMT_UNKNOWN) {
                TIFFErrorExt(tif->tif_clientdata, module,
                        "PixarLog compression can't handle bits depth/data format combination (depth: %d)", 
                        td->td_bitspersample);
                return (0);
        }

        if (inflateInit(&sp->stream) != Z_OK) {
                TIFFErrorExt(tif->tif_clientdata, module, "%s", sp->stream.msg);
                return (0);
        } else {
                sp->state |= PLSTATE_INIT;
                return (1);
        }
}

/*
 * Setup state for decoding a strip.
 */
static int
PixarLogPreDecode(TIFF* tif, uint16 s)
{
        static const char module[] = "PixarLogPreDecode";
        PixarLogState* sp = DecoderState(tif);

        (void) s;
        assert(sp != NULL);
        sp->stream.next_in = tif->tif_rawdata;
        assert(sizeof(sp->stream.avail_in)==4);  /* if this assert gets raised,
            we need to simplify this code to reflect a ZLib that is likely updated
            to deal with 8byte memory sizes, though this code will respond
            apropriately even before we simplify it */
        sp->stream.avail_in = (uInt) tif->tif_rawcc;
        if ((tmsize_t)sp->stream.avail_in != tif->tif_rawcc)
        {
                TIFFErrorExt(tif->tif_clientdata, module, "ZLib cannot deal with buffers this size");
                return (0);
        }
        return (inflateReset(&sp->stream) == Z_OK);
}

static int
PixarLogDecode(TIFF* tif, uint8* op, tmsize_t occ, uint16 s)
{
        static const char module[] = "PixarLogDecode";
        TIFFDirectory *td = &tif->tif_dir;
        PixarLogState* sp = DecoderState(tif);
        tmsize_t i;
        tmsize_t nsamples;
        int llen;
        uint16 *up;

        switch (sp->user_datafmt) {
        case PIXARLOGDATAFMT_FLOAT:
                nsamples = occ / sizeof(float); /* XXX float == 32 bits */
                break;
        case PIXARLOGDATAFMT_16BIT:
        case PIXARLOGDATAFMT_12BITPICIO:
        case PIXARLOGDATAFMT_11BITLOG:
                nsamples = occ / sizeof(uint16); /* XXX uint16 == 16 bits */
                break;
        case PIXARLOGDATAFMT_8BIT:
        case PIXARLOGDATAFMT_8BITABGR:
                nsamples = occ;
                break;
        default:
                TIFFErrorExt(tif->tif_clientdata, module,
                        "%d bit input not supported in PixarLog",
                        td->td_bitspersample);
                return 0;
        }

        llen = sp->stride * td->td_imagewidth;

        (void) s;
        assert(sp != NULL);
        sp->stream.next_out = (unsigned char *) sp->tbuf;
        assert(sizeof(sp->stream.avail_out)==4);  /* if this assert gets raised,
            we need to simplify this code to reflect a ZLib that is likely updated
            to deal with 8byte memory sizes, though this code will respond
            apropriately even before we simplify it */
        sp->stream.avail_out = (uInt) (nsamples * sizeof(uint16));
        if (sp->stream.avail_out != nsamples * sizeof(uint16))
        {
                TIFFErrorExt(tif->tif_clientdata, module, "ZLib cannot deal with buffers this size");
                return (0);
        }
        do {
                int state = inflate(&sp->stream, Z_PARTIAL_FLUSH);
                if (state == Z_STREAM_END) {
                        break;                  /* XXX */
                }
                if (state == Z_DATA_ERROR) {
                        TIFFErrorExt(tif->tif_clientdata, module,
                            "Decoding error at scanline %lu, %s",
                            (unsigned long) tif->tif_row, sp->stream.msg);
                        if (inflateSync(&sp->stream) != Z_OK)
                                return (0);
                        continue;
                }
                if (state != Z_OK) {
                        TIFFErrorExt(tif->tif_clientdata, module, "ZLib error: %s",
                            sp->stream.msg);
                        return (0);
                }
        } while (sp->stream.avail_out > 0);

        /* hopefully, we got all the bytes we needed */
        if (sp->stream.avail_out != 0) {
                TIFFErrorExt(tif->tif_clientdata, module,
                    "Not enough data at scanline %lu (short " TIFF_UINT64_FORMAT " bytes)",
                    (unsigned long) tif->tif_row, (TIFF_UINT64_T) sp->stream.avail_out);
                return (0);
        }

        up = sp->tbuf;
        /* Swap bytes in the data if from a different endian machine. */
        if (tif->tif_flags & TIFF_SWAB)
                TIFFSwabArrayOfShort(up, nsamples);

        /*
         * if llen is not an exact multiple of nsamples, the decode operation
         * may overflow the output buffer, so truncate it enough to prevent
         * that but still salvage as much data as possible.
         */
        if (nsamples % llen) { 
                TIFFWarningExt(tif->tif_clientdata, module,
                        "stride %lu is not a multiple of sample count, "
                        "%lu, data truncated.", (unsigned long) llen, (unsigned long) nsamples);
                nsamples -= nsamples % llen;
        }

        for (i = 0; i < nsamples; i += llen, up += llen) {
                switch (sp->user_datafmt)  {
                case PIXARLOGDATAFMT_FLOAT:
                        horizontalAccumulateF(up, llen, sp->stride,
                                        (float *)op, sp->ToLinearF);
                        op += llen * sizeof(float);
                        break;
                case PIXARLOGDATAFMT_16BIT:
                        horizontalAccumulate16(up, llen, sp->stride,
                                        (uint16 *)op, sp->ToLinear16);
                        op += llen * sizeof(uint16);
                        break;
                case PIXARLOGDATAFMT_12BITPICIO:
                        horizontalAccumulate12(up, llen, sp->stride,
                                        (int16 *)op, sp->ToLinearF);
                        op += llen * sizeof(int16);
                        break;
                case PIXARLOGDATAFMT_11BITLOG:
                        horizontalAccumulate11(up, llen, sp->stride,
                                        (uint16 *)op);
                        op += llen * sizeof(uint16);
                        break;
                case PIXARLOGDATAFMT_8BIT:
                        horizontalAccumulate8(up, llen, sp->stride,
                                        (unsigned char *)op, sp->ToLinear8);
                        op += llen * sizeof(unsigned char);
                        break;
                case PIXARLOGDATAFMT_8BITABGR:
                        horizontalAccumulate8abgr(up, llen, sp->stride,
                                        (unsigned char *)op, sp->ToLinear8);
                        op += llen * sizeof(unsigned char);
                        break;
                default:
                        TIFFErrorExt(tif->tif_clientdata, module,
                                  "Unsupported bits/sample: %d",
                                  td->td_bitspersample);
                        return (0);
                }
        }

        return (1);
}

static int
PixarLogSetupEncode(TIFF* tif)
{
        static const char module[] = "PixarLogSetupEncode";
        TIFFDirectory *td = &tif->tif_dir;
        PixarLogState* sp = EncoderState(tif);
        tmsize_t tbuf_size;

        assert(sp != NULL);

        /* for some reason, we can't do this in TIFFInitPixarLog */

        sp->stride = (td->td_planarconfig == PLANARCONFIG_CONTIG ?
            td->td_samplesperpixel : 1);
        tbuf_size = multiply_ms(multiply_ms(multiply_ms(sp->stride, td->td_imagewidth),
                                      td->td_rowsperstrip), sizeof(uint16));
        if (tbuf_size == 0)
                return (0);  /* TODO: this is an error return without error report through TIFFErrorExt */
        sp->tbuf = (uint16 *) _TIFFmalloc(tbuf_size);
        if (sp->tbuf == NULL)
                return (0);
        if (sp->user_datafmt == PIXARLOGDATAFMT_UNKNOWN)
                sp->user_datafmt = PixarLogGuessDataFmt(td);
        if (sp->user_datafmt == PIXARLOGDATAFMT_UNKNOWN) {
                TIFFErrorExt(tif->tif_clientdata, module, "PixarLog compression can't handle %d bit linear encodings", td->td_bitspersample);
                return (0);
        }

        if (deflateInit(&sp->stream, sp->quality) != Z_OK) {
                TIFFErrorExt(tif->tif_clientdata, module, "%s", sp->stream.msg);
                return (0);
        } else {
                sp->state |= PLSTATE_INIT;
                return (1);
        }
}

/*
 * Reset encoding state at the start of a strip.
 */
static int
PixarLogPreEncode(TIFF* tif, uint16 s)
{
        static const char module[] = "PixarLogPreEncode";
        PixarLogState *sp = EncoderState(tif);

        (void) s;
        assert(sp != NULL);
        sp->stream.next_out = tif->tif_rawdata;
        assert(sizeof(sp->stream.avail_out)==4);  /* if this assert gets raised,
            we need to simplify this code to reflect a ZLib that is likely updated
            to deal with 8byte memory sizes, though this code will respond
            apropriately even before we simplify it */
        sp->stream.avail_out = tif->tif_rawdatasize;
        if ((tmsize_t)sp->stream.avail_out != tif->tif_rawdatasize)
        {
                TIFFErrorExt(tif->tif_clientdata, module, "ZLib cannot deal with buffers this size");
                return (0);
        }
        return (deflateReset(&sp->stream) == Z_OK);
}

static void
horizontalDifferenceF(float *ip, int n, int stride, uint16 *wp, uint16 *FromLT2)
{
    int32 r1, g1, b1, a1, r2, g2, b2, a2, mask;
    float fltsize = Fltsize;

#define  CLAMP(v) ( (v<(float)0.)   ? 0                         \
                  : (v<(float)2.)   ? FromLT2[(int)(v*fltsize)] \
                  : (v>(float)24.2) ? 2047                      \
                  : LogK1*log(v*LogK2) + 0.5 )

    mask = CODE_MASK;
    if (n >= stride) {
        if (stride == 3) {
            r2 = wp[0] = (uint16) CLAMP(ip[0]);
            g2 = wp[1] = (uint16) CLAMP(ip[1]);
            b2 = wp[2] = (uint16) CLAMP(ip[2]);
            n -= 3;
            while (n > 0) {
                n -= 3;
                wp += 3;
                ip += 3;
                r1 = (int32) CLAMP(ip[0]); wp[0] = (r1-r2) & mask; r2 = r1;
                g1 = (int32) CLAMP(ip[1]); wp[1] = (g1-g2) & mask; g2 = g1;
                b1 = (int32) CLAMP(ip[2]); wp[2] = (b1-b2) & mask; b2 = b1;
            }
        } else if (stride == 4) {
            r2 = wp[0] = (uint16) CLAMP(ip[0]);
            g2 = wp[1] = (uint16) CLAMP(ip[1]);
            b2 = wp[2] = (uint16) CLAMP(ip[2]);
            a2 = wp[3] = (uint16) CLAMP(ip[3]);
            n -= 4;
            while (n > 0) {
                n -= 4;
                wp += 4;
                ip += 4;
                r1 = (int32) CLAMP(ip[0]); wp[0] = (r1-r2) & mask; r2 = r1;
                g1 = (int32) CLAMP(ip[1]); wp[1] = (g1-g2) & mask; g2 = g1;
                b1 = (int32) CLAMP(ip[2]); wp[2] = (b1-b2) & mask; b2 = b1;
                a1 = (int32) CLAMP(ip[3]); wp[3] = (a1-a2) & mask; a2 = a1;
            }
        } else {
            ip += n - 1;        /* point to last one */
            wp += n - 1;        /* point to last one */
            n -= stride;
            while (n > 0) {
                REPEAT(stride, wp[0] = (uint16) CLAMP(ip[0]);
                                wp[stride] -= wp[0];
                                wp[stride] &= mask;
                                wp--; ip--)
                n -= stride;
            }
            REPEAT(stride, wp[0] = (uint16) CLAMP(ip[0]); wp--; ip--)
        }
    }
}

static void
horizontalDifference16(unsigned short *ip, int n, int stride, 
        unsigned short *wp, uint16 *From14)
{
    register int  r1, g1, b1, a1, r2, g2, b2, a2, mask;

/* assumption is unsigned pixel values */
#undef   CLAMP
#define  CLAMP(v) From14[(v) >> 2]

    mask = CODE_MASK;
    if (n >= stride) {
        if (stride == 3) {
            r2 = wp[0] = CLAMP(ip[0]);  g2 = wp[1] = CLAMP(ip[1]);
            b2 = wp[2] = CLAMP(ip[2]);
            n -= 3;
            while (n > 0) {
                n -= 3;
                wp += 3;
                ip += 3;
                r1 = CLAMP(ip[0]); wp[0] = (r1-r2) & mask; r2 = r1;
                g1 = CLAMP(ip[1]); wp[1] = (g1-g2) & mask; g2 = g1;
                b1 = CLAMP(ip[2]); wp[2] = (b1-b2) & mask; b2 = b1;
            }
        } else if (stride == 4) {
            r2 = wp[0] = CLAMP(ip[0]);  g2 = wp[1] = CLAMP(ip[1]);
            b2 = wp[2] = CLAMP(ip[2]);  a2 = wp[3] = CLAMP(ip[3]);
            n -= 4;
            while (n > 0) {
                n -= 4;
                wp += 4;
                ip += 4;
                r1 = CLAMP(ip[0]); wp[0] = (r1-r2) & mask; r2 = r1;
                g1 = CLAMP(ip[1]); wp[1] = (g1-g2) & mask; g2 = g1;
                b1 = CLAMP(ip[2]); wp[2] = (b1-b2) & mask; b2 = b1;
                a1 = CLAMP(ip[3]); wp[3] = (a1-a2) & mask; a2 = a1;
            }
        } else {
            ip += n - 1;        /* point to last one */
            wp += n - 1;        /* point to last one */
            n -= stride;
            while (n > 0) {
                REPEAT(stride, wp[0] = CLAMP(ip[0]);
                                wp[stride] -= wp[0];
                                wp[stride] &= mask;
                                wp--; ip--)
                n -= stride;
            }
            REPEAT(stride, wp[0] = CLAMP(ip[0]); wp--; ip--)
        }
    }
}


static void
horizontalDifference8(unsigned char *ip, int n, int stride, 
        unsigned short *wp, uint16 *From8)
{
    register int  r1, g1, b1, a1, r2, g2, b2, a2, mask;

#undef   CLAMP
#define  CLAMP(v) (From8[(v)])

    mask = CODE_MASK;
    if (n >= stride) {
        if (stride == 3) {
            r2 = wp[0] = CLAMP(ip[0]);  g2 = wp[1] = CLAMP(ip[1]);
            b2 = wp[2] = CLAMP(ip[2]);
            n -= 3;
            while (n > 0) {
                n -= 3;
                r1 = CLAMP(ip[3]); wp[3] = (r1-r2) & mask; r2 = r1;
                g1 = CLAMP(ip[4]); wp[4] = (g1-g2) & mask; g2 = g1;
                b1 = CLAMP(ip[5]); wp[5] = (b1-b2) & mask; b2 = b1;
                wp += 3;
                ip += 3;
            }
        } else if (stride == 4) {
            r2 = wp[0] = CLAMP(ip[0]);  g2 = wp[1] = CLAMP(ip[1]);
            b2 = wp[2] = CLAMP(ip[2]);  a2 = wp[3] = CLAMP(ip[3]);
            n -= 4;
            while (n > 0) {
                n -= 4;
                r1 = CLAMP(ip[4]); wp[4] = (r1-r2) & mask; r2 = r1;
                g1 = CLAMP(ip[5]); wp[5] = (g1-g2) & mask; g2 = g1;
                b1 = CLAMP(ip[6]); wp[6] = (b1-b2) & mask; b2 = b1;
                a1 = CLAMP(ip[7]); wp[7] = (a1-a2) & mask; a2 = a1;
                wp += 4;
                ip += 4;
            }
        } else {
            wp += n + stride - 1;       /* point to last one */
            ip += n + stride - 1;       /* point to last one */
            n -= stride;
            while (n > 0) {
                REPEAT(stride, wp[0] = CLAMP(ip[0]);
                                wp[stride] -= wp[0];
                                wp[stride] &= mask;
                                wp--; ip--)
                n -= stride;
            }
            REPEAT(stride, wp[0] = CLAMP(ip[0]); wp--; ip--)
        }
    }
}

/*
 * Encode a chunk of pixels.
 */
static int
PixarLogEncode(TIFF* tif, uint8* bp, tmsize_t cc, uint16 s)
{
        static const char module[] = "PixarLogEncode";
        TIFFDirectory *td = &tif->tif_dir;
        PixarLogState *sp = EncoderState(tif);
        tmsize_t i;
        tmsize_t n;
        int llen;
        unsigned short * up;

        (void) s;

        switch (sp->user_datafmt) {
        case PIXARLOGDATAFMT_FLOAT:
                n = cc / sizeof(float);         /* XXX float == 32 bits */
                break;
        case PIXARLOGDATAFMT_16BIT:
        case PIXARLOGDATAFMT_12BITPICIO:
        case PIXARLOGDATAFMT_11BITLOG:
                n = cc / sizeof(uint16);        /* XXX uint16 == 16 bits */
                break;
        case PIXARLOGDATAFMT_8BIT:
        case PIXARLOGDATAFMT_8BITABGR:
                n = cc;
                break;
        default:
                TIFFErrorExt(tif->tif_clientdata, module,
                        "%d bit input not supported in PixarLog",
                        td->td_bitspersample);
                return 0;
        }

        llen = sp->stride * td->td_imagewidth;

        for (i = 0, up = sp->tbuf; i < n; i += llen, up += llen) {
                switch (sp->user_datafmt)  {
                case PIXARLOGDATAFMT_FLOAT:
                        horizontalDifferenceF((float *)bp, llen, 
                                sp->stride, up, sp->FromLT2);
                        bp += llen * sizeof(float);
                        break;
                case PIXARLOGDATAFMT_16BIT:
                        horizontalDifference16((uint16 *)bp, llen, 
                                sp->stride, up, sp->From14);
                        bp += llen * sizeof(uint16);
                        break;
                case PIXARLOGDATAFMT_8BIT:
                        horizontalDifference8((unsigned char *)bp, llen, 
                                sp->stride, up, sp->From8);
                        bp += llen * sizeof(unsigned char);
                        break;
                default:
                        TIFFErrorExt(tif->tif_clientdata, module,
                                "%d bit input not supported in PixarLog",
                                td->td_bitspersample);
                        return 0;
                }
        }
 
        sp->stream.next_in = (unsigned char *) sp->tbuf;
        assert(sizeof(sp->stream.avail_in)==4);  /* if this assert gets raised,
            we need to simplify this code to reflect a ZLib that is likely updated
            to deal with 8byte memory sizes, though this code will respond
            apropriately even before we simplify it */
        sp->stream.avail_in = (uInt) (n * sizeof(uint16));
        if ((sp->stream.avail_in / sizeof(uint16)) != (uInt) n)
        {
                TIFFErrorExt(tif->tif_clientdata, module,
                             "ZLib cannot deal with buffers this size");
                return (0);
        }

        do {
                if (deflate(&sp->stream, Z_NO_FLUSH) != Z_OK) {
                        TIFFErrorExt(tif->tif_clientdata, module, "Encoder error: %s",
                            sp->stream.msg);
                        return (0);
                }
                if (sp->stream.avail_out == 0) {
                        tif->tif_rawcc = tif->tif_rawdatasize;
                        TIFFFlushData1(tif);
                        sp->stream.next_out = tif->tif_rawdata;
                        sp->stream.avail_out = (uInt) tif->tif_rawdatasize;  /* this is a safe typecast, as check is made already in PixarLogPreEncode */
                }
        } while (sp->stream.avail_in > 0);
        return (1);
}

/*
 * Finish off an encoded strip by flushing the last
 * string and tacking on an End Of Information code.
 */

static int
PixarLogPostEncode(TIFF* tif)
{
        static const char module[] = "PixarLogPostEncode";
        PixarLogState *sp = EncoderState(tif);
        int state;

        sp->stream.avail_in = 0;

        do {
                state = deflate(&sp->stream, Z_FINISH);
                switch (state) {
                case Z_STREAM_END:
                case Z_OK:
                    if ((tmsize_t)sp->stream.avail_out != tif->tif_rawdatasize) {
                            tif->tif_rawcc =
                                tif->tif_rawdatasize - sp->stream.avail_out;
                            TIFFFlushData1(tif);
                            sp->stream.next_out = tif->tif_rawdata;
                            sp->stream.avail_out = (uInt) tif->tif_rawdatasize;  /* this is a safe typecast, as check is made already in PixarLogPreEncode */
                    }
                    break;
                default:
                        TIFFErrorExt(tif->tif_clientdata, module, "ZLib error: %s",
                        sp->stream.msg);
                    return (0);
                }
        } while (state != Z_STREAM_END);
        return (1);
}

static void
PixarLogClose(TIFF* tif)
{
        TIFFDirectory *td = &tif->tif_dir;

        /* In a really sneaky (and really incorrect, and untruthfull, and
         * troublesome, and error-prone) maneuver that completely goes against
         * the spirit of TIFF, and breaks TIFF, on close, we covertly
         * modify both bitspersample and sampleformat in the directory to
         * indicate 8-bit linear.  This way, the decode "just works" even for
         * readers that don't know about PixarLog, or how to set
         * the PIXARLOGDATFMT pseudo-tag.
         */
        td->td_bitspersample = 8;
        td->td_sampleformat = SAMPLEFORMAT_UINT;
}

static void
PixarLogCleanup(TIFF* tif)
{
        PixarLogState* sp = (PixarLogState*) tif->tif_data;

        assert(sp != 0);

        (void)TIFFPredictorCleanup(tif);

        tif->tif_tagmethods.vgetfield = sp->vgetparent;
        tif->tif_tagmethods.vsetfield = sp->vsetparent;

        if (sp->FromLT2) _TIFFfree(sp->FromLT2);
        if (sp->From14) _TIFFfree(sp->From14);
        if (sp->From8) _TIFFfree(sp->From8);
        if (sp->ToLinearF) _TIFFfree(sp->ToLinearF);
        if (sp->ToLinear16) _TIFFfree(sp->ToLinear16);
        if (sp->ToLinear8) _TIFFfree(sp->ToLinear8);
        if (sp->state&PLSTATE_INIT) {
                if (tif->tif_mode == O_RDONLY)
                        inflateEnd(&sp->stream);
                else
                        deflateEnd(&sp->stream);
        }
        if (sp->tbuf)
                _TIFFfree(sp->tbuf);
        _TIFFfree(sp);
        tif->tif_data = NULL;

        _TIFFSetDefaultCompressionState(tif);
}

static int
PixarLogVSetField(TIFF* tif, uint32 tag, va_list ap)
{
    static const char module[] = "PixarLogVSetField";
    PixarLogState *sp = (PixarLogState *)tif->tif_data;
    int result;

    switch (tag) {
     case TIFFTAG_PIXARLOGQUALITY:
                sp->quality = (int) va_arg(ap, int);
                if (tif->tif_mode != O_RDONLY && (sp->state&PLSTATE_INIT)) {
                        if (deflateParams(&sp->stream,
                            sp->quality, Z_DEFAULT_STRATEGY) != Z_OK) {
                                TIFFErrorExt(tif->tif_clientdata, module, "ZLib error: %s",
                                        sp->stream.msg);
                                return (0);
                        }
                }
                return (1);
     case TIFFTAG_PIXARLOGDATAFMT:
        sp->user_datafmt = (int) va_arg(ap, int);
        /* Tweak the TIFF header so that the rest of libtiff knows what
         * size of data will be passed between app and library, and
         * assume that the app knows what it is doing and is not
         * confused by these header manipulations...
         */
        switch (sp->user_datafmt) {
         case PIXARLOGDATAFMT_8BIT:
         case PIXARLOGDATAFMT_8BITABGR:
            TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, 8);
            TIFFSetField(tif, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_UINT);
            break;
         case PIXARLOGDATAFMT_11BITLOG:
            TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, 16);
            TIFFSetField(tif, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_UINT);
            break;
         case PIXARLOGDATAFMT_12BITPICIO:
            TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, 16);
            TIFFSetField(tif, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_INT);
            break;
         case PIXARLOGDATAFMT_16BIT:
            TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, 16);
            TIFFSetField(tif, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_UINT);
            break;
         case PIXARLOGDATAFMT_FLOAT:
            TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, 32);
            TIFFSetField(tif, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_IEEEFP);
            break;
        }
        /*
         * Must recalculate sizes should bits/sample change.
         */
        tif->tif_tilesize = isTiled(tif) ? TIFFTileSize(tif) : (tmsize_t)(-1);
        tif->tif_scanlinesize = TIFFScanlineSize(tif);
        result = 1;             /* NB: pseudo tag */
        break;
     default:
        result = (*sp->vsetparent)(tif, tag, ap);
    }
    return (result);
}

static int
PixarLogVGetField(TIFF* tif, uint32 tag, va_list ap)
{
    PixarLogState *sp = (PixarLogState *)tif->tif_data;

    switch (tag) {
     case TIFFTAG_PIXARLOGQUALITY:
        *va_arg(ap, int*) = sp->quality;
        break;
     case TIFFTAG_PIXARLOGDATAFMT:
        *va_arg(ap, int*) = sp->user_datafmt;
        break;
     default:
        return (*sp->vgetparent)(tif, tag, ap);
    }
    return (1);
}

static const TIFFField pixarlogFields[] = {
    {TIFFTAG_PIXARLOGDATAFMT, 0, 0, TIFF_ANY, 0, TIFF_SETGET_INT, TIFF_SETGET_UNDEFINED, FIELD_PSEUDO, FALSE, FALSE, "", NULL},
    {TIFFTAG_PIXARLOGQUALITY, 0, 0, TIFF_ANY, 0, TIFF_SETGET_INT, TIFF_SETGET_UNDEFINED, FIELD_PSEUDO, FALSE, FALSE, "", NULL}
};

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

        PixarLogState* sp;

        assert(scheme == COMPRESSION_PIXARLOG);

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

        /*
         * Allocate state block so tag methods have storage to record values.
         */
        tif->tif_data = (uint8*) _TIFFmalloc(sizeof (PixarLogState));
        if (tif->tif_data == NULL)
                goto bad;
        sp = (PixarLogState*) tif->tif_data;
        _TIFFmemset(sp, 0, sizeof (*sp));
        sp->stream.data_type = Z_BINARY;
        sp->user_datafmt = PIXARLOGDATAFMT_UNKNOWN;

        /*
         * Install codec methods.
         */
        tif->tif_fixuptags = PixarLogFixupTags; 
        tif->tif_setupdecode = PixarLogSetupDecode;
        tif->tif_predecode = PixarLogPreDecode;
        tif->tif_decoderow = PixarLogDecode;
        tif->tif_decodestrip = PixarLogDecode;  
        tif->tif_decodetile = PixarLogDecode;
        tif->tif_setupencode = PixarLogSetupEncode;
        tif->tif_preencode = PixarLogPreEncode;
        tif->tif_postencode = PixarLogPostEncode;
        tif->tif_encoderow = PixarLogEncode;  
        tif->tif_encodestrip = PixarLogEncode;
        tif->tif_encodetile = PixarLogEncode;  
        tif->tif_close = PixarLogClose;
        tif->tif_cleanup = PixarLogCleanup;

        /* Override SetField so we can handle our private pseudo-tag */
        sp->vgetparent = tif->tif_tagmethods.vgetfield;
        tif->tif_tagmethods.vgetfield = PixarLogVGetField;   /* hook for codec tags */
        sp->vsetparent = tif->tif_tagmethods.vsetfield;
        tif->tif_tagmethods.vsetfield = PixarLogVSetField;   /* hook for codec tags */

        /* Default values for codec-specific fields */
        sp->quality = Z_DEFAULT_COMPRESSION; /* default comp. level */
        sp->state = 0;

        /* we don't wish to use the predictor, 
         * the default is none, which predictor value 1
         */
        (void) TIFFPredictorInit(tif);

        /*
         * build the companding tables 
         */
        PixarLogMakeTables(sp);

        return (1);
bad:
        TIFFErrorExt(tif->tif_clientdata, module,
                     "No space for PixarLog state block");
        return (0);
}
#endif /* PIXARLOG_SUPPORT */

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