tif_luv.c

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/* $Id: tif_luv.c,v 1.17.2.4 2010-06-08 18:50:42 bfriesen Exp $ */

/*
 * Copyright (c) 1997 Greg Ward Larson
 * Copyright (c) 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, Greg Larson 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, Greg Larson 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, GREG LARSON 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 LOGLUV_SUPPORT

/*
 * TIFF Library.
 * LogLuv compression support for high dynamic range images.
 *
 * Contributed by Greg Larson.
 *
 * LogLuv image support uses the TIFF library to store 16 or 10-bit
 * log luminance values with 8 bits each of u and v or a 14-bit index.
 *
 * The codec can take as input and produce as output 32-bit IEEE float values 
 * as well as 16-bit integer values.  A 16-bit luminance is interpreted
 * as a sign bit followed by a 15-bit integer that is converted
 * to and from a linear magnitude using the transformation:
 *
 *  L = 2^( (Le+.5)/256 - 64 )      # real from 15-bit
 *
 *  Le = floor( 256*(log2(L) + 64) )    # 15-bit from real
 *
 * The actual conversion to world luminance units in candelas per sq. meter
 * requires an additional multiplier, which is stored in the TIFFTAG_STONITS.
 * This value is usually set such that a reasonable exposure comes from
 * clamping decoded luminances above 1 to 1 in the displayed image.
 *
 * The 16-bit values for u and v may be converted to real values by dividing
 * each by 32768.  (This allows for negative values, which aren't useful as
 * far as we know, but are left in case of future improvements in human
 * color vision.)
 *
 * Conversion from (u,v), which is actually the CIE (u',v') system for
 * you color scientists, is accomplished by the following transformation:
 *
 *  u = 4*x / (-2*x + 12*y + 3)
 *  v = 9*y / (-2*x + 12*y + 3)
 *
 *  x = 9*u / (6*u - 16*v + 12)
 *  y = 4*v / (6*u - 16*v + 12)
 *
 * This process is greatly simplified by passing 32-bit IEEE floats
 * for each of three CIE XYZ coordinates.  The codec then takes care
 * of conversion to and from LogLuv, though the application is still
 * responsible for interpreting the TIFFTAG_STONITS calibration factor.
 *
 * By definition, a CIE XYZ vector of [1 1 1] corresponds to a neutral white
 * point of (x,y)=(1/3,1/3).  However, most color systems assume some other
 * white point, such as D65, and an absolute color conversion to XYZ then
 * to another color space with a different white point may introduce an
 * unwanted color cast to the image.  It is often desirable, therefore, to
 * perform a white point conversion that maps the input white to [1 1 1]
 * in XYZ, then record the original white point using the TIFFTAG_WHITEPOINT
 * tag value.  A decoder that demands absolute color calibration may use
 * this white point tag to get back the original colors, but usually it
 * will be ignored and the new white point will be used instead that
 * matches the output color space.
 *
 * Pixel information is compressed into one of two basic encodings, depending
 * on the setting of the compression tag, which is one of COMPRESSION_SGILOG
 * or COMPRESSION_SGILOG24.  For COMPRESSION_SGILOG, greyscale data is
 * stored as:
 *
 *   1       15
 *  |-+---------------|
 *
 * COMPRESSION_SGILOG color data is stored as:
 *
 *   1       15           8        8
 *  |-+---------------|--------+--------|
 *   S       Le           ue       ve
 *
 * For the 24-bit COMPRESSION_SGILOG24 color format, the data is stored as:
 *
 *       10           14
 *  |----------|--------------|
 *       Le'          Ce
 *
 * There is no sign bit in the 24-bit case, and the (u,v) chromaticity is
 * encoded as an index for optimal color resolution.  The 10 log bits are
 * defined by the following conversions:
 *
 *  L = 2^((Le'+.5)/64 - 12)        # real from 10-bit
 *
 *  Le' = floor( 64*(log2(L) + 12) )    # 10-bit from real
 *
 * The 10 bits of the smaller format may be converted into the 15 bits of
 * the larger format by multiplying by 4 and adding 13314.  Obviously,
 * a smaller range of magnitudes is covered (about 5 orders of magnitude
 * instead of 38), and the lack of a sign bit means that negative luminances
 * are not allowed.  (Well, they aren't allowed in the real world, either,
 * but they are useful for certain types of image processing.)
 *
 * The desired user format is controlled by the setting the internal
 * pseudo tag TIFFTAG_SGILOGDATAFMT to one of:
 *  SGILOGDATAFMT_FLOAT       = IEEE 32-bit float XYZ values
 *  SGILOGDATAFMT_16BIT       = 16-bit integer encodings of logL, u and v
 * Raw data i/o is also possible using:
 *  SGILOGDATAFMT_RAW         = 32-bit unsigned integer with encoded pixel
 * In addition, the following decoding is provided for ease of display:
 *  SGILOGDATAFMT_8BIT        = 8-bit default RGB gamma-corrected values
 *
 * For grayscale images, we provide the following data formats:
 *  SGILOGDATAFMT_FLOAT       = IEEE 32-bit float Y values
 *  SGILOGDATAFMT_16BIT       = 16-bit integer w/ encoded luminance
 *  SGILOGDATAFMT_8BIT        = 8-bit gray monitor values
 *
 * Note that the COMPRESSION_SGILOG applies a simple run-length encoding
 * scheme by separating the logL, u and v bytes for each row and applying
 * a PackBits type of compression.  Since the 24-bit encoding is not
 * adaptive, the 32-bit color format takes less space in many cases.
 *
 * Further control is provided over the conversion from higher-resolution
 * formats to final encoded values through the pseudo tag
 * TIFFTAG_SGILOGENCODE:
 *  SGILOGENCODE_NODITHER     = do not dither encoded values
 *  SGILOGENCODE_RANDITHER    = apply random dithering during encoding
 *
 * The default value of this tag is SGILOGENCODE_NODITHER for
 * COMPRESSION_SGILOG to maximize run-length encoding and
 * SGILOGENCODE_RANDITHER for COMPRESSION_SGILOG24 to turn
 * quantization errors into noise.
 */

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

/*
 * State block for each open TIFF
 * file using LogLuv compression/decompression.
 */
typedef struct logLuvState LogLuvState;

struct logLuvState {
    int         user_datafmt;   /* user data format */
    int         encode_meth;    /* encoding method */
    int         pixel_size; /* bytes per pixel */

    tidata_t*       tbuf;       /* translation buffer */
    int         tbuflen;    /* buffer length */
    void (*tfunc)(LogLuvState*, tidata_t, int);

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

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

#define SGILOGDATAFMT_UNKNOWN   -1

#define MINRUN      4   /* minimum run length */

/*
 * Decode a string of 16-bit gray pixels.
 */
static int
LogL16Decode(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
{
    LogLuvState* sp = DecoderState(tif);
    int shft, i, npixels;
    unsigned char* bp;
    int16* tp;
    int16 b;
    int cc, rc;

    assert(s == 0);
    assert(sp != NULL);

    npixels = occ / sp->pixel_size;

    if (sp->user_datafmt == SGILOGDATAFMT_16BIT)
        tp = (int16*) op;
    else {
        assert(sp->tbuflen >= npixels);
        tp = (int16*) sp->tbuf;
    }
    _TIFFmemset((tdata_t) tp, 0, npixels*sizeof (tp[0]));

    bp = (unsigned char*) tif->tif_rawcp;
    cc = tif->tif_rawcc;
                    /* get each byte string */
    for (shft = 2*8; (shft -= 8) >= 0; ) {
        for (i = 0; i < npixels && cc > 0; )
            if (*bp >= 128) {       /* run */
                rc = *bp++ + (2-128);
                b = (int16)(*bp++ << shft);
                cc -= 2;
                while (rc-- && i < npixels)
                    tp[i++] |= b;
            } else {            /* non-run */
                rc = *bp++;     /* nul is noop */
                while (--cc && rc-- && i < npixels)
                    tp[i++] |= (int16)*bp++ << shft;
            }
        if (i != npixels) {
            TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
        "LogL16Decode: Not enough data at row %d (short %d pixels)",
                tif->tif_row, npixels - i);
            tif->tif_rawcp = (tidata_t) bp;
            tif->tif_rawcc = cc;
            return (0);
        }
    }
    (*sp->tfunc)(sp, op, npixels);
    tif->tif_rawcp = (tidata_t) bp;
    tif->tif_rawcc = cc;
    return (1);
}

/*
 * Decode a string of 24-bit pixels.
 */
static int
LogLuvDecode24(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
{
    LogLuvState* sp = DecoderState(tif);
    int cc, i, npixels;
    unsigned char* bp;
    uint32* tp;

    assert(s == 0);
    assert(sp != NULL);

    npixels = occ / sp->pixel_size;

    if (sp->user_datafmt == SGILOGDATAFMT_RAW)
        tp = (uint32 *)op;
    else {
        assert(sp->tbuflen >= npixels);
        tp = (uint32 *) sp->tbuf;
    }
                    /* copy to array of uint32 */
    bp = (unsigned char*) tif->tif_rawcp;
    cc = tif->tif_rawcc;
    for (i = 0; i < npixels && cc > 0; i++) {
        tp[i] = bp[0] << 16 | bp[1] << 8 | bp[2];
        bp += 3;
        cc -= 3;
    }
    tif->tif_rawcp = (tidata_t) bp;
    tif->tif_rawcc = cc;
    if (i != npixels) {
        TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
        "LogLuvDecode24: Not enough data at row %d (short %d pixels)",
            tif->tif_row, npixels - i);
        return (0);
    }
    (*sp->tfunc)(sp, op, npixels);
    return (1);
}

/*
 * Decode a string of 32-bit pixels.
 */
static int
LogLuvDecode32(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
{
    LogLuvState* sp;
    int shft, i, npixels;
    unsigned char* bp;
    uint32* tp;
    uint32 b;
    int cc, rc;

    assert(s == 0);
    sp = DecoderState(tif);
    assert(sp != NULL);

    npixels = occ / sp->pixel_size;

    if (sp->user_datafmt == SGILOGDATAFMT_RAW)
        tp = (uint32*) op;
    else {
        assert(sp->tbuflen >= npixels);
        tp = (uint32*) sp->tbuf;
    }
    _TIFFmemset((tdata_t) tp, 0, npixels*sizeof (tp[0]));

    bp = (unsigned char*) tif->tif_rawcp;
    cc = tif->tif_rawcc;
                    /* get each byte string */
    for (shft = 4*8; (shft -= 8) >= 0; ) {
        for (i = 0; i < npixels && cc > 0; )
            if (*bp >= 128) {       /* run */
                rc = *bp++ + (2-128);
                b = (uint32)*bp++ << shft;
                cc -= 2;
                while (rc-- && i < npixels)
                    tp[i++] |= b;
            } else {            /* non-run */
                rc = *bp++;     /* nul is noop */
                while (--cc && rc-- && i < npixels)
                    tp[i++] |= (uint32)*bp++ << shft;
            }
        if (i != npixels) {
            TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
        "LogLuvDecode32: Not enough data at row %d (short %d pixels)",
                tif->tif_row, npixels - i);
            tif->tif_rawcp = (tidata_t) bp;
            tif->tif_rawcc = cc;
            return (0);
        }
    }
    (*sp->tfunc)(sp, op, npixels);
    tif->tif_rawcp = (tidata_t) bp;
    tif->tif_rawcc = cc;
    return (1);
}

/*
 * Decode a strip of pixels.  We break it into rows to
 * maintain synchrony with the encode algorithm, which
 * is row by row.
 */
static int
LogLuvDecodeStrip(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
    tsize_t rowlen = TIFFScanlineSize(tif);

    assert(cc%rowlen == 0);
    while (cc && (*tif->tif_decoderow)(tif, bp, rowlen, s))
        bp += rowlen, cc -= rowlen;
    return (cc == 0);
}

/*
 * Decode a tile of pixels.  We break it into rows to
 * maintain synchrony with the encode algorithm, which
 * is row by row.
 */
static int
LogLuvDecodeTile(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
    tsize_t rowlen = TIFFTileRowSize(tif);

    assert(cc%rowlen == 0);
    while (cc && (*tif->tif_decoderow)(tif, bp, rowlen, s))
        bp += rowlen, cc -= rowlen;
    return (cc == 0);
}

/*
 * Encode a row of 16-bit pixels.
 */
static int
LogL16Encode(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
    LogLuvState* sp = EncoderState(tif);
    int shft, i, j, npixels;
    tidata_t op;
    int16* tp;
    int16 b;
    int occ, rc=0, mask, beg;

    assert(s == 0);
    assert(sp != NULL);
    npixels = cc / sp->pixel_size;

    if (sp->user_datafmt == SGILOGDATAFMT_16BIT)
        tp = (int16*) bp;
    else {
        tp = (int16*) sp->tbuf;
        assert(sp->tbuflen >= npixels);
        (*sp->tfunc)(sp, bp, npixels);
    }
                    /* compress each byte string */
    op = tif->tif_rawcp;
    occ = tif->tif_rawdatasize - tif->tif_rawcc;
    for (shft = 2*8; (shft -= 8) >= 0; )
        for (i = 0; i < npixels; i += rc) {
            if (occ < 4) {
                tif->tif_rawcp = op;
                tif->tif_rawcc = tif->tif_rawdatasize - occ;
                if (!TIFFFlushData1(tif))
                    return (-1);
                op = tif->tif_rawcp;
                occ = tif->tif_rawdatasize - tif->tif_rawcc;
            }
            mask = 0xff << shft;        /* find next run */
            for (beg = i; beg < npixels; beg += rc) {
                b = (int16) (tp[beg] & mask);
                rc = 1;
                while (rc < 127+2 && beg+rc < npixels &&
                        (tp[beg+rc] & mask) == b)
                    rc++;
                if (rc >= MINRUN)
                    break;      /* long enough */
            }
            if (beg-i > 1 && beg-i < MINRUN) {
                b = (int16) (tp[i] & mask);/*check short run */
                j = i+1;
                while ((tp[j++] & mask) == b)
                                    if (j == beg) {
                                        *op++ = (tidataval_t)(128-2+j-i);
                                        *op++ = (tidataval_t) (b >> shft);
                                        occ -= 2;
                                        i = beg;
                                        break;
                                    }
            }
            while (i < beg) {       /* write out non-run */
                if ((j = beg-i) > 127) j = 127;
                if (occ < j+3) {
                                    tif->tif_rawcp = op;
                                    tif->tif_rawcc = tif->tif_rawdatasize - occ;
                                    if (!TIFFFlushData1(tif))
                                        return (-1);
                                    op = tif->tif_rawcp;
                                    occ = tif->tif_rawdatasize - tif->tif_rawcc;
                }
                *op++ = (tidataval_t) j; occ--;
                while (j--) {
                    *op++ = (tidataval_t) (tp[i++] >> shft & 0xff);
                    occ--;
                }
            }
            if (rc >= MINRUN) {     /* write out run */
                *op++ = (tidataval_t) (128-2+rc);
                *op++ = (tidataval_t) (tp[beg] >> shft & 0xff);
                occ -= 2;
            } else
                rc = 0;
        }
    tif->tif_rawcp = op;
    tif->tif_rawcc = tif->tif_rawdatasize - occ;

    return (1);
}

/*
 * Encode a row of 24-bit pixels.
 */
static int
LogLuvEncode24(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
    LogLuvState* sp = EncoderState(tif);
    int i, npixels, occ;
    tidata_t op;
    uint32* tp;

    assert(s == 0);
    assert(sp != NULL);
    npixels = cc / sp->pixel_size;

    if (sp->user_datafmt == SGILOGDATAFMT_RAW)
        tp = (uint32*) bp;
    else {
        tp = (uint32*) sp->tbuf;
        assert(sp->tbuflen >= npixels);
        (*sp->tfunc)(sp, bp, npixels);
    }
                    /* write out encoded pixels */
    op = tif->tif_rawcp;
    occ = tif->tif_rawdatasize - tif->tif_rawcc;
    for (i = npixels; i--; ) {
        if (occ < 3) {
            tif->tif_rawcp = op;
            tif->tif_rawcc = tif->tif_rawdatasize - occ;
            if (!TIFFFlushData1(tif))
                return (-1);
            op = tif->tif_rawcp;
            occ = tif->tif_rawdatasize - tif->tif_rawcc;
        }
        *op++ = (tidataval_t)(*tp >> 16);
        *op++ = (tidataval_t)(*tp >> 8 & 0xff);
        *op++ = (tidataval_t)(*tp++ & 0xff);
        occ -= 3;
    }
    tif->tif_rawcp = op;
    tif->tif_rawcc = tif->tif_rawdatasize - occ;

    return (1);
}

/*
 * Encode a row of 32-bit pixels.
 */
static int
LogLuvEncode32(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
    LogLuvState* sp = EncoderState(tif);
    int shft, i, j, npixels;
    tidata_t op;
    uint32* tp;
    uint32 b;
    int occ, rc=0, mask, beg;

    assert(s == 0);
    assert(sp != NULL);

    npixels = cc / sp->pixel_size;

    if (sp->user_datafmt == SGILOGDATAFMT_RAW)
        tp = (uint32*) bp;
    else {
        tp = (uint32*) sp->tbuf;
        assert(sp->tbuflen >= npixels);
        (*sp->tfunc)(sp, bp, npixels);
    }
                    /* compress each byte string */
    op = tif->tif_rawcp;
    occ = tif->tif_rawdatasize - tif->tif_rawcc;
    for (shft = 4*8; (shft -= 8) >= 0; )
        for (i = 0; i < npixels; i += rc) {
            if (occ < 4) {
                tif->tif_rawcp = op;
                tif->tif_rawcc = tif->tif_rawdatasize - occ;
                if (!TIFFFlushData1(tif))
                    return (-1);
                op = tif->tif_rawcp;
                occ = tif->tif_rawdatasize - tif->tif_rawcc;
            }
            mask = 0xff << shft;        /* find next run */
            for (beg = i; beg < npixels; beg += rc) {
                b = tp[beg] & mask;
                rc = 1;
                while (rc < 127+2 && beg+rc < npixels &&
                        (tp[beg+rc] & mask) == b)
                    rc++;
                if (rc >= MINRUN)
                    break;      /* long enough */
            }
            if (beg-i > 1 && beg-i < MINRUN) {
                b = tp[i] & mask;   /* check short run */
                j = i+1;
                while ((tp[j++] & mask) == b)
                    if (j == beg) {
                        *op++ = (tidataval_t)(128-2+j-i);
                        *op++ = (tidataval_t)(b >> shft);
                        occ -= 2;
                        i = beg;
                        break;
                    }
            }
            while (i < beg) {       /* write out non-run */
                if ((j = beg-i) > 127) j = 127;
                if (occ < j+3) {
                    tif->tif_rawcp = op;
                    tif->tif_rawcc = tif->tif_rawdatasize - occ;
                    if (!TIFFFlushData1(tif))
                        return (-1);
                    op = tif->tif_rawcp;
                    occ = tif->tif_rawdatasize - tif->tif_rawcc;
                }
                *op++ = (tidataval_t) j; occ--;
                while (j--) {
                    *op++ = (tidataval_t)(tp[i++] >> shft & 0xff);
                    occ--;
                }
            }
            if (rc >= MINRUN) {     /* write out run */
                *op++ = (tidataval_t) (128-2+rc);
                *op++ = (tidataval_t)(tp[beg] >> shft & 0xff);
                occ -= 2;
            } else
                rc = 0;
        }
    tif->tif_rawcp = op;
    tif->tif_rawcc = tif->tif_rawdatasize - occ;

    return (1);
}

/*
 * Encode a strip of pixels.  We break it into rows to
 * avoid encoding runs across row boundaries.
 */
static int
LogLuvEncodeStrip(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
    tsize_t rowlen = TIFFScanlineSize(tif);

    assert(cc%rowlen == 0);
    while (cc && (*tif->tif_encoderow)(tif, bp, rowlen, s) == 1)
        bp += rowlen, cc -= rowlen;
    return (cc == 0);
}

/*
 * Encode a tile of pixels.  We break it into rows to
 * avoid encoding runs across row boundaries.
 */
static int
LogLuvEncodeTile(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
    tsize_t rowlen = TIFFTileRowSize(tif);

    assert(cc%rowlen == 0);
    while (cc && (*tif->tif_encoderow)(tif, bp, rowlen, s) == 1)
        bp += rowlen, cc -= rowlen;
    return (cc == 0);
}

/*
 * Encode/Decode functions for converting to and from user formats.
 */

#include "uvcode.h"

#ifndef UVSCALE
#define U_NEU       0.210526316
#define V_NEU       0.473684211
#define UVSCALE     410.
#endif

#ifndef M_LN2
#define M_LN2       0.69314718055994530942
#endif
#ifndef M_PI
#define M_PI        3.14159265358979323846
#endif
#define log2(x)     ((1./M_LN2)*log(x))
#define exp2(x)     exp(M_LN2*(x))

#define itrunc(x,m) ((m)==SGILOGENCODE_NODITHER ? \
                (int)(x) : \
                (int)((x) + rand()*(1./RAND_MAX) - .5))

#if !LOGLUV_PUBLIC
static
#endif
double
LogL16toY(int p16)      /* compute luminance from 16-bit LogL */
{
    int Le = p16 & 0x7fff;
    double  Y;

    if (!Le)
        return (0.);
    Y = exp(M_LN2/256.*(Le+.5) - M_LN2*64.);
    return (!(p16 & 0x8000) ? Y : -Y);
}

#if !LOGLUV_PUBLIC
static
#endif
int
LogL16fromY(double Y, int em)   /* get 16-bit LogL from Y */
{
    if (Y >= 1.8371976e19)
        return (0x7fff);
    if (Y <= -1.8371976e19)
        return (0xffff);
    if (Y > 5.4136769e-20)
        return itrunc(256.*(log2(Y) + 64.), em);
    if (Y < -5.4136769e-20)
        return (~0x7fff | itrunc(256.*(log2(-Y) + 64.), em));
    return (0);
}

static void
L16toY(LogLuvState* sp, tidata_t op, int n)
{
    int16* l16 = (int16*) sp->tbuf;
    float* yp = (float*) op;

    while (n-- > 0)
        *yp++ = (float)LogL16toY(*l16++);
}

static void
L16toGry(LogLuvState* sp, tidata_t op, int n)
{
    int16* l16 = (int16*) sp->tbuf;
    uint8* gp = (uint8*) op;

    while (n-- > 0) {
        double Y = LogL16toY(*l16++);
        *gp++ = (uint8) ((Y <= 0.) ? 0 : (Y >= 1.) ? 255 : (int)(256.*sqrt(Y)));
    }
}

static void
L16fromY(LogLuvState* sp, tidata_t op, int n)
{
    int16* l16 = (int16*) sp->tbuf;
    float* yp = (float*) op;

    while (n-- > 0)
        *l16++ = (int16) (LogL16fromY(*yp++, sp->encode_meth));
}

#if !LOGLUV_PUBLIC
static
#endif
void
XYZtoRGB24(float xyz[3], uint8 rgb[3])
{
    double  r, g, b;
                    /* assume CCIR-709 primaries */
    r =  2.690*xyz[0] + -1.276*xyz[1] + -0.414*xyz[2];
    g = -1.022*xyz[0] +  1.978*xyz[1] +  0.044*xyz[2];
    b =  0.061*xyz[0] + -0.224*xyz[1] +  1.163*xyz[2];
                    /* assume 2.0 gamma for speed */
    /* could use integer sqrt approx., but this is probably faster */
    rgb[0] = (uint8)((r<=0.) ? 0 : (r >= 1.) ? 255 : (int)(256.*sqrt(r)));
    rgb[1] = (uint8)((g<=0.) ? 0 : (g >= 1.) ? 255 : (int)(256.*sqrt(g)));
    rgb[2] = (uint8)((b<=0.) ? 0 : (b >= 1.) ? 255 : (int)(256.*sqrt(b)));
}

#if !LOGLUV_PUBLIC
static
#endif
double
LogL10toY(int p10)      /* compute luminance from 10-bit LogL */
{
    if (p10 == 0)
        return (0.);
    return (exp(M_LN2/64.*(p10+.5) - M_LN2*12.));
}

#if !LOGLUV_PUBLIC
static
#endif
int
LogL10fromY(double Y, int em)   /* get 10-bit LogL from Y */
{
    if (Y >= 15.742)
        return (0x3ff);
    else if (Y <= .00024283)
        return (0);
    else
        return itrunc(64.*(log2(Y) + 12.), em);
}

#define NANGLES     100
#define uv2ang(u, v)    ( (NANGLES*.499999999/M_PI) \
                * atan2((v)-V_NEU,(u)-U_NEU) + .5*NANGLES )

static int
oog_encode(double u, double v)      /* encode out-of-gamut chroma */
{
    static int  oog_table[NANGLES];
    static int  initialized = 0;
    register int    i;
    
    if (!initialized) {     /* set up perimeter table */
        double  eps[NANGLES], ua, va, ang, epsa;
        int ui, vi, ustep;
        for (i = NANGLES; i--; )
            eps[i] = 2.;
        for (vi = UV_NVS; vi--; ) {
            va = UV_VSTART + (vi+.5)*UV_SQSIZ;
            ustep = uv_row[vi].nus-1;
            if (vi == UV_NVS-1 || vi == 0 || ustep <= 0)
                ustep = 1;
            for (ui = uv_row[vi].nus-1; ui >= 0; ui -= ustep) {
                ua = uv_row[vi].ustart + (ui+.5)*UV_SQSIZ;
                ang = uv2ang(ua, va);
                                i = (int) ang;
                epsa = fabs(ang - (i+.5));
                if (epsa < eps[i]) {
                    oog_table[i] = uv_row[vi].ncum + ui;
                    eps[i] = epsa;
                }
            }
        }
        for (i = NANGLES; i--; )    /* fill any holes */
            if (eps[i] > 1.5) {
                int i1, i2;
                for (i1 = 1; i1 < NANGLES/2; i1++)
                    if (eps[(i+i1)%NANGLES] < 1.5)
                        break;
                for (i2 = 1; i2 < NANGLES/2; i2++)
                    if (eps[(i+NANGLES-i2)%NANGLES] < 1.5)
                        break;
                if (i1 < i2)
                    oog_table[i] =
                        oog_table[(i+i1)%NANGLES];
                else
                    oog_table[i] =
                        oog_table[(i+NANGLES-i2)%NANGLES];
            }
        initialized = 1;
    }
    i = (int) uv2ang(u, v);     /* look up hue angle */
    return (oog_table[i]);
}

#undef uv2ang
#undef NANGLES

#if !LOGLUV_PUBLIC
static
#endif
int
uv_encode(double u, double v, int em)   /* encode (u',v') coordinates */
{
    register int    vi, ui;

    if (v < UV_VSTART)
        return oog_encode(u, v);
    vi = itrunc((v - UV_VSTART)*(1./UV_SQSIZ), em);
    if (vi >= UV_NVS)
        return oog_encode(u, v);
    if (u < uv_row[vi].ustart)
        return oog_encode(u, v);
    ui = itrunc((u - uv_row[vi].ustart)*(1./UV_SQSIZ), em);
    if (ui >= uv_row[vi].nus)
        return oog_encode(u, v);

    return (uv_row[vi].ncum + ui);
}

#if !LOGLUV_PUBLIC
static
#endif
int
uv_decode(double *up, double *vp, int c)    /* decode (u',v') index */
{
    int upper, lower;
    register int    ui, vi;

    if (c < 0 || c >= UV_NDIVS)
        return (-1);
    lower = 0;              /* binary search */
    upper = UV_NVS;
    while (upper - lower > 1) {
        vi = (lower + upper) >> 1;
        ui = c - uv_row[vi].ncum;
        if (ui > 0)
            lower = vi;
        else if (ui < 0)
            upper = vi;
        else {
            lower = vi;
            break;
        }
    }
    vi = lower;
    ui = c - uv_row[vi].ncum;
    *up = uv_row[vi].ustart + (ui+.5)*UV_SQSIZ;
    *vp = UV_VSTART + (vi+.5)*UV_SQSIZ;
    return (0);
}

#if !LOGLUV_PUBLIC
static
#endif
void
LogLuv24toXYZ(uint32 p, float XYZ[3])
{
    int Ce;
    double  L, u, v, s, x, y;
                    /* decode luminance */
    L = LogL10toY(p>>14 & 0x3ff);
    if (L <= 0.) {
        XYZ[0] = XYZ[1] = XYZ[2] = 0.;
        return;
    }
                    /* decode color */
    Ce = p & 0x3fff;
    if (uv_decode(&u, &v, Ce) < 0) {
        u = U_NEU; v = V_NEU;
    }
    s = 1./(6.*u - 16.*v + 12.);
    x = 9.*u * s;
    y = 4.*v * s;
                    /* convert to XYZ */
    XYZ[0] = (float)(x/y * L);
    XYZ[1] = (float)L;
    XYZ[2] = (float)((1.-x-y)/y * L);
}

#if !LOGLUV_PUBLIC
static
#endif
uint32
LogLuv24fromXYZ(float XYZ[3], int em)
{
    int Le, Ce;
    double  u, v, s;
                    /* encode luminance */
    Le = LogL10fromY(XYZ[1], em);
                    /* encode color */
    s = XYZ[0] + 15.*XYZ[1] + 3.*XYZ[2];
    if (!Le || s <= 0.) {
        u = U_NEU;
        v = V_NEU;
    } else {
        u = 4.*XYZ[0] / s;
        v = 9.*XYZ[1] / s;
    }
    Ce = uv_encode(u, v, em);
    if (Ce < 0)         /* never happens */
        Ce = uv_encode(U_NEU, V_NEU, SGILOGENCODE_NODITHER);
                    /* combine encodings */
    return (Le << 14 | Ce);
}

static void
Luv24toXYZ(LogLuvState* sp, tidata_t op, int n)
{
    uint32* luv = (uint32*) sp->tbuf;
    float* xyz = (float*) op;

    while (n-- > 0) {
        LogLuv24toXYZ(*luv, xyz);
        xyz += 3;
        luv++;
    }
}

static void
Luv24toLuv48(LogLuvState* sp, tidata_t op, int n)
{
    uint32* luv = (uint32*) sp->tbuf;
    int16* luv3 = (int16*) op;

    while (n-- > 0) {
        double u, v;

        *luv3++ = (int16)((*luv >> 12 & 0xffd) + 13314);
        if (uv_decode(&u, &v, *luv&0x3fff) < 0) {
            u = U_NEU;
            v = V_NEU;
        }
        *luv3++ = (int16)(u * (1L<<15));
        *luv3++ = (int16)(v * (1L<<15));
        luv++;
    }
}

static void
Luv24toRGB(LogLuvState* sp, tidata_t op, int n)
{
    uint32* luv = (uint32*) sp->tbuf;
    uint8* rgb = (uint8*) op;

    while (n-- > 0) {
        float xyz[3];

        LogLuv24toXYZ(*luv++, xyz);
        XYZtoRGB24(xyz, rgb);
        rgb += 3;
    }
}

static void
Luv24fromXYZ(LogLuvState* sp, tidata_t op, int n)
{
    uint32* luv = (uint32*) sp->tbuf;
    float* xyz = (float*) op;

    while (n-- > 0) {
        *luv++ = LogLuv24fromXYZ(xyz, sp->encode_meth);
        xyz += 3;
    }
}

static void
Luv24fromLuv48(LogLuvState* sp, tidata_t op, int n)
{
    uint32* luv = (uint32*) sp->tbuf;
    int16* luv3 = (int16*) op;

    while (n-- > 0) {
        int Le, Ce;

        if (luv3[0] <= 0)
            Le = 0;
        else if (luv3[0] >= (1<<12)+3314)
            Le = (1<<10) - 1;
        else if (sp->encode_meth == SGILOGENCODE_NODITHER)
            Le = (luv3[0]-3314) >> 2;
        else
            Le = itrunc(.25*(luv3[0]-3314.), sp->encode_meth);

        Ce = uv_encode((luv3[1]+.5)/(1<<15), (luv3[2]+.5)/(1<<15),
                    sp->encode_meth);
        if (Ce < 0) /* never happens */
            Ce = uv_encode(U_NEU, V_NEU, SGILOGENCODE_NODITHER);
        *luv++ = (uint32)Le << 14 | Ce;
        luv3 += 3;
    }
}

#if !LOGLUV_PUBLIC
static
#endif
void
LogLuv32toXYZ(uint32 p, float XYZ[3])
{
    double  L, u, v, s, x, y;
                    /* decode luminance */
    L = LogL16toY((int)p >> 16);
    if (L <= 0.) {
        XYZ[0] = XYZ[1] = XYZ[2] = 0.;
        return;
    }
                    /* decode color */
    u = 1./UVSCALE * ((p>>8 & 0xff) + .5);
    v = 1./UVSCALE * ((p & 0xff) + .5);
    s = 1./(6.*u - 16.*v + 12.);
    x = 9.*u * s;
    y = 4.*v * s;
                    /* convert to XYZ */
    XYZ[0] = (float)(x/y * L);
    XYZ[1] = (float)L;
    XYZ[2] = (float)((1.-x-y)/y * L);
}

#if !LOGLUV_PUBLIC
static
#endif
uint32
LogLuv32fromXYZ(float XYZ[3], int em)
{
    unsigned int    Le, ue, ve;
    double  u, v, s;
                    /* encode luminance */
    Le = (unsigned int)LogL16fromY(XYZ[1], em);
                    /* encode color */
    s = XYZ[0] + 15.*XYZ[1] + 3.*XYZ[2];
    if (!Le || s <= 0.) {
        u = U_NEU;
        v = V_NEU;
    } else {
        u = 4.*XYZ[0] / s;
        v = 9.*XYZ[1] / s;
    }
    if (u <= 0.) ue = 0;
    else ue = itrunc(UVSCALE*u, em);
    if (ue > 255) ue = 255;
    if (v <= 0.) ve = 0;
    else ve = itrunc(UVSCALE*v, em);
    if (ve > 255) ve = 255;
                    /* combine encodings */
    return (Le << 16 | ue << 8 | ve);
}

static void
Luv32toXYZ(LogLuvState* sp, tidata_t op, int n)
{
    uint32* luv = (uint32*) sp->tbuf;
    float* xyz = (float*) op;

    while (n-- > 0) {
        LogLuv32toXYZ(*luv++, xyz);
        xyz += 3;
    }
}

static void
Luv32toLuv48(LogLuvState* sp, tidata_t op, int n)
{
    uint32* luv = (uint32*) sp->tbuf;
    int16* luv3 = (int16*) op;

    while (n-- > 0) {
        double u, v;

        *luv3++ = (int16)(*luv >> 16);
        u = 1./UVSCALE * ((*luv>>8 & 0xff) + .5);
        v = 1./UVSCALE * ((*luv & 0xff) + .5);
        *luv3++ = (int16)(u * (1L<<15));
        *luv3++ = (int16)(v * (1L<<15));
        luv++;
    }
}

static void
Luv32toRGB(LogLuvState* sp, tidata_t op, int n)
{
    uint32* luv = (uint32*) sp->tbuf;
    uint8* rgb = (uint8*) op;

    while (n-- > 0) {
        float xyz[3];

        LogLuv32toXYZ(*luv++, xyz);
        XYZtoRGB24(xyz, rgb);
        rgb += 3;
    }
}

static void
Luv32fromXYZ(LogLuvState* sp, tidata_t op, int n)
{
    uint32* luv = (uint32*) sp->tbuf;
    float* xyz = (float*) op;

    while (n-- > 0) {
        *luv++ = LogLuv32fromXYZ(xyz, sp->encode_meth);
        xyz += 3;
    }
}

static void
Luv32fromLuv48(LogLuvState* sp, tidata_t op, int n)
{
    uint32* luv = (uint32*) sp->tbuf;
    int16* luv3 = (int16*) op;

    if (sp->encode_meth == SGILOGENCODE_NODITHER) {
        while (n-- > 0) {
            *luv++ = (uint32)luv3[0] << 16 |
                (luv3[1]*(uint32)(UVSCALE+.5) >> 7 & 0xff00) |
                (luv3[2]*(uint32)(UVSCALE+.5) >> 15 & 0xff);
            luv3 += 3;
        }
        return;
    }
    while (n-- > 0) {
        *luv++ = (uint32)luv3[0] << 16 |
    (itrunc(luv3[1]*(UVSCALE/(1<<15)), sp->encode_meth) << 8 & 0xff00) |
        (itrunc(luv3[2]*(UVSCALE/(1<<15)), sp->encode_meth) & 0xff);
        luv3 += 3;
    }
}

static void
_logLuvNop(LogLuvState* sp, tidata_t op, int n)
{
    (void) sp; (void) op; (void) n;
}

static int
LogL16GuessDataFmt(TIFFDirectory *td)
{
#define PACK(s,b,f) (((b)<<6)|((s)<<3)|(f))
    switch (PACK(td->td_samplesperpixel, td->td_bitspersample, td->td_sampleformat)) {
    case PACK(1, 32, SAMPLEFORMAT_IEEEFP):
        return (SGILOGDATAFMT_FLOAT);
    case PACK(1, 16, SAMPLEFORMAT_VOID):
    case PACK(1, 16, SAMPLEFORMAT_INT):
    case PACK(1, 16, SAMPLEFORMAT_UINT):
        return (SGILOGDATAFMT_16BIT);
    case PACK(1,  8, SAMPLEFORMAT_VOID):
    case PACK(1,  8, SAMPLEFORMAT_UINT):
        return (SGILOGDATAFMT_8BIT);
    }
#undef PACK
    return (SGILOGDATAFMT_UNKNOWN);
}

static uint32
multiply(size_t m1, size_t m2)
{
    uint32  bytes = m1 * m2;

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

    return bytes;
}

static int
LogL16InitState(TIFF* tif)
{
    TIFFDirectory *td = &tif->tif_dir;
    LogLuvState* sp = DecoderState(tif);
    static const char module[] = "LogL16InitState";

    assert(sp != NULL);
    assert(td->td_photometric == PHOTOMETRIC_LOGL);

    /* for some reason, we can't do this in TIFFInitLogL16 */
    if (sp->user_datafmt == SGILOGDATAFMT_UNKNOWN)
        sp->user_datafmt = LogL16GuessDataFmt(td);
    switch (sp->user_datafmt) {
    case SGILOGDATAFMT_FLOAT:
        sp->pixel_size = sizeof (float);
        break;
    case SGILOGDATAFMT_16BIT:
        sp->pixel_size = sizeof (int16);
        break;
    case SGILOGDATAFMT_8BIT:
        sp->pixel_size = sizeof (uint8);
        break;
    default:
        TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
            "No support for converting user data format to LogL");
        return (0);
    }
        if( isTiled(tif) )
            sp->tbuflen = multiply(td->td_tilewidth, td->td_tilelength);
        else
            sp->tbuflen = multiply(td->td_imagewidth, td->td_rowsperstrip);
    if (multiply(sp->tbuflen, sizeof (int16)) == 0 ||
        (sp->tbuf = (tidata_t*) _TIFFmalloc(sp->tbuflen * sizeof (int16))) == NULL) {
        TIFFErrorExt(tif->tif_clientdata, module, "%s: No space for SGILog translation buffer",
            tif->tif_name);
        return (0);
    }
    return (1);
}

static int
LogLuvGuessDataFmt(TIFFDirectory *td)
{
    int guess;

    /*
     * If the user didn't tell us their datafmt,
     * take our best guess from the bitspersample.
     */
#define PACK(a,b)   (((a)<<3)|(b))
    switch (PACK(td->td_bitspersample, td->td_sampleformat)) {
    case PACK(32, SAMPLEFORMAT_IEEEFP):
        guess = SGILOGDATAFMT_FLOAT;
        break;
    case PACK(32, SAMPLEFORMAT_VOID):
    case PACK(32, SAMPLEFORMAT_UINT):
    case PACK(32, SAMPLEFORMAT_INT):
        guess = SGILOGDATAFMT_RAW;
        break;
    case PACK(16, SAMPLEFORMAT_VOID):
    case PACK(16, SAMPLEFORMAT_INT):
    case PACK(16, SAMPLEFORMAT_UINT):
        guess = SGILOGDATAFMT_16BIT;
        break;
    case PACK( 8, SAMPLEFORMAT_VOID):
    case PACK( 8, SAMPLEFORMAT_UINT):
        guess = SGILOGDATAFMT_8BIT;
        break;
    default:
        guess = SGILOGDATAFMT_UNKNOWN;
        break;
#undef PACK
    }
    /*
     * Double-check samples per pixel.
     */
    switch (td->td_samplesperpixel) {
    case 1:
        if (guess != SGILOGDATAFMT_RAW)
            guess = SGILOGDATAFMT_UNKNOWN;
        break;
    case 3:
        if (guess == SGILOGDATAFMT_RAW)
            guess = SGILOGDATAFMT_UNKNOWN;
        break;
    default:
        guess = SGILOGDATAFMT_UNKNOWN;
        break;
    }
    return (guess);
}

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

    assert(sp != NULL);
    assert(td->td_photometric == PHOTOMETRIC_LOGLUV);

    /* for some reason, we can't do this in TIFFInitLogLuv */
    if (td->td_planarconfig != PLANARCONFIG_CONTIG) {
        TIFFErrorExt(tif->tif_clientdata, module,
            "SGILog compression cannot handle non-contiguous data");
        return (0);
    }
    if (sp->user_datafmt == SGILOGDATAFMT_UNKNOWN)
        sp->user_datafmt = LogLuvGuessDataFmt(td);
    switch (sp->user_datafmt) {
    case SGILOGDATAFMT_FLOAT:
        sp->pixel_size = 3*sizeof (float);
        break;
    case SGILOGDATAFMT_16BIT:
        sp->pixel_size = 3*sizeof (int16);
        break;
    case SGILOGDATAFMT_RAW:
        sp->pixel_size = sizeof (uint32);
        break;
    case SGILOGDATAFMT_8BIT:
        sp->pixel_size = 3*sizeof (uint8);
        break;
    default:
        TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
            "No support for converting user data format to LogLuv");
        return (0);
    }
        if( isTiled(tif) )
            sp->tbuflen = multiply(td->td_tilewidth, td->td_tilelength);
        else
            sp->tbuflen = multiply(td->td_imagewidth, td->td_rowsperstrip);
    if (multiply(sp->tbuflen, sizeof (uint32)) == 0 ||
        (sp->tbuf = (tidata_t*) _TIFFmalloc(sp->tbuflen * sizeof (uint32))) == NULL) {
        TIFFErrorExt(tif->tif_clientdata, module, "%s: No space for SGILog translation buffer",
            tif->tif_name);
        return (0);
    }
    return (1);
}

static int
LogLuvSetupDecode(TIFF* tif)
{
    LogLuvState* sp = DecoderState(tif);
    TIFFDirectory* td = &tif->tif_dir;

    tif->tif_postdecode = _TIFFNoPostDecode;
    switch (td->td_photometric) {
    case PHOTOMETRIC_LOGLUV:
        if (!LogLuvInitState(tif))
            break;
        if (td->td_compression == COMPRESSION_SGILOG24) {
            tif->tif_decoderow = LogLuvDecode24;
            switch (sp->user_datafmt) {
            case SGILOGDATAFMT_FLOAT:
                sp->tfunc = Luv24toXYZ;
                break;
            case SGILOGDATAFMT_16BIT:
                sp->tfunc = Luv24toLuv48;
                break;
            case SGILOGDATAFMT_8BIT:
                sp->tfunc = Luv24toRGB;
                break;
            }
        } else {
            tif->tif_decoderow = LogLuvDecode32;
            switch (sp->user_datafmt) {
            case SGILOGDATAFMT_FLOAT:
                sp->tfunc = Luv32toXYZ;
                break;
            case SGILOGDATAFMT_16BIT:
                sp->tfunc = Luv32toLuv48;
                break;
            case SGILOGDATAFMT_8BIT:
                sp->tfunc = Luv32toRGB;
                break;
            }
        }
        return (1);
    case PHOTOMETRIC_LOGL:
        if (!LogL16InitState(tif))
            break;
        tif->tif_decoderow = LogL16Decode;
        switch (sp->user_datafmt) {
        case SGILOGDATAFMT_FLOAT:
            sp->tfunc = L16toY;
            break;
        case SGILOGDATAFMT_8BIT:
            sp->tfunc = L16toGry;
            break;
        }
        return (1);
    default:
        TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
    "Inappropriate photometric interpretation %d for SGILog compression; %s",
            td->td_photometric, "must be either LogLUV or LogL");
        break;
    }
    return (0);
}

static int
LogLuvSetupEncode(TIFF* tif)
{
    LogLuvState* sp = EncoderState(tif);
    TIFFDirectory* td = &tif->tif_dir;

    switch (td->td_photometric) {
    case PHOTOMETRIC_LOGLUV:
        if (!LogLuvInitState(tif))
            break;
        if (td->td_compression == COMPRESSION_SGILOG24) {
            tif->tif_encoderow = LogLuvEncode24;
            switch (sp->user_datafmt) {
            case SGILOGDATAFMT_FLOAT:
                sp->tfunc = Luv24fromXYZ;
                break;
            case SGILOGDATAFMT_16BIT:
                sp->tfunc = Luv24fromLuv48;
                break;
            case SGILOGDATAFMT_RAW:
                break;
            default:
                goto notsupported;
            }
        } else {
            tif->tif_encoderow = LogLuvEncode32;
            switch (sp->user_datafmt) {
            case SGILOGDATAFMT_FLOAT:
                sp->tfunc = Luv32fromXYZ;
                break;
            case SGILOGDATAFMT_16BIT:
                sp->tfunc = Luv32fromLuv48;
                break;
            case SGILOGDATAFMT_RAW:
                break;
            default:
                goto notsupported;
            }
        }
        break;
    case PHOTOMETRIC_LOGL:
        if (!LogL16InitState(tif))
            break;
        tif->tif_encoderow = LogL16Encode;
        switch (sp->user_datafmt) {
        case SGILOGDATAFMT_FLOAT:
            sp->tfunc = L16fromY;
            break;
        case SGILOGDATAFMT_16BIT:
            break;
        default:
            goto notsupported;
        }
        break;
    default:
        TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
    "Inappropriate photometric interpretation %d for SGILog compression; %s",
                td->td_photometric, "must be either LogLUV or LogL");
        break;
    }
    return (1);
notsupported:
    TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
        "SGILog compression supported only for %s, or raw data",
        td->td_photometric == PHOTOMETRIC_LOGL ? "Y, L" : "XYZ, Luv");
    return (0);
}

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

    /*
     * For consistency, we always want to write out the same
     * bitspersample and sampleformat for our TIFF file,
     * regardless of the data format being used by the application.
     * Since this routine is called after tags have been set but
     * before they have been recorded in the file, we reset them here.
     */
    td->td_samplesperpixel =
        (td->td_photometric == PHOTOMETRIC_LOGL) ? 1 : 3;
    td->td_bitspersample = 16;
    td->td_sampleformat = SAMPLEFORMAT_INT;
}

static void
LogLuvCleanup(TIFF* tif)
{
    LogLuvState* sp = (LogLuvState *)tif->tif_data;

    assert(sp != 0);

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

    if (sp->tbuf)
        _TIFFfree(sp->tbuf);
    _TIFFfree(sp);
    tif->tif_data = NULL;

    _TIFFSetDefaultCompressionState(tif);
}

static int
LogLuvVSetField(TIFF* tif, ttag_t tag, va_list ap)
{
    LogLuvState* sp = DecoderState(tif);
    int bps, fmt;

    switch (tag) {
    case TIFFTAG_SGILOGDATAFMT:
        sp->user_datafmt = 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 SGILOGDATAFMT_FLOAT:
            bps = 32, fmt = SAMPLEFORMAT_IEEEFP;
            break;
        case SGILOGDATAFMT_16BIT:
            bps = 16, fmt = SAMPLEFORMAT_INT;
            break;
        case SGILOGDATAFMT_RAW:
            bps = 32, fmt = SAMPLEFORMAT_UINT;
            TIFFSetField(tif, TIFFTAG_SAMPLESPERPIXEL, 1);
            break;
        case SGILOGDATAFMT_8BIT:
            bps = 8, fmt = SAMPLEFORMAT_UINT;
            break;
        default:
            TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
                "Unknown data format %d for LogLuv compression",
                sp->user_datafmt);
            return (0);
        }
        TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, bps);
        TIFFSetField(tif, TIFFTAG_SAMPLEFORMAT, fmt);
        /*
         * Must recalculate sizes should bits/sample change.
         */
        tif->tif_tilesize = isTiled(tif) ? TIFFTileSize(tif) : (tsize_t) -1;
        tif->tif_scanlinesize = TIFFScanlineSize(tif);
        return (1);
    case TIFFTAG_SGILOGENCODE:
        sp->encode_meth = va_arg(ap, int);
        if (sp->encode_meth != SGILOGENCODE_NODITHER &&
                sp->encode_meth != SGILOGENCODE_RANDITHER) {
            TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
                "Unknown encoding %d for LogLuv compression",
                sp->encode_meth);
            return (0);
        }
        return (1);
    default:
        return (*sp->vsetparent)(tif, tag, ap);
    }
}

static int
LogLuvVGetField(TIFF* tif, ttag_t tag, va_list ap)
{
    LogLuvState *sp = (LogLuvState *)tif->tif_data;

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

static const TIFFFieldInfo LogLuvFieldInfo[] = {
    { TIFFTAG_SGILOGDATAFMT,      0, 0, TIFF_SHORT, FIELD_PSEUDO,
      TRUE, FALSE,  "SGILogDataFmt"},
    { TIFFTAG_SGILOGENCODE,   0, 0, TIFF_SHORT, FIELD_PSEUDO,
      TRUE, FALSE,  "SGILogEncode"}
};

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

    assert(scheme == COMPRESSION_SGILOG24 || scheme == COMPRESSION_SGILOG);

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

    /*
     * Allocate state block so tag methods have storage to record values.
     */
    tif->tif_data = (tidata_t) _TIFFmalloc(sizeof (LogLuvState));
    if (tif->tif_data == NULL)
        goto bad;
    sp = (LogLuvState*) tif->tif_data;
    _TIFFmemset((tdata_t)sp, 0, sizeof (*sp));
    sp->user_datafmt = SGILOGDATAFMT_UNKNOWN;
    sp->encode_meth = (scheme == COMPRESSION_SGILOG24) ?
                SGILOGENCODE_RANDITHER : SGILOGENCODE_NODITHER;
    sp->tfunc = _logLuvNop;

    /*
     * Install codec methods.
     * NB: tif_decoderow & tif_encoderow are filled
     *     in at setup time.
     */
    tif->tif_setupdecode = LogLuvSetupDecode;
    tif->tif_decodestrip = LogLuvDecodeStrip;
    tif->tif_decodetile = LogLuvDecodeTile;
    tif->tif_setupencode = LogLuvSetupEncode;
    tif->tif_encodestrip = LogLuvEncodeStrip;
    tif->tif_encodetile = LogLuvEncodeTile;
    tif->tif_close = LogLuvClose;
    tif->tif_cleanup = LogLuvCleanup;

    /* 
     * Override parent get/set field methods.
     */
    sp->vgetparent = tif->tif_tagmethods.vgetfield;
    tif->tif_tagmethods.vgetfield = LogLuvVGetField;   /* hook for codec tags */
    sp->vsetparent = tif->tif_tagmethods.vsetfield;
    tif->tif_tagmethods.vsetfield = LogLuvVSetField;   /* hook for codec tags */

    return (1);
bad:
    TIFFErrorExt(tif->tif_clientdata, module,
             "%s: No space for LogLuv state block", tif->tif_name);
    return (0);
}
#endif /* LOGLUV_SUPPORT */

/* vim: set ts=8 sts=8 sw=8 noet: */
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 * End:
 */