/src/libtiff/libtiff/tif_luv.c

Source
/*
 * 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 <limits.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

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

struct logLuvState
{
    int encoder_state; /* 1 if encoder correctly initialized */
    int user_datafmt;  /* user data format */
    int encode_meth;   /* encoding method */
    int pixel_size;    /* bytes per pixel */

    uint8_t *tbuf;    /* translation buffer */
    tmsize_t tbuflen; /* buffer length */
    void (*tfunc)(LogLuvState *, uint8_t *, tmsize_t);

    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 */

static void L16toL16(LogLuvState *sp, uint8_t *op, tmsize_t n);
static void L16fromL16(LogLuvState *sp, uint8_t *op, tmsize_t n);
static void LuvRawToRaw(LogLuvState *sp, uint8_t *op, tmsize_t n);
static void LuvRawFromRaw(LogLuvState *sp, uint8_t *op, tmsize_t n);

/*
 * Decode a string of 16-bit gray pixels.
 */
static int LogL16Decode(TIFF *tif, uint8_t *op, tmsize_t occ, uint16_t s)
{
    static const char module[] = "LogL16Decode";
    LogLuvState *sp = DecoderState(tif);
    int shft;
    tmsize_t i;
    tmsize_t npixels;
    unsigned char *bp;
    int16_t *tp;
    int16_t b;
    tmsize_t cc;
    int rc;

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

    npixels = occ / sp->pixel_size;

    if (sp->tbuflen < npixels)
    {
        TIFFErrorExtR(tif, module, "Translation buffer too short");
        return (0);
    }
    tp = (int16_t *)sp->tbuf;
    _TIFFmemset((void *)tp, 0, (tmsize_t)((size_t)npixels * sizeof(tp[0])));

    bp = (unsigned char *)tif->tif_rawcp;
    cc = tif->tif_rawcc;
    /* get each byte string */
    for (shft = 8; shft >= 0; shft -= 8)
    {
        for (i = 0; i < npixels && cc > 0;)
        {
            if (*bp >= 128)
            { /* run */
                if (cc < 2)
                    break;
                rc = *bp++ + (2 - 128);
                b = (int16_t)(*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_t)(*bp++ << shft);
            }
        }
        if (i != npixels)
        {
            TIFFErrorExtR(tif, module,
                          "Not enough data at row %" PRIu32
                          " (short %" TIFF_SSIZE_FORMAT " pixels)",
                          tif->tif_dir.td_row, npixels - i);
            tif->tif_rawcp = (uint8_t *)bp;
            tif->tif_rawcc = cc;
            return (0);
        }
    }
    if (sp->user_datafmt == SGILOGDATAFMT_16BIT)
        L16toL16(sp, op, npixels);
    else
        (*sp->tfunc)(sp, op, npixels);
    tif->tif_rawcp = (uint8_t *)bp;
    tif->tif_rawcc = cc;
    return (1);
}

/*
 * Decode a string of 24-bit pixels.
 */
static int LogLuvDecode24(TIFF *tif, uint8_t *op, tmsize_t occ, uint16_t s)
{
    static const char module[] = "LogLuvDecode24";
    LogLuvState *sp = DecoderState(tif);
    tmsize_t cc;
    tmsize_t i;
    tmsize_t npixels;
    unsigned char *bp;
    uint32_t *tp;

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

    npixels = occ / sp->pixel_size;

    if (sp->tbuflen < npixels)
    {
        TIFFErrorExtR(tif, module, "Translation buffer too short");
        return (0);
    }
    tp = (uint32_t *)sp->tbuf;
    /* copy to array of uint32_t */
    bp = (unsigned char *)tif->tif_rawcp;
    cc = tif->tif_rawcc;
    for (i = 0; i < npixels && cc >= 3; i++)
    {
        tp[i] = (uint32_t)bp[0] << 16 | (uint32_t)bp[1] << 8 | bp[2];
        bp += 3;
        cc -= 3;
    }
    tif->tif_rawcp = (uint8_t *)bp;
    tif->tif_rawcc = cc;
    if (i != npixels)
    {
        TIFFErrorExtR(tif, module,
                      "Not enough data at row %" PRIu32
                      " (short %" TIFF_SSIZE_FORMAT " pixels)",
                      tif->tif_dir.td_row, npixels - i);
        return (0);
    }
    if (sp->user_datafmt == SGILOGDATAFMT_RAW)
        LuvRawToRaw(sp, op, npixels);
    else
        (*sp->tfunc)(sp, op, npixels);
    return (1);
}

/*
 * Decode a string of 32-bit pixels.
 */
static int LogLuvDecode32(TIFF *tif, uint8_t *op, tmsize_t occ, uint16_t s)
{
    static const char module[] = "LogLuvDecode32";
    LogLuvState *sp;
    int shft;
    tmsize_t i;
    tmsize_t npixels;
    unsigned char *bp;
    uint32_t *tp;
    uint32_t b;
    tmsize_t cc;
    int rc;

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

    npixels = occ / sp->pixel_size;

    if (sp->tbuflen < npixels)
    {
        TIFFErrorExtR(tif, module, "Translation buffer too short");
        return (0);
    }
    tp = (uint32_t *)sp->tbuf;
    _TIFFmemset((void *)tp, 0, (tmsize_t)((size_t)npixels * sizeof(tp[0])));

    bp = (unsigned char *)tif->tif_rawcp;
    cc = tif->tif_rawcc;
    /* get each byte string */
    for (shft = 24; shft >= 0; shft -= 8)
    {
        for (i = 0; i < npixels && cc > 0;)
        {
            if (*bp >= 128)
            { /* run */
                if (cc < 2)
                    break;
                rc = *bp++ + (2 - 128);
                b = (uint32_t)*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_t)*bp++ << shft;
            }
        }
        if (i != npixels)
        {
            TIFFErrorExtR(tif, module,
                          "Not enough data at row %" PRIu32
                          " (short %" TIFF_SSIZE_FORMAT " pixels)",
                          tif->tif_dir.td_row, npixels - i);
            tif->tif_rawcp = (uint8_t *)bp;
            tif->tif_rawcc = cc;
            return (0);
        }
    }
    if (sp->user_datafmt == SGILOGDATAFMT_RAW)
        LuvRawToRaw(sp, op, npixels);
    else
        (*sp->tfunc)(sp, op, npixels);
    tif->tif_rawcp = (uint8_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, uint8_t *bp, tmsize_t cc, uint16_t s)
{
    tmsize_t rowlen = TIFFScanlineSize(tif);

    if (rowlen == 0)
        return 0;

    if (cc % rowlen != 0)
    {
        TIFFErrorExtR(tif, "LogLuvDecodeStrip",
                      "Fractional scanline cannot be read");
        return 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, uint8_t *bp, tmsize_t cc, uint16_t s)
{
    tmsize_t rowlen = TIFFTileRowSize(tif);

    if (rowlen == 0)
        return 0;

    if (cc % rowlen != 0)
    {
        TIFFErrorExtR(tif, "LogLuvDecodeTile",
                      "Fractional scanline cannot be read");
        return 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, uint8_t *bp, tmsize_t cc, uint16_t s)
{
    static const char module[] = "LogL16Encode";
    LogLuvState *sp = EncoderState(tif);
    int shft;
    tmsize_t i;
    tmsize_t j;
    tmsize_t npixels;
    uint8_t *op;
    int16_t *tp;
    int16_t b;
    tmsize_t occ;
    int rc = 0, mask;
    tmsize_t beg;

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

    tp = (int16_t *)sp->tbuf;
    if (sp->tbuflen < npixels)
    {
        TIFFErrorExtR(tif, module, "Translation buffer too short");
        return (0);
    }
    if (sp->user_datafmt == SGILOGDATAFMT_16BIT)
        L16fromL16(sp, bp, npixels);
    else
        (*sp->tfunc)(sp, bp, npixels);
    /* compress each byte string */
    op = tif->tif_rawcp;
    occ = tif->tif_rawdatasize - tif->tif_rawcc;
    for (shft = 8; shft >= 0; shft -= 8)
    {
        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 (0);
                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_t)(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_t)(tp[i] & mask); /*check short run */
                j = i + 1;
                while ((tp[j++] & mask) == b)
                    if (j == beg)
                    {
                        *op++ = (uint8_t)(128 - 2 + j - i);
                        *op++ = (uint8_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 (0);
                    op = tif->tif_rawcp;
                    occ = tif->tif_rawdatasize - tif->tif_rawcc;
                }
                *op++ = (uint8_t)j;
                occ--;
                while (j--)
                {
                    *op++ = (uint8_t)(tp[i++] >> shft & 0xff);
                    occ--;
                }
            }
            if (rc >= MINRUN)
            { /* write out run */
                *op++ = (uint8_t)(128 - 2 + rc);
                *op++ = (uint8_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, uint8_t *bp, tmsize_t cc, uint16_t s)
{
    static const char module[] = "LogLuvEncode24";
    LogLuvState *sp = EncoderState(tif);
    tmsize_t i;
    tmsize_t npixels;
    tmsize_t occ;
    uint8_t *op;
    uint32_t *tp;

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

    tp = (uint32_t *)sp->tbuf;
    if (sp->tbuflen < npixels)
    {
        TIFFErrorExtR(tif, module, "Translation buffer too short");
        return (0);
    }
    if (sp->user_datafmt == SGILOGDATAFMT_RAW)
        LuvRawFromRaw(sp, bp, npixels);
    else
        (*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 (0);
            op = tif->tif_rawcp;
            occ = tif->tif_rawdatasize - tif->tif_rawcc;
        }
        *op++ = (uint8_t)(*tp >> 16);
        *op++ = (uint8_t)(*tp >> 8 & 0xff);
        *op++ = (uint8_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, uint8_t *bp, tmsize_t cc, uint16_t s)
{
    static const char module[] = "LogLuvEncode32";
    LogLuvState *sp = EncoderState(tif);
    int shft;
    tmsize_t i;
    tmsize_t j;
    tmsize_t npixels;
    uint8_t *op;
    uint32_t *tp;
    uint32_t b;
    tmsize_t occ;
    int rc = 0;
    tmsize_t beg;

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

    npixels = cc / sp->pixel_size;

    tp = (uint32_t *)sp->tbuf;
    if (sp->tbuflen < npixels)
    {
        TIFFErrorExtR(tif, module, "Translation buffer too short");
        return (0);
    }
    if (sp->user_datafmt == SGILOGDATAFMT_RAW)
        LuvRawFromRaw(sp, bp, npixels);
    else
        (*sp->tfunc)(sp, bp, npixels);
    /* compress each byte string */
    op = tif->tif_rawcp;
    occ = tif->tif_rawdatasize - tif->tif_rawcc;
    for (shft = 24; shft >= 0; shft -= 8)
    {
        const uint32_t mask = 0xffU << shft; /* find next run */
        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 (0);
                op = tif->tif_rawcp;
                occ = tif->tif_rawdatasize - tif->tif_rawcc;
            }
            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++ = (uint8_t)(128 - 2 + j - i);
                        *op++ = (uint8_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 (0);
                    op = tif->tif_rawcp;
                    occ = tif->tif_rawdatasize - tif->tif_rawcc;
                }
                *op++ = (uint8_t)j;
                occ--;
                while (j--)
                {
                    *op++ = (uint8_t)(tp[i++] >> shft & 0xff);
                    occ--;
                }
            }
            if (rc >= MINRUN)
            { /* write out run */
                *op++ = (uint8_t)(128 - 2 + rc);
                *op++ = (uint8_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, uint8_t *bp, tmsize_t cc, uint16_t s)
{
    tmsize_t rowlen = TIFFScanlineSize(tif);

    if (rowlen == 0)
        return 0;

    if (cc % rowlen != 0)
    {
        TIFFErrorExtR(tif, "LogLuvEncodeStrip",
                      "Fractional scanline cannot be written");
        return 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, uint8_t *bp, tmsize_t cc, uint16_t s)
{
    tmsize_t rowlen = TIFFTileRowSize(tif);

    if (rowlen == 0)
        return 0;

    if (cc % rowlen != 0)
    {
        TIFFErrorExtR(tif, "LogLuvEncodeTile",
                      "Fractional scanline cannot be written");
        return 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 TIFF_RAND_MAX 32767

// From POSIX.1-2001 as an example of an implementation of rand()
static uint32_t _TIFFRand(void)
{
    static uint32_t nCounter = 0;
    if (!nCounter)
        nCounter = (uint32_t)(time(NULL) & UINT32_MAX);
    ++nCounter;
    uint32_t nCounterLocal =
        (uint32_t)(((uint64_t)(nCounter) * 1103515245U + 12345U) & UINT32_MAX);
    nCounter = nCounterLocal;
    return (nCounterLocal / 65536U) % (TIFF_RAND_MAX + 1);
}

static int tiff_itrunc(double x, int m)
{
    if (m == SGILOGENCODE_NODITHER)
        return (int)x;
    return (int)(x + _TIFFRand() * (1. / TIFF_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 tiff_itrunc(256. * (log2(Y) + 64.), em);
    if (Y < -5.4136769e-20)
        return (~0x7fff | tiff_itrunc(256. * (log2(-Y) + 64.), em));
    return (0);
}

/*
 * SGILOGDATAFMT_* buffers are application-facing user data buffers in native
 * byte order.  The helpers below do not perform TIFF file byte-order
 * conversion; they only avoid unaligned typed access to public byte buffers.
 * Use fixed-size memcpy() calls directly so optimizing compilers can expand
 * them in these per-pixel paths.  _TIFFmemcpy() is an out-of-line wrapper in
 * non-LTO builds.
 */
static float LogLuvLoadFloatNativeUnaligned(const uint8_t *cp)
{
    float v;
    memcpy(&v, cp, sizeof(v));
    return v;
}

static void LogLuvStoreFloatNativeUnaligned(uint8_t *cp, float v)
{
    memcpy(cp, &v, sizeof(v));
}

static int16_t LogLuvLoad16NativeUnaligned(const uint8_t *cp)
{
    int16_t v;
    memcpy(&v, cp, sizeof(v));
    return v;
}

static void LogLuvStore16NativeUnaligned(uint8_t *cp, int16_t v)
{
    memcpy(cp, &v, sizeof(v));
}

static uint32_t LogLuvLoad32NativeUnaligned(const uint8_t *cp)
{
    uint32_t v;
    memcpy(&v, cp, sizeof(v));
    return v;
}

static void LogLuvStore32NativeUnaligned(uint8_t *cp, uint32_t v)
{
    memcpy(cp, &v, sizeof(v));
}

static void L16toL16(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    int16_t *l16 = (int16_t *)sp->tbuf;

    while (n-- > 0)
    {
        LogLuvStore16NativeUnaligned(op, *l16++);
        op += sizeof(int16_t);
    }
}

static void L16fromL16(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    int16_t *l16 = (int16_t *)sp->tbuf;

    while (n-- > 0)
    {
        *l16++ = LogLuvLoad16NativeUnaligned(op);
        op += sizeof(int16_t);
    }
}

static void LuvRawToRaw(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    uint32_t *luv = (uint32_t *)sp->tbuf;

    while (n-- > 0)
    {
        LogLuvStore32NativeUnaligned(op, *luv++);
        op += sizeof(uint32_t);
    }
}

static void LuvRawFromRaw(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    uint32_t *luv = (uint32_t *)sp->tbuf;

    while (n-- > 0)
    {
        *luv++ = LogLuvLoad32NativeUnaligned(op);
        op += sizeof(uint32_t);
    }
}

static void L16toY(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    int16_t *l16 = (int16_t *)sp->tbuf;

    while (n-- > 0)
    {
        LogLuvStoreFloatNativeUnaligned(op, (float)LogL16toY(*l16++));
        op += sizeof(float);
    }
}

static void L16toGry(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    int16_t *l16 = (int16_t *)sp->tbuf;
    uint8_t *gp = (uint8_t *)op;

    while (n-- > 0)
    {
        double Y = LogL16toY(*l16++);
        *gp++ = (uint8_t)((Y <= 0.)   ? 0
                          : (Y >= 1.) ? 255
                                      : (int)(256. * sqrt(Y)));
    }
}

static void L16fromY(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    int16_t *l16 = (int16_t *)sp->tbuf;

    while (n-- > 0)
    {
        *l16++ = (int16_t)(LogL16fromY(
            (double)LogLuvLoadFloatNativeUnaligned(op), sp->encode_meth));
        op += sizeof(float);
    }
}

#if !LOGLUV_PUBLIC
static
#endif
    void XYZtoRGB24(float *xyz, uint8_t *rgb)
{
    double r, g, b;
    /* assume CCIR-709 primaries */
    r = 2.690 * (double)xyz[0] + -1.276 * (double)xyz[1] +
        -0.414 * (double)xyz[2];
    g = -1.022 * (double)xyz[0] + 1.978 * (double)xyz[1] +
        0.044 * (double)xyz[2];
    b = 0.061 * (double)xyz[0] + -0.224 * (double)xyz[1] +
        1.163 * (double)xyz[2];
    /* assume 2.0 gamma for speed */
    /* could use integer sqrt approx., but this is probably faster */
    rgb[0] = (uint8_t)((r <= 0.) ? 0 : (r >= 1.) ? 255 : (int)(256. * sqrt(r)));
    rgb[1] = (uint8_t)((g <= 0.) ? 0 : (g >= 1.) ? 255 : (int)(256. * sqrt(g)));
    rgb[2] = (uint8_t)((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 tiff_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;
    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 = (double)UV_VSTART + ((double)vi + .5) * (double)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 = (double)uv_row[vi].ustart +
                     ((double)ui + .5) * (double)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 */
{
    unsigned int vi;
    int ui;

    /* check for NaN */
    if (isnan(u) || isnan(v))
    {
        u = U_NEU;
        v = V_NEU;
    }

    if ((double)v < (double)UV_VSTART)
        return oog_encode(u, v);
    vi = (unsigned int)tiff_itrunc(
        ((double)v - (double)UV_VSTART) * (1. / (double)UV_SQSIZ), em);
    if (vi >= UV_NVS)
        return oog_encode(u, v);
    if ((double)u < (double)uv_row[vi].ustart)
        return oog_encode(u, v);
    ui = tiff_itrunc(
        ((double)u - (double)uv_row[vi].ustart) * (1. / (double)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 */
{
    unsigned int upper, lower;
    int ui;
    unsigned int 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 = (double)uv_row[vi].ustart + ((double)ui + .5) * (double)UV_SQSIZ;
    *vp = (double)UV_VSTART + ((double)vi + .5) * (double)UV_SQSIZ;
    return (0);
}

#if !LOGLUV_PUBLIC
static
#endif
    void LogLuv24toXYZ(uint32_t p, float *XYZ)
{
    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_t LogLuv24fromXYZ(float *XYZ, int em)
{
    int Le, Ce;
    double u, v, s;
    /* encode luminance */
    Le = LogL10fromY((double)XYZ[1], em);
    /* encode color */
    s = (double)XYZ[0] + 15. * (double)XYZ[1] + 3. * (double)XYZ[2];
    if (!Le || s <= 0.)
    {
        u = U_NEU;
        v = V_NEU;
    }
    else
    {
        u = 4. * (double)XYZ[0] / s;
        v = 9. * (double)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 (uint32_t)Le << 14 | (uint32_t)Ce;
}

static void Luv24toXYZ(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    uint32_t *luv = (uint32_t *)sp->tbuf;

    while (n-- > 0)
    {
        float xyz[3];
        LogLuv24toXYZ(*luv, xyz);
        LogLuvStoreFloatNativeUnaligned(op, xyz[0]);
        LogLuvStoreFloatNativeUnaligned(op + sizeof(float), xyz[1]);
        LogLuvStoreFloatNativeUnaligned(op + 2 * sizeof(float), xyz[2]);
        op += 3 * sizeof(float);
        luv++;
    }
}

static void Luv24toLuv48(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    uint32_t *luv = (uint32_t *)sp->tbuf;

    while (n-- > 0)
    {
        double u, v;
        int16_t luv0;
        int16_t luv1;
        int16_t luv2;

        luv0 = (int16_t)((*luv >> 12 & 0xffd) + 13314);
        if (uv_decode(&u, &v, *luv & 0x3fff) < 0)
        {
            u = U_NEU;
            v = V_NEU;
        }
        luv1 = (int16_t)(u * (1 << 15));
        luv2 = (int16_t)(v * (1 << 15));
        LogLuvStore16NativeUnaligned(op, luv0);
        LogLuvStore16NativeUnaligned(op + sizeof(int16_t), luv1);
        LogLuvStore16NativeUnaligned(op + 2 * sizeof(int16_t), luv2);
        op += 3 * sizeof(int16_t);
        luv++;
    }
}

static void Luv24toRGB(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    uint32_t *luv = (uint32_t *)sp->tbuf;
    uint8_t *rgb = (uint8_t *)op;

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

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

static void Luv24fromXYZ(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    uint32_t *luv = (uint32_t *)sp->tbuf;

    while (n-- > 0)
    {
        float xyz[3];
        xyz[0] = LogLuvLoadFloatNativeUnaligned(op);
        xyz[1] = LogLuvLoadFloatNativeUnaligned(op + sizeof(float));
        xyz[2] = LogLuvLoadFloatNativeUnaligned(op + 2 * sizeof(float));
        *luv++ = LogLuv24fromXYZ(xyz, sp->encode_meth);
        op += 3 * sizeof(float);
    }
}

static void Luv24fromLuv48(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    uint32_t *luv = (uint32_t *)sp->tbuf;

    while (n-- > 0)
    {
        int Le, Ce;
        int16_t luv0 = LogLuvLoad16NativeUnaligned(op);
        int16_t luv1 = LogLuvLoad16NativeUnaligned(op + sizeof(int16_t));
        int16_t luv2 = LogLuvLoad16NativeUnaligned(op + 2 * sizeof(int16_t));

        if (luv0 <= 0)
            Le = 0;
        else if (luv0 >= (1 << 12) + 3314)
            Le = (1 << 10) - 1;
        else if (sp->encode_meth == SGILOGENCODE_NODITHER)
            Le = (luv0 - 3314) >> 2;
        else
            Le = tiff_itrunc(.25 * (luv0 - 3314.), sp->encode_meth);

        Ce = uv_encode((luv1 + .5) / (1 << 15), (luv2 + .5) / (1 << 15),
                       sp->encode_meth);
        if (Ce < 0) /* never happens */
            Ce = uv_encode(U_NEU, V_NEU, SGILOGENCODE_NODITHER);
        *luv++ = (uint32_t)Le << 14 | (uint32_t)Ce;
        op += 3 * sizeof(int16_t);
    }
}

#if !LOGLUV_PUBLIC
static
#endif
    void LogLuv32toXYZ(uint32_t p, float *XYZ)
{
    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_t LogLuv32fromXYZ(float *XYZ, int em)
{
    unsigned int Le, ue, ve;
    double u, v, s;
    /* encode luminance */
    Le = (unsigned int)LogL16fromY((double)XYZ[1], em);
    /* encode color */
    s = (double)XYZ[0] + 15. * (double)XYZ[1] + 3. * (double)XYZ[2];
    if (!Le || s <= 0.)
    {
        u = U_NEU;
        v = V_NEU;
    }
    else
    {
        u = 4. * (double)XYZ[0] / s;
        v = 9. * (double)XYZ[1] / s;
    }
    if (u <= 0.)
        ue = 0;
    else
        ue = (unsigned int)tiff_itrunc(UVSCALE * u, em);
    if (ue > 255)
        ue = 255;
    if (v <= 0.)
        ve = 0;
    else
        ve = (unsigned int)tiff_itrunc(UVSCALE * v, em);
    if (ve > 255)
        ve = 255;
    /* combine encodings */
    return (Le << 16 | ue << 8 | ve);
}

static void Luv32toXYZ(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    uint32_t *luv = (uint32_t *)sp->tbuf;

    while (n-- > 0)
    {
        float xyz[3];
        LogLuv32toXYZ(*luv++, xyz);
        LogLuvStoreFloatNativeUnaligned(op, xyz[0]);
        LogLuvStoreFloatNativeUnaligned(op + sizeof(float), xyz[1]);
        LogLuvStoreFloatNativeUnaligned(op + 2 * sizeof(float), xyz[2]);
        op += 3 * sizeof(float);
    }
}

static void Luv32toLuv48(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    uint32_t *luv = (uint32_t *)sp->tbuf;

    while (n-- > 0)
    {
        double u, v;
        int16_t luv0 = (int16_t)(*luv >> 16);
        int16_t luv1;
        int16_t luv2;

        u = 1. / UVSCALE * ((*luv >> 8 & 0xff) + .5);
        v = 1. / UVSCALE * ((*luv & 0xff) + .5);
        luv1 = (int16_t)(u * (1 << 15));
        luv2 = (int16_t)(v * (1 << 15));
        LogLuvStore16NativeUnaligned(op, luv0);
        LogLuvStore16NativeUnaligned(op + sizeof(int16_t), luv1);
        LogLuvStore16NativeUnaligned(op + 2 * sizeof(int16_t), luv2);
        op += 3 * sizeof(int16_t);
        luv++;
    }
}

static void Luv32toRGB(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    uint32_t *luv = (uint32_t *)sp->tbuf;
    uint8_t *rgb = (uint8_t *)op;

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

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

static void Luv32fromXYZ(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    uint32_t *luv = (uint32_t *)sp->tbuf;

    while (n-- > 0)
    {
        float xyz[3];
        xyz[0] = LogLuvLoadFloatNativeUnaligned(op);
        xyz[1] = LogLuvLoadFloatNativeUnaligned(op + sizeof(float));
        xyz[2] = LogLuvLoadFloatNativeUnaligned(op + 2 * sizeof(float));
        *luv++ = LogLuv32fromXYZ(xyz, sp->encode_meth);
        op += 3 * sizeof(float);
    }
}

static void Luv32fromLuv48(LogLuvState *sp, uint8_t *op, tmsize_t n)
{
    uint32_t *luv = (uint32_t *)sp->tbuf;

    if (sp->encode_meth == SGILOGENCODE_NODITHER)
    {
        while (n-- > 0)
        {
            int16_t luv0 = LogLuvLoad16NativeUnaligned(op);
            int16_t luv1 = LogLuvLoad16NativeUnaligned(op + sizeof(int16_t));
            int16_t luv2 =
                LogLuvLoad16NativeUnaligned(op + 2 * sizeof(int16_t));
            *luv++ = (uint32_t)luv0 << 16 |
                     ((uint32_t)luv1 * (uint32_t)(UVSCALE + .5) >> 7 & 0xff00) |
                     ((uint32_t)luv2 * (uint32_t)(UVSCALE + .5) >> 15 & 0xff);
            op += 3 * sizeof(int16_t);
        }
        return;
    }
    while (n-- > 0)
    {
        int16_t luv0 = LogLuvLoad16NativeUnaligned(op);
        int16_t luv1 = LogLuvLoad16NativeUnaligned(op + sizeof(int16_t));
        int16_t luv2 = LogLuvLoad16NativeUnaligned(op + 2 * sizeof(int16_t));
        *luv++ = (uint32_t)luv0 << 16 |
                 ((uint32_t)tiff_itrunc(luv1 * (UVSCALE / (1 << 15)),
                                        sp->encode_meth)
                      << 8 &
                  0xff00) |
                 ((uint32_t)tiff_itrunc(luv2 * (UVSCALE / (1 << 15)),
                                        sp->encode_meth) &
                  0xff);
        op += 3 * sizeof(int16_t);
    }
}

static void _logLuvNop(LogLuvState *sp, uint8_t *op, tmsize_t 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);
        default:
            break;
    }
#undef PACK
    return (SGILOGDATAFMT_UNKNOWN);
}

static tmsize_t multiply_ms(tmsize_t m1, tmsize_t m2)
{
    return _TIFFMultiplySSize(NULL, m1, m2, NULL);
}

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

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

    if (td->td_samplesperpixel != 1)
    {
        TIFFErrorExtR(tif, module,
                      "Sorry, can not handle LogL image with %s=%" PRIu16,
                      "Samples/pixel", td->td_samplesperpixel);
        return 0;
    }

    /* 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_t);
            break;
        case SGILOGDATAFMT_8BIT:
            sp->pixel_size = sizeof(uint8_t);
            break;
        default:
            TIFFErrorExtR(tif, module,
                          "No support for converting user data format to LogL");
            return (0);
    }
    if (isTiled(tif))
        sp->tbuflen = multiply_ms(td->td_tilewidth, td->td_tilelength);
    else if (td->td_rowsperstrip < td->td_imagelength)
        sp->tbuflen = multiply_ms(td->td_imagewidth, td->td_rowsperstrip);
    else
        sp->tbuflen = multiply_ms(td->td_imagewidth, td->td_imagelength);
    if (multiply_ms(sp->tbuflen, sizeof(int16_t)) == 0 ||
        (sp->tbuf = (uint8_t *)_TIFFmallocExt(
             tif, (tmsize_t)((size_t)sp->tbuflen * sizeof(int16_t)))) == NULL)
    {
        TIFFErrorExtR(tif, module, "No space for SGILog translation buffer");
        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)
{
    static const char module[] = "LogLuvInitState";
    TIFFDirectory *td = &tif->tif_dir;
    LogLuvState *sp = DecoderState(tif);

    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)
    {
        TIFFErrorExtR(tif, 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_t);
            break;
        case SGILOGDATAFMT_RAW:
            sp->pixel_size = sizeof(uint32_t);
            break;
        case SGILOGDATAFMT_8BIT:
            sp->pixel_size = 3 * sizeof(uint8_t);
            break;
        default:
            TIFFErrorExtR(
                tif, module,
                "No support for converting user data format to LogLuv");
            return (0);
    }
    if (isTiled(tif))
        sp->tbuflen = multiply_ms(td->td_tilewidth, td->td_tilelength);
    else if (td->td_rowsperstrip < td->td_imagelength)
        sp->tbuflen = multiply_ms(td->td_imagewidth, td->td_rowsperstrip);
    else
        sp->tbuflen = multiply_ms(td->td_imagewidth, td->td_imagelength);
    if (multiply_ms(sp->tbuflen, sizeof(uint32_t)) == 0 ||
        (sp->tbuf = (uint8_t *)_TIFFmallocExt(
             tif, (tmsize_t)((size_t)sp->tbuflen * sizeof(uint32_t)))) == NULL)
    {
        TIFFErrorExtR(tif, module, "No space for SGILog translation buffer");
        return (0);
    }
    return (1);
}

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

static int LogLuvSetupDecode(TIFF *tif)
{
    static const char module[] = "LogLuvSetupDecode";
    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;
                    default:
                        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;
                    default:
                        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;
                default:
                    break;
            }
            return (1);
        default:
            TIFFErrorExtR(tif, module,
                          "Inappropriate photometric interpretation %" PRIu16
                          " for SGILog compression; %s",
                          td->td_photometric, "must be either LogLUV or LogL");
            break;
    }
    return (0);
}

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

    switch (td->td_photometric)
    {
        case PHOTOMETRIC_LOGLUV:
            if (!LogLuvInitState(tif))
                return (0);
            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))
                return (0);
            tif->tif_encoderow = LogL16Encode;
            switch (sp->user_datafmt)
            {
                case SGILOGDATAFMT_FLOAT:
                    sp->tfunc = L16fromY;
                    break;
                case SGILOGDATAFMT_16BIT:
                    break;
                default:
                    goto notsupported;
            }
            break;
        default:
            TIFFErrorExtR(tif, module,
                          "Inappropriate photometric interpretation %" PRIu16
                          " for SGILog compression; %s",
                          td->td_photometric, "must be either LogLUV or LogL");
            return (0);
    }
    sp->encoder_state = 1;
    return (1);
notsupported:
    TIFFErrorExtR(tif, module,
                  "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)
{
    LogLuvState *sp = (LogLuvState *)tif->tif_data;
    TIFFDirectory *td = &tif->tif_dir;

    assert(sp != 0);
    /*
     * 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.
     * Note: this is really a nasty approach. See PixarLogClose
     */
    if (sp->encoder_state)
    {
        /* See PixarLogClose. Might avoid issues with tags whose size depends
         * on those below, but not completely sure this is enough. */
        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)
        _TIFFfreeExt(tif, sp->tbuf);
    _TIFFfreeExt(tif, sp);
    tif->tif_data = NULL;

    _TIFFSetDefaultCompressionState(tif);
}

static int LogLuvVSetField(TIFF *tif, uint32_t tag, va_list ap)
{
    static const char module[] = "LogLuvVSetField";
    LogLuvState *sp = DecoderState(tif);
    int bps, fmt;

    switch (tag)
    {
        case TIFFTAG_SGILOGDATAFMT:
            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 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:
                    TIFFErrorExtR(
                        tif, 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_dir.td_tilesize =
                isTiled(tif) ? TIFFTileSize(tif) : (tmsize_t)-1;
            tif->tif_dir.td_scanlinesize = TIFFScanlineSize(tif);
            return (1);
        case TIFFTAG_SGILOGENCODE:
            sp->encode_meth = (int)va_arg(ap, int);
            if (sp->encode_meth != SGILOGENCODE_NODITHER &&
                sp->encode_meth != SGILOGENCODE_RANDITHER)
            {
                TIFFErrorExtR(tif, module,
                              "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, uint32_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 TIFFField LogLuvFields[] = {
    {TIFFTAG_SGILOGDATAFMT, 0, 0, TIFF_SHORT, 0, TIFF_SETGET_INT, FIELD_PSEUDO,
     TRUE, FALSE, "SGILogDataFmt", NULL},
    {TIFFTAG_SGILOGENCODE, 0, 0, TIFF_SHORT, 0, TIFF_SETGET_INT, FIELD_PSEUDO,
     TRUE, FALSE, "SGILogEncode", NULL}};

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 (!_TIFFMergeFields(tif, LogLuvFields, TIFFArrayCount(LogLuvFields)))
    {
        TIFFErrorExtR(tif, module, "Merging SGILog codec-specific tags failed");
        return 0;
    }

    /*
     * Allocate state block so tag methods have storage to record values.
     */
    tif->tif_data = (uint8_t *)_TIFFmallocExt(tif, sizeof(LogLuvState));
    if (tif->tif_data == NULL)
        goto bad;
    sp = (LogLuvState *)tif->tif_data;
    _TIFFmemset((void *)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_fixuptags = LogLuvFixupTags;
    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:
    TIFFErrorExtR(tif, module, "%s: No space for LogLuv state block",
                  tif->tif_name);
    return (0);
}
#endif /* LOGLUV_SUPPORT */

Coverage Report

Created: 2026-11-12 06:47