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src/Source/LibTIFF4/tif_pixarlog.c  view on Meta::CPAN

	ToLinearF[j++] = (float)(b*exp(c*i));

    ToLinearF[2048] = ToLinearF[2047];

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

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

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

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

    Fltsize = (float)(lt2size/2);

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

    return 1;
}

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

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

#define PIXARLOGDATAFMT_UNKNOWN	-1

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

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

	return guess;
}

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

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

	return bytes;
}

static tmsize_t
add_ms(tmsize_t m1, tmsize_t m2)
{
	tmsize_t bytes = m1 + m2;

	/* if either input is zero, assume overflow already occurred */
	if (m1 == 0 || m2 == 0)
		bytes = 0;
	else if (bytes <= m1 || bytes <= m2)
		bytes = 0;

	return bytes;
}

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

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

	assert(sp != NULL);

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

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

	sp->stride = (td->td_planarconfig == PLANARCONFIG_CONTIG ?
	    td->td_samplesperpixel : 1);
	tbuf_size = multiply_ms(multiply_ms(multiply_ms(sp->stride, td->td_imagewidth),
				      td->td_rowsperstrip), sizeof(uint16));
	/* add one more stride in case input ends mid-stride */
	tbuf_size = add_ms(tbuf_size, sizeof(uint16) * sp->stride);
	if (tbuf_size == 0)
		return (0);   /* TODO: this is an error return without error report through TIFFErrorExt */
	sp->tbuf = (uint16 *) _TIFFmalloc(tbuf_size);
	if (sp->tbuf == NULL)