tif_pixarlog.c

一个国人自己实现图像库的程序（有参考价值）

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

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

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

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


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

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

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

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

	(void) s;

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

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

	for (i = 0, up = sp->tbuf; i < n; i += llen, up += llen) {
		switch (sp->user_datafmt)  {
		case PIXARLOGDATAFMT_FLOAT:
			horizontalDifferenceF((float *)bp, llen, 
				sp->stride, up, sp->FromLT2);
			bp += llen * sizeof(float);
			break;
		case PIXARLOGDATAFMT_16BIT:
			horizontalDifference16((uint16 *)bp, llen, 
				sp->stride, up, sp->From14);
			bp += llen * sizeof(uint16);
			break;
		case PIXARLOGDATAFMT_8BIT:
			horizontalDifference8((unsigned char *)bp, llen, 
				sp->stride, up, sp->From8);
			bp += llen * sizeof(unsigned char);
			break;
		default:
			TIFFError(tif->tif_name,
				"%d bit input not supported in PixarLog",
				td->td_bitspersample);
			return 0;
		}
	}
 
	sp->stream.next_in = (unsigned char *) sp->tbuf;
	sp->stream.avail_in = n * sizeof(uint16);

	do {
		if (deflate(&sp->stream, Z_NO_FLUSH) != Z_OK) {
			TIFFError(module, "%s: Encoder error: %s",
			    tif->tif_name, sp->stream.msg);
			return (0);
		}
		if (sp->stream.avail_out == 0) {
			tif->tif_rawcc = tif->tif_rawdatasize;
			TIFFFlushData1(tif);
			sp->stream.next_out = tif->tif_rawdata;
			sp->stream.avail_out = tif->tif_rawdatasize;
		}
	} while (sp->stream.avail_in > 0);
	return (1);
}

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

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

	sp->stream.avail_in = 0;

	do {
		state = deflate(&sp->stream, Z_FINISH);
		switch (state) {
		case Z_STREAM_END:
		case Z_OK:
		    if (sp->stream.avail_out != tif->tif_rawdatasize) {
			    tif->tif_rawcc =
				tif->tif_rawdatasize - sp->stream.avail_out;
			    TIFFFlushData1(tif);
			    sp->stream.next_out = tif->tif_rawdata;
			    sp->stream.avail_out = tif->tif_rawdatasize;
		    }
		    break;
		default:
		    TIFFError(module, "%s: zlib error: %s",
			tif->tif_name, sp->stream.msg);
		    return (0);
		}
	} while (state != Z_STREAM_END);
	return (1);
}

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

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

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

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

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

    switch (tag) {
     case TIFFTAG_PIXARLOGQUALITY:
		sp->quality = va_arg(ap, int);
		if (tif->tif_mode != O_RDONLY && (sp->state&PLSTATE_INIT)) {
			if (deflateParams(&sp->stream,
			    sp->quality, Z_DEFAULT_STRATEGY) != Z_OK) {
				TIFFError(module, "%s: zlib error: %s",
					tif->tif_name, sp->stream.msg);
				return (0);
			}
		}
		return (1);
     case TIFFTAG_PIXARLOGDATAFMT:
	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 PIXARLOGDATAFMT_8BIT:
	 case PIXARLOGDATAFMT_8BITABGR:
	    TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, 8);
	    TIFFSetField(tif, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_UINT);
	    break;
	 case PIXARLOGDATAFMT_11BITLOG:
	    TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, 16);
	    TIFFSetField(tif, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_UINT);
	    break;
	 case PIXARLOGDATAFMT_12BITPICIO:
	    TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, 16);
	    TIFFSetField(tif, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_INT);
	    break;
	 case PIXARLOGDATAFMT_16BIT:
	    TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, 16);
	    TIFFSetField(tif, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_UINT);
	    break;
	 case PIXARLOGDATAFMT_FLOAT:
	    TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, 32);
	    TIFFSetField(tif, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_IEEEFP);
	    break;
	}
	/*
	 * Must recalculate sizes should bits/sample change.
	 */
	tif->tif_tilesize = TIFFTileSize(tif);
	tif->tif_scanlinesize = TIFFScanlineSize(tif);
	result = 1;		/* NB: pseudo tag */
	break;
     default:
	result = (*sp->vsetparent)(tif, tag, ap);
    }
    return (result);
}

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

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

static const TIFFFieldInfo pixarlogFieldInfo[] = {
    {TIFFTAG_PIXARLOGDATAFMT,0,0,TIFF_ANY,  FIELD_PSEUDO,FALSE,FALSE,""},
    {TIFFTAG_PIXARLOGQUALITY,0,0,TIFF_ANY,  FIELD_PSEUDO,FALSE,FALSE,""}
};

int
TIFFInitPixarLog(TIFF* tif, int scheme)
{
	PixarLogState* sp;

	assert(scheme == COMPRESSION_PIXARLOG);

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

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

	/* Override SetField so we can handle our private pseudo-tag */
	_TIFFMergeFieldInfo(tif, pixarlogFieldInfo, N(pixarlogFieldInfo));
	sp->vgetparent = tif->tif_vgetfield;
	tif->tif_vgetfield = PixarLogVGetField;   /* hook for codec tags */
	sp->vsetparent = tif->tif_vsetfield;
	tif->tif_vsetfield = PixarLogVSetField;   /* hook for codec tags */

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

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

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

	return (1);
bad:
	TIFFError("TIFFInitPixarLog", "No space for PixarLog state block");
	return (0);
}
#endif /* PIXARLOG_SUPPORT */