tif_dirwrite.c

一个国人自己实现图像库的程序（有参考价值）

#undef WriteRationalPair

/*
 * Process tags that are not special cased.
 */
static int
TIFFWriteNormalTag(TIFF* tif, TIFFDirEntry* dir, const TIFFFieldInfo* fip)
{
	u_short wc = (u_short) fip->field_writecount;
	uint32 wc2;

	dir->tdir_tag = (uint16) fip->field_tag;
	dir->tdir_type = (u_short) fip->field_type;
	dir->tdir_count = wc;
#define	WRITEF(x,y)	x(tif, fip->field_type, fip->field_tag, dir, wc, y)
	switch (fip->field_type) {
	case TIFF_SHORT:
	case TIFF_SSHORT:
		if (wc > 1) {
			uint16* wp;
			if (wc == (u_short) TIFF_VARIABLE)
				TIFFGetField(tif, fip->field_tag, &wc, &wp);
			else
				TIFFGetField(tif, fip->field_tag, &wp);
			if (!WRITEF(TIFFWriteShortArray, wp))
				return (0);
		} else {
			uint16 sv;
			TIFFGetField(tif, fip->field_tag, &sv);
			dir->tdir_offset =
			    TIFFInsertData(tif, dir->tdir_type, sv);
		}
		break;
	case TIFF_LONG:
	case TIFF_SLONG:
		if (wc > 1) {
			uint32* lp;
			if (wc == (u_short) TIFF_VARIABLE)
				TIFFGetField(tif, fip->field_tag, &wc, &lp);
			else
				TIFFGetField(tif, fip->field_tag, &lp);
			if (!WRITEF(TIFFWriteLongArray, lp))
				return (0);
		} else {
			/* XXX handle LONG->SHORT conversion */
			TIFFGetField(tif, fip->field_tag, &dir->tdir_offset);
		}
		break;
	case TIFF_RATIONAL:
	case TIFF_SRATIONAL:
		if (wc > 1) {
			float* fp;
			if (wc == (u_short) TIFF_VARIABLE)
				TIFFGetField(tif, fip->field_tag, &wc, &fp);
			else
				TIFFGetField(tif, fip->field_tag, &fp);
			if (!WRITEF(TIFFWriteRationalArray, fp))
				return (0);
		} else {
			float fv;
			TIFFGetField(tif, fip->field_tag, &fv);
			if (!WRITEF(TIFFWriteRationalArray, &fv))
				return (0);
		}
		break;
	case TIFF_FLOAT:
		if (wc > 1) {
			float* fp;
			if (wc == (u_short) TIFF_VARIABLE)
				TIFFGetField(tif, fip->field_tag, &wc, &fp);
			else
				TIFFGetField(tif, fip->field_tag, &fp);
			if (!WRITEF(TIFFWriteFloatArray, fp))
				return (0);
		} else {
			float fv;
			TIFFGetField(tif, fip->field_tag, &fv);
			if (!WRITEF(TIFFWriteFloatArray, &fv))
				return (0);
		}
		break;
	case TIFF_DOUBLE:
		if (wc > 1) {
			double* dp;
			if (wc == (u_short) TIFF_VARIABLE)
				TIFFGetField(tif, fip->field_tag, &wc, &dp);
			else
				TIFFGetField(tif, fip->field_tag, &dp);
			if (!WRITEF(TIFFWriteDoubleArray, dp))
				return (0);
		} else {
			double dv;
			TIFFGetField(tif, fip->field_tag, &dv);
			if (!WRITEF(TIFFWriteDoubleArray, &dv))
				return (0);
		}
		break;
	case TIFF_ASCII:
		{ char* cp;
		  TIFFGetField(tif, fip->field_tag, &cp);
		  dir->tdir_count = (uint32) (strlen(cp) + 1);
		  if (!TIFFWriteByteArray(tif, dir, cp))
			return (0);
		}
		break;

        /* added based on patch request from [e-mail],
           correctness not verified (FW, 99/08) */
        case TIFF_BYTE:
        case TIFF_SBYTE:          
                if (wc > 1) {
                    char* cp;
                    if (wc == (u_short) TIFF_VARIABLE) {
                        TIFFGetField(tif, fip->field_tag, &wc, &cp);
                        dir->tdir_count = wc;
                    } else if (wc == (u_short) TIFF_VARIABLE2) {
			TIFFGetField(tif, fip->field_tag, &wc2, &cp);
			dir->tdir_count = wc2;
                    } else
                        TIFFGetField(tif, fip->field_tag, &cp);
                    if (!TIFFWriteByteArray(tif, dir, cp))
                        return (0);
                } else {
                    char cv;
                    TIFFGetField(tif, fip->field_tag, &cv);
                    if (!TIFFWriteByteArray(tif, dir, &cv))
                        return (0);
                }
                break;

	case TIFF_UNDEFINED:
		{ char* cp;
		  if (wc == (u_short) TIFF_VARIABLE) {
			TIFFGetField(tif, fip->field_tag, &wc, &cp);
			dir->tdir_count = wc;
		  } else if (wc == (u_short) TIFF_VARIABLE2) {
			TIFFGetField(tif, fip->field_tag, &wc2, &cp);
			dir->tdir_count = wc2;
		  } else 
			TIFFGetField(tif, fip->field_tag, &cp);
		  if (!TIFFWriteByteArray(tif, dir, cp))
			return (0);
		}
		break;

        case TIFF_NOTYPE:
                break;
	}
	return (1);
}
#undef WRITEF

/*
 * Setup a directory entry with either a SHORT
 * or LONG type according to the value.
 */
static void
TIFFSetupShortLong(TIFF* tif, ttag_t tag, TIFFDirEntry* dir, uint32 v)
{
	dir->tdir_tag = (uint16) tag;
	dir->tdir_count = 1;
	if (v > 0xffffL) {
		dir->tdir_type = (short) TIFF_LONG;
		dir->tdir_offset = v;
	} else {
		dir->tdir_type = (short) TIFF_SHORT;
		dir->tdir_offset = TIFFInsertData(tif, (int) TIFF_SHORT, v);
	}
}
#undef MakeShortDirent

#ifndef TIFFWriteRational
/*
 * Setup a RATIONAL directory entry and
 * write the associated indirect value.
 */
static int
TIFFWriteRational(TIFF* tif,
    TIFFDataType type, ttag_t tag, TIFFDirEntry* dir, float v)
{
	return (TIFFWriteRationalArray(tif, type, tag, dir, 1, &v));
}
#endif

#define	NITEMS(x)	(sizeof (x) / sizeof (x[0]))
/*
 * Setup a directory entry that references a
 * samples/pixel array of SHORT values and
 * (potentially) write the associated indirect
 * values.
 */
static int
TIFFWritePerSampleShorts(TIFF* tif, ttag_t tag, TIFFDirEntry* dir)
{
	uint16 buf[10], v;
	uint16* w = buf;
	int i, status, samples = tif->tif_dir.td_samplesperpixel;

	if (samples > NITEMS(buf))
		w = (uint16*) _TIFFmalloc(samples * sizeof (uint16));
	TIFFGetField(tif, tag, &v);
	for (i = 0; i < samples; i++)
		w[i] = v;
	status = TIFFWriteShortArray(tif, TIFF_SHORT, tag, dir, samples, w);
	if (w != buf)
		_TIFFfree((char*) w);
	return (status);
}

/*
 * Setup a directory entry that references a samples/pixel array of ``type''
 * values and (potentially) write the associated indirect values.  The source
 * data from TIFFGetField() for the specified tag must be returned as double.
 */
static int
TIFFWritePerSampleAnys(TIFF* tif,
    TIFFDataType type, ttag_t tag, TIFFDirEntry* dir)
{
	double buf[10], v;
	double* w = buf;
	int i, status;
	int samples = (int) tif->tif_dir.td_samplesperpixel;

	if (samples > NITEMS(buf))
		w = (double*) _TIFFmalloc(samples * sizeof (double));
	TIFFGetField(tif, tag, &v);
	for (i = 0; i < samples; i++)
		w[i] = v;
	status = TIFFWriteAnyArray(tif, type, tag, dir, samples, w);
	if (w != buf)
		_TIFFfree(w);
	return (status);
}
#undef NITEMS

/*
 * Setup a pair of shorts that are returned by
 * value, rather than as a reference to an array.
 */
static int
TIFFSetupShortPair(TIFF* tif, ttag_t tag, TIFFDirEntry* dir)
{
	uint16 v[2];

	TIFFGetField(tif, tag, &v[0], &v[1]);
	return (TIFFWriteShortArray(tif, TIFF_SHORT, tag, dir, 2, v));
}

/*
 * Setup a directory entry for an NxM table of shorts,
 * where M is known to be 2**bitspersample, and write
 * the associated indirect data.
 */
static int
TIFFWriteShortTable(TIFF* tif,
    ttag_t tag, TIFFDirEntry* dir, uint32 n, uint16** table)
{
	uint32 i, off;

	dir->tdir_tag = (uint16) tag;
	dir->tdir_type = (short) TIFF_SHORT;
	/* XXX -- yech, fool TIFFWriteData */
	dir->tdir_count = (uint32) (1L<<tif->tif_dir.td_bitspersample);
	off = tif->tif_dataoff;
	for (i = 0; i < n; i++)
		if (!TIFFWriteData(tif, dir, (char *)table[i]))
			return (0);
	dir->tdir_count *= n;
	dir->tdir_offset = off;
	return (1);
}

/*
 * Write/copy data associated with an ASCII or opaque tag value.
 */
static int
TIFFWriteByteArray(TIFF* tif, TIFFDirEntry* dir, char* cp)
{
	if (dir->tdir_count > 4) {
		if (!TIFFWriteData(tif, dir, cp))
			return (0);
	} else
		_TIFFmemcpy(&dir->tdir_offset, cp, dir->tdir_count);
	return (1);
}

/*
 * Setup a directory entry of an array of SHORT
 * or SSHORT and write the associated indirect values.
 */
static int
TIFFWriteShortArray(TIFF* tif,
    TIFFDataType type, ttag_t tag, TIFFDirEntry* dir, uint32 n, uint16* v)
{
	dir->tdir_tag = (uint16) tag;
	dir->tdir_type = (short) type;
	dir->tdir_count = n;
	if (n <= 2) {
		if (tif->tif_header.tiff_magic == TIFF_BIGENDIAN) {
			dir->tdir_offset = (uint32) ((long) v[0] << 16);
			if (n == 2)
				dir->tdir_offset |= v[1] & 0xffff;
		} else {
			dir->tdir_offset = v[0] & 0xffff;
			if (n == 2)
				dir->tdir_offset |= (long) v[1] << 16;
		}
		return (1);
	} else
		return (TIFFWriteData(tif, dir, (char*) v));
}

/*
 * Setup a directory entry of an array of LONG
 * or SLONG and write the associated indirect values.
 */
static int
TIFFWriteLongArray(TIFF* tif,
    TIFFDataType type, ttag_t tag, TIFFDirEntry* dir, uint32 n, uint32* v)
{
	dir->tdir_tag = (uint16) tag;
	dir->tdir_type = (short) type;
	dir->tdir_count = n;
	if (n == 1) {
		dir->tdir_offset = v[0];
		return (1);
	} else
		return (TIFFWriteData(tif, dir, (char*) v));
}

/*
 * Setup a directory entry of an array of RATIONAL
 * or SRATIONAL and write the associated indirect values.
 */
static int
TIFFWriteRationalArray(TIFF* tif,
    TIFFDataType type, ttag_t tag, TIFFDirEntry* dir, uint32 n, float* v)
{
	uint32 i;
	uint32* t;
	int status;

	dir->tdir_tag = (uint16) tag;
	dir->tdir_type = (short) type;
	dir->tdir_count = n;
	t = (uint32*) _TIFFmalloc(2*n * sizeof (uint32));
	for (i = 0; i < n; i++) {
		float fv = v[i];
		int sign = 1;
		uint32 den;

		if (fv < 0) {
			if (type == TIFF_RATIONAL) {
				TIFFWarning(tif->tif_name,
	"\"%s\": Information lost writing value (%g) as (unsigned) RATIONAL",
				_TIFFFieldWithTag(tif,tag)->field_name, fv);
				fv = 0;
			} else
				fv = -fv, sign = -1;
		}
		den = 1L;
		if (fv > 0) {
			while (fv < 1L<<(31-3) && den < 1L<<(31-3))
				fv *= 1<<3, den *= 1L<<3;
		}
		t[2*i+0] = (uint32) (sign * (fv + 0.5));
		t[2*i+1] = den;
	}