tif_write.c

一个国人自己实现图像库的程序（有参考价值）

	if (!WRITECHECKTILES(tif, module))
		return ((tsize_t) -1);
	td = &tif->tif_dir;
	if (tile >= td->td_nstrips) {
		TIFFError(module, "%s: Tile %lu out of range, max %lu",
		    tif->tif_name, (u_long) tile, (u_long) td->td_nstrips);
		return ((tsize_t) -1);
	}
	/*
	 * Handle delayed allocation of data buffer.  This
	 * permits it to be sized more intelligently (using
	 * directory information).
	 */
	if (!BUFFERCHECK(tif))
		return ((tsize_t) -1);
	tif->tif_curtile = tile;

#ifdef REWRITE_HACK        
	tif->tif_rawcc = 0;
	tif->tif_rawcp = tif->tif_rawdata;

        if( td->td_stripbytecount[tile] > 0 )
        {
            /* if we are writing over existing tiles, zero length. */
            td->td_stripbytecount[tile] = 0;

            /* this forces TIFFAppendToStrip() to do a seek */
            tif->tif_curoff = 0;
        }
#endif
        
	/* 
	 * Compute tiles per row & per column to compute
	 * current row and column
	 */
	tif->tif_row = (tile % TIFFhowmany(td->td_imagelength, td->td_tilelength))
		* td->td_tilelength;
	tif->tif_col = (tile % TIFFhowmany(td->td_imagewidth, td->td_tilewidth))
		* td->td_tilewidth;

	if ((tif->tif_flags & TIFF_CODERSETUP) == 0) {
		if (!(*tif->tif_setupencode)(tif))
			return ((tsize_t) -1);
		tif->tif_flags |= TIFF_CODERSETUP;
	}
	tif->tif_flags &= ~TIFF_POSTENCODE;
	sample = (tsample_t)(tile/td->td_stripsperimage);
	if (!(*tif->tif_preencode)(tif, sample))
		return ((tsize_t) -1);
	/*
	 * Clamp write amount to the tile size.  This is mostly
	 * done so that callers can pass in some large number
	 * (e.g. -1) and have the tile size used instead.
	 */
	if ( cc < 1 || cc > tif->tif_tilesize)
		cc = tif->tif_tilesize;
	if (!(*tif->tif_encodetile)(tif, (tidata_t) data, cc, sample))
		return ((tsize_t) 0);
	if (!(*tif->tif_postencode)(tif))
		return ((tsize_t) -1);
	if (!isFillOrder(tif, td->td_fillorder) &&
	    (tif->tif_flags & TIFF_NOBITREV) == 0)
		TIFFReverseBits((u_char *)tif->tif_rawdata, tif->tif_rawcc);
	if (tif->tif_rawcc > 0 && !TIFFAppendToStrip(tif, tile,
	    tif->tif_rawdata, tif->tif_rawcc))
		return ((tsize_t) -1);
	tif->tif_rawcc = 0;
	tif->tif_rawcp = tif->tif_rawdata;
	return (cc);
}

/*
 * Write the supplied data to the specified strip.
 * There must be space for the data; we don't check
 * if strips overlap!
 *
 * NB: Image length must be setup before writing; this
 *     interface does not support automatically growing
 *     the image on each write (as TIFFWriteScanline does).
 */
tsize_t
TIFFWriteRawTile(TIFF* tif, ttile_t tile, tdata_t data, tsize_t cc)
{
	static const char module[] = "TIFFWriteRawTile";

	if (!WRITECHECKTILES(tif, module))
		return ((tsize_t) -1);
	if (tile >= tif->tif_dir.td_nstrips) {
		TIFFError(module, "%s: Tile %lu out of range, max %lu",
		    tif->tif_name, (u_long) tile,
		    (u_long) tif->tif_dir.td_nstrips);
		return ((tsize_t) -1);
	}
	return (TIFFAppendToStrip(tif, tile, (tidata_t) data, cc) ?
	    cc : (tsize_t) -1);
}

#define	isUnspecified(tif, f) \
    (TIFFFieldSet(tif,f) && (tif)->tif_dir.td_imagelength == 0)

static int
TIFFSetupStrips(TIFF* tif)
{
	TIFFDirectory* td = &tif->tif_dir;

	if (isTiled(tif))
		td->td_stripsperimage =
		    isUnspecified(tif, FIELD_TILEDIMENSIONS) ?
			td->td_samplesperpixel : TIFFNumberOfTiles(tif);
	else
		td->td_stripsperimage =
		    isUnspecified(tif, FIELD_ROWSPERSTRIP) ?
			td->td_samplesperpixel : TIFFNumberOfStrips(tif);
	td->td_nstrips = td->td_stripsperimage;
	if (td->td_planarconfig == PLANARCONFIG_SEPARATE)
		td->td_stripsperimage /= td->td_samplesperpixel;
	td->td_stripoffset = (uint32 *)
	    _TIFFmalloc(td->td_nstrips * sizeof (uint32));
	td->td_stripbytecount = (uint32 *)
	    _TIFFmalloc(td->td_nstrips * sizeof (uint32));
	if (td->td_stripoffset == NULL || td->td_stripbytecount == NULL)
		return (0);
	/*
	 * Place data at the end-of-file
	 * (by setting offsets to zero).
	 */
	_TIFFmemset(td->td_stripoffset, 0, td->td_nstrips*sizeof (uint32));
	_TIFFmemset(td->td_stripbytecount, 0, td->td_nstrips*sizeof (uint32));
	TIFFSetFieldBit(tif, FIELD_STRIPOFFSETS);
	TIFFSetFieldBit(tif, FIELD_STRIPBYTECOUNTS);
	return (1);
}
#undef isUnspecified

/*
 * Verify file is writable and that the directory
 * information is setup properly.  In doing the latter
 * we also "freeze" the state of the directory so
 * that important information is not changed.
 */
int
TIFFWriteCheck(TIFF* tif, int tiles, const char* module)
{
	if (tif->tif_mode == O_RDONLY) {
		TIFFError(module, "%s: File not open for writing",
		    tif->tif_name);
		return (0);
	}
	if (tiles ^ isTiled(tif)) {
		TIFFError(tif->tif_name, tiles ?
		    "Can not write tiles to a stripped image" :
		    "Can not write scanlines to a tiled image");
		return (0);
	}
	/*
	 * On the first write verify all the required information
	 * has been setup and initialize any data structures that
	 * had to wait until directory information was set.
	 * Note that a lot of our work is assumed to remain valid
	 * because we disallow any of the important parameters
	 * from changing after we start writing (i.e. once
	 * TIFF_BEENWRITING is set, TIFFSetField will only allow
	 * the image's length to be changed).
	 */
	if (!TIFFFieldSet(tif, FIELD_IMAGEDIMENSIONS)) {
		TIFFError(module,
		    "%s: Must set \"ImageWidth\" before writing data",
		    tif->tif_name);
		return (0);
	}
	if (!TIFFFieldSet(tif, FIELD_PLANARCONFIG)) {
		TIFFError(module,
	    "%s: Must set \"PlanarConfiguration\" before writing data",
		    tif->tif_name);
		return (0);
	}
	if (tif->tif_dir.td_stripoffset == NULL && !TIFFSetupStrips(tif)) {
		tif->tif_dir.td_nstrips = 0;
		TIFFError(module, "%s: No space for %s arrays",
		    tif->tif_name, isTiled(tif) ? "tile" : "strip");
		return (0);
	}
	tif->tif_tilesize = TIFFTileSize(tif);
	tif->tif_scanlinesize = TIFFScanlineSize(tif);
	tif->tif_flags |= TIFF_BEENWRITING;
	return (1);
}

/*
 * Setup the raw data buffer used for encoding.
 */
int
TIFFWriteBufferSetup(TIFF* tif, tdata_t bp, tsize_t size)
{
	static const char module[] = "TIFFWriteBufferSetup";

	if (tif->tif_rawdata) {
		if (tif->tif_flags & TIFF_MYBUFFER) {
			_TIFFfree(tif->tif_rawdata);
			tif->tif_flags &= ~TIFF_MYBUFFER;
		}
		tif->tif_rawdata = NULL;
	}
	if (size == (tsize_t) -1) {
		size = (isTiled(tif) ?
		    tif->tif_tilesize : tif->tif_scanlinesize);
		/*
		 * Make raw data buffer at least 8K
		 */
		if (size < 8*1024)
			size = 8*1024;
		bp = NULL;			/* NB: force malloc */
	}
	if (bp == NULL) {
		bp = _TIFFmalloc(size);
		if (bp == NULL) {
			TIFFError(module, "%s: No space for output buffer",
			    tif->tif_name);
			return (0);
		}
		tif->tif_flags |= TIFF_MYBUFFER;
	} else
		tif->tif_flags &= ~TIFF_MYBUFFER;
	tif->tif_rawdata = (tidata_t) bp;
	tif->tif_rawdatasize = size;
	tif->tif_rawcc = 0;
	tif->tif_rawcp = tif->tif_rawdata;
	tif->tif_flags |= TIFF_BUFFERSETUP;
	return (1);
}

/*
 * Grow the strip data structures by delta strips.
 */
static int
TIFFGrowStrips(TIFF* tif, int delta, const char* module)
{
	TIFFDirectory *td = &tif->tif_dir;

	assert(td->td_planarconfig == PLANARCONFIG_CONTIG);
	td->td_stripoffset = (uint32*)_TIFFrealloc(td->td_stripoffset,
	    (td->td_nstrips + delta) * sizeof (uint32));
	td->td_stripbytecount = (uint32*)_TIFFrealloc(td->td_stripbytecount,
	    (td->td_nstrips + delta) * sizeof (uint32));
	if (td->td_stripoffset == NULL || td->td_stripbytecount == NULL) {
		td->td_nstrips = 0;
		TIFFError(module, "%s: No space to expand strip arrays",
		    tif->tif_name);
		return (0);
	}
	_TIFFmemset(td->td_stripoffset+td->td_nstrips, 0, delta*sizeof (uint32));
	_TIFFmemset(td->td_stripbytecount+td->td_nstrips, 0, delta*sizeof (uint32));
	td->td_nstrips += delta;
	return (1);
}

/*
 * Append the data to the specified strip.
 *
 * NB: We don't check that there's space in the
 *     file (i.e. that strips do not overlap).
 */
static int
TIFFAppendToStrip(TIFF* tif, tstrip_t strip, tidata_t data, tsize_t cc)
{
	TIFFDirectory *td = &tif->tif_dir;
	static const char module[] = "TIFFAppendToStrip";

	if (td->td_stripoffset[strip] == 0 || tif->tif_curoff == 0) {
		/*
		 * No current offset, set the current strip.
		 */
		if (td->td_stripoffset[strip] != 0) {
			if (!SeekOK(tif, td->td_stripoffset[strip])) {
				TIFFError(module,
				    "%s: Seek error at scanline %lu",
				    tif->tif_name, (u_long) tif->tif_row);
				return (0);
			}
		} else
			td->td_stripoffset[strip] =
			    TIFFSeekFile(tif, (toff_t) 0, SEEK_END);
		tif->tif_curoff = td->td_stripoffset[strip];
	}
	if (!WriteOK(tif, data, cc)) {
		TIFFError(module, "%s: Write error at scanline %lu",
		    tif->tif_name, (u_long) tif->tif_row);
		return (0);
	}
	tif->tif_curoff += cc;
	td->td_stripbytecount[strip] += cc;
	return (1);
}

/*
 * Internal version of TIFFFlushData that can be
 * called by ``encodestrip routines'' w/o concern
 * for infinite recursion.
 */
int
TIFFFlushData1(TIFF* tif)
{
	if (tif->tif_rawcc > 0) {
		if (!isFillOrder(tif, tif->tif_dir.td_fillorder) &&
		    (tif->tif_flags & TIFF_NOBITREV) == 0)
			TIFFReverseBits((u_char *)tif->tif_rawdata,
			    tif->tif_rawcc);
		if (!TIFFAppendToStrip(tif,
		    isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip,
		    tif->tif_rawdata, tif->tif_rawcc))
			return (0);
		tif->tif_rawcc = 0;
		tif->tif_rawcp = tif->tif_rawdata;
	}
	return (1);
}

/*
 * Set the current write offset.  This should only be
 * used to set the offset to a known previous location
 * (very carefully), or to 0 so that the next write gets
 * appended to the end of the file.
 */
void
TIFFSetWriteOffset(TIFF* tif, toff_t off)
{
	tif->tif_curoff = off;
}