Initial revision

1 files changed, 192 insertions, 0 deletions

diff --git a/libtiff/tif_strip.c b/libtiff/tif_strip.c
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+/* $Header: /cvs/maptools/cvsroot/libtiff/libtiff/tif_strip.c,v 1.1 1999-07-27 21:50:27 mike Exp $ */
+
+/*
+ * Copyright (c) 1991-1997 Sam Leffler
+ * Copyright (c) 1991-1997 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 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 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 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.
+ */
+
+/*
+ * TIFF Library.
+ *
+ * Strip-organized Image Support Routines.
+ */
+#include "tiffiop.h"
+
+/*
+ * Compute which strip a (row,sample) value is in.
+ */
+tstrip_t
+TIFFComputeStrip(TIFF* tif, uint32 row, tsample_t sample)
+{
+	TIFFDirectory *td = &tif->tif_dir;
+	tstrip_t strip;
+
+	strip = row / td->td_rowsperstrip;
+	if (td->td_planarconfig == PLANARCONFIG_SEPARATE) {
+		if (sample >= td->td_samplesperpixel) {
+			TIFFError(tif->tif_name,
+			    "%u: Sample out of range, max %u",
+			    sample, td->td_samplesperpixel);
+			return ((tstrip_t) 0);
+		}
+		strip += sample*td->td_stripsperimage;
+	}
+	return (strip);
+}
+
+/*
+ * Compute how many strips are in an image.
+ */
+tstrip_t
+TIFFNumberOfStrips(TIFF* tif)
+{
+	TIFFDirectory *td = &tif->tif_dir;
+	tstrip_t nstrips;
+
+	nstrips = (td->td_rowsperstrip == (uint32) -1 ?
+	     (td->td_imagelength != 0 ? 1 : 0) :
+	     TIFFhowmany(td->td_imagelength, td->td_rowsperstrip));
+	if (td->td_planarconfig == PLANARCONFIG_SEPARATE)
+		nstrips *= td->td_samplesperpixel;
+	return (nstrips);
+}
+
+/*
+ * Compute the # bytes in a variable height, row-aligned strip.
+ */
+tsize_t
+TIFFVStripSize(TIFF* tif, uint32 nrows)
+{
+	TIFFDirectory *td = &tif->tif_dir;
+
+	if (nrows == (uint32) -1)
+		nrows = td->td_imagelength;
+#ifdef YCBCR_SUPPORT
+	if (td->td_planarconfig == PLANARCONFIG_CONTIG &&
+	    td->td_photometric == PHOTOMETRIC_YCBCR &&
+	    !isUpSampled(tif)) {
+		/*
+		 * Packed YCbCr data contain one Cb+Cr for every
+		 * HorizontalSampling*VerticalSampling Y values.
+		 * Must also roundup width and height when calculating
+		 * since images that are not a multiple of the
+		 * horizontal/vertical subsampling area include
+		 * YCbCr data for the extended image.
+		 */
+		tsize_t w =
+		    TIFFroundup(td->td_imagewidth, td->td_ycbcrsubsampling[0]);
+		tsize_t scanline = TIFFhowmany(w*td->td_bitspersample, 8);
+		tsize_t samplingarea =
+		    td->td_ycbcrsubsampling[0]*td->td_ycbcrsubsampling[1];
+		nrows = TIFFroundup(nrows, td->td_ycbcrsubsampling[1]);
+		/* NB: don't need TIFFhowmany here 'cuz everything is rounded */
+		return ((tsize_t)
+		    (nrows*scanline + 2*(nrows*scanline / samplingarea)));
+	} else
+#endif
+		return ((tsize_t)(nrows * TIFFScanlineSize(tif)));
+}
+
+/*
+ * Compute the # bytes in a (row-aligned) strip.
+ *
+ * Note that if RowsPerStrip is larger than the
+ * recorded ImageLength, then the strip size is
+ * truncated to reflect the actual space required
+ * to hold the strip.
+ */
+tsize_t
+TIFFStripSize(TIFF* tif)
+{
+	TIFFDirectory* td = &tif->tif_dir;
+	uint32 rps = td->td_rowsperstrip;
+	if (rps > td->td_imagelength)
+		rps = td->td_imagelength;
+	return (TIFFVStripSize(tif, rps));
+}
+
+/*
+ * Compute a default strip size based on the image
+ * characteristics and a requested value.  If the
+ * request is <1 then we choose a strip size according
+ * to certain heuristics.
+ */
+uint32
+TIFFDefaultStripSize(TIFF* tif, uint32 request)
+{
+	return (*tif->tif_defstripsize)(tif, request);
+}
+
+uint32
+_TIFFDefaultStripSize(TIFF* tif, uint32 s)
+{
+	if ((int32) s < 1) {
+		/*
+		 * If RowsPerStrip is unspecified, try to break the
+		 * image up into strips that are approximately 8Kbytes.
+		 */
+		tsize_t scanline = TIFFScanlineSize(tif);
+		s = (uint32)(8*1024) / (scanline == 0 ? 1 : scanline);
+		if (s == 0)		/* very wide images */
+			s = 1;
+	}
+	return (s);
+}
+
+/*
+ * Return the number of bytes to read/write in a call to
+ * one of the scanline-oriented i/o routines.  Note that
+ * this number may be 1/samples-per-pixel if data is
+ * stored as separate planes.
+ */
+tsize_t
+TIFFScanlineSize(TIFF* tif)
+{
+	TIFFDirectory *td = &tif->tif_dir;
+	tsize_t scanline;
+	
+	scanline = td->td_bitspersample * td->td_imagewidth;
+	if (td->td_planarconfig == PLANARCONFIG_CONTIG)
+		scanline *= td->td_samplesperpixel;
+	return ((tsize_t) TIFFhowmany(scanline, 8));
+}
+
+/*
+ * Return the number of bytes required to store a complete
+ * decoded and packed raster scanline (as opposed to the
+ * I/O size returned by TIFFScanlineSize which may be less
+ * if data is store as separate planes).
+ */
+tsize_t
+TIFFRasterScanlineSize(TIFF* tif)
+{
+	TIFFDirectory *td = &tif->tif_dir;
+	tsize_t scanline;
+	
+	scanline = td->td_bitspersample * td->td_imagewidth;
+	if (td->td_planarconfig == PLANARCONFIG_CONTIG) {
+		scanline *= td->td_samplesperpixel;
+		return ((tsize_t) TIFFhowmany(scanline, 8));
+	} else
+		return ((tsize_t)
+		    TIFFhowmany(scanline, 8)*td->td_samplesperpixel);
+}