1/* PDFlib GmbH cvsid: $Id: tif_strip.c 14574 2005-10-29 16:27:43Z bonefish $ */
2
3/*
4 * Copyright (c) 1991-1997 Sam Leffler
5 * Copyright (c) 1991-1997 Silicon Graphics, Inc.
6 *
7 * Permission to use, copy, modify, distribute, and sell this software and
8 * its documentation for any purpose is hereby granted without fee, provided
9 * that (i) the above copyright notices and this permission notice appear in
10 * all copies of the software and related documentation, and (ii) the names of
11 * Sam Leffler and Silicon Graphics may not be used in any advertising or
12 * publicity relating to the software without the specific, prior written
13 * permission of Sam Leffler and Silicon Graphics.
14 *
15 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
17 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
18 *
19 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
20 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
21 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
22 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
23 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
24 * OF THIS SOFTWARE.
25 */
26
27/*
28 * TIFF Library.
29 *
30 * Strip-organized Image Support Routines.
31 */
32#include "tiffiop.h"
33
34/*
35 * Compute which strip a (row,sample) value is in.
36 */
37tstrip_t
38TIFFComputeStrip(TIFF* tif, uint32 row, tsample_t sample)
39{
40	TIFFDirectory *td = &tif->tif_dir;
41	tstrip_t strip;
42
43	strip = row / td->td_rowsperstrip;
44	if (td->td_planarconfig == PLANARCONFIG_SEPARATE) {
45		if (sample >= td->td_samplesperpixel) {
46			TIFFError(tif->tif_name,
47			    "%u: Sample out of range, max %u",
48			    sample, td->td_samplesperpixel);
49			return ((tstrip_t) 0);
50		}
51		strip += sample*td->td_stripsperimage;
52	}
53	return (strip);
54}
55
56/*
57 * Compute how many strips are in an image.
58 */
59tstrip_t
60TIFFNumberOfStrips(TIFF* tif)
61{
62	TIFFDirectory *td = &tif->tif_dir;
63	tstrip_t nstrips;
64
65	nstrips = (td->td_rowsperstrip == (uint32) -1 ?
66	     (td->td_imagelength != 0 ? 1 : 0) :
67	     TIFFhowmany(td->td_imagelength, td->td_rowsperstrip));
68	if (td->td_planarconfig == PLANARCONFIG_SEPARATE)
69		nstrips *= td->td_samplesperpixel;
70	return (nstrips);
71}
72
73/*
74 * Compute the # bytes in a variable height, row-aligned strip.
75 */
76tsize_t
77TIFFVStripSize(TIFF* tif, uint32 nrows)
78{
79	TIFFDirectory *td = &tif->tif_dir;
80
81	if (nrows == (uint32) -1)
82		nrows = td->td_imagelength;
83#ifdef YCBCR_SUPPORT
84	if (td->td_planarconfig == PLANARCONFIG_CONTIG &&
85	    td->td_photometric == PHOTOMETRIC_YCBCR &&
86	    !isUpSampled(tif)) {
87		/*
88		 * Packed YCbCr data contain one Cb+Cr for every
89		 * HorizontalSampling*VerticalSampling Y values.
90		 * Must also roundup width and height when calculating
91		 * since images that are not a multiple of the
92		 * horizontal/vertical subsampling area include
93		 * YCbCr data for the extended image.
94		 */
95		tsize_t w =
96		    TIFFroundup(td->td_imagewidth, td->td_ycbcrsubsampling[0]);
97		tsize_t scanline = TIFFhowmany(w*td->td_bitspersample, 8);
98		tsize_t samplingarea =
99		    td->td_ycbcrsubsampling[0]*td->td_ycbcrsubsampling[1];
100		nrows = TIFFroundup(nrows, td->td_ycbcrsubsampling[1]);
101		/* NB: don't need TIFFhowmany here 'cuz everything is rounded */
102		return ((tsize_t)
103		    (nrows*scanline + 2*(nrows*scanline / samplingarea)));
104	} else
105#endif
106		return ((tsize_t)(nrows * TIFFScanlineSize(tif)));
107}
108
109/*
110 * Compute the # bytes in a (row-aligned) strip.
111 *
112 * Note that if RowsPerStrip is larger than the
113 * recorded ImageLength, then the strip size is
114 * truncated to reflect the actual space required
115 * to hold the strip.
116 */
117tsize_t
118TIFFStripSize(TIFF* tif)
119{
120	TIFFDirectory* td = &tif->tif_dir;
121	uint32 rps = td->td_rowsperstrip;
122	if (rps > td->td_imagelength)
123		rps = td->td_imagelength;
124	return (TIFFVStripSize(tif, rps));
125}
126
127/*
128 * Compute a default strip size based on the image
129 * characteristics and a requested value.  If the
130 * request is <1 then we choose a strip size according
131 * to certain heuristics.
132 */
133uint32
134TIFFDefaultStripSize(TIFF* tif, uint32 request)
135{
136	return (*tif->tif_defstripsize)(tif, request);
137}
138
139uint32
140_TIFFDefaultStripSize(TIFF* tif, uint32 s)
141{
142	if ((int32) s < 1) {
143		/*
144		 * If RowsPerStrip is unspecified, try to break the
145		 * image up into strips that are approximately 8Kbytes.
146		 */
147		tsize_t scanline = TIFFScanlineSize(tif);
148		s = (uint32)(8*1024) / (scanline == 0 ? 1 : scanline);
149		if (s == 0)		/* very wide images */
150			s = 1;
151	}
152	return (s);
153}
154
155/*
156 * Return the number of bytes to read/write in a call to
157 * one of the scanline-oriented i/o routines.  Note that
158 * this number may be 1/samples-per-pixel if data is
159 * stored as separate planes.
160 */
161tsize_t
162TIFFScanlineSize(TIFF* tif)
163{
164	TIFFDirectory *td = &tif->tif_dir;
165	tsize_t scanline;
166
167	scanline = td->td_bitspersample * td->td_imagewidth;
168	if (td->td_planarconfig == PLANARCONFIG_CONTIG)
169		scanline *= td->td_samplesperpixel;
170	return ((tsize_t) TIFFhowmany(scanline, 8));
171}
172
173/*
174 * Return the number of bytes required to store a complete
175 * decoded and packed raster scanline (as opposed to the
176 * I/O size returned by TIFFScanlineSize which may be less
177 * if data is store as separate planes).
178 */
179tsize_t
180TIFFRasterScanlineSize(TIFF* tif)
181{
182	TIFFDirectory *td = &tif->tif_dir;
183	tsize_t scanline;
184
185	scanline = td->td_bitspersample * td->td_imagewidth;
186	if (td->td_planarconfig == PLANARCONFIG_CONTIG) {
187		scanline *= td->td_samplesperpixel;
188		return ((tsize_t) TIFFhowmany(scanline, 8));
189	} else
190		return ((tsize_t)
191		    TIFFhowmany(scanline, 8)*td->td_samplesperpixel);
192}
193