src/tiff/tif_strip.c

   1 /* $Header$ */
   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  */
  37 tstrip_t
  38 TIFFComputeStrip(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  */
  59 tstrip_t
  60 TIFFNumberOfStrips(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  */
  76 tsize_t
  77 TIFFVStripSize(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  */
 117 tsize_t
 118 TIFFStripSize(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  */
 133 uint32
 134 TIFFDefaultStripSize(TIFF* tif, uint32 request)
 135 {
 136         return (*tif->tif_defstripsize)(tif, request);
 137 }
 138
 139 uint32
 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  */
 161 tsize_t
 162 TIFFScanlineSize(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  */
 179 tsize_t
 180 TIFFRasterScanlineSize(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 }