text: #ifndef lint
  static char rcsid[] = "$Header: /usr/people/sam/tiff/libtiff/RCS/tif_strip.c,v 1.9 92/10/21 13:42:18 sam Exp $";
  #endif
  
  /*
   * Copyright (c) 1991, 1992 Sam Leffler
   * Copyright (c) 1991, 1992 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.
   */
  u_int
  DECLARE3(TIFFComputeStrip, TIFF*, tif, u_long, row, u_int, sample)
  {
      TIFFDirectory *td = &tif->tif_dir;
      u_int strip;
  
      strip = row / td->td_rowsperstrip;
      if (td->td_planarconfig == PLANARCONFIG_SEPARATE) {
          if (sample >= td->td_samplesperpixel) {
              TIFFError(tif->tif_name,
                  "%d: Sample out of range, max %d",
                  sample, td->td_samplesperpixel);
              return (0);
          }
          strip += sample*td->td_stripsperimage;
      }
      return (strip);
  }
  
  /*
   * Compute how many strips are in an image.
   */
  u_int
  DECLARE1(TIFFNumberOfStrips, TIFF*, tif)
  {
      TIFFDirectory *td = &tif->tif_dir;
  
      return (td->td_rowsperstrip == 0xffffffff ?
           (td->td_imagelength != 0 ? 1 : 0) :
           howmany(td->td_imagelength, td->td_rowsperstrip));
  }
  
  /*
   * Compute the # bytes in a variable height, row-aligned strip.
   */
  u_long
  DECLARE2(TIFFVStripSize, TIFF*, tif, u_long, nrows)
  {
      TIFFDirectory *td = &tif->tif_dir;
  
      if (nrows == (u_long)-1)
          nrows = td->td_imagelength;
  #ifdef YCBCR_SUPPORT
      if (td->td_planarconfig == PLANARCONFIG_CONTIG &&
          td->td_photometric == PHOTOMETRIC_YCBCR) {
          /*
           * 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.
           */
          u_long w =
              roundup(td->td_imagewidth, td->td_ycbcrsubsampling[0]);
          u_long scanline = howmany(w*td->td_bitspersample, 8);
          u_long samplingarea =
              td->td_ycbcrsubsampling[0]*td->td_ycbcrsubsampling[1];
          nrows = roundup(nrows, td->td_ycbcrsubsampling[1]);
          /* NB: don't need howmany here 'cuz everything is rounded */
          return (nrows*scanline + 2*(nrows*scanline / samplingarea));
      } else
  #endif
          return (nrows * TIFFScanlineSize(tif));
  }
  
  /*
   * Compute the # bytes in a (row-aligned) strip.
   */
  u_long
  DECLARE1(TIFFStripSize, TIFF*, tif)
  {
      return (TIFFVStripSize(tif, tif->tif_dir.td_rowsperstrip));
  }
  
  