text: #ifndef lint
  static char rcsid[] = "$Header: /usr/people/sam/tiff/libtiff/RCS/tif_tile.c,v 1.9 92/02/10 19:06:47 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.
   *
   * Tiled Image Support Routines.
   */
  #include "tiffioP.h"
  
  /*
   * Compute which tile an (x,y,z,s) value is in.
   */
  u_int
  TIFFComputeTile(tif, x, y, s, z)
  	TIFF *tif;
  	u_long x, y, z;
  	u_int s;
  {
  	TIFFDirectory *td = &tif->tif_dir;
  	u_long dx = td->td_tilewidth;
  	u_long dy = td->td_tilelength;
  	u_long dz = td->td_tiledepth;
  	u_int tile = 1;
  
  	if (td->td_imagedepth == 1)
  		z = 0;
  	if (dx == (u_long) -1)
  		dx = td->td_imagewidth;
  	if (dy == (u_long) -1)
  		dy = td->td_imagelength;
  	if (dz == (u_long) -1)
  		dz = td->td_imagedepth;
  	if (dx != 0 && dy != 0 && dz != 0) {
  		u_int xpt = howmany(td->td_imagewidth, dx); 
  		u_int ypt = howmany(td->td_imagelength, dy); 
  		u_int zpt = howmany(td->td_imagedepth, dz); 
  
  		if (td->td_planarconfig == PLANARCONFIG_SEPARATE) 
  			tile = (xpt*ypt*zpt)*s +
  			     (xpt*ypt)*(z/dz) +
  			     xpt*(y/dy) +
  			     x/dx;
  		else
  			tile = (xpt*ypt)*(z/dz) + xpt*(y/dy) + x/dx + s;
  	}
  	return (tile);
  }
  
  /*
   * Check an (x,y,z,s) coordinate
   * against the image bounds.
   */
  TIFFCheckTile(tif, x, y, z, s)
  	TIFF *tif;
  	u_long x, y, z;
  	u_int s;
  {
  	TIFFDirectory *td = &tif->tif_dir;
  
  	if (x >= td->td_imagewidth) {
  		TIFFError(tif->tif_name, "Col %d out of range, max %d",
  		    x, td->td_imagewidth);
  		return (0);
  	}
  	if (y >= td->td_imagelength) {
  		TIFFError(tif->tif_name, "Row %d out of range, max %d",
  		    y, td->td_imagelength);
  		return (0);
  	}
  	if (z >= td->td_imagedepth) {
  		TIFFError(tif->tif_name, "Depth %d out of range, max %d",
  		    z, td->td_imagedepth);
  		return (0);
  	}
  	if (td->td_planarconfig == PLANARCONFIG_SEPARATE &&
  	    s >= td->td_samplesperpixel) {
  		TIFFError(tif->tif_name, "Sample %d out of range, max %d",
  		    s, td->td_samplesperpixel);
  		return (0);
  	}
  	return (1);
  }
  
  /*
   * Compute how many tiles are in an image.
   */
  u_int
  TIFFNumberOfTiles(tif)
  	TIFF *tif;
  {
  	TIFFDirectory *td = &tif->tif_dir;
  	u_long dx = td->td_tilewidth;
  	u_long dy = td->td_tilelength;
  	u_long dz = td->td_tiledepth;
  	u_int ntiles;
  
  	if (dx == (u_long) -1)
  		dx = td->td_imagewidth;
  	if (dy == (u_long) -1)
  		dy = td->td_imagelength;
  	if (dz == (u_long) -1)
  		dz = td->td_imagedepth;
  	ntiles = (dx != 0 && dy != 0 && dz != 0) ?
  	    (howmany(td->td_imagewidth, dx) * howmany(td->td_imagelength, dy) *
  		howmany(td->td_imagedepth, dz)) :
  	    0;
  	return (ntiles);
  }
  
  /*
   * Compute the # bytes in each row of a tile.
   */
  u_long
  TIFFTileRowSize(tif)
  	TIFF *tif;
  {
  	TIFFDirectory *td = &tif->tif_dir;
  	u_long rowsize;
  	
  	if (td->td_tilelength == 0 || td->td_tilewidth == 0)
  		return (0);
  	rowsize = td->td_bitspersample * td->td_tilewidth;
  	if (td->td_planarconfig == PLANARCONFIG_CONTIG)
  		rowsize *= td->td_samplesperpixel;
  	return (howmany(rowsize, 8));
  }
  
  /*
   * Compute the # bytes in a variable length, row-aligned tile.
   */
  u_long
  TIFFVTileSize(tif, nrows)
  	TIFF *tif;
  	u_long nrows;
  {
  	TIFFDirectory *td = &tif->tif_dir;
  	u_long tilesize;
  
  	if (td->td_tilelength == 0 || td->td_tilewidth == 0 ||
  	    td->td_tiledepth == 0)
  		return (0);
  #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_tilewidth, td->td_ycbcrsubsampling[0]);
  		u_long rowsize = 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 */
  		tilesize = nrows*rowsize + 2*(nrows*rowsize / samplingarea);
  	} else
  #endif
  		tilesize = nrows * TIFFTileRowSize(tif);
  	return (tilesize * td->td_tiledepth);
  }
  
  /*
   * Compute the # bytes in a row-aligned tile.
   */
  u_long
  TIFFTileSize(tif)
  	TIFF *tif;
  {
  	return (TIFFVTileSize(tif, tif->tif_dir.td_tilelength));
  }
  