/* $Id: tif_strip.c,v 1.4 2005/11/19 16:02:59 malaterre 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"

static uint32
summarize(TIFF* tif, size_t summand1, size_t summand2, const char* where)
{
  /*
   * XXX: We are using casting to uint32 here, bacause sizeof(size_t)
   * may be larger than sizeof(uint32) on 64-bit architectures.
   */
  uint32  bytes = summand1 + summand2;

  if (bytes - summand1 != summand2) {
    TIFFError(tif->tif_name, "Integer overflow in %s", where);
    bytes = 0;
  }

  return (bytes);
}

static uint32
multiply(TIFF* tif, size_t nmemb, size_t elem_size, const char* where)
{
  uint32  bytes = nmemb * elem_size;

  if (elem_size && bytes / elem_size != nmemb) {
    TIFFError(tif->tif_name, "Integer overflow in %s", where);
    bytes = 0;
  }

  return (bytes);
}

/*
 * 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,
          "%lu: Sample out of range, max %lu",
          (unsigned long) sample, (unsigned long) 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 ? 1 :
       TIFFhowmany(td->td_imagelength, td->td_rowsperstrip));
  if (td->td_planarconfig == PLANARCONFIG_SEPARATE)
    nstrips = multiply(tif, nstrips, td->td_samplesperpixel,
           "TIFFNumberOfStrips");
  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;
  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.
     */
                uint16 ycbcrsubsampling[2];
                tsize_t w, scanline, samplingarea;

                TIFFGetField( tif, TIFFTAG_YCBCRSUBSAMPLING, 
                              ycbcrsubsampling + 0, 
                              ycbcrsubsampling + 1 );

    samplingarea = ycbcrsubsampling[0]*ycbcrsubsampling[1];
    if (samplingarea == 0) {
      TIFFError(tif->tif_name, "Invalid YCbCr subsampling");
      return 0;
    }

    w = TIFFroundup(td->td_imagewidth, ycbcrsubsampling[0]);
    scanline = TIFFhowmany8(multiply(tif, w, td->td_bitspersample,
             "TIFFVStripSize"));
    nrows = TIFFroundup(nrows, ycbcrsubsampling[1]);
    /* NB: don't need TIFFhowmany here 'cuz everything is rounded */
    scanline = multiply(tif, nrows, scanline, "TIFFVStripSize");
    return ((tsize_t)
        summarize(tif, scanline,
            multiply(tif, 2, scanline / samplingarea,
               "TIFFVStripSize"), "TIFFVStripSize"));
  } else
    return ((tsize_t) multiply(tif, nrows, TIFFScanlineSize(tif),
             "TIFFVStripSize"));
}


/*
 * Compute the # bytes in a raw strip.
 */
tsize_t
TIFFRawStripSize(TIFF* tif, tstrip_t strip)
{
  TIFFDirectory* td = &tif->tif_dir;
  tsize_t bytecount = td->td_stripbytecount[strip];

  if (bytecount <= 0) {
    TIFFError(tif->tif_name,
        "%lu: Invalid strip byte count, strip %lu",
        (unsigned long) bytecount, (unsigned long) strip);
    bytecount = (tsize_t) -1;
  }

  return bytecount;
}

/*
 * 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 = multiply (tif, td->td_bitspersample, td->td_imagewidth,
           "TIFFScanlineSize");
  if (td->td_planarconfig == PLANARCONFIG_CONTIG)
    scanline = multiply (tif, scanline, td->td_samplesperpixel,
             "TIFFScanlineSize");
  return ((tsize_t) TIFFhowmany8(scanline));
}

/*
 * 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 = multiply (tif, td->td_bitspersample, td->td_imagewidth,
           "TIFFRasterScanlineSize");
  if (td->td_planarconfig == PLANARCONFIG_CONTIG) {
    scanline = multiply (tif, scanline, td->td_samplesperpixel,
             "TIFFRasterScanlineSize");
    return ((tsize_t) TIFFhowmany8(scanline));
  } else
    return ((tsize_t) multiply (tif, TIFFhowmany8(scanline),
              td->td_samplesperpixel,
              "TIFFRasterScanlineSize"));
}

