/* Id */

/*
 * 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) {
                TIFFErrorExt(tif->tif_clientdata, 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) {
                TIFFErrorExt(tif->tif_clientdata, 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) {
                        TIFFErrorExt(tif->tif_clientdata, 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) {
                        TIFFErrorExt(tif->tif_clientdata, 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) {
                TIFFErrorExt(tif->tif_clientdata, 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
TEXPORT
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
                 * STRIP_SIZE_DEFAULT bytes long.
                 */
                tsize_t scanline = TIFFScanlineSize(tif);
                s = (uint32)STRIP_SIZE_DEFAULT / (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
TEXPORT
TIFFScanlineSize(TIFF* tif)
{
        TIFFDirectory *td = &tif->tif_dir;
        tsize_t scanline;
        
        if (td->td_planarconfig == PLANARCONFIG_CONTIG) {
                if (td->td_photometric == PHOTOMETRIC_YCBCR
                    && !isUpSampled(tif)) {
                        uint16 ycbcrsubsampling[2];

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

                        if (ycbcrsubsampling[0] == 0) {
                                TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
                                             "Invalid YCbCr subsampling");
                                return 0;
                        }

                        scanline = TIFFroundup(td->td_imagewidth,
                                               ycbcrsubsampling[0]);
                        scanline = TIFFhowmany8(multiply(tif, scanline,
                                                         td->td_bitspersample,
                                                         "TIFFScanlineSize"));
                        return ((tsize_t)
                                summarize(tif, scanline,
                                          multiply(tif, 2,
                                                scanline / ycbcrsubsampling[0],
                                                "TIFFVStripSize"),
                                          "TIFFVStripSize"));
                } else {
                        scanline = multiply(tif, td->td_imagewidth,
                                            td->td_samplesperpixel,
                                            "TIFFScanlineSize");
                }
        } else
                scanline = td->td_imagewidth;
        return ((tsize_t) TIFFhowmany8(multiply(tif, scanline,
                                                td->td_bitspersample,
                                                "TIFFScanlineSize")));
}

/*
 * 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"));
}

/* vim: set ts=8 sts=8 sw=8 noet: */
