libtiff/libtiff/tif_flush.c

/*
 * Copyright (c) 1988-1997 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.
 */
#include "tiffiop.h"

int
TIFFFlush(TIFF* tif)
{
    if( tif->tif_mode == O_RDONLY )
        return 1;

    if (!TIFFFlushData(tif))
        return (0);
                
    /* In update (r+) mode we try to detect the case where 
       only the strip/tile map has been altered, and we try to 
       rewrite only that portion of the directory without 
       making any other changes */
                
    if( (tif->tif_flags & TIFF_DIRTYSTRIP)
        && !(tif->tif_flags & TIFF_DIRTYDIRECT) 
        && tif->tif_mode == O_RDWR )
    {
        if( TIFFForceStrileArrayWriting(tif) )
            return 1;
    }

    if ((tif->tif_flags & (TIFF_DIRTYDIRECT|TIFF_DIRTYSTRIP)) 
        && !TIFFRewriteDirectory(tif))
        return (0);

    return (1);
}

/*
 * This is an advanced writing function that must be used in a particular
 * sequence, and together with TIFFDeferStrileArrayWriting(),
 * to make its intended effect. Its aim is to force the writing of
 * the [Strip/Tile][Offsets/ByteCounts] arrays at the end of the file, when
 * they have not yet been rewritten.
 *
 * The typical sequence of calls is:
 * TIFFOpen()
 * [ TIFFCreateDirectory(tif) ]
 * Set fields with calls to TIFFSetField(tif, ...)
 * TIFFDeferStrileArrayWriting(tif)
 * TIFFWriteCheck(tif, ...)
 * TIFFWriteDirectory(tif)
 * ... potentially create other directories and come back to the above directory
 * TIFFForceStrileArrayWriting(tif)
 *
 * Returns 1 in case of success, 0 otherwise.
 */
int TIFFForceStrileArrayWriting(TIFF* tif)
{
    static const char module[] = "TIFFForceStrileArrayWriting";
    const int isTiled = TIFFIsTiled(tif);

    if (tif->tif_mode == O_RDONLY)
    {
        TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
                     "File opened in read-only mode");
        return 0;
    }
    if( tif->tif_diroff == 0 )
    {
        TIFFErrorExt(tif->tif_clientdata, module,
                     "Directory has not yet been written");
        return 0;
    }
    if( (tif->tif_flags & TIFF_DIRTYDIRECT) != 0 )
    {
        TIFFErrorExt(tif->tif_clientdata, module,
                     "Directory has changes other than the strile arrays. "
                     "TIFFRewriteDirectory() should be called instead");
        return 0;
    }

    if( !(tif->tif_flags & TIFF_DIRTYSTRIP) )
    {
        if( !(tif->tif_dir.td_stripoffset_entry.tdir_tag != 0 &&
             tif->tif_dir.td_stripoffset_entry.tdir_count == 0 &&
             tif->tif_dir.td_stripoffset_entry.tdir_type == 0 &&
             tif->tif_dir.td_stripoffset_entry.tdir_offset.toff_long8 == 0 &&
             tif->tif_dir.td_stripbytecount_entry.tdir_tag != 0 &&
             tif->tif_dir.td_stripbytecount_entry.tdir_count == 0 &&
             tif->tif_dir.td_stripbytecount_entry.tdir_type == 0 &&
             tif->tif_dir.td_stripbytecount_entry.tdir_offset.toff_long8 == 0) )
        {
            TIFFErrorExt(tif->tif_clientdata, module,
                        "Function not called together with "
                        "TIFFDeferStrileArrayWriting()");
            return 0;
        }

        if (tif->tif_dir.td_stripoffset_p == NULL && !TIFFSetupStrips(tif))
            return 0;
    }

    if( _TIFFRewriteField( tif,
                           isTiled ? TIFFTAG_TILEOFFSETS :
                                     TIFFTAG_STRIPOFFSETS,
                           TIFF_LONG8,
                           tif->tif_dir.td_nstrips,
                           tif->tif_dir.td_stripoffset_p )
        && _TIFFRewriteField( tif,
                              isTiled ? TIFFTAG_TILEBYTECOUNTS :
                                        TIFFTAG_STRIPBYTECOUNTS,
                              TIFF_LONG8,
                              tif->tif_dir.td_nstrips,
                              tif->tif_dir.td_stripbytecount_p ) )
    {
        tif->tif_flags &= ~TIFF_DIRTYSTRIP;
        tif->tif_flags &= ~TIFF_BEENWRITING;
        return 1;
    }

    return 0;
}

/*
 * Flush buffered data to the file.
 *
 * Frank Warmerdam'2000: I modified this to return 1 if TIFF_BEENWRITING
 * is not set, so that TIFFFlush() will proceed to write out the directory.
 * The documentation says returning 1 is an error indicator, but not having
 * been writing isn't exactly a an error.  Hopefully this doesn't cause
 * problems for other people. 
 */
int
TIFFFlushData(TIFF* tif)
{
	if ((tif->tif_flags & TIFF_BEENWRITING) == 0)
		return (1);
	if (tif->tif_flags & TIFF_POSTENCODE) {
		tif->tif_flags &= ~TIFF_POSTENCODE;
		if (!(*tif->tif_postencode)(tif))
			return (0);
	}
	return (TIFFFlushData1(tif));
}

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