tif_stream.cxx

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/* $Id: tif_stream.cxx,v 1.5 2005/07/26 08:11:13 dron Exp $ */

/*
 * Copyright (c) 1988-1996 Sam Leffler
 * Copyright (c) 1991-1996 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 UNIX-specific Routines.
 */
#include "tiffiop.h"
#include <iostream>

using namespace std;

class tiffis_data
{
  public:

    istream *myIS;
        long    myStreamStartPos;
};

class tiffos_data
{
  public:

    ostream *myOS;
    long    myStreamStartPos;
};

static tsize_t
_tiffosReadProc(thandle_t, tdata_t, tsize_t)
{
        return 0;
}

static tsize_t
_tiffisReadProc(thandle_t fd, tdata_t buf, tsize_t size)
{
        tiffis_data *data = (tiffis_data *)fd;

        data->myIS->read((char *)buf, (int)size);

        return data->myIS->gcount();
}

static tsize_t
_tiffosWriteProc(thandle_t fd, tdata_t buf, tsize_t size)
{
    tiffos_data *data = (tiffos_data *)fd;
    ostream     *os = data->myOS;
    int     pos = os->tellp();

    os->write((const char *)buf, size);

    return ((int)os->tellp()) - pos;
}

static tsize_t
_tiffisWriteProc(thandle_t, tdata_t, tsize_t)
{
    return 0;
}

static toff_t
_tiffosSeekProc(thandle_t fd, toff_t off, int whence)
{
    tiffos_data *data = (tiffos_data *)fd;
    ostream *os = data->myOS;

    // if the stream has already failed, don't do anything
    if( os->fail() )
        return os->tellp();

    switch(whence) {
    case SEEK_SET:
        os->seekp(data->myStreamStartPos + off, ios::beg);
        break;
    case SEEK_CUR:
        os->seekp(off, ios::cur);
        break;
    case SEEK_END:
        os->seekp(off, ios::end);
        break;
    }

    // Attempt to workaround problems with seeking past the end of the
    // stream.  ofstream doesn't have a problem with this but
    // ostrstream/ostringstream does. In that situation, add intermediate
    // '\0' characters.
    if( os->fail() ) {
        ios::iostate    old_state;
        toff_t      origin;

        old_state = os->rdstate();
        // reset the fail bit or else tellp() won't work below
        os->clear(os->rdstate() & ~ios::failbit);
        switch( whence ) {
            case SEEK_SET:
                origin = data->myStreamStartPos;
                break;
            case SEEK_CUR:
                origin = os->tellp();
                break;
            case SEEK_END:
                os->seekp(0, ios::end);
                origin = os->tellp();
                break;
        }
        // restore original stream state
        os->clear(old_state);   

        // only do something if desired seek position is valid
        if( origin + off > data->myStreamStartPos ) {
            toff_t  num_fill;

            // clear the fail bit 
            os->clear(os->rdstate() & ~ios::failbit);

            // extend the stream to the expected size
            os->seekp(0, ios::end);
            num_fill = origin + off - (toff_t)os->tellp();
            for( toff_t i = 0; i < num_fill; i++ )
                os->put('\0');

            // retry the seek
            os->seekp(origin + off, ios::beg);
        }
    }

    return os->tellp();
}

static toff_t
_tiffisSeekProc(thandle_t fd, toff_t off, int whence)
{
    tiffis_data *data = (tiffis_data *)fd;

    switch(whence) {
    case SEEK_SET:
        data->myIS->seekg(data->myStreamStartPos + off, ios::beg);
        break;
    case SEEK_CUR:
        data->myIS->seekg(off, ios::cur);
        break;
    case SEEK_END:
        data->myIS->seekg(off, ios::end);
        break;
    }

    return ((long)data->myIS->tellg()) - data->myStreamStartPos;
}

static toff_t
_tiffosSizeProc(thandle_t fd)
{
    tiffos_data *data = (tiffos_data *)fd;
    ostream     *os = data->myOS;
    toff_t      pos = os->tellp();
    toff_t      len;

    os->seekp(0, ios::end);
    len = os->tellp();
    os->seekp(pos);

    return len;
}

static toff_t
_tiffisSizeProc(thandle_t fd)
{
    tiffis_data *data = (tiffis_data *)fd;
    int     pos = data->myIS->tellg();
    int     len;

    data->myIS->seekg(0, ios::end);
    len = data->myIS->tellg();
    data->myIS->seekg(pos);

    return len;
}

static int
_tiffosCloseProc(thandle_t fd)
{
    // Our stream was not allocated by us, so it shouldn't be closed by us.
    delete (tiffos_data *)fd;
    return 0;
}

static int
_tiffisCloseProc(thandle_t fd)
{
    // Our stream was not allocated by us, so it shouldn't be closed by us.
    delete (tiffis_data *)fd;
    return 0;
}

static int
_tiffDummyMapProc(thandle_t , tdata_t* , toff_t* )
{
    return (0);
}

static void
_tiffDummyUnmapProc(thandle_t , tdata_t , toff_t )
{
}

/*
 * Open a TIFF file descriptor for read/writing.
 */
static TIFF*
_tiffStreamOpen(const char* name, const char* mode, void *fd)
{
    TIFF*   tif;

    if( strchr(mode, 'w') ) {
        tiffos_data *data = new tiffos_data;
        data->myOS = (ostream *)fd;
        data->myStreamStartPos = data->myOS->tellp();

        // Open for writing.
        tif = TIFFClientOpen(name, mode,
                (thandle_t) data,
                _tiffosReadProc, _tiffosWriteProc,
                _tiffosSeekProc, _tiffosCloseProc,
                _tiffosSizeProc,
                _tiffDummyMapProc, _tiffDummyUnmapProc);
    } else {
        tiffis_data *data = new tiffis_data;
        data->myIS = (istream *)fd;
        data->myStreamStartPos = data->myIS->tellg();
        // Open for reading.
        tif = TIFFClientOpen(name, mode,
                (thandle_t) data,
                _tiffisReadProc, _tiffisWriteProc,
                _tiffisSeekProc, _tiffisCloseProc,
                _tiffisSizeProc,
                _tiffDummyMapProc, _tiffDummyUnmapProc);
    }

    return (tif);
}

TIFF*
TIFFStreamOpen(const char* name, ostream *os)
{
    // If os is either a ostrstream or ostringstream, and has no data
    // written to it yet, then tellp() will return -1 which will break us.
    // We workaround this by writing out a dummy character and
    // then seek back to the beginning.
    if( !os->fail() && (int)os->tellp() < 0 ) {
        *os << '\0';
        os->seekp(0);
    }

    // NB: We don't support mapped files with streams so add 'm'
    return _tiffStreamOpen(name, "wm", os);
}

TIFF*
TIFFStreamOpen(const char* name, istream *is)
{
    // NB: We don't support mapped files with streams so add 'm'
    return _tiffStreamOpen(name, "rm", is);
}

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