/* $Id: tif_stream.cxx,v 1.1 2005/09/16 19:52:26 jjomier 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 <iostream>
#include "tiffiop.h"

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);
}

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