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2005.01.27 21:51 "Re: issues with TIFFStreamOpen", by Edward Lam
Edward Lam wrote:
> I've attached a new tif_stream.cxx incorporating all the changes
> mentioned above. I haven't tested them though. Please let me know if it
> works for you. It's much appreciated, Michael!
Oops, I forgot to change the call to TIFFClientOpen() in the write code path to
pass data instead of fd. Try this attachment instead which should work better.
-Edward
/* $Id: tif_stream.cxx,v 1.2 2004/11/13 11:19:15 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 <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_base::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);
// fill the intermediate space
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: */