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Fixes for C++ stream interface from Michael Rinne and Edward Lam.

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This commit is contained in:
Andrey Kiselev 2005-01-30 12:05:54 +00:00
parent 4f0f56dae1
commit 9690ab1ea1
1 changed files with 100 additions and 25 deletions
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99
libtiff/tif_stream.cxx
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@ -1,4 +1,4 @@
/* $Id: tif_stream.cxx,v 1.2 2004-11-13 11:19:15 dron Exp $ */
/* $Id: tif_stream.cxx,v 1.3 2005-01-30 12:05:54 dron Exp $ */
/*
* Copyright (c) 1988-1996 Sam Leffler
@ -40,6 +40,14 @@ class tiffis_data
long myStreamStartPos;
};
class tiffos_data
{
public:
ostream *myOS;
long myStreamStartPos;
};
static tsize_t
_tiffosReadProc(thandle_t, tdata_t, tsize_t)
{
@ -59,7 +67,8 @@ _tiffisReadProc(thandle_t fd, tdata_t buf, tsize_t size)
static tsize_t
_tiffosWriteProc(thandle_t fd, tdata_t buf, tsize_t size)
{
ostream *os = (ostream *)fd;
tiffos_data *data = (tiffos_data *)fd;
ostream *os = data->myOS;
int pos = os->tellp();
os->write((const char *)buf, size);
@ -76,11 +85,16 @@ _tiffisWriteProc(thandle_t, tdata_t, tsize_t)
static toff_t
_tiffosSeekProc(thandle_t fd, toff_t off, int whence)
{
ostream *os = (ostream *)fd;
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(off, ios::beg);
os->seekp(data->myStreamStartPos + off, ios::beg);
break;
case SEEK_CUR:
os->seekp(off, ios::cur);
@ -90,6 +104,50 @@ _tiffosSeekProc(thandle_t fd, toff_t off, int whence)
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);
// 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();
}
@ -116,9 +174,10 @@ _tiffisSeekProc(thandle_t fd, toff_t off, int whence)
static toff_t
_tiffosSizeProc(thandle_t fd)
{
ostream *os = (ostream *)fd;
int pos = os->tellp();
int len;
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();
@ -145,6 +204,7 @@ 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;
}
@ -176,11 +236,16 @@ _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) fd,
(thandle_t) data,
_tiffosReadProc, _tiffosWriteProc,
_tiffosSeekProc, _tiffosCloseProc, _tiffosSizeProc,
_tiffosSeekProc, _tiffosCloseProc,
_tiffosSizeProc,
_tiffDummyMapProc, _tiffDummyUnmapProc);
} else {
tiffis_data *data = new tiffis_data;
@ -190,7 +255,8 @@ _tiffStreamOpen(const char* name, const char* mode, void *fd)
tif = TIFFClientOpen(name, mode,
(thandle_t) data,
_tiffisReadProc, _tiffisWriteProc,
_tiffisSeekProc, _tiffisCloseProc, _tiffisSizeProc,
_tiffisSeekProc, _tiffisCloseProc,
_tiffisSizeProc,
_tiffDummyMapProc, _tiffDummyUnmapProc);
}
@ -200,14 +266,23 @@ _tiffStreamOpen(const char* name, const char* mode, void *fd)
TIFF*
TIFFStreamOpen(const char* name, ostream *os)
{
// NB: We don't support mapped files with streams
// 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
// NB: We don't support mapped files with streams so add 'm'
return _tiffStreamOpen(name, "rm", is);
}