libstdc++/9875: filebuf doesn't handle codecvt::encoding() > 1

[Pétur Runólfsson]

The following reply was made to PR libstdc++/9875; it has been noted by GNATS.

From: =?iso-8859-1?Q?P=E9tur_Run=F3lfsson?= <peturr02@ru.is>
To: "Paolo Carlini" <pcarlini@unitus.it>
Cc: <paolo@gcc.gnu.org>,
	<gcc-bugs@gcc.gnu.org>,
	<gcc-gnats@gcc.gnu.org>
Subject: RE: libstdc++/9875: filebuf doesn't handle codecvt::encoding() > 1
Date: Mon, 3 Mar 2003 18:38:27 -0000

 > >>    The underflow bits are still missing, however. Are you
 > >>    willing to provide some tests for it too?
 > >>   =20
 > >>
 > >Will do.
 > >
 > Thanks P=E9tur.
 > By the way, I would appreciate also some actual ;) tests for=20
 > overflow,=20
 > since those
 > present in the PR didn't really lead to overflow for the default 8192=20
 > chars wide buffer.
 > (temporarily I have added some using setbuf to shorten the buffer)
 
 These are a bit hairy, but that is by design. The seekoff in
 _M_really_overflow is only called when _M_filepos !=3D _M_out_beg
 which only happens when switching modes, and the seekoff in
 _M_underflow_common only happens when _M_in_cur !=3D _M_filepos,
 which never happens when underflow is called from any public
 members of streambuf or filebuf.
 
 Petur
 
 void test4()
 {
 	using namespace std;
 
 	// overflow
 	locale loc (locale::classic(), new Cvt);
 	wfilebuf fb1;
 	fb1.pubimbue(loc);
 	fb1.open("tmp", ios_base::out | ios_base::trunc);
 	fb1.sputn(L"0123456789", 10);
 	fb1.close();
 
 	wfilebuf fb2;
 	fb2.pubimbue(loc);
 	fb2.open("tmp", ios_base::in | ios_base::out);
 
 	fb2.sgetc();
 =09
 	int written =3D 0;
 	for (int i =3D 0; i < BUFSIZ; ++i)
 		written +=3D fb2.sputn(L"abc", 3);
 
 	fb2.close();
 
 	wfilebuf fb3;
 	fb3.pubimbue(loc);
 	fb3.open("tmp", ios_base::in);
 
 	for (int j =3D 0; j < BUFSIZ; ++j)
 	{
 		wchar_t buf[] =3D L"xxx\n";
 		int n =3D fb3.sgetn(buf, 3);
 		assert(n =3D=3D 3);
 		fputws(buf, stderr);
 		assert(!wmemcmp(buf, L"abc", 3));
 	}
 =09
 	fb3.close();
 }
 
 class Buf : public std::wfilebuf
 {
 public:
 	int_type pub_underflow()
 		{ return underflow(); }
 };
 
 void test5()
 {
 	using namespace std;
 
 	// underflow
 	const wchar_t* strlit =3D L"0123456789";
 	locale loc (locale::classic(), new Cvt);
 	wfilebuf fb1;
 	fb1.pubimbue(loc);
 	fb1.open("tmp", ios_base::out | ios_base::trunc);
 	fb1.sputn(strlit, 10);
 	fb1.close();
 
 	Buf fb2;
 	fb2.pubimbue(loc);
 	fb2.open("tmp", ios_base::in);
 
 	for (int i =3D 0; i < 10; ++i)
 	{
 		assert(fb2.pub_underflow() =3D=3D strlit[i]);
 		fb2.sbumpc();
 	}
 
 	fb2.close();
 }