re PR libstdc++/47921 (pbump will overflow when input n is larger than 2G-1)

re PR libstdc++/47921 (pbump will overflow when input n is larger than 2G-1)

2011-02-28  Paolo Carlini  <paolo.carlini@oracle.com>

	PR libstdc++/47921
	* include/std/streambuf (basic_streambuf<>::__safe_gbump,
	__safe_pbump): Add.
	* include/bits/streambuf.tcc (basic_streambuf<>::xgetn,
	xputn): Use the latter.
	* include/bits/streambuf_iterator.h: Likewise.
	* src/strstream.cc: Likewise.
	* src/streambuf.cc: Likewise.
	* src/compatibility.cc: Likewise.
	* src/istream.cc: Likewise.
	* include/bits/fstream.tcc (basic_filebuf<>::xsgetn): Use setg
	instead of gbump.
	* include/std/sstream (basic_stringbuf<>::_M_pbump): Add.
	* include/bits/sstream.tcc (basic_stringbuf<>::seekoff,
	seekpos, _M_sync): Use setg, setp, and _M_pbump.
	* config/abi/pre/gnu.ver: Tweak.

From-SVN: r170579