libstdc++/4150: catastrophic performance decrease in C++ code

[Jason Merrill]

Here's a more limited patch, which just avoids the seeking.  Rather than
define _M_in_end to indicate the file pointer, it adds another member.

2002-04-20  Jason Merrill  <jason@redhat.com>

	PR libstdc++/4150
	* include/std/std_streambuf.h (basic_streambuf::_M_set_indeterminate): 
	Move to filebuf.
	(basic_streambuf::_M_set_determinate): Likewise.
	(basic_streambuf::_M_is_indeterminate): Likewise.
	* include/bits/std_fstream.h (basic_filebuf::_M_filepos): New 
	non-static data member.
	(basic_filebuf::_M_underflow_common): New non-static member function.
	(basic_filebuf::_M_underflow, _M_uflow): Call it.
	(basic_filebuf::sync): Avoid useless seeking.
	(basic_filebuf::_M_set_indeterminate): Move here from streambuf.
	Set _M_filepos.
	(basic_filebuf::_M_set_determinate): Likewise.
	(basic_filebuf::_M_is_indeterminate): Likewise.
	* include/bits/fstream.tcc (basic_filebuf::_M_really_overflow): Seek
	back to _M_out_beg if necessary.
	(basic_filebuf::seekoff): Likewise.
	(basic_filebuf::_M_underflow_common): Generalization of old 
	underflow().  Don't seek back to _M_in_beg.
	* src/ios.cc: Lose _GLIBCPP_AVOID_FSEEK stuff.
	* config/os/solaris/solaris2.?/bits/os_defines.h: Likewise.
	* config/os/bsd/freebsd/bits/os_defines.h: Likewise.
	* config/os/mingw32/bits/os_defines.h: Likewise.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: text/x-patch
Size: 12178 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/libstdc++/attachments/20020422/5c4d0cfc/attachment.bin>