r271167 - in /trunk/libstdc++-v3: ChangeLog inc...

[redi@gcc.gnu.org]

Author: redi
Date: Tue May 14 12:19:05 2019
New Revision: 271167

URL: https://gcc.gnu.org/viewcvs?rev=271167&root=gcc&view=rev
Log:
Make std::match_results::_M_resize more useful

As both callers of match_results::_M_resize(unsigned) immediately follow
it with a loop to update the value of each sub_match, that behaviour can
be moved into _M_resize itself. The first caller fills the container
with unmatched subs, which can be done with vector::assign, and the
second caller clears the container to establish a specific state, which
can be provided by a new member function specific to that purpose.

Tangentially, I also noticed that match_results::max_size() doesn't
account for the three special sub_match objects that are always present
in a fully established result state. This patch also fixes that.

	* include/bits/regex.h (match_results::max_size()): Adjust return
	value to account for prefix/suffix/unmatched subs.
	(match_results::_M_resize(unsigned int)): Use _Base_type::assign to
	reset the contained sub matches.
	(match_results::_M_establish_failed_match(_Bi_iter)): Add new member
	function to set result state following a failed match.
	* include/bits/regex.tcc (__regex_algo_impl): Remove loop to set
	sub_match states after _M_resize. Use _M_establish_failed_match.

Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/include/bits/regex.h
    trunk/libstdc++-v3/include/bits/regex.tcc