[Bug libstdc++/64441] A match_results returns an incorrect sub_match if the sub_match::matched is false

[Bug libstdc++/64441] A match_results returns an incorrect sub_match if the sub_match::matched is false

[timshen at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64441

--- Comment #1 from Tim Shen <timshen at gcc dot gnu.org> ---
Author: timshen
Date: Wed Dec 31 10:27:41 2014
New Revision: 219121

URL: https://gcc.gnu.org/viewcvs?rev=219121&root=gcc&view=rev
Log:
    PR libstdc++/64441
    * include/bits/regex.tcc (__regex_algo_impl): s/auto/auto&/.
    * include/bits/regex_executor.tcc (_Executor<>::_M_dfs): Likewise.

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

[Bug libstdc++/64441] A match_results returns an incorrect sub_match if the sub_match::matched is false

[kariya_mitsuru at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64441

--- Comment #2 from Mitsuru Kariya <kariya_mitsuru at hotmail dot com> ---
The rev.219121 seems to satisfy the sample code above, but does not satisfy
another sample code like below.

====================================== sample code
======================================
#include <iostream>
#include <regex>

int main()
{
    const char s[] = "abc";
    const std::regex re("(\\d+)|(\\w+)");

    std::cmatch m;
    std::regex_search(s, m, re);
    std::cout << std::boolalpha;
    for (size_t i = 0, n = m.size(); i <= n; ++i) {
        auto&& sub = m[i];
        std::cout << i << ":" << sub.matched << ", str = '" << sub.str() << "',
"
            "range = [" << sub.first - s << ", " << sub.second - s << ")" <<
std::endl;
    }
}
=========================================================================================
============================= output =============================
0:true, str = 'abc', range = [0, 3)
1:false, str = '', range = [3, 3)
2:true, str = 'abc', range = [0, 3)
3:false, str = '', range = [-140735878146800, -140735878146800)
==================================================================

According to the C++11 standard 28.10.4[re.results.acc]/p.8,

If n >= size() then returns a sub_match object representing an unmatched
sub-expression.

So, I think that n = 1 and n = 3 should be an identical result, and the output
should be

============================= output =============================
0:true, str = 'abc', range = [0, 3)
1:false, str = '', range = [3, 3)
2:true, str = 'abc', range = [0, 3)
3:false, str = '', range = [3, 3)
==================================================================

[Bug libstdc++/64441] A match_results returns an incorrect sub_match if the sub_match::matched is false

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64441

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-03-09
     Ever confirmed|0                           |1

[Bug libstdc++/64441] A match_results returns an incorrect sub_match if the sub_match::matched is false

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64441

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kaballo86 at hotmail dot com

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
*** Bug 64781 has been marked as a duplicate of this bug. ***

[Bug libstdc++/64441] A match_results returns an incorrect sub_match if the sub_match::matched is false

[timshen at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64441

--- Comment #4 from Tim Shen <timshen at gcc dot gnu.org> ---
Author: timshen
Date: Tue Mar 10 18:41:46 2015
New Revision: 221330

URL: https://gcc.gnu.org/viewcvs?rev=221330&root=gcc&view=rev
Log:
    PR libstdc++/64441
    * include/bits/regex.h (match_results<>::size,
    match_results<>::position, match_results<>::str,
    match_results<>::operator[], match_results<>::prefix,
    match_results<>::suffix, match_results<>::end,
    match_results<>::_M_resize, match_results<>::_M_unmatched_sub,
    match_results<>::_M_prefix, match_results<>::_M_suffix): Remove
    global __unmatched_sub. Add unmatched submatch as part of
    match_results.
    * include/bits/regex.tcc (__regex_algo_impl<>, regex_replace<>,
    regex_iterator<>::operator++): Adjust to use match_results::_M_prefix.
    * testsuite/28_regex/match_results/out_of_range_submatches.cc:
    New testcases.

Added:
   
trunk/libstdc++-v3/testsuite/28_regex/match_results/out_of_range_submatches.cc
Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/include/bits/regex.h
    trunk/libstdc++-v3/include/bits/regex.tcc

[Bug libstdc++/64441] A match_results returns an incorrect sub_match if the sub_match::matched is false

[timshen at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64441

Tim Shen <timshen at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from Tim Shen <timshen at gcc dot gnu.org> ---
Fixed.

[Bug libstdc++/64441] A match_results returns an incorrect sub_match if the sub_match::matched is false

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64441

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |5.0