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| author | Jonathan Wakely <jwakely@redhat.com> | 2019-05-29 23:00:45 +0100 |
|---|---|---|
| committer | Jonathan Wakely <redi@gcc.gnu.org> | 2019-05-29 23:00:45 +0100 |
| commit | e5ccb10ad04e5cc1c44ea4d50a501840927ad70e (patch) | |
| tree | d0b2dd96111966903022c5a8936a2ab2a4297fcf | |
| parent | e800d6dc2cb329a1b64bb3af136164910778a40c (diff) | |
| download | gcc-e5ccb10ad04e5cc1c44ea4d50a501840927ad70e.zip gcc-e5ccb10ad04e5cc1c44ea4d50a501840927ad70e.tar.gz gcc-e5ccb10ad04e5cc1c44ea4d50a501840927ad70e.tar.bz2 | |
Optimize filesystem::path::parent_path()
Parsing a complete string is more efficient than appending each
component one-by-one.
* src/c++17/fs_path.cc (path::parent_path()): Create whole path at
once instead of building it iteratively.
From-SVN: r271754
| -rw-r--r-- | libstdc++-v3/ChangeLog | 3 | ||||
| -rw-r--r-- | libstdc++-v3/src/c++17/fs_path.cc | 8 |
2 files changed, 6 insertions, 5 deletions
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index b209460..b6b7a05 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,5 +1,8 @@ 2019-05-29 Jonathan Wakely <jwakely@redhat.com> + * src/c++17/fs_path.cc (path::parent_path()): Create whole path at + once instead of building it iteratively. + * testsuite/util/testsuite_api.h: Remove names of unused parameters. PR libstdc++/85494 use rdseed and rand_s in std::random_device diff --git a/libstdc++-v3/src/c++17/fs_path.cc b/libstdc++-v3/src/c++17/fs_path.cc index 8e01bf5..c438ddc 100644 --- a/libstdc++-v3/src/c++17/fs_path.cc +++ b/libstdc++-v3/src/c++17/fs_path.cc @@ -1523,11 +1523,9 @@ path::parent_path() const __ret = *this; else if (_M_cmpts.size() >= 2) { - for (auto __it = _M_cmpts.begin(), __end = std::prev(_M_cmpts.end()); - __it != __end; ++__it) - { - __ret /= *__it; - } + const auto parent = std::prev(_M_cmpts.end(), 2); + const auto len = parent->_M_pos + parent->_M_pathname.length(); + __ret.assign(_M_pathname.substr(0, len)); } return __ret; } |