Introduce a new _M_compile function which does the common work needed by
all constructors and assignment. Call that directly to avoid multiple
levels of constructor delegation or calls to basic_regex::assign
overloads.
For assignment, there is no need to construct a std::basic_string if we
already have a contiguous sequence of the correct character type, and no
need to construct a temporary basic_regex when assigning from an
existing basic_regex.
Also define the copy and move assignment operators as defaulted, which
does the right thing without constructing a temporary and swapping it.
Copying or moving the shared_ptr member cannot fail, so they can be
noexcept. The assign(const basic_regex&) and assign(basic_regex&&)
member can then be defined in terms of copy or move assignment.
The new _M_compile function takes pointer arguments, so the caller has
to convert arbitrary iterator ranges into a contiguous sequence of
characters. With that simplification, the __compile_nfa helpers are not
needed and can be removed.
This also fixes a bug where construction from a contiguous sequence with
the wrong character type would fail to compile, rather than converting
the elements to the regex character type.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/bits/regex.h (__detail::__is_contiguous_iter): Move
here from <bits/regex_compiler.h>.
(basic_regex::_M_compile): New function to compile an NFA from
a regular expression string.
(basic_regex::basic_regex): Use _M_compile instead of delegating
to other constructors.
(basic_regex::operator=(const basic_regex&)): Define as
defaulted.
(basic_regex::operator=(initializer_list<C>)): Use _M_compile.
(basic_regex::assign(const basic_regex&)): Use copy assignment.
(basic_regex::assign(basic_regex&&)): Use move assignment.
(basic_regex::assign(const C*, flag_type)): Use _M_compile
instead of constructing a temporary string.
(basic_regex::assign(const C*, size_t, flag_type)): Likewise.
(basic_regex::assign(const basic_string<C,T,A>&, flag_type)):
Use _M_compile instead of constructing a temporary basic_regex.
(basic_regex::assign(InputIter, InputIter, flag_type)): Avoid
constructing a temporary string for contiguous iterators of the
right value type.
* include/bits/regex_compiler.h (__is_contiguous_iter): Move to
<bits/regex.h>.
(__enable_if_contiguous_iter, __disable_if_contiguous_iter)
(__compile_nfa): Remove.
* testsuite/28_regex/basic_regex/assign/exception_safety.cc: New
test.
* testsuite/28_regex/basic_regex/ctors/char/other.cc: New test.
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