Add basic_string::__resize_default_init (from P1072)
This patch adds an implementation of __resize_default_init as
described in P1072R2. Additionally, it uses it in filesystem to
demonstrate its intended utility.
Once P1072 lands, or if it changes it's interface, I will adjust
the internal libc++ implementation to match.
llvm-svn: 347589
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 01a87ef88b77034ab6a9ea7bc9da24fb380e91e8
diff --git a/include/string b/include/string
index 0c9f1cf..383b5c0 100644
--- a/include/string
+++ b/include/string
@@ -956,6 +956,8 @@
void resize(size_type __n, value_type __c);
_LIBCPP_INLINE_VISIBILITY void resize(size_type __n) {resize(__n, value_type());}
+ _LIBCPP_INLINE_VISIBILITY void __resize_default_init(size_type __n);
+
void reserve(size_type __res_arg = 0);
_LIBCPP_INLINE_VISIBILITY
void shrink_to_fit() _NOEXCEPT {reserve();}
@@ -1010,6 +1012,10 @@
basic_string& append(const value_type* __s, size_type __n);
basic_string& append(const value_type* __s);
basic_string& append(size_type __n, value_type __c);
+
+ _LIBCPP_INLINE_VISIBILITY
+ void __append_default_init(size_type __n);
+
template <class _ForwardIterator>
_LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
basic_string& __append_forward_unsafe(_ForwardIterator, _ForwardIterator);
@@ -2428,6 +2434,23 @@
}
template <class _CharT, class _Traits, class _Allocator>
+inline void
+basic_string<_CharT, _Traits, _Allocator>::__append_default_init(size_type __n)
+{
+ if (__n)
+ {
+ size_type __cap = capacity();
+ size_type __sz = size();
+ if (__cap - __sz < __n)
+ __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
+ pointer __p = __get_pointer();
+ __sz += __n;
+ __set_size(__sz);
+ traits_type::assign(__p[__sz], value_type());
+ }
+}
+
+template <class _CharT, class _Traits, class _Allocator>
void
basic_string<_CharT, _Traits, _Allocator>::push_back(value_type __c)
{
@@ -3083,6 +3106,17 @@
}
template <class _CharT, class _Traits, class _Allocator>
+inline void
+basic_string<_CharT, _Traits, _Allocator>::__resize_default_init(size_type __n)
+{
+ size_type __sz = size();
+ if (__n > __sz) {
+ __append_default_init(__n - __sz);
+ } else
+ __erase_to_end(__n);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
inline _LIBCPP_INLINE_VISIBILITY
typename basic_string<_CharT, _Traits, _Allocator>::size_type
basic_string<_CharT, _Traits, _Allocator>::max_size() const _NOEXCEPT