[libc++][P1115][C++20] Improving the Return Value of Erase-Like Algorithms II: Free erase/erase if.
Summary:
This patch adds return type to std::erase and std::erase_if functions.
Also:
* Update __cpp_lib_erase_if to 202002L.
* Fix synopsis in unordered_map.
* Fix generate_feature_test_macro_components.py script.
Reviewers: EricWF, mclow.lists, ldionne, #libc
Reviewed By: ldionne, #libc
Subscribers: broadwaylamb, zoecarver, dexonsmith, ldionne, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D75905
Cr-Mirrored-From: https://chromium.googlesource.com/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 3e895085de0afdd85574b35de48a1bcc6544f2ec
diff --git a/include/string b/include/string
index 6938ee4..179080d 100644
--- a/include/string
+++ b/include/string
@@ -437,9 +437,11 @@
getline(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str);
template<class charT, class traits, class Allocator, class U>
-void erase(basic_string<charT, traits, Allocator>& c, const U& value); // C++20
+typename basic_string<charT, traits, Allocator>::size_type
+erase(basic_string<charT, traits, Allocator>& c, const U& value); // C++20
template<class charT, class traits, class Allocator, class Predicate>
-void erase_if(basic_string<charT, traits, Allocator>& c, Predicate pred); // C++20
+typename basic_string<charT, traits, Allocator>::size_type
+erase_if(basic_string<charT, traits, Allocator>& c, Predicate pred); // C++20
typedef basic_string<char> string;
typedef basic_string<wchar_t> wstring;
@@ -4379,15 +4381,25 @@
#endif // _LIBCPP_CXX03_LANG
#if _LIBCPP_STD_VER > 17
-template<class _CharT, class _Traits, class _Allocator, class _Up>
+template <class _CharT, class _Traits, class _Allocator, class _Up>
inline _LIBCPP_INLINE_VISIBILITY
-void erase(basic_string<_CharT, _Traits, _Allocator>& __str, const _Up& __v)
-{ __str.erase(_VSTD::remove(__str.begin(), __str.end(), __v), __str.end()); }
+ typename basic_string<_CharT, _Traits, _Allocator>::size_type
+ erase(basic_string<_CharT, _Traits, _Allocator>& __str, const _Up& __v) {
+ auto __old_size = __str.size();
+ __str.erase(_VSTD::remove(__str.begin(), __str.end(), __v), __str.end());
+ return __old_size - __str.size();
+}
-template<class _CharT, class _Traits, class _Allocator, class _Predicate>
+template <class _CharT, class _Traits, class _Allocator, class _Predicate>
inline _LIBCPP_INLINE_VISIBILITY
-void erase_if(basic_string<_CharT, _Traits, _Allocator>& __str, _Predicate __pred)
-{ __str.erase(_VSTD::remove_if(__str.begin(), __str.end(), __pred), __str.end()); }
+ typename basic_string<_CharT, _Traits, _Allocator>::size_type
+ erase_if(basic_string<_CharT, _Traits, _Allocator>& __str,
+ _Predicate __pred) {
+ auto __old_size = __str.size();
+ __str.erase(_VSTD::remove_if(__str.begin(), __str.end(), __pred),
+ __str.end());
+ return __old_size - __str.size();
+}
#endif
#if _LIBCPP_DEBUG_LEVEL >= 2