mclow.lists created this revision.
mclow.lists added a reviewer: EricWF.
First of the C++17 deduction guides (I think).
Uses the new `__is_allocator` trait.
The failing test is not quite right yet, but the success bits all work.
https://reviews.llvm.org/D41958
Files:
include/string
test/std/strings/basic.string/string.cons/iter_alloc.fail.cpp
test/std/strings/basic.string/string.cons/iter_alloc.pass.cpp
Index: test/std/strings/basic.string/string.cons/iter_alloc.pass.cpp
===================================================================
--- test/std/strings/basic.string/string.cons/iter_alloc.pass.cpp
+++ test/std/strings/basic.string/string.cons/iter_alloc.pass.cpp
@@ -13,6 +13,18 @@
// basic_string(InputIterator begin, InputIterator end,
// const Allocator& a = Allocator());
+// template<class InputIterator,
+// class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
+// basic_string(InputIterator, InputIterator, Allocator = Allocator())
+// -> basic_string<typename iterator_traits<InputIterator>::value_type,
+// char_traits<typename iterator_traits<InputIterator>::value_type>,
+// Allocator>;
+//
+// The deduction guide shall not participate in overload resolution if InputIterator
+// is a type that does not qualify as an input iterator, or if Allocator is a type
+// that does not qualify as an allocator.
+
+
#include <string>
#include <iterator>
#include <cassert>
@@ -116,4 +128,48 @@
test(input_iterator<const char*>(s), input_iterator<const char*>(s+50), A());
}
#endif
+
+// Test deduction guides
+#if TEST_STD_VER > 14
+ {
+ const char* s = "12345678901234";
+ std::basic_string s1{s, s+10, std::allocator<char>{}};
+ using S = decltype(s1); // what type did we get?
+ static_assert(std::is_same_v<S::value_type, char>, "");
+ static_assert(std::is_same_v<S::traits_type, std::char_traits<char>>, "");
+ static_assert(std::is_same_v<S::allocator_type, std::allocator<char>>, "");
+ assert(s1.size() == 10);
+ assert(s1.compare(0, s1.size(), s, s1.size()) == 0);
+ }
+ {
+ const wchar_t* s = L"12345678901234";
+ std::basic_string s1{s, s+10, test_allocator<wchar_t>{}};
+ using S = decltype(s1); // what type did we get?
+ static_assert(std::is_same_v<S::value_type, wchar_t>, "");
+ static_assert(std::is_same_v<S::traits_type, std::char_traits<wchar_t>>, "");
+ static_assert(std::is_same_v<S::allocator_type, test_allocator<wchar_t>>, "");
+ assert(s1.size() == 10);
+ assert(s1.compare(0, s1.size(), s, s1.size()) == 0);
+ }
+ {
+ const char16_t* s = u"12345678901234";
+ std::basic_string s1{s, s+10, min_allocator<char16_t>{}};
+ using S = decltype(s1); // what type did we get?
+ static_assert(std::is_same_v<S::value_type, char16_t>, "");
+ static_assert(std::is_same_v<S::traits_type, std::char_traits<char16_t>>, "");
+ static_assert(std::is_same_v<S::allocator_type, min_allocator<char16_t>>, "");
+ assert(s1.size() == 10);
+ assert(s1.compare(0, s1.size(), s, s1.size()) == 0);
+ }
+ {
+ const char32_t* s = U"12345678901234";
+ std::basic_string s1{s, s+10, explicit_allocator<char32_t>{}};
+ using S = decltype(s1); // what type did we get?
+ static_assert(std::is_same_v<S::value_type, char32_t>, "");
+ static_assert(std::is_same_v<S::traits_type, std::char_traits<char32_t>>, "");
+ static_assert(std::is_same_v<S::allocator_type, explicit_allocator<char32_t>>, "");
+ assert(s1.size() == 10);
+ assert(s1.compare(0, s1.size(), s, s1.size()) == 0);
+ }
+#endif
}
Index: test/std/strings/basic.string/string.cons/iter_alloc.fail.cpp
===================================================================
--- test/std/strings/basic.string/string.cons/iter_alloc.fail.cpp
+++ test/std/strings/basic.string/string.cons/iter_alloc.fail.cpp
@@ -0,0 +1,53 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <string>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// template<class InputIterator,
+// class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
+// basic_string(InputIterator, InputIterator, Allocator = Allocator())
+// -> basic_string<typename iterator_traits<InputIterator>::value_type,
+// char_traits<typename iterator_traits<InputIterator>::value_type>,
+// Allocator>;
+//
+// The deduction guide shall not participate in overload resolution if InputIterator
+// is a type that does not qualify as an input iterator, or if Allocator is a type
+// that does not qualify as an allocator.
+
+
+#include <string>
+#include <iterator>
+#include <cassert>
+#include <cstddef>
+
+#include "test_macros.h"
+
+class NotAnItertor {};
+
+template <typename T>
+class NotAnAllocator {};
+
+int main()
+{
+ { // Not an iterator at all
+ std::basic_string s1{NotAnItertor{}, NotAnItertor{}, std::allocator<char>{}}; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'basic_string'}}
+ }
+ { // Not an input iterator
+ const char16_t* s = u"12345678901234";
+ std::basic_string<char16_t> s0;
+ std::basic_string s1{std::back_insert_iterator(s0),
+ std::back_insert_iterator(s0),
+ std::allocator<char16_t>{}}; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'basic_string'}}
+ }
+ { // Not an allocator
+ const wchar_t* s = L"12345678901234";
+ std::basic_string s1{s, s+10, NotAnAllocator<wchar_t>{}}; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'basic_string'}}
+ }
+}
Index: include/string
===================================================================
--- include/string
+++ include/string
@@ -311,6 +311,13 @@
bool __invariants() const;
};
+template<class InputIterator,
+ class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
+basic_string(InputIterator, InputIterator, Allocator = Allocator())
+ -> basic_string<typename iterator_traits<InputIterator>::value_type,
+ char_traits<typename iterator_traits<InputIterator>::value_type>,
+ Allocator>; // C++17
+
template<class charT, class traits, class Allocator>
basic_string<charT, traits, Allocator>
operator+(const basic_string<charT, traits, Allocator>& lhs,
@@ -1481,6 +1488,18 @@
friend basic_string operator+<>(const basic_string&, value_type);
};
+#if _LIBCPP_STD_VER > 14
+template<class _InputIterator,
+ class _CharT = typename iterator_traits<_InputIterator>::value_type,
+ class _Allocator = allocator<_CharT>,
+ class = typename enable_if<__is_input_iterator<_InputIterator>::value, void>::type,
+ class = typename enable_if<__is_allocator<_Allocator>::value, void>::type
+ >
+basic_string(_InputIterator, _InputIterator, _Allocator = _Allocator())
+ -> basic_string<_CharT, char_traits<_CharT>, _Allocator>;
+#endif
+
+
template <class _CharT, class _Traits, class _Allocator>
inline _LIBCPP_INLINE_VISIBILITY
void
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
