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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17
// TODO: Change to XFAIL once https://github.com/llvm/llvm-project/issues/40340 is fixed
// UNSUPPORTED: availability-pmr-missing
// This test ensures that we properly propagate allocators from stringstream's
// inner string object to the new string returned from .str().
// `str() const&` is specified to preserve the allocator (not copy the string).
// `str() &&` isn't specified, but should preserve the allocator (move the string).
#include <cassert>
#include <memory>
#include <memory_resource>
#include <sstream>
#include <string>
#include <string_view>
#include <type_traits>
#include "make_string.h"
#include "test_allocator.h"
#include "test_macros.h"
template <class CharT>
void test_soccc_behavior() {
using Alloc = SocccAllocator<CharT>;
using SS = std::basic_stringstream<CharT, std::char_traits<CharT>, Alloc>;
using S = std::basic_string<CharT, std::char_traits<CharT>, Alloc>;
{
SS ss = SS(std::ios_base::out, Alloc(10));
// [stringbuf.members]/6 specifies that the allocator is copied,
// not select_on_container_copy_construction'ed.
//
S copied = ss.str();
assert(copied.get_allocator().count_ == 10);
assert(ss.rdbuf()->get_allocator().count_ == 10);
assert(copied.empty());
// sanity-check that SOCCC does in fact work
assert(S(copied).get_allocator().count_ == 11);
// [stringbuf.members]/10 doesn't specify the allocator to use,
// but copying the allocator as-if-by moving the string makes sense.
//
S moved = std::move(ss).str();
assert(moved.get_allocator().count_ == 10);
assert(ss.rdbuf()->get_allocator().count_ == 10);
assert(moved.empty());
}
}
template <class CharT,
class Base = std::basic_stringbuf<CharT, std::char_traits<CharT>, std::pmr::polymorphic_allocator<CharT>>>
struct StringBuf : Base {
explicit StringBuf(std::pmr::memory_resource* mr) : Base(std::ios_base::in, mr) {}
void public_setg(int a, int b, int c) {
CharT* p = this->eback();
assert(this->view().data() == p);
this->setg(p + a, p + b, p + c);
assert(this->eback() == p + a);
assert(this->view().data() == p + a);
}
};
template <class CharT>
void test_allocation_is_pilfered() {
using SS = std::basic_stringstream<CharT, std::char_traits<CharT>, std::pmr::polymorphic_allocator<CharT>>;
using S = std::pmr::basic_string<CharT>;
alignas(void*) char buf[80 * sizeof(CharT)];
const CharT* initial =
MAKE_CSTRING(CharT, "a very long string that exceeds the small string optimization buffer length");
{
std::pmr::set_default_resource(std::pmr::null_memory_resource());
auto mr1 = std::pmr::monotonic_buffer_resource(buf, sizeof(buf), std::pmr::null_memory_resource());
SS ss = SS(S(initial, &mr1));
S s = std::move(ss).str();
assert(s == initial);
}
{
// Try moving-out-of a stringbuf whose view() is not the entire string.
// This is libc++'s behavior; libstdc++ doesn't allow such stringbufs to be created.
//
std::pmr::set_default_resource(std::pmr::null_memory_resource());
auto mr1 = std::pmr::monotonic_buffer_resource(buf, sizeof(buf), std::pmr::null_memory_resource());
auto src = StringBuf<CharT>(&mr1);
src.str(S(initial, &mr1));
src.public_setg(2, 6, 40);
SS ss(std::ios_base::in, &mr1);
*ss.rdbuf() = std::move(src);
LIBCPP_ASSERT(ss.view() == std::basic_string_view<CharT>(initial).substr(2, 38));
S s = std::move(ss).str();
LIBCPP_ASSERT(s == std::basic_string_view<CharT>(initial).substr(2, 38));
}
}
template <class CharT>
void test_no_foreign_allocations() {
using SS = std::basic_stringstream<CharT, std::char_traits<CharT>, std::pmr::polymorphic_allocator<CharT>>;
using S = std::pmr::basic_string<CharT>;
const CharT* initial =
MAKE_CSTRING(CharT, "a very long string that exceeds the small string optimization buffer length");
{
std::pmr::set_default_resource(std::pmr::null_memory_resource());
auto mr1 = std::pmr::monotonic_buffer_resource(std::pmr::new_delete_resource());
auto ss = SS(S(initial, &mr1));
assert(ss.rdbuf()->get_allocator().resource() == &mr1);
// [stringbuf.members]/6 specifies that the result of `str() const &`
// does NOT use the default allocator; it uses the original allocator.
//
S copied = ss.str();
assert(copied.get_allocator().resource() == &mr1);
assert(ss.rdbuf()->get_allocator().resource() == &mr1);
assert(copied == initial);
// [stringbuf.members]/10 doesn't specify the allocator to use,
// but copying the allocator as-if-by moving the string makes sense.
//
S moved = std::move(ss).str();
assert(moved.get_allocator().resource() == &mr1);
assert(ss.rdbuf()->get_allocator().resource() == &mr1);
assert(moved == initial);
}
}
int main(int, char**) {
test_soccc_behavior<char>();
test_allocation_is_pilfered<char>();
test_no_foreign_allocations<char>();
#ifndef TEST_HAS_NO_WIDE_CHARACTERS
test_soccc_behavior<wchar_t>();
test_allocation_is_pilfered<wchar_t>();
test_no_foreign_allocations<wchar_t>();
#endif
return 0;
}
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