When basic_stringbuf::setbuf has been called we need to copy the
contents of the buffer into _M_string first, before returning that.
libstdc++-v3/ChangeLog:
PR libstdc++/123100
* include/std/sstream (basic_stringbuf::str()&&): Handle the
case where _M_string is not being used for the buffer.
* testsuite/27_io/basic_stringbuf/str/char/123100.cc: New test.
---
Tested x86_64-linux.
libstdc++-v3/include/std/sstream | 9 ++-
.../27_io/basic_stringbuf/str/char/123100.cc | 58 +++++++++++++++++++
2 files changed, 64 insertions(+), 3 deletions(-)
create mode 100644
libstdc++-v3/testsuite/27_io/basic_stringbuf/str/char/123100.cc
diff --git a/libstdc++-v3/include/std/sstream b/libstdc++-v3/include/std/sstream
index 4a5c090f97ba..f036165909df 100644
--- a/libstdc++-v3/include/std/sstream
+++ b/libstdc++-v3/include/std/sstream
@@ -298,7 +298,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
#if __cplusplus > 201703L
#if _GLIBCXX_USE_CXX11_ABI
#if __cpp_concepts
- // P0407 Allocator-aware basic_streambuf
+ // P0407 Allocator-aware basic_streambuf
template<__allocator_like _SAlloc>
_GLIBCXX_NODISCARD
basic_string<_CharT, _Traits, _SAlloc>
@@ -315,8 +315,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
{
if (char_type* __hi = _M_high_mark())
{
- // Set length to end of character sequence and add null terminator.
- _M_string._M_set_length(_M_high_mark() - this->pbase());
+ if (_M_string.c_str() == this->pbase()) [[likely]]
+ // Set length to end of sequence and add null terminator.
+ _M_string._M_set_length(__hi - this->pbase());
+ else
+ _M_string.assign(this->pbase(), __hi);
}
auto __str = std::move(_M_string);
_M_string.clear();
diff --git a/libstdc++-v3/testsuite/27_io/basic_stringbuf/str/char/123100.cc
b/libstdc++-v3/testsuite/27_io/basic_stringbuf/str/char/123100.cc
new file mode 100644
index 000000000000..174fe0ece1d6
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_stringbuf/str/char/123100.cc
@@ -0,0 +1,58 @@
+// { dg-do run }
+
+#include <sstream>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+ const int n = 20;
+ const char data[n] = "abcde";
+ char buf[n] = "0123456789";
+ std::string expected("abcde56789\0\0\0\0\0\0\0\0\0\0", n);
+
+ std::ostringstream out;
+ out.rdbuf()->pubsetbuf(buf, n);
+ out << data;
+ VERIFY( out.str() == expected );
+ VERIFY( out.str() == expected );
+#if __cplusplus >= 201103L
+ VERIFY( std::move(out).str() == expected );
+#if __cplusplus >= 202002L && _GLIBCXX_USE_CXX11_ABI
+ expected.clear();
+#endif
+ VERIFY( out.str() == expected );
+ VERIFY( std::move(out).str() == expected );
+#endif
+}
+
+void
+test02()
+{
+ const int n = 20;
+ const char data[n] = "abcde";
+ char buf[n] = "0123456789";
+ std::string expected("abcde56789\0\0\0\0\0\0\0\0\0\0", n);
+
+ std::ostringstream out;
+ out << std::string(n * 2, 'a');
+ VERIFY( out.str() == std::string(n * 2, 'a') );
+ out.rdbuf()->pubsetbuf(buf, n);
+ out << data; // writes 6 chars
+ VERIFY( out.str() == expected );
+ VERIFY( out.str() == expected );
+#if __cplusplus >= 201103L
+ VERIFY( std::move(out).str() == expected );
+#if __cplusplus >= 202002L && _GLIBCXX_USE_CXX11_ABI
+ expected.clear();
+#endif
+ VERIFY( out.str() == expected );
+ VERIFY( std::move(out).str() == expected );
+#endif
+}
+
+int main()
+{
+ test01();
+ test02();
+}
--
2.52.0
