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* [gcc r12-6829] libstdc++: Fix std::spanstream move assignment [PR104032]
@ 2022-01-23 22:49 Jonathan Wakely
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From: Jonathan Wakely @ 2022-01-23 22:49 UTC (permalink / raw)
To: gcc-cvs, libstdc++-cvs
https://gcc.gnu.org/g:51631875a2fa0af62ebda7484ac48368e1805dff
commit r12-6829-g51631875a2fa0af62ebda7484ac48368e1805dff
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Sun Jan 23 21:55:57 2022 +0000
libstdc++: Fix std::spanstream move assignment [PR104032]
libstdc++-v3/ChangeLog:
PR libstdc++/104032
* include/std/spanstream (basic_spanbuf(basic_spanbuf&&)): Use
mem-initializer for _M_buf.
(basic_spanbuf::Operator=(basic_spanbuf&&)): Fix ill-formed
member access.
* testsuite/27_io/spanstream/2.cc: New test.
Diff:
---
libstdc++-v3/include/std/spanstream | 15 +++-
libstdc++-v3/testsuite/27_io/spanstream/2.cc | 113 +++++++++++++++++++++++++++
2 files changed, 124 insertions(+), 4 deletions(-)
diff --git a/libstdc++-v3/include/std/spanstream b/libstdc++-v3/include/std/spanstream
index 240866ff26f..000bda52a1e 100644
--- a/libstdc++-v3/include/std/spanstream
+++ b/libstdc++-v3/include/std/spanstream
@@ -75,10 +75,17 @@ template<typename _CharT, typename _Traits = char_traits<_CharT>>
basic_spanbuf(const basic_spanbuf&) = delete;
- /// Move constructor. In this implementation `rhs` is left unchanged.
+ /** Move constructor.
+ *
+ * Transfers the buffer and pointers into the get and put areas from
+ * `__rhs` to `*this`.
+ *
+ * In this implementation `rhs` is left unchanged,
+ * but that is not guaranteed by the standard.
+ */
basic_spanbuf(basic_spanbuf&& __rhs)
- : __streambuf_type(__rhs), _M_mode(__rhs._M_mode)
- { span(__rhs._M_buf); }
+ : __streambuf_type(__rhs), _M_mode(__rhs._M_mode), _M_buf(__rhs._M_buf)
+ { }
// [spanbuf.assign], assignment and swap
basic_spanbuf& operator=(const basic_spanbuf&) = delete;
@@ -86,7 +93,7 @@ template<typename _CharT, typename _Traits = char_traits<_CharT>>
basic_spanbuf&
operator=(basic_spanbuf&& __rhs)
{
- basic_spanbuf(std::move(__rhs))->swap(*this);
+ basic_spanbuf(std::move(__rhs)).swap(*this);
return *this;
}
diff --git a/libstdc++-v3/testsuite/27_io/spanstream/2.cc b/libstdc++-v3/testsuite/27_io/spanstream/2.cc
new file mode 100644
index 00000000000..a13a50b0dce
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/spanstream/2.cc
@@ -0,0 +1,113 @@
+// { dg-options "-std=gnu++23" }
+// { dg-do run { target c++23 } }
+
+#include <spanstream>
+#include <testsuite_hooks.h>
+
+using std::ispanstream;
+using std::ospanstream;
+using std::span;
+
+void
+test_move()
+{
+ char c;
+ {
+ const char str[] = "chars";
+ std::ispanstream a(str);
+ std::ispanstream b = std::move(a);
+ VERIFY( b.span().data() == str && b.span().size() == 6 );
+ VERIFY( b >> c );
+ VERIFY( c == 'c' );
+
+ a = std::move(b);
+ VERIFY( a.span().data() == str && a.span().size() == 6 );
+ VERIFY( a >> c >> c );
+ VERIFY( c == 'a' );
+ }
+
+ {
+ char buf[10] = {};
+ std::ospanstream a(buf);
+ std::ospanstream b = std::move(a);
+ VERIFY( b << 'c' );
+ VERIFY( buf[0] == 'c' );
+ VERIFY( !std::char_traits<char>::compare(buf, "c", 2) );
+
+ a = std::move(b);
+ VERIFY( a << 'h' << 'a' << "rs" );
+ VERIFY( !std::char_traits<char>::compare(buf, "chars", 6) );
+ }
+
+ {
+ char buf[10] = {};
+ std::spanstream a(buf);
+ std::spanstream b = std::move(a);
+ VERIFY( b.span().empty() );
+ VERIFY( b << 'c' );
+ VERIFY( buf[0] == 'c' );
+ VERIFY( !std::char_traits<char>::compare(buf, "c", 2) );
+ VERIFY( b.span().data() == buf && b.span().size() == 1 );
+ VERIFY( b >> c );
+ VERIFY( c == 'c' );
+
+ a = std::move(b);
+ VERIFY( a.span().data() == buf && a.span().size() == 1 );
+ VERIFY( a << 'h' << 'a' << "rs" );
+ VERIFY( !std::char_traits<char>::compare(buf, "chars", 6) );
+ VERIFY( a.span().data() == buf && a.span().size() == 5 );
+ }
+}
+
+void
+test_swap()
+{
+ {
+ const char str1[] = "chars";
+ const char str2[] = "STRING";
+ std::ispanstream a(str1);
+ std::ispanstream b(str2);
+ a.swap(b);
+ VERIFY( a.span().data() == str2 && a.span().size() == 7 );
+ VERIFY( b.span().data() == str1 && b.span().size() == 6 );
+ char c;
+ VERIFY( a >> c );
+ VERIFY( c == 'S' );
+ VERIFY( b >> c );
+ VERIFY( c == 'c' );
+
+ swap(a, b);
+ VERIFY( a.span().data() == str1 && a.span().size() == 6 );
+ VERIFY( b.span().data() == str2 && b.span().size() == 7 );
+ VERIFY( a >> c >> c );
+ VERIFY( c == 'a' );
+ VERIFY( b >> c >> c );
+ VERIFY( c == 'R' );
+ }
+
+ {
+ char buf1[] = "xxxxxxxxxxxxxxx";
+ char buf2[] = "xxxxxxxxxxxxxxx";
+ std::ospanstream a(buf1);
+ std::ospanstream b(buf2);
+ a.swap(b);
+ VERIFY( a << "STR" );
+ VERIFY( !std::char_traits<char>::compare(buf2, "STRx", 4) );
+ VERIFY( b << 'c' << 'h' );
+ VERIFY( !std::char_traits<char>::compare(buf1, "chx", 3) );
+
+ swap(a, b);
+ VERIFY( a.span().size() == 2 );
+ VERIFY( b.span().size() == 3 );
+ VERIFY( a << 'a' << "rs" );
+ VERIFY( !std::char_traits<char>::compare(buf1, "charsx", 6) );
+ VERIFY( b << "IN" << 'G' );
+ VERIFY( !std::char_traits<char>::compare(buf2, "STRINGx", 7) );
+ }
+}
+
+int main()
+{
+ test_move();
+ test_swap();
+}
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