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[PATCH] libstdc++/8466
- From: Paolo Carlini <pcarlini at unitus dot it>
- To: libstdc++ at gcc dot gnu dot org
- Cc: bkoz <bkoz at redhat dot com>
- Date: Tue, 05 Nov 2002 23:35:34 +0100
- Subject: [PATCH] libstdc++/8466
Hi,
the bug is due to the Copy On Write nature of v3 string: in
varios members of basic_stringbuf and basic_(i,o)stringstream
a string is simply considered as a buffer of chars.
Therefore
void
str(const __string_type& __s)
{
_M_string = __s;
_M_stringbuf_init(_M_mode);
}
which produces an _M_string having the Rep shared with __s
is very dangerous, since, as soon as the buffer (the Rep)
is directly modified, the original __s ends up being clobbered!
I have fixed this with a "low-level assignment" of __s
to _M_string:
void
str(const __string_type& __s)
{
_M_string.assign(__s.c_str(), __s.size());
_M_stringbuf_init(_M_mode);
}
Tested x86-linux.
Ok?
Ciao, Paolo.
//////////
2002-11-05 Paolo Carlini <pcarlini@unitus.it>
PR libstdc++/8466
* include/std/std_sstream.h
(basic_stringbuf::str(const __string_type&)):
Cannot use simple assignment since the COW-nature of v3
basic_string is not taken into account in basic_stringbuf.
* testsuite/27_io/stringstream_members.cc: Add test04 from PR.
diff -urN libstdc++-v3-orig/include/std/std_sstream.h libstdc++-v3/include/std/std_sstream.h
--- libstdc++-v3-orig/include/std/std_sstream.h 2002-03-06 22:22:55.000000000 +0100
+++ libstdc++-v3/include/std/std_sstream.h 2002-11-05 23:05:44.000000000 +0100
@@ -105,7 +105,8 @@
void
str(const __string_type& __s)
{
- _M_string = __s;
+ // Cannot use _M_string = __s, since v3 strings are COW.
+ _M_string.assign(__s.c_str(), __s.size());
_M_stringbuf_init(_M_mode);
}
diff -urN libstdc++-v3-orig/testsuite/27_io/stringstream_members.cc libstdc++-v3/testsuite/27_io/stringstream_members.cc
--- libstdc++-v3-orig/testsuite/27_io/stringstream_members.cc 2002-07-26 03:49:36.000000000 +0200
+++ libstdc++-v3/testsuite/27_io/stringstream_members.cc 2002-11-05 22:57:05.000000000 +0100
@@ -177,10 +177,26 @@
std::stringstream ss2(str3, std::ios_base::in|std::ios_base::out);
}
+// libstdc++/8466
+void test04()
+{
+ bool test = true;
+
+ const char* strlit00 = "orvieto";
+ const std::string str00 = strlit00;
+
+ std::ostringstream oss;
+
+ oss.str(str00);
+ oss << "cortona";
+ VERIFY( str00 == strlit00 );
+}
+
int main()
{
test01();
test02();
test03();
+ test04();
return 0;
}