[STDCXX-576] std::basic_streambuf<>::xsputn() incorrectly inserts the data, that is the part of the internal buffer

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.2.0
• Component/s: 27. Input/Output

Environment

All

• Patch Info: Patch Available
• Severity: Incorrect Behavior
• Assignee: Farid Zaripov
• Reporter: Farid Zaripov
• Created: 04/Oct/07 12:05
• Updated: 04/Oct/07 12:20
• Resolved: 04/Oct/07 12:19

Description

The test below aborts on assert.

test.cpp:
------------------
#include <sstream> // for stringbuf
#include <string> // for string
#include <cassert> // for assert()

struct PubBuf: std::stringbuf
{
char* Pbase () const

{ return this->pbase (); }

};

int main ()
{
// 512 is the default buffer size of the basic_stringbuf
std::string s (512, 'a');

std::stringbuf sbuf (s);
PubBuf& buf = (PubBuf&)sbuf;

std::streamsize res = buf.sputn (buf.Pbase (), 128);
s.append (s.begin (), s.begin () + 128);

const std::string& str = buf.str ();

assert (res == 128);
assert (str.size () == s.size ());
assert (str == s);

return 0;
}
------------------

The test output:
------------------
test: test.cpp:25: int main (): Assertion `str == s' failed.
Aborted
------------------