make stream operators leave variables in original state on failure

this aligns them with the behaviour of std::stream, and makes things
like

sal_uInt32 n(0);
rSt >> n;
if (n)
{
   ...
}

safe if there was a short read of e.g. 3 bytes instead of the required 4

1 files changed, 4 insertions, 1 deletions

diff --git a/tools/qa/cppunit/test_streamstate.cxx b/tools/qa/cppunit/test_streamstate.cxx
index c2a4be0c5e00..182ad6c45561 100644
--- a/tools/qa/cppunit/test_streamstate.cxx
+++ b/tools/qa/cppunit/test_streamstate.cxx
@@ -94,6 +94,9 @@ namespace
         //yet, the read didn't succeed
         CPPUNIT_ASSERT(!aMemStream.good());
 
+        //set things up so that there is only one byte available on an attempt
+        //to read a two-byte sal_uInt16.  The byte should be consumed, but the
+        //operation should fail, and tools_b should remain unchanged,
         sal_uInt16 tools_b = 0x1122;
         aMemStream.SeekRel(-1);
         CPPUNIT_ASSERT(!aMemStream.eof());
@@ -101,7 +104,7 @@ namespace
         aMemStream >> tools_b;
         CPPUNIT_ASSERT(!aMemStream.good());
         CPPUNIT_ASSERT(aMemStream.eof());
-//        CPPUNIT_ASSERT(tools_b == 0x1122); //nasty, real nasty
+        CPPUNIT_ASSERT(tools_b == 0x1122);
 
         iss.clear();
         iss.seekg(0);