Avoid dereferencing a pointer before the start of the buffer. This fixes bug 2963782.
Avoid dereferencing a pointer before the start of the buffer.
This fixes bug 2963782.

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb