[Doxygen-develop] Memory underrun in util.cpp:5584

[Michael M. <Mic...@tt...>]

Hi there,

I took the doxygen-1.4.4-20050815.tar.gz CVS tarball and ran it under
valgrind.  I found a byte being accessed before the start of a buffer:

  // search for trailing empty lines
  int b=l-1,bi=-1;
  p=s.data()+b;
  while (b>=0)
  {
    c=*--p;  <------ Can read before s.data
    if (c==' ' || c=='\t' || c=='\r') b--;
    else if (c=='\n') bi=b,b--;
    else break;
  }

I think the problem is that --p occurs before the dereference, and so the
code would be better written as:

  while (b>=0)
  {
    c=*p; 
    p--;
    if (c==' ' || c=='\t' || c=='\r') b--;

This avoids p[-1] being accessed if something like "\n" is in the buffer.

I've not put it into Bugzilla, but let me know if you would prefer it filed
there instead.

Regards,

Mike