static internal string GetParameter (string header, string attr)
{
int ap = header.IndexOf (attr);
if (ap == -1)
return null;
ap += attr.Length;
if (ap >= header.Length)
return null;
char ending = header [ap];
if (ending != '"')
ending = ' ';
int end = header.IndexOf (ending, ap+1);
if (end == -1)
return (ending == '"') ? null : header.Substring (ap);
return header.Substring (ap+1, end-ap-1);
}