base64_table uses the sentinel 0xff for bytes outside the base64 alphabet.
The old code read that through (char), producing signed -1, which made the
three (c << N) expressions in Base64Decode undefined behaviour when the
input contained any invalid byte.
Keep c and c1 as unsigned char so the shifts are well-defined. Reachable
pre-auth via CHTTPSock::ReadLine for the Authorization: Basic value.
MarkLee131
026b88e2fa