#64 TryNum2Long/TryHex2Long/TryDec2Long return True for a number that does not fit into UInt32 and for an empty string

[Thomas Mueller]

TryNum2Long in u_dzConvertUtils (both the string and the AnsiString overload), and with it TryHex2Long and TryDec2Long, multiply up the digits in a UInt32 without checking for overflow:

• With overflow checks off, which is Delphi's default, a number that does not fit (e.g. TryHex2Long('100000000'), 9 hex digits, or TryDec2Long('4294967296')) wraps around, and the function returns True with a wrong value.
• In a program compiled with {$Q+} the same input raises EIntOverflow, so the Try function raises.

Also, an empty string returns True with the value 0.

Expected: False in all three cases. (The callers in u_dzGuidUtils check the lengths first and are not affected.)

[Thomas Mueller]

Fixed in revision #2470.

TryNum2Long, and with it TryHex2Long and TryDec2Long, now return False for an empty string and for a number that does not fit into UInt32, and Value is 0 then. The overflow is checked before multiplying, so they no longer raise EIntOverflow with {$Q+} either. The AnsiString overload now calls the string one. New tests in ConvertUtils.