CodeSnip Old Code (SVN)

* Rationalised use of TStringStream with relation to the required encoding when Unicode enabled.
* Replaced calls to TStringStreamEx with calls to TStringStream with TEncoding.Unicode passed to constructor.
* Removed TStringStreamEx from UUnicodeHelper and re-organised code somewhat.

Modified non-Unicode implementation of IsWhiteSpace in UUnicodeHelper.pas to test for white space characters defined in UConsts unit.

Added support for ASCII string type to UUnicodeHelper.pas: code page constant, string type and conversion routines.

* Extended TLatin1Encoding class with a class property the provides a singleton instance.
* Added Latin1Encoding encoding function that provide alternative access to TLatin1Encoding singleton.
* Removed unused IsLatin1Char function.
* Reimplemented ANSI version of ASCIIBytesOf function to replace non-ASCII chars with '?' character.
* Documented the UUnicodeHelper.pas unit.

* Changed TUserDBBackup.Backup to convert string for which checksum is required to Latin1 bytes using Latin1Bytes from UUnicodeHelper.pas rather than BytesOf.
* Removed Ansi compiler only implementation of BytesOf from public section of UUnicodeHelper.pas and renamed implementation as AnsiStringBytesOf for internal use only.

Added routines to UUnicodeHelper unit to safely convert a string to a Latin-1 encoded AnsiString and to check if a character is Latin-1.

* Changed character set testing code in several units to use char set helper functions added to UUnicodeHelper.pas instead of testing directly against literal or constant sets. This prevents Delphi 2010 warnings about WideChar being reduced to byte char in set expressions.
* Changed use of UpCase built-in to use ToUpperCase function added to UUnicodeHelper.pas.
* Added various set handling routines along with ToUpperCase function. These mainly call TCharacter methods on Unicode Delphis and have custom implementations on other Delphis.

Modified TAppInfo.GenerateKey to be Unicode compatible: now uses new ASCIIBytesOf routine (added to UUnicodeHelper unit) to ensure program key contains only ASCII characters.

* Added support for Latin1 code page: string definition, code page constant, custom encoding class and Latin1BytesOf helper function.
* Defined TBytes for non-Unicode Delphis.
* Provided BytesOf function for non-Unicode Delphis.

* Added new UUnicodeHelper unit that contains code designed to aid porting to Unicode.
* Initially new unit contains only the TStringStreamEx class.