[fpc-devel] Unicodestring branch, please test and help fixing

[Graeme Geldenhuys]

On 9/10/08, Marco van de Voort <marcov at stack.nl> wrote:
>
> Like everybody, I have read GOF several times, and even got some of the
>  successor books.

I don't think anybody has read GOF only once.  :-)


>  The problem is how it applies to strings, and how they can be more
>  memory saving than a straight array of 16-bit values which are
>  copy-on-write.

I think for a good code example of this, have a look at Java's
Document class. It's not exactly what I'm talking about, but it's got
the idea. The Document class forms the basic storing medium of all
their text based components - from a simple TextEdit, TextArea to
complex rich text documents. So it scales well.

Each character can have individual characteristics set. Storage down
to character level. Similar to what I am suggesting with the Flyweight
pattern - characters of a string with encoding information.

The Document class also uses an internal gapped buffer implementation
to store it's content - apparently good for performance.  Again
something like this could be used in the "character pool" manager
object - though I'm not 100% sure.


Please note, this is just a thought. I haven't written any Object
Pascal code implementing something like this - to prove the concept. I
simply know the Flyweight pattern and it seems to be a possible
option.

Remember, Unicode support is much more that simply storing and
displaying text. You have various encodings, RTL or LTR direction etc.
 I can't see how a simple type can keep track of all such information
- but then, I don't know the internals of FPC either.  ;-)

Regards,
  - Graeme -


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