Ola!
Se não me falha a memória, era um projeto do Minguel, ai o Przemek "meteu o pau" dizendo que era copia dos projetos dele. Isso no xHarbour.
No harbour ele então recriou. Esse Miguel sumiu no mapa, nunca mais li/vi commits dele no [XHarbour].
2010-11-25 02:28 UTC+0100 Przemyslaw Czerpak (druzus/at/priv.onet.pl)
+ harbour/contrib/rddbmcdx
+ harbour/contrib/rddbmcdx/rddbmcdx.hbp
+ harbour/contrib/rddbmcdx/rddbmcdx.hbc
+ harbour/contrib/rddbmcdx/bmdbfcdx.c
+ added new alternative BMDBFCDX implementation which respects RDD
inheritance scheme and gives similar functionality and PRG functions
as modified by Miguel Angel Marchuet <miguelangel@marchuet.net> DBFCDX
with directly hardcoded bitmap filters.
This code is completely new implementation and does not contain
any code created by Miguel.
This RDD inherits from DBFCDX so it's called BMDBFCDX anyhow
it can inherit from any other RDDs so if users are interesting
I can add also BMDBFNTX and BMDBFNSX.
I haven't time of any deeper tests so please make them.
BMDBFCDX works as clipper 5.3b filter on SET OPTIMIZE ON
with pseudo static bitmap filter. after it's created all
functions as OrdKeyNo, OrdKeyCount, Skip, RecNo, ... are quicker
than dynamic filter
with SET OPTIMIZE OFF the filter is dynamic as DBFCDX, in this case really no filter
is created, each record is consulted for any function. for example if you ask OrdKeyCount()
it consumes the same time as the creation of the static filter. If you need to navigate
in browse with filter is always more quick SET OPTIMIZE ON and BMDBFCDX.
Best regards,
Miguel Angel Marchuet
É um RDD para DBF mais rápido. Só sei isso.
Mais coisas pode achar aqui neste link.
http://comp.lang.xharbour.narkive.com/1I6Q1F6N/advantage-of-bmdbfcdx-rdd