INDEXING...

 BBS: Inland Empire Archive
Date: 04-13-92 (14:57)             Number: 154
From: DOUGLAS LUSHER               Refer#: NONE
  To: ASA ROSSOFF                   Recvd: NO  
Subj: INDEXING...                    Conf: (2) Quik_Bas

On 04-07-92 at 10:15:10, ASA ROSSOFF wrote:

>I wrote a program to display quotes from a file.... But
>it's very slow the
>first time it's run, because it creates an index file... I
>see programs written
>in other languages creating similar index files in
>seconds, while my program
>takes about 20 minutes.... (for a 360k quote file)
>
>Here's my code to create the index file... any ideas or
>suggestions would be
>GREATLY appreciated...
>
>COOKIE.TXT is simply a text file, and a blank line
>designates the beginning of
>a new cookie...
>
...a *bunch* of code follows...

Asa, I'm not positive I know what you're doing here, but if
you're doing
what I think you're doing, you're sure doing it the hard
way. I would
suggest that you get your QuickBASIC manual and check out
the SEEK function
and statement. If I understand you correctly, you're
writing an index file
that is a list of long integer pointers that point to the
beginning of the
records in your COOKIE.TXT file. If that is the case, you
can accomplish
the same thing much easier and faster as follows:

'''

DIM RecordPointer&

BufferLength% = 2 ^ 12   'set this even higher if you can,
the more the better
OPEN "cookie.idx" FOR RANDOM ACCESS WRITE LOCK READ WRITE
AS #1_
     LEN = LEN(RecordPointer&)

OPEN "cookie.txt" FOR INPUT AS #2 LEN = BufferLength%

RecordPointer& = 1

PUT #1, , RecordPointer&        'assume first record starts
at the beginning
DO UNTIL EOF(2)

  LINE INPUT #2, L$

  IF LEN(L$) = 0 THEN            'a blank line means the
end of the record
    IF NOT EOF(2) THEN           'but we're not at the end
of the file
      RecordPointer& = SEEK(2)    'SEEK() returns the next
position in the file
      PUT #1, , RecordPointer&    'so save it in the index
file
    END IF

  END IF

LOOP

CLOSE 1, 2

****

*note* I have not tested the above code, but I think it
will work.
Now, to get at any particular record:

OPEN "cookie.idx" FOR RANDOM AS #1 LEN =
LEN(RecordPointer&)
GET #1, DesiredRecordNumber%, RecordPointer&

CLOSE 1

OPEN "cookie.txt" FOR INPUT AS #2 LEN = BufferLength%

SEEK #2, RecordPointer&    'point to the record with the
SEEK statement
DO

  LINE INPUT #2, L$        'grab the record

  PRINT L$

LOOP UNTIL LEN(L$) = 0     'keep grabbing until you hit a
blank line
CLOSE 2

*****


*if this is what you are attempting to do, then this should
be much
simpler and faster, 'though there are some ways this could
be speeded
up still more, I've just given you this much so make clear
the usefulness
of SEEK() and SEEK.

If this is not what you are trying to do just ignore me!

Best regards,

Doug


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