MID$ function speed

 BBS: Inland Empire Archive
Date: 02-07-93 (06:37)             Number: 375
From: ROB FLOR                     Refer#: NONE
  To: ROB MCKEE                     Recvd: NO  
Subj: MID$ function speed            Conf: (2) Quik_Bas
RM>Hello Rob!
  >   You wrote in a message to Peter Tepperman:

RM>PT>  I'm writing a program that makes extensive use of the MID$ function.

RM> RF>    Its a fast way to replace strings of equal size, a slow
  > RF> way to    find the ascii value of characters in the middle
  > RF> of a string.

RM>What is the faster pure QB way of finding ASC values in the middle of the
  >string?  It sure would help me out..  Integer Array??


Take this apart...it's an old test piece from some instr$ and mid$
and asc(mid$,x) trials.  You should be able to adapt it to your needs.

 You can change it to a function that return single asc values given the
work$ and a position, or scan the length of a string as shown below.

It's comparable in speed with instr$ (fast) for finding the position of
a single character and much faster than ASC(MID$,Position%) for
returning the ascii value in position%.



defint a-z

OPEN "TEST" FOR INPUT AS 1
OPEN "TEST.OUT" FOR OUTPUT AS 2
SEARCH%=101
replace%=102

FOR R= 1 TO LOF(1) \4096

WORK$=INPUT$(4096,1)
DEF SEG=VARSEG(Work$)
S=SADD(WORK$)

FOR j = Position% TO LEN(work$)-1
X=PEEK(S+J)
IF X=SEARCH% THEN POKE S+J,REPLACE%
NEXT

PRINT #2,work$;
NEXT

YLEN=LOF(1) MOD 4096
Y$=INPUT$(YLEN,1)

DEF SEG=VARSEG(Y$)
S=SADD(Y$)

FOR j = Position% TO LEN(Y$)-1
X=PEEK(S+J)
IF X=SEARCH% THEN POKE S+J,REPLACE%
NEXT
PRINT #2,Y$;





Rob


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