;***********************************************************************
; CLRAND - CLEARs a RANDOM FILE
;
; by Dave Heyliger - AMUS Staff
;
; Usage: L OPR:
; CLRAND {filespec}
;
; Purpose: great after you use CREATE and you want the file clean
;***********************************************************************
SEARCH SYS ;search the regulars
SEARCH SYSSYM
SEARCH TRM
PHDR -1,0,PH$REE!PH$REU!PH$OPR ;must be in OPR: (note PH$OPR)
.OFINI
.OFDEF IDDB,D.DDB ;DDB for the file
.OFSIZ IMPSIZ
;get the inpure space
GETIMP IMPSIZ,A3 ;A3 points to varibles
;process input line
BYP ;bypass bs
LIN ;just a CR?
BNE INOK
TYPECR <Usage: CLRAND {filespec}, where filespec is a random file.>
TYPECR < (default extension is .DAT)>
EXIT
;looks good, see if random file
INOK: LEA A1,IDDB(A3) ;point to DDB
FSPEC @A1,DAT ;create filename in DDB
INIT @A1 ;initialize
LOOKUP @A1 ;find the file
BNE NOFILE ;nope - error
CMPW IDDB+D.WRK+6(A3),#-1 ;random file?
BEQ AOK ;yup, continue
TYPE <?> ;nope, start error msg
PFILE @A1 ;type out filename
TYPECR < is not a random file.> ;and rest of message
EXIT ;then quit
NOFILE: TYPECR <?This file does not exist.> ;couldn't find the puppy
EXIT ;so quit
;double check the users intentions
AOK: CRLF
TYPE <You are about to zero out all data in this file. Enter Y to confirm: >
KBD
CTRLC END ;quit on ^C
CMPB @A2,#'Y ;yes?
JNE END ;nope
;now get the number of blocks and clear each one
MOVW IDDB+D.WRK+2(A3),D2 ;D2 holds the number of blocks
OPENR @A1 ;open the file
READIT: READ @A1 ;get a block
LOOP: MOV #128.,D3 ;number of longword clears
MOV IDDB+D.BUF(A3),A4 ;A4 points to block
10$: CLR (A4)+ ;zero it out
DEC D3 ;one less to do
BNE 10$ ;still more to do
WRITE @A1 ;write the block
DECW D2 ;one less block to do
BEQ END ;if zero, we are done
INCW IDDB+D.REC+2(A3) ;point to next block
BR READIT ;and go read it and clear it
