acliu@skat.usc.edu (Alex C. Liu) (12/10/89)
FILE: help unhexf.bas
LAST CHANGE: Dec 8th, 1989
VERSION: UX-Maze Server V2.0c
100 REM SIMPLE UNHEXIFY PROGRAM (UNTESTED)
110 REM BY ALEX C. LIU
111 REM NOTE THIS PROGRAM IS SIMPLY INTENDED AS AN EXAMPLE
112 REM ON HOW TO DECODE HEXF FILES
113 REM NO ATTEMPT HAS BEEN MADE TO VERIFY THE CORRECTNESS OF
114 REM THE CODE
115 REM
120 INPUT "ENTER SEQ FILE TO UNHEXIFY", F$
130 INPUT "ENTER DEFAULT OUT FILE TYPE", T$
140 OPEN 1,8,8,F$+",S,R"
150 GOSUB 1000
160 IF LEFT$(X$,5) = "HEXF " OR LEFT$(X$,5) = "hexf " THEN
170 Z$ = MID$(X$,6):C = 0
180 OPEN 2,8,9,Z$+","+T$+",W"
190 GOSUB 1000:C = C + 1
200 IF LEFT$(X$,3) = "END" OR LEFT$(X$,3) = "end" THEN 310
205 IF(LEFT$(X$,1)<>":")THEN PRINT"NO : ON LINE "C" (INGNORING LINE)":GOTO 300
210 H$ = MID$(X$,2,2)
220 GOSUB 2000
230 L=X: SUM = 0: IF NOT(L) THEN 280
240 FOR N=1 TO L
250 H$=MID$(X$,N*2 + 2,2):GOSUB 2000
260 SUM = SUM + X: PRINT#2,CHR$(X);
270 NEXT
280 H$=MID$(X$,L*2+4,2):GOSUB 2000
290 IF (X <> (SUM AND 255)) THEN PRINT "BAD CHECKSUM ON LINE "C
300 IF (SS = 0) THEN 190
310 CLOSE 1:CLOSE 2
320 END
1000 X$=""
1010 GET#1,U$: SS = ST: IF SS <> 0 THEN RETURN
1020 IF U$=CHR$(13) THEN RETURN
1030 X$=X$+U$:GOTO 1010
2000 MH$ = LEFT$(H$,1): GOSUB 3000: X = MX
2010 MH$ = RIGHT$(H$,1):GOSUB 3000: X = X * 16 + MX
2020 RETURN
3000 IF ("0" <= MH$ AND MH$ <= "9") THEN MX=VAL(MH$):RETURN
3010 IF ("A" <= MH$ AND MH$ <= "F") THEN MX=ASC(MH$)-ASC("A") + 15:RETURN
3020 IF ("a" <= MH$ AND MH$ <= "f") THEN MX=ASC(MH$)-ASC("a") + 15:RETURN
3030 PRINT "BAD HEX DIGIT "MH$"!"
3040 MX=0:RETURN
---
Alex C. Liu
acliu%skat@usc.edu acliu@skat.usc.edu
(Simple .signature, $CHEAP$)