'" Comp ,  Compare Two Files
'" P. Kittel, CBM Ffm, Start 11.01.87, 24.02.87

PRINT "Comp  -  Compare Two Files.":PRINT 
PRINT "Filename 1 ?":LINE INPUT f1$:PRINT 
PRINT "Filename 2 ?":LINE INPUT f2$
PRINT 
PRINT "Show contents (mark differences) (y/n) ? ";
a$="":WHILE a$<>"y" AND a$<>"n":a$=INKEY$:WEND
fi=a$="y":PRINT a$:PRINT 

PRINT "Abort process with q key, pause with any.":PRINT 

OPEN f1$ FOR INPUT AS 1:l1=LOF(1)
OPEN f2$ FOR INPUT AS 2:l2=LOF(2)
fuu=0:IF l1<>l2 THEN PRINT :PRINT "Files unequal, different in length!":PRINT :fuu=-1
   
n=1000:n1=0:n2=0:fu=0:m=0:m1$="":m2$="":mn=0
WHILE n1<l1 AND (fu=0 OR fi) AND a$<>"q" '" loop for file 1
  a$=INKEY$:IF a$<>"" THEN GOSUB taste   '" pause or abort?
  IF n1+n>l1 THEN n=l1-n1
  i1$=INPUT$(n,1)  '" read from files
  IF n2+n>l2 THEN
    IF n2<l2 THEN i2$=INPUT$(l2-n2,2) :ELSE i2$=""
             ELSE
    i2$=INPUT$(n,2)
    END IF
  n3=n1:n1=n1+n:n2=n2+n
  IF fi THEN                      '" show contents as hexdump
    FOR j=1 TO LEN(i1$)
      IF m>15 THEN GOSUB inhalt
      m1$=m1$+MID$(i1$,j,1)
      m2$=m2$+MID$(i2$,j,1)
      m  =m+1
      NEXT
    END IF
      
  IF i1$<>i2$ AND fu=0 THEN      '" tell when unequal
    i=1
    FOR j=1 TO LEN(i1$)
      IF MID$(i1$,j,1)<>MID$(i2$,j,1) THEN i=j:j=1e+09
      NEXT
    PRINT "Files unequal from byte";i+n3
    fu=-1
    END IF
  WEND
IF fi THEN IF m>0 THEN GOSUB inhalt  '" show rest of contents
  
IF fu=0 AND fuu=0 THEN PRINT :PRINT "Files equal." :ELSE PRINT :PRINT "Files unequal."
CLOSE 1:CLOSE 2
END

inhalt:   '" subroutine for hexdump
a$=INKEY$:IF a$<>"" THEN GOSUB taste
PRINT RIGHT$("000"+HEX$(mn),4);" ";  '" address in file
FOR jj=1 TO LEN(m1$)                 '" loop for one line
  j1$=MID$(m1$,jj,1):j2$=MID$(m2$,jj,1)
  IF j1$<>j2$ THEN COLOR 3  '" mark differences by color
  PRINT RIGHT$("0"+HEX$(ASC(j1$)),2);" ";  '" single byte in hex
  COLOR 1
  NEXT
PRINT SPC(2+3*(16-LEN(m1$)));        '" show also as character on the right
FOR jj=1 TO LEN(m1$)
  j1=ASC(MID$(m1$,jj,1))
  IF j1<32 THEN
    COLOR 2:PRINT CHR$(j1+64);:COLOR 1  '" mark control chars by color
           ELSE
    PRINT CHR$(j1);
    END IF
  NEXT
PRINT 
mn=mn+LEN(m1$):m1$="":m2$="":m=0
RETURN

taste:  '" subroutine for pause by key pressed
IF a$<>"q" THEN a$="":WHILE a$="":a$=INKEY$:WEND '" wait for next key
IF a$="q" THEN  '" q key for end of program
  IF fu=0 AND fuu=0 THEN PRINT :PRINT "Files equal." :ELSE PRINT :PRINT "Files unequal."
  CLOSE 1:CLOSE 2
  END
  END IF
RETURN