option base 0

'un-REM whichever of the following you want to play with

'plaintext$ = "A B C D E G H I J K L M N O P Q R S T U V W X Y Z"
'plaintext$ = "ABCDEGHIJKLMNOPQRSTUVWXYZ"
'plaintext$ = "TOBEORNOTTOBEORTOBEORNOT"
'plaintext$ = "TTOBEORNOTTOBEORTOBEORNOTTOBEORNOTTOBEORTOBEORNOTTOBEORNOTTOBEORTOBEORNOTTOBEORNOTTOBEORTOBEORNOTTOBEORNOTTOBEORTOBEORN OT"
plaintext$ = "following may not be necessary due to wifi for above construct mains outlets, power shelf and G8 lightning string (12VDC beefy PSU)"
'plaintext$ = "a can opener can open anything a can opener can but if it can't open anything a can opener can it can't be called a can opener can it?"

zipped$ = encodeLZW$(plaintext$)

? len(plaintext$), len(zipped$)
?


end

FOR i% = 1 TO LEN(zipped$) 'STEP 2
PRINT ASC(MID$(zipped$,i%)); '+ 256*ASC(MID$(encodeLZW$,i%+1)) " " ;
NEXT

'end

'? zipped$

'? FNdecodeLZW(zipped$)


Function encodeLZW$(ii$)
local integer newindex, d, slicesize, freeptr
local string o$, sliceword$
Local string dict$(4095) length 8
FOR d = 0 TO 255 : dict$(d) = CHR$(d) : NEXT
freeptr = d 'first free place in the dictionary is 256
slicesize = 1
sliceword$ = LEFT$(ii$,1)
do
d = 0
do
newindex = d
IF slicesize > LEN(ii$) THEN EXIT
FOR d = 1 TO freeptr-1
IF sliceword$ = dict$(d) THEN EXIT FOR
NEXT
IF d < freeptr Then
slicesize =slicesize+ 1
sliceword$ =sliceword$+ MID$(ii$, slicesize, 1)
EndIf
loop UNTIL d >= freeptr
? freeptr,"!"+sliceword$+"!"
dict$(freeptr) = sliceword$
freeptr =freeptr+ 1
sliceword$ = RIGHT$(sliceword$, 1)
o$ =o$+ CHR$(newindex MOD 256) + CHR$(newindex \ 256)
loop UNTIL slicesize >= LEN(ii$)
encodeLZW$= o$
memory
End Function

'I have not worked on this part at all beyond obvious syntax translation
Function decodeLZW$(ii$)
local integer c, i, l
local string o$, t$, w$
local string dict$(4095) length 4
FOR i = 0 TO 255 : dict$(i) = CHR$(i) : NEXT i
l = i
c = ASC(ii$) + 256*ASC(MID$(ii$,2))
w$ = dict$(c)
o$ = w$
IF LEN(i$) < 4 THEN decodeLZW$= o$:Exit Function
FOR i = 3 TO LEN(i$) STEP 2
c = ASC(MID$(ii$,i)) + 256*ASC(MID$(ii$,i+1))
IF c < l Then
t$ = dict$(c)
ELSE
t$ = w$ + LEFT$(w$,1)
EndIf
o$ =o$+ t$
dict$(l) = w$ + LEFT$(t$,1)
l =l+ 1
w$ = t$
NEXT
decodeLZW$= o$
End Function