RosettaCodeData/Task/LZW-compression/Arturo/lzw-compression.arturo

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compress: function [str][
dict: #[]
loop 0..255 'i -> dict\[to :char i]: i
w: ""
result: new []
loop str 'c [
wc: w ++ c
if? key? dict wc -> w: wc
else [
'result ++ dict\[w]
dict\[wc]: size dict
w: to :string c
]
]
if 0 < size w -> 'result ++ dict\[w]
return result
]
decompress: function [compressed][
dict: #[]
arr: new compressed
loop 0..255 'i -> dict\[i]: to :string to :char i
w: dict\[first arr]
remove 'arr .index 0
result: w
loop arr 'k [
entry: ""
if? key? dict k -> entry: dict\[k]
else [
if? k = size dict -> entry: w ++ first w
else -> panic ~"Error with compressed: |k|"
]
'result ++ entry
dict\[size dict]: w ++ first entry
w: entry
]
return result
]
compressed: compress "TOBEORNOTTOBEORTOBEORNOT"
print "Compressed:"
print compressed
print ""
decompressed: decompress compressed
print "Decompressed:"
print decompressed