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LZW compression: Difference between revisions

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LZW compression (view source)

Revision as of 13:54, 3 June 2021

11,049 bytes added ,  2 years ago
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→‎{{header|Phix}}: added syntax colouring the hard way
m (→‎{{header|Phix}}: added syntax colouring the hard way)
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=={{header|Phix}}==
{{trans|Lua}}
<!--<lang Phix>function compress(string uncompressedphixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
integer dict = new_dict()
<span style="color: #008080;">function</span> <span style="color: #000000;">compress</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">uncompressed</span><span style="color: #0000FF;">)</span>
sequence result = {}
<span style="color: #004080;">integer</span> <span style="color: #000000;">dict</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">new_dict</span><span style="color: #0000FF;">()</span>
integer dictSize = 255, c
<span style="color: #004080;">sequence</span> <span style="color: #000000;">result</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>
string word = ""
<span style="color: #004080;">integer</span> <span style="color: #000000;">dictSize</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">255</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">c</span>
for i=0 to 255 do
<span style="color: #004080;">string</span> <span style="color: #000000;">word</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">""</span>
setd(""&i,i,dict)
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">to</span> <span style="color: #000000;">255</span> <span style="color: #008080;">do</span>
end for
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">""</span><span style="color: #0000FF;">&</span><span style="color: #000000;">i</span><span style="color: #0000FF;">,</span><span style="color: #000000;">i</span><span style="color: #0000FF;">,</span><span style="color: #000000;">dict</span><span style="color: #0000FF;">)</span>
for i=1 to length(uncompressed) do
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
c = uncompressed[i]
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">uncompressed</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
if getd_index(word&c,dict) then
<span style="color: #000000;">c</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">uncompressed</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span>
word &= c
<span style="color: #008080;">if</span> <span style="color: #7060A8;">getd_index</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">&</span><span style="color: #000000;">c</span><span style="color: #0000FF;">,</span><span style="color: #000000;">dict</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span>
else
<span style="color: #000000;">word</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">c</span>
result &= getd(word,dict)
<span dictSize +style="color: 1#008080;">else</span>
<span style="color: #000000;">result</span> <span style="color: #0000FF;">&=</span> <span style="color: #7060A8;">getd</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">,</span><span style="color: #000000;">dict</span><span style="color: #0000FF;">)</span>
setd(word&c,dictSize,dict)
<span style="color: #000000;">dictSize</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
word = ""&c
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">&</span><span style="color: #000000;">c</span><span style="color: #0000FF;">,</span><span style="color: #000000;">dictSize</span><span style="color: #0000FF;">,</span><span style="color: #000000;">dict</span><span style="color: #0000FF;">)</span>
end if
<span style="color: #000000;">word</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">""</span><span style="color: #0000FF;">&</span><span style="color: #000000;">c</span>
end for
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
if word!="" then
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
result &= getd(word,dict)
<span style="color: #008080;">if</span> <span style="color: #000000;">word</span><span style="color: #0000FF;">!=</span><span style="color: #008000;">""</span> <span style="color: #008080;">then</span>
end if
<span style="color: #000000;">result</span> <span style="color: #0000FF;">&=</span> <span style="color: #7060A8;">getd</span><span style="color: #0000FF;">(</span><span style="color: #000000;">word</span><span style="color: #0000FF;">,</span><span style="color: #000000;">dict</span><span style="color: #0000FF;">)</span>
destroy_dict(dict)
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
return result
<span style="color: #7060A8;">destroy_dict</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dict</span><span style="color: #0000FF;">)</span>
end function
<span style="color: #008080;">return</span> <span style="color: #000000;">result</span>
 
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
function decompress(sequence compressed)
integer dict = new_dict()
<span style="color: #008080;">function</span> <span style="color: #000000;">decompress</span><span style="color: #0000FF;">(</span><span style="color: #004080;">sequence</span> <span style="color: #000000;">compressed</span><span style="color: #0000FF;">)</span>
integer dictSize = 255, k, ki
<span style="color: #004080;">integer</span> <span style="color: #000000;">dict</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">new_dict</span><span style="color: #0000FF;">()</span>
string dent = "", result = "", word = ""
<span style="color: #004080;">integer</span> <span style="color: #000000;">dictSize</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">255</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">k</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">ki</span>
for i=0 to 255 do
<span style="color: #004080;">string</span> <span style="color: #000000;">dent</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">""</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">result</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">""</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">word</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">""</span>
setd(i,""&i,dict)
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">to</span> <span style="color: #000000;">255</span> <span style="color: #008080;">do</span>
end for
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">,</span><span style="color: #008000;">""</span><span style="color: #0000FF;">&</span><span style="color: #000000;">i</span><span style="color: #0000FF;">,</span><span style="color: #000000;">dict</span><span style="color: #0000FF;">)</span>
for i=1 to length(compressed) do
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
k = compressed[i]
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">compressed</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
ki = getd_index(k,dict)
<span style="color: #000000;">k</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">compressed</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span>
if ki then
<span style="color: #000000;">ki</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">getd_index</span><span style="color: #0000FF;">(</span><span style="color: #000000;">k</span><span style="color: #0000FF;">,</span><span style="color: #000000;">dict</span><span style="color: #0000FF;">)</span>
dent = getd_by_index(ki,dict)
<span style="color: #008080;">if</span> <span style="color: #000000;">ki</span> <span style="color: #008080;">then</span>
elsif k=dictSize then
<span style="color: #000000;">dent</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">getd_by_index</span><span style="color: #0000FF;">(</span><span style="color: #000000;">ki</span><span style="color: #0000FF;">,</span><span style="color: #000000;">dict</span><span style="color: #0000FF;">)</span>
dent = word&word[1]
<span style="color: #008080;">elsif</span> <span style="color: #000000;">k</span><span style="color: #0000FF;">=</span><span style="color: #000000;">dictSize</span> <span style="color: #008080;">then</span>
else
<span style="color: #000000;">dent</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">word</span><span style="color: #0000FF;">&</span><span style="color: #000000;">word</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span>
return {NULL,i}
<span style="color: #008080;">else</span>
end if
<span style="color: #008080;">return</span> <span style="color: #0000FF;">{</span><span style="color: #004600;">NULL</span><span style="color: #0000FF;">,</span><span style="color: #000000;">i</span><span style="color: #0000FF;">}</span>
result &= dent
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
setd(dictSize,word&dent[1],dict)
<span style="color: #000000;">result</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">dent</span>
dictSize += 1
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dictSize</span><span style="color: #0000FF;">,</span><span style="color: #000000;">word</span><span style="color: #0000FF;">&</span><span style="color: #000000;">dent</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">],</span><span style="color: #000000;">dict</span><span style="color: #0000FF;">)</span>
word = dent
<span style="color: #000000;">dictSize</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
end for
<span style="color: #000000;">word</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">dent</span>
destroy_dict(dict)
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
return result
<span style="color: #7060A8;">destroy_dict</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dict</span><span style="color: #0000FF;">)</span>
end function
<span style="color: #008080;">return</span> <span style="color: #000000;">result</span>
 
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
constant example = "TOBEORNOTTOBEORTOBEORNOT"
sequence com = compress(example)
<span style="color: #008080;">constant</span> <span style="color: #000000;">example</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">"TOBEORNOTTOBEORTOBEORNOT"</span>
--?com
<span style="color: #004080;">sequence</span> <span style="color: #000000;">com</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">compress</span><span style="color: #0000FF;">(</span><span style="color: #000000;">example</span><span style="color: #0000FF;">)</span>
pp(com)
<span style="color: #7060A8;">pp</span><span style="color: #0000FF;">(</span><span style="color: #000000;">com</span><span style="color: #0000FF;">,{</span><span style="color: #004600;">pp_IntCh</span><span style="color: #0000FF;">,</span><span style="color: #004600;">true</span><span style="color: #0000FF;">,</span><span style="color: #004600;">pp_Maxlen</span><span style="color: #0000FF;">,</span><span style="color: #000000;">90</span><span style="color: #0000FF;">})</span>
?decompress(com)
<span style="color: #0000FF;">?</span><span style="color: #000000;">decompress</span><span style="color: #0000FF;">(</span><span style="color: #000000;">com</span><span style="color: #0000FF;">)</span>
</lang>
<!--</lang>-->
{{out}}
<pre>
Petelomax
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