LZW compression: Difference between revisions
→{{header|Objective-C}}
Line 1,592:
"TOBEORNOTTOBEORTOBEORNOT"</pre>
=={{header|Objeck}}==
<lang objeck>use Collection;
class LZW {
function : Main(args : String[]) ~ Nil {
compressed := Compress("TOBEORNOTTOBEORTOBEORNOT");
Show(compressed);
decompressed := Decompress(compressed);
decompressed->PrintLine();
}
function : native : Compress(uncompressed : String) ~ IntVector {
# Build the dictionary.
dictSize := 256;
dictionary := StringMap->New();
for (i := 0; i < 256; i+=1;) {
key := "";
key->Append(i->As(Char));
dictionary->Insert(key, IntHolder->New(i));
};
w := "";
result := IntVector->New();
each (i : uncompressed) {
c := uncompressed->Get(i);
wc := String->New(w);
wc->Append(c);
if (dictionary->Has(wc)) {
w := wc;
}
else {
value := dictionary->Find(w)->As(IntHolder);
result->AddBack(value->Get());
# Add wc to the dictionary.
dictionary->Insert(wc, IntHolder->New(dictSize));
dictSize+=1;
w := "";
w->Append(c);
};
};
# Output the code for w.
if (w->Size() > 0) {
value := dictionary->Find(w)->As(IntHolder);
result->AddBack(value->Get());
};
return result;
}
function : Decompress(compressed : IntVector) ~ String {
# Build the dictionary.
dictSize := 256;
dictionary := IntMap->New();
for (i := 0; i < 256; i+=1;) {
value := "";
value->Append(i->As(Char));
dictionary->Insert(i, value);
};
w := "";
found := compressed->Remove(0);
w->Append(found->As(Char));
result := String->New(w);
each (i : compressed) {
k := compressed->Get(i);
entry : String;
if (dictionary->Has(k)) {
entry := dictionary->Find(k);
}
else if (k = dictSize) {
entry := String->New(w);
entry->Append(w->Get(0));
}
else {
return "";
};
result->Append(entry);
# Add w+entry[0] to the dictionary.
value := String->New(w);
value->Append(entry->Get(0));
dictionary->Insert(dictSize, value);
dictSize+=1;
w := entry;
};
return result;
}
function : Show(results : IntVector) ~ Nil {
"["->Print();
each(i : results) {
results->Get(i)->Print();
if(i + 1 < results->Size()) {
", "->Print();
};
};
"]"->PrintLine();
}
}</lang>
<pre></pre>
=={{header|Objective-C}}==
| |||