public TemplateBasedCompressor(short tid, byte[] tmplt, bool huff)
{
log = LogManager.GetLogger(GetType());
templateId = tid;
template = tmplt;
tc = new TrieCompressor(templateId, template);
tc.DictionaryShortcutChanged += HandleNewAnnouncement;
hc = new HuffmanCompressor(templateId);
hc.HuffmanFrequenciesChanged += HandleUpdatedFrequencies;
hc.HuffmanEncoding = huff;
}
internal void CheckSameState(TrieCompressor other)
{
InvalidStateException.Assert(decodingTable.Count == other.decodingTable.Count,
"decoding tables have different lengths", this);
for (int i = 0; i < decodingTable.Count; i++)
{
InvalidStateException.Assert(ByteUtils.Compare(decodingTable[i], other.decodingTable[i]),
"different decoding value for " + i, this);
}
InvalidStateException.Assert(shortcuts.Count == other.shortcuts.Count,
"shortcut dictionaries have different counts", this);
InvalidStateException.Assert(inverseShortcuts.Length == other.inverseShortcuts.Length,
"inverse shortcut lengths have different counts", this);
InvalidStateException.Assert(inverseShortcuts[0] == 0 && inverseShortcuts[1] == 0,
"bytes 0 and 1 are reserved!", this);
for (int i = MinimumShortcut; i <= MaximumShortcut; i++)
{
InvalidStateException.Assert(shortcuts.ContainsValue((byte)i) == other.shortcuts.ContainsValue((byte)i),
"difference in byte mapping", this);
InvalidStateException.Assert(inverseShortcuts[i] == other.inverseShortcuts[i],
"difference in byte mapping", this);
if (shortcuts.ContainsValue((byte)i))
{
InvalidStateException.Assert(shortcuts[inverseShortcuts[i]] == i,
"Mismatch between instance's shortcuts and inverseShortcuts!", this);
InvalidStateException.Assert(inverseShortcuts[i] == other.inverseShortcuts[i],
"Mismatch between instances' inverseShortcuts!", this);
InvalidStateException.Assert(shortcuts[inverseShortcuts[i]] == other.shortcuts[other.inverseShortcuts[i]],
"Mismatch between instances' inverseShortcuts!", this);
}
}
}
/// <summary>
/// Check if the provided candidate would make a good template
/// FIXME: Why are we throwing the template rep away?
/// </summary>
/// <param name="templateCandidate">the template</param>
/// <returns></returns>
public bool ShouldGenerateNewTemplate(byte[] templateCandidate)
{
TrieCompressor tc = new TrieCompressor(-1, templateCandidate);
int candidateSize = 0;
int currentSize = 0;
foreach(byte[] message in savedMessages) {
candidateSize += tc.EncodedSize(message);
// This assumes the trie encoding approximates the overall encoding...
currentSize += FindBestTrieEncoding(message);
}
return candidateSize < currentSize;
}