TargetPhraseVectorPtr PhraseDecoder::DecodeCollection(
TargetPhraseVectorPtr tpv, BitWrapper<> &encodedBitStream,
const Phrase &sourcePhrase, bool topLevel)
{
bool extending = tpv->size();
size_t bitsLeft = encodedBitStream.TellFromEnd();
typedef std::pair<size_t, size_t> AlignPointSizeT;
std::vector<int> sourceWords;
if(m_coding == REnc)
{
for(size_t i = 0; i < sourcePhrase.GetSize(); i++)
{
std::string sourceWord
= sourcePhrase.GetWord(i).GetString(*m_input, false);
unsigned idx = GetSourceSymbolId(sourceWord);
sourceWords.push_back(idx);
}
}
unsigned phraseStopSymbol = 0;
AlignPoint alignStopSymbol(-1, -1);
std::vector<float> scores;
std::set<AlignPointSizeT> alignment;
enum DecodeState { New, Symbol, Score, Alignment, Add } state = New;
size_t srcSize = sourcePhrase.GetSize();
TargetPhrase* targetPhrase = NULL;
while(encodedBitStream.TellFromEnd())
{
if(state == New)
{
// Creating new TargetPhrase on the heap
tpv->push_back(TargetPhrase(Output));
targetPhrase = &tpv->back();
targetPhrase->SetSourcePhrase(sourcePhrase);
alignment.clear();
scores.clear();
state = Symbol;
}
if(state == Symbol)
{
unsigned symbol = m_symbolTree->Read(encodedBitStream);
if(symbol == phraseStopSymbol)
{
state = Score;
}
else
{
if(m_coding == REnc)
{
std::string wordString;
size_t type = GetREncType(symbol);
if(type == 1)
{
unsigned decodedSymbol = DecodeREncSymbol1(symbol);
wordString = GetTargetSymbol(decodedSymbol);
}
else if (type == 2)
{
size_t rank = DecodeREncSymbol2Rank(symbol);
size_t srcPos = DecodeREncSymbol2Position(symbol);
if(srcPos >= sourceWords.size())
return TargetPhraseVectorPtr();
wordString = GetTargetSymbol(GetTranslation(sourceWords[srcPos], rank));
if(m_phraseDictionary.m_useAlignmentInfo)
{
size_t trgPos = targetPhrase->GetSize();
alignment.insert(AlignPoint(srcPos, trgPos));
}
}
else if(type == 3)
{
size_t rank = DecodeREncSymbol3(symbol);
size_t srcPos = targetPhrase->GetSize();
if(srcPos >= sourceWords.size())
return TargetPhraseVectorPtr();
wordString = GetTargetSymbol(GetTranslation(sourceWords[srcPos], rank));
if(m_phraseDictionary.m_useAlignmentInfo)
{
size_t trgPos = srcPos;
alignment.insert(AlignPoint(srcPos, trgPos));
}
}
Word word;
word.CreateFromString(Output, *m_output, wordString, false);
targetPhrase->AddWord(word);
}
else if(m_coding == PREnc)
{
// if the symbol is just a word
if(GetPREncType(symbol) == 1)
{
unsigned decodedSymbol = DecodePREncSymbol1(symbol);
Word word;
word.CreateFromString(Output, *m_output,
GetTargetSymbol(decodedSymbol), false);
targetPhrase->AddWord(word);
}
// if the symbol is a subphrase pointer
else
{
int left = DecodePREncSymbol2Left(symbol);
int right = DecodePREncSymbol2Right(symbol);
unsigned rank = DecodePREncSymbol2Rank(symbol);
int srcStart = left + targetPhrase->GetSize();
int srcEnd = srcSize - right - 1;
// false positive consistency check
if(0 > srcStart || srcStart > srcEnd || unsigned(srcEnd) >= srcSize)
return TargetPhraseVectorPtr();
// false positive consistency check
if(m_maxRank && rank > m_maxRank)
return TargetPhraseVectorPtr();
// set subphrase by default to itself
TargetPhraseVectorPtr subTpv = tpv;
// if range smaller than source phrase retrieve subphrase
if(unsigned(srcEnd - srcStart + 1) != srcSize)
{
Phrase subPhrase = sourcePhrase.GetSubString(WordsRange(srcStart, srcEnd));
subTpv = CreateTargetPhraseCollection(subPhrase, false);
}
// false positive consistency check
if(subTpv != NULL && rank < subTpv->size())
{
// insert the subphrase into the main target phrase
TargetPhrase& subTp = subTpv->at(rank);
if(m_phraseDictionary.m_useAlignmentInfo)
{
// reconstruct the alignment data based on the alignment of the subphrase
for(AlignmentInfo::const_iterator it = subTp.GetAlignmentInfo().begin();
it != subTp.GetAlignmentInfo().end(); it++)
{
alignment.insert(AlignPointSizeT(srcStart + it->first,
targetPhrase->GetSize() + it->second));
}
}
targetPhrase->Append(subTp);
}
else
return TargetPhraseVectorPtr();
}
}
else
{
Word word;
word.CreateFromString(Output, *m_output,
GetTargetSymbol(symbol), false);
targetPhrase->AddWord(word);
}
}
}
else if(state == Score)
{
size_t idx = m_multipleScoreTrees ? scores.size() : 0;
float score = m_scoreTrees[idx]->Read(encodedBitStream);
scores.push_back(score);
if(scores.size() == m_numScoreComponent)
{
targetPhrase->SetScore(m_feature, scores, ScoreComponentCollection() /*sparse*/,*m_weight, m_weightWP, *m_languageModels);
if(m_containsAlignmentInfo)
state = Alignment;
else
state = Add;
}
}
else if(state == Alignment)
{
AlignPoint alignPoint = m_alignTree->Read(encodedBitStream);
if(alignPoint == alignStopSymbol)
{
state = Add;
}
else
{
if(m_phraseDictionary.m_useAlignmentInfo)
alignment.insert(AlignPointSizeT(alignPoint));
}
}
if(state == Add)
{
if(m_phraseDictionary.m_useAlignmentInfo)
targetPhrase->SetAlignmentInfo(alignment);
if(m_coding == PREnc)
{
if(!m_maxRank || tpv->size() <= m_maxRank)
bitsLeft = encodedBitStream.TellFromEnd();
if(!topLevel && m_maxRank && tpv->size() >= m_maxRank)
break;
}
if(encodedBitStream.TellFromEnd() <= 8)
break;
state = New;
}
}
if(m_coding == PREnc && !extending)
{
bitsLeft = bitsLeft > 8 ? bitsLeft : 0;
m_decodingCache.Cache(sourcePhrase, tpv, bitsLeft, m_maxRank);
}
return tpv;
}
std::string PhraseTableCreator::CompressEncodedCollection(std::string encodedCollection)
{
enum EncodeState {
ReadSymbol, ReadScore, ReadAlignment,
EncodeSymbol, EncodeScore, EncodeAlignment
};
EncodeState state = ReadSymbol;
unsigned phraseStopSymbolId;
if(m_coding == REnc)
phraseStopSymbolId = EncodeREncSymbol1(GetTargetSymbolId(m_phraseStopSymbol));
else if(m_coding == PREnc)
phraseStopSymbolId = EncodePREncSymbol1(GetTargetSymbolId(m_phraseStopSymbol));
else
phraseStopSymbolId = GetTargetSymbolId(m_phraseStopSymbol);
AlignPoint alignStopSymbol(-1, -1);
std::stringstream encodedStream(encodedCollection);
encodedStream.unsetf(std::ios::skipws);
std::string compressedEncodedCollection;
BitWrapper<> bitStream(compressedEncodedCollection);
unsigned symbol;
float score;
size_t currScore = 0;
AlignPoint alignPoint;
while(encodedStream) {
switch(state) {
case ReadSymbol:
encodedStream.read((char*) &symbol, sizeof(unsigned));
state = EncodeSymbol;
break;
case ReadScore:
if(currScore == m_numScoreComponent) {
currScore = 0;
if(m_useAlignmentInfo)
state = ReadAlignment;
else
state = ReadSymbol;
} else {
encodedStream.read((char*) &score, sizeof(float));
currScore++;
state = EncodeScore;
}
break;
case ReadAlignment:
encodedStream.read((char*) &alignPoint, sizeof(AlignPoint));
state = EncodeAlignment;
break;
case EncodeSymbol:
state = (symbol == phraseStopSymbolId) ? ReadScore : ReadSymbol;
m_symbolTree->Put(bitStream, symbol);
break;
case EncodeScore: {
state = ReadScore;
size_t idx = m_multipleScoreTrees ? currScore-1 : 0;
if(m_quantize)
score = m_scoreCounters[idx]->LowerBound(score);
m_scoreTrees[idx]->Put(bitStream, score);
}
break;
case EncodeAlignment:
state = (alignPoint == alignStopSymbol) ? ReadSymbol : ReadAlignment;
m_alignTree->Put(bitStream, alignPoint);
break;
}
}
return compressedEncodedCollection;
}
