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#ifndef __BLEUSCORER_H__
#define __BLEUSCORER_H__
#include <iostream>
#include <string>
#include <vector>
#include "Types.h"
#include "ScoreData.h"
#include "Scorer.h"
#include "ScopedVector.h"
using namespace std;
enum BleuReferenceLengthStrategy { BLEU_AVERAGE, BLEU_SHORTEST, BLEU_CLOSEST };
/**
* Bleu scoring
*/
class BleuScorer: public StatisticsBasedScorer
{
public:
explicit BleuScorer(const string& config = "");
~BleuScorer();
virtual void setReferenceFiles(const vector<string>& referenceFiles);
virtual void prepareStats(size_t sid, const string& text, ScoreStats& entry);
virtual float calculateScore(const vector<int>& comps) const;
virtual size_t NumberOfScores() const {
return 2 * kLENGTH + 1;
}
private:
//Used to construct the ngram map
struct CompareNgrams {
bool operator()(const vector<int>& a, const vector<int>& b) const {
size_t i;
const size_t as = a.size();
const size_t bs = b.size();
for (i = 0; i < as && i < bs; ++i) {
if (a[i] < b[i]) {
//cerr << "true" << endl;
return true;
}
if (a[i] > b[i]) {
//cerr << "false" << endl;
return false;
}
}
//entries are equal, shortest wins
return as < bs;;
}
};
typedef map<vector<int>,int,CompareNgrams> counts_t;
typedef map<vector<int>,int,CompareNgrams>::iterator counts_iterator;
typedef map<vector<int>,int,CompareNgrams>::const_iterator counts_const_iterator;
typedef ScopedVector<counts_t> refcounts_t;
/**
* Count the ngrams of each type, up to the given length in the input line.
*/
size_t countNgrams(const string& line, counts_t& counts, unsigned int n);
void dump_counts(counts_t& counts) const;
const int kLENGTH;
BleuReferenceLengthStrategy _refLengthStrategy;
// data extracted from reference files
refcounts_t _refcounts;
vector<vector<size_t> > _reflengths;
// no copying allowed
BleuScorer(const BleuScorer&);
BleuScorer& operator=(const BleuScorer&);
};
#endif // __BLEUSCORER_H__
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