mosesdecoder/moses/TranslationModel/fuzzy-match/SuffixArray.cpp

241 lines
6.3 KiB
C++

#include "SuffixArray.h"
#include <string>
#include <stdlib.h>
#include <cstring>
using namespace std;
namespace tmmt
{
SuffixArray::SuffixArray( string fileName )
{
m_vcb.StoreIfNew( "<uNk>" );
m_endOfSentence = m_vcb.StoreIfNew( "<s>" );
ifstream extractFile;
// count the number of words first;
extractFile.open(fileName.c_str());
istream *fileP = &extractFile;
m_size = 0;
size_t sentenceCount = 0;
string line;
while(getline(*fileP, line)) {
vector< WORD_ID > words = m_vcb.Tokenize( line.c_str() );
m_size += words.size() + 1;
sentenceCount++;
}
extractFile.close();
cerr << m_size << " words (incl. sentence boundaries)" << endl;
// allocate memory
m_array = (WORD_ID*) calloc( sizeof( WORD_ID ), m_size );
m_index = (INDEX*) calloc( sizeof( INDEX ), m_size );
m_wordInSentence = (char*) calloc( sizeof( char ), m_size );
m_sentence = (size_t*) calloc( sizeof( size_t ), m_size );
m_sentenceLength = (char*) calloc( sizeof( char ), sentenceCount );
// fill the array
int wordIndex = 0;
int sentenceId = 0;
extractFile.open(fileName.c_str());
fileP = &extractFile;
while(getline(*fileP, line)) {
vector< WORD_ID > words = m_vcb.Tokenize( line.c_str() );
// add to corpus vector
corpus.push_back(words);
// create SA
vector< WORD_ID >::const_iterator i;
for( i=words.begin(); i!=words.end(); i++) {
m_index[ wordIndex ] = wordIndex;
m_sentence[ wordIndex ] = sentenceId;
m_wordInSentence[ wordIndex ] = i-words.begin();
m_array[ wordIndex++ ] = *i;
}
m_index[ wordIndex ] = wordIndex;
m_array[ wordIndex++ ] = m_endOfSentence;
m_sentenceLength[ sentenceId++ ] = words.size();
}
extractFile.close();
cerr << "done reading " << wordIndex << " words, " << sentenceId << " sentences." << endl;
// List(0,9);
// sort
m_buffer = (INDEX*) calloc( sizeof( INDEX ), m_size );
Sort( 0, m_size-1 );
free( m_buffer );
cerr << "done sorting" << endl;
}
// good ol' quick sort
void SuffixArray::Sort(INDEX start, INDEX end)
{
if (start == end) return;
INDEX mid = (start+end+1)/2;
Sort( start, mid-1 );
Sort( mid, end );
// merge
size_t i = start;
size_t j = mid;
size_t k = 0;
size_t length = end-start+1;
while( k<length ) {
if (i == mid ) {
m_buffer[ k++ ] = m_index[ j++ ];
} else if (j > end ) {
m_buffer[ k++ ] = m_index[ i++ ];
} else {
if (CompareIndex( m_index[i], m_index[j] ) < 0) {
m_buffer[ k++ ] = m_index[ i++ ];
} else {
m_buffer[ k++ ] = m_index[ j++ ];
}
}
}
memcpy( ((char*)m_index) + sizeof( INDEX ) * start,
((char*)m_buffer), sizeof( INDEX ) * (end-start+1) );
}
SuffixArray::~SuffixArray()
{
free(m_index);
free(m_array);
}
int SuffixArray::CompareIndex( INDEX a, INDEX b ) const
{
// skip over identical words
INDEX offset = 0;
while( a+offset < m_size &&
b+offset < m_size &&
m_array[ a+offset ] == m_array[ b+offset ] ) {
offset++;
}
if( a+offset == m_size ) return -1;
if( b+offset == m_size ) return 1;
return CompareWord( m_array[ a+offset ], m_array[ b+offset ] );
}
inline int SuffixArray::CompareWord( WORD_ID a, WORD_ID b ) const
{
// cerr << "c(" << m_vcb.GetWord(a) << ":" << m_vcb.GetWord(b) << ")=" << m_vcb.GetWord(a).compare( m_vcb.GetWord(b) ) << endl;
return m_vcb.GetWord(a).compare( m_vcb.GetWord(b) );
}
int SuffixArray::Count( const vector< WORD > &phrase )
{
INDEX dummy;
return LimitedCount( phrase, m_size, dummy, dummy, 0, m_size-1 );
}
bool SuffixArray::MinCount( const vector< WORD > &phrase, INDEX min )
{
INDEX dummy;
return LimitedCount( phrase, min, dummy, dummy, 0, m_size-1 ) >= min;
}
bool SuffixArray::Exists( const vector< WORD > &phrase )
{
INDEX dummy;
return LimitedCount( phrase, 1, dummy, dummy, 0, m_size-1 ) == 1;
}
int SuffixArray::FindMatches( const vector< WORD > &phrase, INDEX &firstMatch, INDEX &lastMatch, INDEX search_start, INDEX search_end )
{
return LimitedCount( phrase, m_size, firstMatch, lastMatch, search_start, search_end );
}
int SuffixArray::LimitedCount( const vector< WORD > &phrase, INDEX min, INDEX &firstMatch, INDEX &lastMatch, INDEX search_start, INDEX search_end )
{
// cerr << "FindFirst\n";
INDEX start = search_start;
INDEX end = (search_end == -1) ? (m_size-1) : search_end;
INDEX mid = FindFirst( phrase, start, end );
// cerr << "done\n";
if (mid == m_size) return 0; // no matches
if (min == 1) return 1; // only existance check
int matchCount = 1;
//cerr << "before...\n";
firstMatch = FindLast( phrase, mid, start, -1 );
matchCount += mid - firstMatch;
//cerr << "after...\n";
lastMatch = FindLast( phrase, mid, end, 1 );
matchCount += lastMatch - mid;
return matchCount;
}
SuffixArray::INDEX SuffixArray::FindLast( const vector< WORD > &phrase, INDEX start, INDEX end, int direction )
{
end += direction;
while(true) {
INDEX mid = ( start + end + (direction>0 ? 0 : 1) )/2;
int match = Match( phrase, mid );
int matchNext = Match( phrase, mid+direction );
//cerr << "\t" << start << ";" << mid << ";" << end << " -> " << match << "," << matchNext << endl;
if (match == 0 && matchNext != 0) return mid;
if (match == 0) // mid point is a match
start = mid;
else
end = mid;
}
}
SuffixArray::INDEX SuffixArray::FindFirst( const vector< WORD > &phrase, INDEX &start, INDEX &end )
{
while(true) {
INDEX mid = ( start + end + 1 )/2;
//cerr << "FindFirst(" << start << ";" << mid << ";" << end << ")\n";
int match = Match( phrase, mid );
if (match == 0) return mid;
if (start >= end && match != 0 ) return m_size;
if (match > 0)
start = mid+1;
else
end = mid-1;
}
}
int SuffixArray::Match( const vector< WORD > &phrase, INDEX index )
{
INDEX pos = m_index[ index ];
for(INDEX i=0; i<phrase.size() && i+pos<m_size; i++) {
int match = CompareWord( m_vcb.GetWordID( phrase[i] ), m_array[ pos+i ] );
// cerr << "{" << index << "+" << i << "," << pos+i << ":" << match << "}" << endl;
if (match != 0)
return match;
}
return 0;
}
void SuffixArray::List(INDEX start, INDEX end)
{
for(INDEX i=start; i<=end; i++) {
INDEX pos = m_index[ i ];
// cerr << i << ":" << pos << "\t";
for(int j=0; j<5 && j+pos<m_size; j++) {
//cout << " " << m_vcb.GetWord( m_array[ pos+j ] );
}
// cerr << "\n";
}
}
}