private void WriteTerm(Term term)
{
int start = StringHelper.StringDifference(lastTerm.text, term.text);
int length = term.text.Length - start;
output.WriteVInt(start); // write shared prefix length
output.WriteVInt(length); // write delta length
output.WriteChars(term.text, start, length); // write delta chars
output.WriteVInt(fieldInfos.FieldNumber(term.field)); // write field num
lastTerm = term;
}
private void WriteField()
{
// remember where this field is written
currentField.tvfPointer = tvf.GetFilePointer();
//System.out.println("Field Pointer: " + currentField.tvfPointer);
int size = terms.Count;
tvf.WriteVInt(size);
bool storePositions = currentField.storePositions;
bool storeOffsets = currentField.storeOffsets;
byte bits = (byte)(0x0);
if (storePositions)
{
bits |= STORE_POSITIONS_WITH_TERMVECTOR;
}
if (storeOffsets)
{
bits |= STORE_OFFSET_WITH_TERMVECTOR;
}
tvf.WriteByte(bits);
System.String lastTermText = "";
for (int i = 0; i < size; i++)
{
TVTerm term = (TVTerm)terms[i];
int start = StringHelper.StringDifference(lastTermText, term.termText);
int length = term.termText.Length - start;
tvf.WriteVInt(start); // write shared prefix length
tvf.WriteVInt(length); // write delta length
tvf.WriteChars(term.termText, start, length); // write delta chars
tvf.WriteVInt(term.freq);
lastTermText = term.termText;
if (storePositions)
{
if (term.positions == null)
{
throw new System.SystemException("Trying to write positions that are null!");
}
// use delta encoding for positions
int position = 0;
for (int j = 0; j < term.freq; j++)
{
tvf.WriteVInt(term.positions[j] - position);
position = term.positions[j];
}
}
if (storeOffsets)
{
if (term.offsets == null)
{
throw new System.SystemException("Trying to write offsets that are null!");
}
// use delta encoding for offsets
int position = 0;
for (int j = 0; j < term.freq; j++)
{
tvf.WriteVInt(term.offsets[j].GetStartOffset() - position);
tvf.WriteVInt(term.offsets[j].GetEndOffset() - term.offsets[j].GetStartOffset()); //Save the diff between the two.
position = term.offsets[j].GetEndOffset();
}
}
}
}
/// <summary> Add a complete document specified by all its term vectors. If document has no
/// term vectors, add value for tvx.
///
/// </summary>
/// <param name="vectors">
/// </param>
/// <throws> IOException </throws>
public void AddAllDocVectors(TermFreqVector[] vectors)
{
tvx.WriteLong(tvd.GetFilePointer());
if (vectors != null)
{
int numFields = vectors.Length;
tvd.WriteVInt(numFields);
long[] fieldPointers = new long[numFields];
for (int i = 0; i < numFields; i++)
{
fieldPointers[i] = tvf.GetFilePointer();
int fieldNumber = fieldInfos.FieldNumber(vectors[i].GetField());
// 1st pass: write field numbers to tvd
tvd.WriteVInt(fieldNumber);
int numTerms = vectors[i].Size();
tvf.WriteVInt(numTerms);
TermPositionVector tpVector;
byte bits;
bool storePositions;
bool storeOffsets;
if (vectors[i] is TermPositionVector)
{
// May have positions & offsets
tpVector = (TermPositionVector)vectors[i];
storePositions = tpVector.Size() > 0 && tpVector.GetTermPositions(0) != null;
storeOffsets = tpVector.Size() > 0 && tpVector.GetOffsets(0) != null;
bits = (byte)((storePositions ? TermVectorsReader.STORE_POSITIONS_WITH_TERMVECTOR : (byte)0) + (storeOffsets ? TermVectorsReader.STORE_OFFSET_WITH_TERMVECTOR : (byte)0));
}
else
{
tpVector = null;
bits = 0;
storePositions = false;
storeOffsets = false;
}
tvf.WriteVInt(bits);
System.String[] terms = vectors[i].GetTerms();
int[] freqs = vectors[i].GetTermFrequencies();
System.String lastTermText = "";
for (int j = 0; j < numTerms; j++)
{
System.String termText = terms[j];
int start = StringHelper.StringDifference(lastTermText, termText);
int length = termText.Length - start;
tvf.WriteVInt(start); // write shared prefix length
tvf.WriteVInt(length); // write delta length
tvf.WriteChars(termText, start, length); // write delta chars
lastTermText = termText;
int termFreq = freqs[j];
tvf.WriteVInt(termFreq);
if (storePositions)
{
int[] positions = tpVector.GetTermPositions(j);
if (positions == null)
{
throw new System.SystemException("Trying to write positions that are null!");
}
System.Diagnostics.Debug.Assert(positions.Length == termFreq);
// use delta encoding for positions
int lastPosition = 0;
for (int k = 0; k < positions.Length; k++)
{
int position = positions[k];
tvf.WriteVInt(position - lastPosition);
lastPosition = position;
}
}
if (storeOffsets)
{
TermVectorOffsetInfo[] offsets = tpVector.GetOffsets(j);
if (offsets == null)
{
throw new System.SystemException("Trying to write offsets that are null!");
}
System.Diagnostics.Debug.Assert(offsets.Length == termFreq);
// use delta encoding for offsets
int lastEndOffset = 0;
for (int k = 0; k < offsets.Length; k++)
{
int startOffset = offsets[k].GetStartOffset();
int endOffset = offsets[k].GetEndOffset();
tvf.WriteVInt(startOffset - lastEndOffset);
tvf.WriteVInt(endOffset - startOffset);
lastEndOffset = endOffset;
}
}
}
}
// 2nd pass: write field pointers to tvd
long lastFieldPointer = 0;
for (int i = 0; i < numFields; i++)
{
long fieldPointer = fieldPointers[i];
tvd.WriteVLong(fieldPointer - lastFieldPointer);
lastFieldPointer = fieldPointer;
}
}
else
{
tvd.WriteVInt(0);
}
}