/// <summary>
/// Returns the next token in the stream, or null at EOS.
/// </summary>
public override sealed bool IncrementToken()
{
while (true)
{
if (curTermBuffer == null)
{
if (!m_input.IncrementToken())
{
return(false);
}
else
{
curTermBuffer = (char[])termAtt.Buffer.Clone();
curTermLength = termAtt.Length;
curCodePointCount = charUtils.CodePointCount(termAtt.ToString());
curGramSize = minGram;
curPos = 0;
curPosInc = posIncAtt.PositionIncrement;
curPosLen = posLenAtt.PositionLength;
tokStart = offsetAtt.StartOffset;
tokEnd = offsetAtt.EndOffset;
// if length by start + end offsets doesn't match the term text then assume
// this is a synonym and don't adjust the offsets.
hasIllegalOffsets = (tokStart + curTermLength) != tokEnd;
}
}
#pragma warning disable 612, 618
if (version.OnOrAfter(LuceneVersion.LUCENE_44))
#pragma warning restore 612, 618
{
if (curGramSize > maxGram || (curPos + curGramSize) > curCodePointCount)
{
++curPos;
curGramSize = minGram;
}
if ((curPos + curGramSize) <= curCodePointCount)
{
ClearAttributes();
int start = charUtils.OffsetByCodePoints(curTermBuffer, 0, curTermLength, 0, curPos);
int end = charUtils.OffsetByCodePoints(curTermBuffer, 0, curTermLength, start, curGramSize);
termAtt.CopyBuffer(curTermBuffer, start, end - start);
posIncAtt.PositionIncrement = curPosInc;
curPosInc = 0;
posLenAtt.PositionLength = curPosLen;
offsetAtt.SetOffset(tokStart, tokEnd);
curGramSize++;
return(true);
}
}
else
{
while (curGramSize <= maxGram)
{
while (curPos + curGramSize <= curTermLength) // while there is input
{
ClearAttributes();
termAtt.CopyBuffer(curTermBuffer, curPos, curGramSize);
if (hasIllegalOffsets)
{
offsetAtt.SetOffset(tokStart, tokEnd);
}
else
{
offsetAtt.SetOffset(tokStart + curPos, tokStart + curPos + curGramSize);
}
curPos++;
return(true);
}
curGramSize++; // increase n-gram size
curPos = 0;
}
}
curTermBuffer = null;
}
}
public override sealed bool IncrementToken()
{
while (true)
{
if (curTermBuffer == null)
{
if (!m_input.IncrementToken())
{
return(false);
}
else
{
curTermBuffer = (char[])termAtt.Buffer.Clone();
curTermLength = termAtt.Length;
curCodePointCount = charUtils.CodePointCount(termAtt);
curGramSize = minGram;
tokStart = offsetAtt.StartOffset;
tokEnd = offsetAtt.EndOffset;
#pragma warning disable 612, 618
if (version.OnOrAfter(LuceneVersion.LUCENE_44))
#pragma warning restore 612, 618
{
// Never update offsets
updateOffsets = false;
}
else
{
// if length by start + end offsets doesn't match the term text then assume
// this is a synonym and don't adjust the offsets.
updateOffsets = (tokStart + curTermLength) == tokEnd;
}
savePosIncr += posIncrAtt.PositionIncrement;
savePosLen = posLenAtt.PositionLength;
}
}
if (curGramSize <= maxGram) // if we have hit the end of our n-gram size range, quit
{
if (curGramSize <= curCodePointCount) // if the remaining input is too short, we can't generate any n-grams
{
// grab gramSize chars from front or back
int start = side == Side.FRONT ? 0 : charUtils.OffsetByCodePoints(curTermBuffer, 0, curTermLength, curTermLength, -curGramSize);
int end = charUtils.OffsetByCodePoints(curTermBuffer, 0, curTermLength, start, curGramSize);
ClearAttributes();
if (updateOffsets)
{
offsetAtt.SetOffset(tokStart + start, tokStart + end);
}
else
{
offsetAtt.SetOffset(tokStart, tokEnd);
}
// first ngram gets increment, others don't
if (curGramSize == minGram)
{
posIncrAtt.PositionIncrement = savePosIncr;
savePosIncr = 0;
}
else
{
posIncrAtt.PositionIncrement = 0;
}
posLenAtt.PositionLength = savePosLen;
termAtt.CopyBuffer(curTermBuffer, start, end - start);
curGramSize++;
return(true);
}
}
curTermBuffer = null;
}
}
