public CoreFieldIndex(long indexStart, long termsStart, long packedIndexStart, long packedOffsetsStart,
int numIndexTerms, FixedGapTermsIndexReader fgtir)
{
TermsStart = termsStart;
TermBytesStart = fgtir._termBytes.Pointer;
var clone = (IndexInput)fgtir._input.Clone();
clone.Seek(indexStart);
// -1 is passed to mean "don't load term index", but
// if we are then later loaded it's overwritten with
// a real value
Debug.Assert(fgtir._indexDivisor > 0);
NumIndexTerms = 1 + (numIndexTerms - 1) / fgtir._indexDivisor;
Debug.Assert(NumIndexTerms > 0,
String.Format("NumIndexTerms: {0}, IndexDivisor: {1}", NumIndexTerms, fgtir._indexDivisor));
if (fgtir._indexDivisor == 1)
{
// Default (load all index terms) is fast -- slurp in the images from disk:
try
{
var numTermBytes = packedIndexStart - indexStart;
fgtir._termBytes.Copy(clone, numTermBytes);
// records offsets into main terms dict file
TermsDictOffsets = PackedInts.GetReader(clone);
Debug.Assert(TermsDictOffsets.Size() == numIndexTerms);
// records offsets into byte[] term data
TermOffsets = PackedInts.GetReader(clone);
Debug.Assert(TermOffsets.Size() == 1 + numIndexTerms);
}
finally
{
clone.Dispose();
}
}
else
{
// Get packed iterators
var clone1 = (IndexInput)fgtir._input.Clone();
var clone2 = (IndexInput)fgtir._input.Clone();
try
{
// Subsample the index terms
clone1.Seek(packedIndexStart);
PackedInts.ReaderIterator termsDictOffsetsIter = PackedInts.GetReaderIterator(clone1,
PackedInts.DEFAULT_BUFFER_SIZE);
clone2.Seek(packedOffsetsStart);
PackedInts.ReaderIterator termOffsetsIter = PackedInts.GetReaderIterator(clone2,
PackedInts.DEFAULT_BUFFER_SIZE);
// TODO: often we can get by w/ fewer bits per
// value, below.. .but this'd be more complex:
// we'd have to try @ fewer bits and then grow
// if we overflowed it.
PackedInts.Mutable termsDictOffsetsM = PackedInts.GetMutable(NumIndexTerms,
termsDictOffsetsIter.BitsPerValue, PackedInts.DEFAULT);
PackedInts.Mutable termOffsetsM = PackedInts.GetMutable(NumIndexTerms + 1,
termOffsetsIter.BitsPerValue, PackedInts.DEFAULT);
TermsDictOffsets = termsDictOffsetsM;
TermOffsets = termOffsetsM;
var upto = 0;
long termOffsetUpto = 0;
while (upto < NumIndexTerms)
{
// main file offset copies straight over
termsDictOffsetsM.Set(upto, termsDictOffsetsIter.Next());
termOffsetsM.Set(upto, termOffsetUpto);
var termOffset = termOffsetsIter.Next();
var nextTermOffset = termOffsetsIter.Next();
var numTermBytes = (int)(nextTermOffset - termOffset);
clone.Seek(indexStart + termOffset);
Debug.Assert(indexStart + termOffset < clone.Length(),
String.Format("IndexStart: {0}, TermOffset: {1}, Len: {2}", indexStart, termOffset,
clone.Length()));
Debug.Assert(indexStart + termOffset + numTermBytes < clone.Length());
fgtir._termBytes.Copy(clone, numTermBytes);
termOffsetUpto += numTermBytes;
upto++;
if (upto == NumIndexTerms)
{
break;
}
// skip terms:
termsDictOffsetsIter.Next();
for (var i = 0; i < fgtir._indexDivisor - 2; i++)
{
termOffsetsIter.Next();
termsDictOffsetsIter.Next();
}
}
termOffsetsM.Set(upto, termOffsetUpto);
}
finally
{
clone1.Dispose();
clone2.Dispose();
clone.Dispose();
}
}
}