private void WriteBlock()
{
Debug.Assert(blockChunks > 0);
fieldsIndexOut.WriteVInt32(blockChunks);
// The trick here is that we only store the difference from the average start
// pointer or doc base, this helps save bits per value.
// And in order to prevent a few chunks that would be far from the average to
// raise the number of bits per value for all of them, we only encode blocks
// of 1024 chunks at once
// See LUCENE-4512
// doc bases
int avgChunkDocs;
if (blockChunks == 1)
{
avgChunkDocs = 0;
}
else
{
avgChunkDocs = (int)Math.Round((float)(blockDocs - docBaseDeltas[blockChunks - 1]) / (blockChunks - 1));
}
fieldsIndexOut.WriteVInt32(totalDocs - blockDocs); // docBase
fieldsIndexOut.WriteVInt32(avgChunkDocs);
int docBase = 0;
long maxDelta = 0;
for (int i = 0; i < blockChunks; ++i)
{
int delta = docBase - avgChunkDocs * i;
maxDelta |= MoveSignToLowOrderBit(delta);
docBase += docBaseDeltas[i];
}
int bitsPerDocBase = PackedInt32s.BitsRequired(maxDelta);
fieldsIndexOut.WriteVInt32(bitsPerDocBase);
PackedInt32s.Writer writer = PackedInt32s.GetWriterNoHeader(fieldsIndexOut, PackedInt32s.Format.PACKED, blockChunks, bitsPerDocBase, 1);
docBase = 0;
for (int i = 0; i < blockChunks; ++i)
{
long delta = docBase - avgChunkDocs * i;
Debug.Assert(PackedInt32s.BitsRequired(MoveSignToLowOrderBit(delta)) <= writer.BitsPerValue);
writer.Add(MoveSignToLowOrderBit(delta));
docBase += docBaseDeltas[i];
}
writer.Finish();
// start pointers
fieldsIndexOut.WriteVInt64(firstStartPointer);
long avgChunkSize;
if (blockChunks == 1)
{
avgChunkSize = 0;
}
else
{
avgChunkSize = (maxStartPointer - firstStartPointer) / (blockChunks - 1);
}
fieldsIndexOut.WriteVInt64(avgChunkSize);
long startPointer = 0;
maxDelta = 0;
for (int i = 0; i < blockChunks; ++i)
{
startPointer += startPointerDeltas[i];
long delta = startPointer - avgChunkSize * i;
maxDelta |= MoveSignToLowOrderBit(delta);
}
int bitsPerStartPointer = PackedInt32s.BitsRequired(maxDelta);
fieldsIndexOut.WriteVInt32(bitsPerStartPointer);
writer = PackedInt32s.GetWriterNoHeader(fieldsIndexOut, PackedInt32s.Format.PACKED, blockChunks, bitsPerStartPointer, 1);
startPointer = 0;
for (int i = 0; i < blockChunks; ++i)
{
startPointer += startPointerDeltas[i];
long delta = startPointer - avgChunkSize * i;
Debug.Assert(PackedInt32s.BitsRequired(MoveSignToLowOrderBit(delta)) <= writer.BitsPerValue);
writer.Add(MoveSignToLowOrderBit(delta));
}
writer.Finish();
}
internal void Persist()
{
UninterruptableMonitor.Enter(this);
try
{
string fileName = SNAPSHOTS_PREFIX + nextWriteGen;
IndexOutput @out = dir.CreateOutput(fileName, IOContext.DEFAULT);
bool success = false;
try
{
CodecUtil.WriteHeader(@out, CODEC_NAME, VERSION_CURRENT);
@out.WriteVInt32(m_refCounts.Count);
foreach (KeyValuePair <long, int> ent in m_refCounts)
{
@out.WriteVInt64(ent.Key);
@out.WriteVInt32(ent.Value);
}
success = true;
}
finally
{
if (!success)
{
IOUtils.DisposeWhileHandlingException(@out);
try
{
dir.DeleteFile(fileName);
}
catch (Exception e) when(e.IsException())
{
// Suppress so we keep throwing original exception
}
}
else
{
IOUtils.Dispose(@out);
}
}
dir.Sync(/*Collections.singletonList(*/ new[] { fileName } /*)*/);
if (nextWriteGen > 0)
{
string lastSaveFile = SNAPSHOTS_PREFIX + (nextWriteGen - 1);
try
{
dir.DeleteFile(lastSaveFile);
}
catch (Exception ioe) when(ioe.IsIOException())
{
// OK: likely it didn't exist
}
}
nextWriteGen++;
}
finally
{
UninterruptableMonitor.Exit(this);
}
}
