private ulong NextNumber()
{
if (indxInBuffer >= dataInBuffer)
{
var toRead = buffer.Length;
if (listEndOffset - readOffset < toRead)
{
checked
{
toRead = (int)(listEndOffset - readOffset);
}
}
if (toRead == 0)
{
isEof = true;
return(0);
}
persistentStorage.ReadAll(readOffset, buffer, 0, toRead);
for (int i = toRead; i < buffer.Length; ++i)
{
buffer[i] = 0;
}
readOffset += toRead;
dataInBuffer = toRead;
indxInBuffer = 0;
}
indxInBuffer += VarInt.ReadVUInt64(buffer, indxInBuffer, out var result);
return(result);
}
public bool MoveNext()
{
while (true)
{
if (state == 0)
{
if (isEof)
{
return(false);
}
var header = new byte[HeaderLength];
persistentStorage.ReadAll(readOffset, header, 0, header.Length);
if (header[0] != (byte)'L')
{
throw new Exception("Invalid List Header");
}
var listLength = BitConverter.ToInt32(header, 1);
var recordCount = BitConverter.ToInt32(header, 1 + sizeof(int));
listEndOffset = readOffset + HeaderLength + listLength;
readOffset += header.Length;
state = 17;
}
if (state == 17)
{
// Seek state
var left = (listEndOffset - readOffset) / buffer.Length;
if (left < SkipSearchBlocksThreshold || !(current < firstValue))
{
state = 1;
}
else
{
// Allocate space for two blocks, find two consecutive blocks that contain
// occurrence that is requested
var t = new byte[buffer.Length * 2];
var a = 0L;
var b = left;
var mid = a;
while (a != b)
{
mid = (a + b) >> 1;
// Read two blocks
var midOffset = readOffset + buffer.Length * mid;
var inList = (listEndOffset - midOffset - buffer.Length);
var toRead = inList > t.Length ? t.Length : (int)inList;
persistentStorage.ReadAll(midOffset, t, 0, toRead);
// Block 1: Full value
var j = 0;
j += VarInt.ReadVUInt64(t, j, out var v1);
// Block 2: Full value
j = buffer.Length;
j += VarInt.ReadVUInt64(t, j, out var v2);
if (v1 < firstValue)
{
if (v2 >= firstValue)
{
break;
}
else
{
a = mid + 1;
}
}
else
{
b = mid;
}
}
state = 1;
indxInBuffer = 0;
dataInBuffer = 0;
readOffset = readOffset + buffer.Length * mid;
}
}
if (state == 1)
{
current = NextNumber();
state = 2;
if (!(current < firstValue))
{
return(true);
}
}
if (state == 2)
{
if (indxInBuffer >= dataInBuffer)
{
if (readOffset < listEndOffset)
{
// Next block
state = 1;
continue;
}
}
var delta = NextNumber();
if (delta == 0)
{
if (readOffset < listEndOffset)
{
if (indxInBuffer < dataInBuffer)
{
// Case when buffer is filled with zeros at the end
indxInBuffer = dataInBuffer;
}
state = 1; // Next block
}
else
{
state = 0; // EOF
}
continue;
}
current += delta;
if (!(current < firstValue))
{
return(true);
}
}
}
}
public bool MoveNext()
{
while (true)
{
if (state == 0)
{
if (continuationOffset > 0)
{
readOffset = continuationOffset;
isEof = false;
dataInBuffer = 0;
indxInBuffer = 0;
}
if (isEof)
{
return(false);
}
var header = new byte[HeaderLength];
persistentStorage.ReadAll(readOffset, header, 0, header.Length);
continuationOffset = BitConverter.ToInt64(header, 0);
listEndOffset = readOffset + HeaderLength + BitConverter.ToInt32(header, sizeof(long));
readOffset += header.Length;
state = 17;
}
if (state == 17)
{
// Seek state
var left = (listEndOffset - readOffset) / buffer.Length;
if (left < SkipSearchBlocksThreshold || !(current < firstOccurrence))
{
state = 1;
}
else
{
// Allocate space for two blocks, find two consecutive blocks that contain
// occurrence that is requested
var t = new byte[buffer.Length * 2];
var a = 0L;
var b = left;
var mid = a;
while (a != b)
{
mid = (a + b) >> 1;
// Read two blocks
var midOffset = readOffset + buffer.Length * mid;
var inList = (listEndOffset - midOffset - buffer.Length);
var toRead = inList > t.Length ? t.Length : (int)inList;
persistentStorage.ReadAll(midOffset, t, 0, toRead);
// Block 1: Full occurrence
var j = 0;
j += VarInt.ReadVUInt64(t, j, out var o1_1);
j += VarInt.ReadVUInt64(t, j, out var o1_2);
j += VarInt.ReadVUInt64(t, j, out var o1_3);
// Block 2: Full occurrence
j = buffer.Length;
j += VarInt.ReadVUInt64(t, j, out var o2_1);
j += VarInt.ReadVUInt64(t, j, out var o2_2);
j += VarInt.ReadVUInt64(t, j, out var o2_3);
if (Occurrence.O(o1_1, o1_2, o1_3).CompareTo(firstOccurrence) < 0)
{
if (Occurrence.O(o2_1, o2_2, o2_3).CompareTo(firstOccurrence) >= 0)
{
break;
}
else
{
a = mid + 1;
}
}
else
{
b = mid;
}
}
state = 1;
indxInBuffer = 0;
dataInBuffer = 0;
readOffset = readOffset + buffer.Length * mid;
}
}
if (state == 1)
{
current = Occurrence.O(NextNumber(),
NextNumber(),
NextNumber());
state = 2;
if (!(current < firstOccurrence))
{
return(true);
}
}
if (state == 2)
{
if (indxInBuffer >= dataInBuffer)
{
if (readOffset < listEndOffset)
{
// Next block
state = 1;
continue;
}
}
int delta = (int)NextNumber();
switch (delta)
{
case 0:
{
if (readOffset < listEndOffset)
{
if (indxInBuffer < dataInBuffer)
{
// Case when buffer is filled with zeros at the end
indxInBuffer = dataInBuffer;
}
state = 1; // Next block
}
else
{
state = 0; // Continuation or EOF
}
continue;
}
case 1:
{
// Next is the same as current
break;
}
case 2:
{
var deltaToken = NextNumber();
current = Occurrence.O(current.DocumentId,
current.FieldId,
current.TokenId + deltaToken);
break;
}
case 3:
{
var deltaFieldId = NextNumber();
var token = NextNumber();
current = Occurrence.O(current.DocumentId,
current.FieldId + deltaFieldId,
token);
break;
}
case 4:
{
var deltaDocId = NextNumber();
var fieldId = NextNumber();
var token = NextNumber();
current = Occurrence.O(current.DocumentId + deltaDocId,
fieldId,
token);
break;
}
default:
{
throw new Exception("Something wrong");
}
}
if (!(current < firstOccurrence))
{
return(true);
}
}
}
}