public IndexAddressColumn(IRawFile kData, int capacity, long recordCountHint)
{
_fileID = kData.FileID;
_partitionID = kData.PartitionID;
int keycountHint = Math.Max(capacity, 1);
// Nuber of records per keyblock
// is a half of statistically expected
// but minimum size is 10
_rowBlockLenBitHint = (int)Math.Floor(Math.Log(Math.Max(recordCountHint / keycountHint / 2, 16), 2.0)) - 1;
_rowBlockLenBitHint = Math.Max(_rowBlockLenBitHint, 4);
int rowBlockLen = 1 << _rowBlockLenBitHint;
_kData = kData;
if (kData.GetAppendOffset() > 0)
{
rowBlockLen = _kData.ReadInt32(ROW_BLOK_LEN_ADDRESS_OFFSET);
_rowBlockLenBitHint = (int)Math.Log(rowBlockLen, 2);
if (1 << _rowBlockLenBitHint != rowBlockLen)
{
throw new NFSdbInvalidStateException("Row block length specified in file '{0}' equals " +
"{1}. Only power of 2 values are supported.",
_kData.Filename, rowBlockLen);
}
}
else if (kData.Access == EFileAccess.ReadWrite)
{
kData.WriteInt64(0, rowBlockLen); // 8
kData.WriteInt64(KEY_BLOCK_ADDRESS_OFFSET, INITIAL_KEYBLOCK_OFFSET); // 8
const int defaultKeyBlockSize = 0;
kData.WriteInt64(INITIAL_KEYBLOCK_OFFSET, defaultKeyBlockSize); // 8
kData.WriteInt64(INITIAL_KEYBLOCK_OFFSET + 8, 0); // 8
kData.SetAppendOffset(INITIAL_APPEND_OFFSET);
}
_rowBlockSize = rowBlockLen * 8 + 8;
}
public void Clean()
{
_data.SetAppendOffset(0);
}