private void WriteRecordToDbStream(QdbmRecord rec)
{
_databaseStream.Seek(rec.Header.Offset, SeekOrigin.Begin);
_databaseBinaryWriter.Write(rec.Header.Flags);
_databaseBinaryWriter.Write(rec.Key.SecondaryHashCode);
_databaseBinaryWriter.Write(rec.Header.KeySize);
_databaseBinaryWriter.Write(rec.Header.ValueSize);
_databaseBinaryWriter.Write(rec.Header.PaddingSize);
_databaseBinaryWriter.Write(0);
_databaseBinaryWriter.Write(0);
if (rec.Key.KeyBytes.Length > 0)
{
_databaseBinaryWriter.Write(rec.Key.KeyBytes);
}
if (rec.Value.Length > 0)
{
_databaseBinaryWriter.Write(rec.Value);
}
if (rec.PaddingData?.Length > 0)
{
_databaseBinaryWriter.Write(rec.PaddingData);
}
}
public void Put(QdbmKey key, byte[] value)
{
if (key == null || key.KeyBytes.Length == 0)
{
throw new ArgumentException("key must be specified", nameof(key));
}
if (value == null || value.Length == 0)
{
throw new ArgumentException("value must be specified", nameof(value));
}
_databaseStream.Seek(Constants.OffsetHeaderRecordCount, SeekOrigin.Begin);
var existingRecordHeader = GetRecordHeader(key);
var keySize = key.KeyBytes.Length;
var valueSize = value.Length;
var recordHeader = new QdbmRecordHeader
{
KeySize = keySize,
ValueSize = valueSize
};
var record = new QdbmRecord(key, recordHeader, value);
if (existingRecordHeader?.Size >= recordHeader.Size)
{
record.Header.Offset = existingRecordHeader.Offset;
WriteRecordToDbStream(record);
}
else
{
AppendRecordToDbStream(record);
}
var recordOffset = record.Header.Offset;
var bucketOffset = CalculateBucketOffset(record.Key, out var bucketId);
_databaseStream.Seek(bucketOffset, SeekOrigin.Begin);
var existingRecordOffset = _databaseBinaryReader.ReadInt32();
if (existingRecordOffset == 0)
{
_databaseStream.Seek(bucketOffset, SeekOrigin.Begin);
_databaseBinaryWriter.Write(recordOffset);
_buckets[bucketId] = bucketOffset;
}
else
{
SetChildOffset(record.Key.SecondaryHashCode, existingRecordOffset, recordOffset);
}
}
private QdbmRecord ReadRecord(QdbmRecordHeader recordHeader)
{
_databaseStream.Seek(recordHeader.Offset + Constants.OffsetRecordKeyOffset, SeekOrigin.Begin);
var key = _databaseBinaryReader.ReadBytes(recordHeader.KeySize);
var value = _databaseBinaryReader.ReadBytes(recordHeader.ValueSize);
var qdbmKey = new QdbmKey(key);
if (qdbmKey.SecondaryHashCode != recordHeader.SecondHashValue)
{
throw new InvalidOperationException("Database is corrupt.");
}
var qdbmRecord = new QdbmRecord(qdbmKey, recordHeader, value);
return(qdbmRecord);
}
private void AppendRecordToDbStream(QdbmRecord rec)
{
var paddingSize = CalculatePaddingSize(rec.Header.KeySize, rec.Header.ValueSize);
rec.PaddingData = new byte[paddingSize];
_databaseStream.Seek(0, SeekOrigin.End);
var recordOffset = (int)_databaseStream.Position;
rec.Header.Offset = recordOffset;
WriteRecordToDbStream(rec);
_databaseStream.Seek(Constants.OffsetHeaderRecordCount, SeekOrigin.Begin);
_databaseBinaryWriter.Write(Header.RecordCount++);
_databaseBinaryWriter.Seek(Constants.OffsetHeaderFileSize, SeekOrigin.Begin);
_databaseBinaryWriter.Write(_databaseStream.Length);
Header.FileSize = _databaseStream.Length;
}
