/// <summary>
/// Writes all key value pairs in current prefix to stream (prefix itself is not written)
/// </summary>
/// <param name="transaction">transaction from where export all data</param>
/// <param name="stream">where to write it to</param>
public static void Export(IKeyValueDBTransaction transaction, Stream stream)
{
if (transaction == null)
{
throw new ArgumentNullException(nameof(transaction));
}
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
if (!stream.CanWrite)
{
throw new ArgumentException("stream must be writeable", nameof(stream));
}
var keyValueCount = transaction.GetKeyValueCount();
var tempbuf = new byte[16];
tempbuf[0] = (byte)'B';
tempbuf[1] = (byte)'T';
tempbuf[2] = (byte)'D';
tempbuf[3] = (byte)'B';
tempbuf[4] = (byte)'E';
tempbuf[5] = (byte)'X';
tempbuf[6] = (byte)'P';
tempbuf[7] = (byte)'2';
PackUnpack.PackInt64LE(tempbuf, 8, keyValueCount);
stream.Write(tempbuf, 0, 16);
transaction.FindFirstKey(new ReadOnlySpan <byte>());
Span <byte> keyBuffer = stackalloc byte[256];
for (long kv = 0; kv < keyValueCount; kv++)
{
var key = transaction.GetKey(ref MemoryMarshal.GetReference(keyBuffer), keyBuffer.Length);
PackUnpack.PackInt32LE(tempbuf, 0, key.Length);
stream.Write(tempbuf, 0, 4);
stream.Write(key);
var value = transaction.GetValue();
PackUnpack.PackInt32LE(tempbuf, 0, value.Length);
stream.Write(tempbuf, 0, 4);
stream.Write(value);
transaction.FindNextKey(new ReadOnlySpan <byte>());
}
var ulongCount = transaction.GetUlongCount();
if (transaction.GetCommitUlong() != 0 || ulongCount != 0)
{
PackUnpack.PackUInt64LE(tempbuf, 0, transaction.GetCommitUlong());
stream.Write(tempbuf, 0, 8);
}
if (ulongCount != 0)
{
PackUnpack.PackUInt32LE(tempbuf, 0, ulongCount);
stream.Write(tempbuf, 0, 4);
for (var i = 0u; i < ulongCount; i++)
{
PackUnpack.PackUInt64LE(tempbuf, 0, transaction.GetUlong(i));
stream.Write(tempbuf, 0, 8);
}
}
}
void WriteOneBlock(ByteBuffer block, BlockType blockType)
{
var blockLen = (uint)block.Length;
var o = block.Offset - 4;
PackUnpack.PackUInt32LE(block.Buffer, o, (blockLen << 8) + (uint)blockType);
var checksum = Checksum.CalcFletcher32(block.Buffer, (uint)o, blockLen + 4);
o -= 4;
PackUnpack.PackUInt32LE(block.Buffer, o, checksum);
o -= (int)EndBufferLen;
Array.Copy(EndBuffer, 0, block.Buffer, o, EndBufferLen);
var lenWithoutEndPadding = (int)(EndBufferLen + HeaderSize + blockLen);
block = ByteBuffer.NewAsync(block.Buffer, o, (int)((uint)(lenWithoutEndPadding + SectorSize - 1) & SectorMaskUInt));
File.Write(block, EndBufferPosition);
NextReadPosition = EndBufferPosition + (ulong)lenWithoutEndPadding;
EndBufferPosition = NextReadPosition & SectorMask;
EndBufferLen = (uint)(NextReadPosition - EndBufferPosition);
Array.Copy(block.Buffer, block.Offset + lenWithoutEndPadding - EndBufferLen, EndBuffer, 0, EndBufferLen);
}
internal static void Pack(byte[] data, int offset, SectorPtr value)
{
PackUnpack.PackInt64LE(data, offset, value.Ptr);
PackUnpack.PackUInt32LE(data, offset + 8, value.Checksum);
}