public async Task WriteLevelAsync(int level, IntPtr[] segment, CancellationToken ct)
{
ct.ThrowIfCancellationRequested();
if (m_jumpTable[level].Value > 0)
{
throw new InvalidOperationException("The level has already be written to this snapshot");
}
var levelStart = checked (m_file.Length + (uint)m_writer.Position);
//Console.WriteLine("## level " + level + " starts at " + levelStart);
//TODO: ensure that we start on a PAGE?
//Console.WriteLine("> Writing level " + level);
// "LVL_"
m_writer.WriteFixed32(SnapshotFormat.LEVEL_MAGIC_NUMBER);
// Level Flags
m_writer.WriteFixed32(0); //TODO: flags!
// Level ID
m_writer.WriteFixed32((uint)level);
// Item count (always 2^level)
m_writer.WriteFixed32((uint)segment.Length);
for (int i = 0; i < segment.Length; i++)
{
unsafe
{
#if __MonoCS__
var valuePointer = new IntPtr((void *)MemoryDatabaseHandler.ResolveValueAtVersion(segment[i], m_sequence));
if (valuePointer == IntPtr.Zero)
{
continue;
}
Value value = new Value();
Marshal.PtrToStructure(valuePointer, value);
var keyPointer = new IntPtr((void *)segment[i]);
Key key = new Key();
Marshal.PtrToStructure(keyPointer, key);
Contract.Assert(key.Size <= MemoryDatabaseHandler.MAX_KEY_SIZE);
// Key Size
uint size = key.Size;
m_writer.WriteVarint32(size);
m_writer.WriteBytesUnsafe(&(key.Data), (int)size);
// Value
m_writer.WriteVarint64(value.Sequence); // sequence
size = value.Size;
if (size == 0)
{ // empty key
m_writer.WriteByte(0);
}
else
{
m_writer.WriteVarint32(size); // value size
m_writer.WriteBytesUnsafe(&(value.Data), (int)size); // value data
}
#else
Value *value = MemoryDatabaseHandler.ResolveValueAtVersion(segment[i], m_sequence);
if (value == null)
{
continue;
}
Key *key = (Key *)segment[i]; //.ToPointer();
Contract.Assert(key != null && key->Size <= MemoryDatabaseHandler.MAX_KEY_SIZE);
// Key Size
uint size = key->Size;
m_writer.WriteVarint32(size);
m_writer.WriteBytesUnsafe(&(key->Data), (int)size);
// Value
m_writer.WriteVarint64(value->Sequence); // sequence
size = value->Size;
if (size == 0)
{ // empty key
m_writer.WriteByte(0);
}
else
{
m_writer.WriteVarint32(size); // value size
m_writer.WriteBytesUnsafe(&(value->Data), (int)size); // value data
}
#endif
}
if (m_writer.Position >= SnapshotFormat.FLUSH_SIZE)
{
//Console.WriteLine("> partial flush (" + writer.Position + ")");
int written = await m_file.WriteCompletePagesAsync(m_writer.Buffer, m_writer.Position, ct).ConfigureAwait(false);
if (written > 0)
{
m_writer.Flush(written);
}
}
}
m_writer.WriteFixed32(uint.MaxValue);
//TODO: CRC? (would need to be computed on the fly, because we don't have the full slice in memory probably)
m_writer.WriteFixed32(0);
var levelEnd = checked (m_file.Length + (uint)m_writer.Position);
m_jumpTable[level] = new KeyValuePair <ulong, ulong>(levelStart, levelEnd - levelStart);
//Console.WriteLine("## level " + level + " ends at " + levelEnd);
// optional padding to fill the rest of the page
PadPageIfNeeded(SnapshotFormat.PAGE_SIZE, (byte)(0xFC - level));
}