/// <summary>
/// Batch-loading dataitems from storage. Storage determs the most optimal order for loading pointers, so items will be returned in other order than pointers.
/// </summary>
public IEnumerable<Tuple<IPtr, byte[]>> BatchLoad(IPtr[] ptrs, int sizeOfbatchInMb = 1024)
{
var md5 = new MD5CryptoServiceProvider();
long sizeOfbatch = ((long) sizeOfbatchInMb)*1024*1024;
var groupsByFile = ptrs.GroupBy(p => ((Ptr) p).FileNum);
foreach (var group in groupsByFile)
{
var ordered = group.OrderBy(p => ((Ptr) p).Position).ToArray();
int processed = 0;
while (processed < ordered.Length)
{
var dbFile = dbFiles[group.Key];
List<Tuple<Ptr, byte[], byte[]>> loaded = new List<Tuple<Ptr, byte[], byte[]>>();
byte[] data, hash;
long readedBytes = 0;
lock (dbFile)
{
while (readedBytes < sizeOfbatch && processed < ordered.Length)
{
var ptr = (Ptr) ordered[processed];
ReadFromDbFile(dbFile, ptr.Capacity, ptr.Position, out data, out hash);
loaded.Add(Tuple.Create(ptr, data, hash));
if (data != null) readedBytes += data.Length + hash.Length;
++processed;
}
}
foreach (var item in loaded)
{
var ptr = item.Item1;
data = item.Item2;
hash = item.Item3;
var control = md5.ComputeHash(data);
if (!control.SequenceEqual(hash)) yield return new Tuple<IPtr, byte[]>(ptr, null);
else yield return new Tuple<IPtr, byte[]>(ptr, data);
}
}
}
}
