public bool AddItem(BaseSnapshotItem obj, int id)
{
if (obj == null)
{
Debug.Warning("snapshots", "add null object");
return(false);
}
if (SnapshotItems.Count + 1 >= MaxItems)
{
Debug.Warning("snapshots", "too many items");
return(false);
}
var itemSize = SnapshotItemsInfo.GetSize(obj.GetType());
if (SnapshotSize + itemSize >= Snapshot.MaxSize)
{
Debug.Warning("snapshots", "too much data");
return(false);
}
var item = new SnapshotItem(id, obj);
SnapshotSize += itemSize;
SnapshotItems.Add(item);
return(true);
}
public int[] ToArray()
{
var array = new int[SnapshotItemsInfo.GetSize(GetType()) / sizeof(int)];
var handle = GCHandle.Alloc(array, GCHandleType.Pinned);
var ptr = handle.AddrOfPinnedObject();
Marshal.StructureToPtr(this, ptr, false);
handle.Free();
return(array);
}
public T NewItem <T>(int id) where T : BaseSnapshotItem, new()
{
if (SnapshotItems.Count + 1 >= MaxItems)
{
Debug.Warning("snapshots", "too many items");
return(null);
}
var itemSize = SnapshotItemsInfo.GetSize <T>();
if (SnapshotSize + itemSize >= Snapshot.MaxSize)
{
Debug.Warning("snapshots", "too much data");
return(null);
}
var item = new SnapshotItem(id, new T());
SnapshotSize += itemSize;
SnapshotItems.Add(item);
return((T)item.Item);
}
public static int CreateDelta(Snapshot from, Snapshot to, int[] outputData)
{
var numDeletedItems = 0;
var numUpdatedItems = 0;
var numTempItems = 0;
var outputOffset = 3;
var hashItems = new HashItem[HASHLIST_SIZE];
for (var i = 0; i < hashItems.Length; i++)
{
hashItems[i] = new HashItem();
}
GenerateHash(hashItems, to);
for (var i = 0; i < from.ItemsCount; i++)
{
var fromItem = from[i];
if (GetItemIndexHashed(fromItem.Key, hashItems) == -1)
{
numDeletedItems++;
outputData[outputOffset++] = fromItem.Key;
}
}
GenerateHash(hashItems, from);
var pastIndecies = new int[SnapshotBuilder.MaxItems];
// fetch previous indices
// we do this as a separate pass because it helps the cache
for (var i = 0; i < to.ItemsCount; i++)
{
pastIndecies[i] = GetItemIndexHashed(to[i].Key, hashItems);
}
for (var i = 0; i < to.ItemsCount; i++)
{
var currentItem = to[i];
var itemSize = SnapshotItemsInfo.GetSize(currentItem.Item.GetType());
var pastIndex = pastIndecies[i];
if (pastIndex != -1)
{
var pastItem = from[pastIndex];
var offset = outputOffset + 3;
if (itemSize != 0)
{
offset = outputOffset + 2;
}
if (DiffItem(pastItem.Item, currentItem.Item,
outputData, offset) != 0)
{
outputData[outputOffset++] = (int)currentItem.Item.Type;
outputData[outputOffset++] = currentItem.Id;
if (itemSize == 0)
{
outputData[outputOffset++] = itemSize / sizeof(int);
}
outputOffset += itemSize / sizeof(int); // count item int fields
numUpdatedItems++;
}
}
else
{
outputData[outputOffset++] = (int)currentItem.Item.Type;
outputData[outputOffset++] = currentItem.Id;
if (itemSize == 0)
{
outputData[outputOffset++] = itemSize / sizeof(int);
}
var data = currentItem.Item.ToArray();
var output = outputData.AsSpan(outputOffset, data.Length);
data.CopyTo(output);
outputOffset += data.Length;
numUpdatedItems++;
}
}
if (numDeletedItems == 0 && numUpdatedItems == 0 && numTempItems == 0)
{
return(0);
}
outputData[0] = numDeletedItems;
outputData[1] = numUpdatedItems;
outputData[2] = numTempItems;
return(outputOffset);
}