block_head
if (GetFreeSpace() + sizeof(block_head) > GetBlockSize()) {
GetFreeSpace(), GetBlockSize() - sizeof(block_head)));
block_head *
return (block_head*)fData;
return (const Key*)((uint8*)fData + sizeof(block_head));
return (ItemHeader*)((uint8*)fData + sizeof(block_head));
return sizeof(ItemHeader) * CountItems() + sizeof(block_head);
block_head *GetHeader() const;