XHASHFORMAT

This is the file system layout for the xhash storage system.  The implementation is based on the data structure described by Split Ordered Lists (Shalev, Shavit.)  The basic data structure is a linked list in the data file.  A hashed index into the linked list is maintained in a separate file.  The main data file format looks like so:

header 48 bytes:
	identifier: 2bytes = XD
	version:2bytes
	size:4bytes
	head-pointer: 8bytes
	reserved: 32bytes
node header=18bytes:
	keyhash: 4bytes
	nextptr: 8bytes
	keysize: 2bytes
	datasize: 4bytes
	key: variable
	data: variable bytes
	
and the index file:

header 40 bytes:
	identifier: 2bytes = XI
	version:2bytes
	capacity:4bytes
	reserved: 32bytes
table array:
	pointer: 8bytes