scan file format

FILE HEADER
	xdr_float:	VERSION  (1.3)
	xdr_long:	scan number
	xdr_short	data's rank
	xdr_vector(rank, xdr_short) dims;
	xdr_short	isRegular (true=1, false=0)			
	xdr_long:	pointer to the extra pvs


SCAN
	HEADER:
	xdr_short:		this scan's rank
	xdr_short:		number of requested points (NPTS)
	xdr_short:		current point (CPT)
	if the scan rank is > 1
	  xdr_vector(NPTS, xdr_long)	pointer to the lower scans

	INFO:
	xdr_counted_string:	scan name
	xdr_counted_string:	time stamp


	xdr_short:		number of positioners
	xdr_short:		number of detectors
	xdr_short:		number of triggers

	for each positioner
	  xdr_short:		positioner number
	  xdr_counted_string:	positioner name
	  xdr_counted_string:	positioner desc
	  xdr_counted_string:	positioner step mode
	  xdr_counted_string:	positioner unit
	  xdr_counted_string:	readback name
	  xdr_counted_string:	readback description
	  xdr_counted_string:	readback unit

	for each detector
	  xdr_short:		detector number
	  xdr_counted_string:	detector name
	  xdr_counted_string:	detector desc
	  xdr_counted_string:	detector unit

	for each trigger
	  xdr_short:		trigger number
	  xdr_counted_string:	trigger name
	  xdr_float:		trigger command

	DATA:
	for each positioner
	  xdr_vector(NPTS, xdr_double):	readback array

	for each detector
	  xdr_vector(NPTS, xdr_float):	detector array

[SCAN]
...
...
...
[SCAN]

EXTRA PVs
	xdr_short:	number of extra pvs

	for each pv
	  xdr_counted_string:	name
	  xdr_counted_string:	desc
	  xdr_short:		type
	  if type != DBR_STRING
	    xdr_short:		count
	    xdr_counted_string:	unit

	  depending on the type:
	    DBR_STRING:
		xdr_counted_string:		value
	    DBR_CTRL_SHORT:
		xdr_bytes(count):		value
	    DBR_CTRL_SHORT:
		xdr_vector(count, xdr_short):	value
	    DBR_CTRL_LONG:
		xdr_vector(count, xdr_long):	value
	    DBR_CTRL_FLOAT:
		xdr_vector(count, xdr_float):	value
	    DBR_CTRL_DOUBLE:
		xdr_vector(count, xdr_double):	value
-----------------------------------------------------------------------

A 1D scan looks like this:

header
scan1
extra PV's

A 2D scan looks like this

header
scan2
	scan1
	scan1
	...
extra PV's

A 3D scan looks like this

header
scan3
	scan2
		scan1
		scan1
		...
	scan2
		scan1
		scan1
		...
	...
extra PV's