function dbxval,entry,idltype,nvalues,sbyte,nbytes ;+ ; NAME: ; DBXVAL ; ; PURPOSE: ; Quickly return a value of the specified item number ; EXPLANATION: ; Procedure to quickly return a value of the specified item number ; from the entry. ; ; CALLING SEQUENCE: ; result = dbxval( entry, idltype, nvalues, sbyte, nbytes ) ; ; INPUTS ; entry - entry or entries from data base (bytarr) ; idltype - idl data type (obtained with db_item_info) ; nvalues - number of values to return (obtained with db_item) ; sbyte - starting byte in the entry (obtained with db_item) ; nbytes - number of bytes (needed only for string type) ; (obtained with db_item) ; ; OUTPUTS: ; function value is value of the specified item in entry ; ; RESTRICTIONS: ; To increase speed the routine assumes that entry and item are ; valid and that the data base is already opened using dbopen. ; ; REVISION HISTORY: ; version 0 D. Lindler Nov. 1987 (for new db format) ; Version 1, William Thompson, GSFC, 28 March 1994. ; Incorporated into CDS library. ; Version 2, Richard Schwartz, GSFC/SDAC, 23 August 1996 ; Allowed Entry to have 2 dimensions ; Version 2.1, 22 Feb 1997, JK Feggans, ; avoid reform for strings arrays. ; Version 2.2 Use overwrite with REFORM(), W. Landsman, May 1997 ; Converted to IDL V5.0 W. Landsman September 1997 ; Work for multiple-valued strings W. Landsman October 2000 ; Add new 64bit & unsigned integer datatypes W.Landsman July 2001 ;- ;---------------------------------------------------------------- ; ; nentry = n_elements(entry[0,*]) case idltype of ;case of data type 1: val = byte(entry[sbyte:sbyte+nvalues-1,*],0,nvalues,nentry) 2: val = fix(entry[sbyte:sbyte+nvalues*2-1,*],0,nvalues,nentry) 3: val = long(entry[sbyte:sbyte+nvalues*4-1,*],0,nvalues,nentry) 4: val = float(entry[sbyte:sbyte+nvalues*4-1,*],0,nvalues,nentry) 5: val = double(entry[sbyte:sbyte+nvalues*8-1,*],0,nvalues,nentry) 7: val = string( reform( entry[sbyte:sbyte+nbytes-1,*], nbytes/nvalues, $ nvalues, nentry)) 12: val = uint(entry[sbyte:sbyte+nvalues*2-1,*],0,nvalues,nentry) 13: val = ulong(entry[sbyte:sbyte+nvalues*4-1,*],0,nvalues,nentry) 14: val = long64(entry[sbyte:sbyte+nvalues*8-1,*],0,nvalues,nentry) 15: val = ulong64(entry[sbyte:sbyte+nvalues*8-1,*],0,nvalues,nentry) endcase ; if ( nvalues EQ 1 and nentry EQ 1) then return,val[0] else $ if idltype eq 7 then return,val else return,reform(val,/overwrite) end