pro ieee_to_host, data, IDLTYPE = idltype ;+ ; NAME: ; IEEE_TO_HOST ; PURPOSE: ; Translate an IDL variable from IEEE-754 to host representation ; EXPLANATION: ; The variable is translated from IEEE-754 ("big-endian" as used, for ; example, in FITS data ), into the host machine architecture. ; ; Duplicates most of the functionality of the SWAP_ENDIAN_INPLACE procedure ; introduced in V5.6, with the addition of the IDLTYPE keyword. ; CALLING SEQUENCE: ; IEEE_TO_HOST, data, [ IDLTYPE = , ] ; ; INPUT-OUTPUT PARAMETERS: ; data - any IDL variable, scalar or vector. It will be modified by ; IEEE_TO_HOST to convert from IEEE to host representation. Byte ; and string variables are returned by IEEE_TO_HOST unchanged ; ; OPTIONAL KEYWORD INPUTS: ; IDLTYPE - scalar integer (1-15) specifying the IDL datatype according ; to the code given by the SIZE function. This keyword ; is usually when DATA is a byte array to be interpreted as ; another datatype (e.g. FLOAT). ; ; EXAMPLE: ; A 2880 byte array (named FITARR) from a FITS record is to be ; interpreted as floating and converted to the host representaton: ; ; IDL> IEEE_TO_HOST, fitarr, IDLTYPE = 4 ; ; METHOD: ; The BYTEORDER procedure is called with the appropriate keyword ; ; MODIFICATION HISTORY: ; Written, W. Landsman Hughes/STX May, 1992 ; Converted to IDL V5.0 W. Landsman September 1997 ; Under VMS check for IEEE -0.0 values January 1998 ; VMS now handle -0.0 values under IDL V5.1 July 1998 ; Added new integer datatypes C. Markwardt/W. Landsman July 2000 ; Post-V5.1 version, no VMS negative zero check W. Landsman July 2001 ; Use size(/type) W. Landsman December 2002 ; Use /SWAP_IF_LITTLE_ENDIAN keyword for 64bit types W. Landsman Feb 2003 ; Do not use XDR keywords to BYTEORDER for much improved speed ; W. Landsman April 2006 ; Update cosmetic typo for structures W. Landsman October 2006 ;- On_error,2 if N_params() EQ 0 then begin print,'Syntax - IEEE_TO_HOST, data, [ IDLTYPE = ]' return endif npts = N_elements( data ) if npts EQ 0 then $ message,'ERROR - IDL data variable (first parameter) not defined' if not keyword_set( idltype) then idltype = size(data,/type) case idltype of 1: return ;byte 2: byteorder, data, /SSWAP,/SWAP_IF_LITTLE ;integer 3: byteorder, data, /LSWAP,/SWAP_IF_LITTLE ;long 4: byteorder, data, /LSWAP, /SWAP_IF_LITTLE ;float 5: byteorder,data,/L64SWAP, /SWAP_IF_LITTLE ;double 6: byteorder, data, /LSWAP, /SWAP_IF_LITTLE 7: return ;string 8: BEGIN ;structure Ntag = N_tags( data ) for t=0,Ntag-1 do begin temp = data.(t) ieee_to_host, temp data.(t) = temp endfor END 9: byteorder, data, /L64SWAP, /SWAP_IF_LITTLE 12: byteorder, data, /SSWAP, /SWAP_IF_LITTLE 13: byteorder, data, /LSWAP, /SWAP_IF_LITTLE 14: byteorder, data, /L64swap, /SWAP_IF_LITTLE 15: byteorder, data, /L64swap, /SWAP_IF_LITTLE else: message,'Unrecognized datatype ' + strtrim(idltype,2) ENDCASE return end