function SXPAR, hdr, name, abort, COUNT=matches, COMMENT = comments, $ NoContinue = NoContinue ;+ ; NAME: ; SXPAR ; PURPOSE: ; Obtain the value of a parameter in a FITS header ; ; CALLING SEQUENCE: ; result = SXPAR( Hdr, Name, [ Abort, COUNT=, COMMENT =, /NoCONTINUE ]) ; ; INPUTS: ; Hdr = FITS header array, (e.g. as returned by READFITS) ; string array, each element should have a length of 80 characters ; ; Name = String name of the parameter to return. If Name is of the ; form 'keyword*' then an array is returned containing values of ; keywordN where N is an integer. The value of keywordN will be ; placed in RESULT(N-1). The data type of RESULT will be the ; type of the first valid match of keywordN found. ; ; OPTIONAL INPUTS: ; ABORT - string specifying that SXPAR should do a RETALL ; if a parameter is not found. ABORT should contain ; a string to be printed if the keyword parameter is not found. ; If not supplied, SXPAR will return quietly with COUNT = 0 ; (and !ERR = -1) if a keyword is not found. ; ; OPTIONAL INPUT KEYWORDS: ; /NOCONTINUE = If set, then continuation lines will not be read, even ; if present in the header ; ; OPTIONAL OUTPUT KEYWORDS: ; COUNT - Optional keyword to return a value equal to the number of ; parameters found by SXPAR, integer scalar ; ; COMMENT - Array of comments associated with the returned values ; ; OUTPUTS: ; Function value = value of parameter in header. ; If parameter is double precision, floating, long or string, ; the result is of that type. Apostrophes are stripped ; from strings. If the parameter is logical, 1b is ; returned for T, and 0b is returned for F. ; If Name was of form 'keyword*' then a vector of values ; are returned. ; ; SIDE EFFECTS: ; !ERR is set to -1 if parameter not found, 0 for a scalar ; value returned. If a vector is returned it is set to the ; number of keyword matches found. The use of !ERR is deprecated, and ; instead the COUNT keyword is preferred ; ; If a keyword occurs more than once in a header, a warning is given, ; and the first occurence is used. ; ; EXAMPLES: ; Given a FITS header, h, return the values of all the NAXISi values ; into a vector. Then place the history records into a string vector. ; ; IDL> naxisi = sxpar( h ,'NAXIS*') ; Extract NAXISi value ; IDL> history = sxpar( h, 'HISTORY' ) ; Extract HISTORY records ; ; PROCEDURE: ; The first 8 chacters of each element of Hdr are searched for a ; match to Name. The value from the last 20 characters is returned. ; An error occurs if there is no parameter with the given name. ; ; If a numeric value has no decimal point it is returned as type ; LONG. If it contains more than 8 numerals, or contains the ; characters 'D' or 'E', then it is returned as type DOUBLE. Otherwise ; it is returned as type FLOAT. Very large integer values, outside ; the range of valid LONG, are returned as DOUBLE. ; ; If the value is too long for one line, it may be continued on to the ; the next input card, using the OGIP CONTINUE convention. For more info, ; http://heasarc.gsfc.nasa.gov/docs/heasarc/ofwg/docs/ofwg_recomm/r13.html ; ; Complex numbers are recognized as two numbers separated by one or more ; space characters. ; ; If a numeric value has no decimal point (or E or D) it is returned as ; type LONG. If it contains more than 8 numerals, or contains the ; character 'D', then it is returned as type DOUBLE. Otherwise it is ; returned as type FLOAT. If an integer is too large to be stored as ; type LONG, then it is returned as DOUBLE. ; ; NOTES: ; The functions SXPAR() and FXPAR() are nearly identical, although ; FXPAR() has slightly more sophisticated parsing. There is no ; particular reason for having two nearly identical procedures, but ; both are too widely used to drop either one. ; ; PROCEDURES CALLED: ; GETTOK(), STRNUMBER(), VALID_NUM() ; MODIFICATION HISTORY: ; DMS, May, 1983, STPAR Written. ; D. Lindler Jan 90 added ABORT input parameter ; J. Isensee Jul,90 added COUNT keyword ; W. Thompson, Feb. 1992, added support for FITS complex values. ; W. Thompson, May 1992, corrected problem with HISTORY/COMMENT/blank ; keywords, and complex value error correction. ; W. Landsman, November 1994, fix case where NAME is an empty string ; W. Landsman, March 1995, Added COMMENT keyword, ability to read ; values longer than 20 character ; W. Landsman, July 1995, Removed /NOZERO from MAKE_ARRAY call ; T. Beck May 1998, Return logical as type BYTE ; W. Landsman May 1998, Make sure integer values are within range of LONG ; Converted to IDL V5.0, May 1998 ; W. Landsman Feb 1998, Recognize CONTINUE convention ; W. Landsman Oct 1999, Recognize numbers such as 1E-10 as floating point ; W. Landsman Jan 2000, Only accept integer N values when name = keywordN ;- ;---------------------------------------------------------------------- if N_params() LT 2 then begin print,'Syntax - result = sxpar( hdr, name, [abort, COUNT = ]) return, -1 endif VALUE = 0 if N_params() LE 2 then begin abort_return = 0 abort = 'FITS Header' end else abort_return = 1 if abort_return then On_error,1 else On_error,2 ; Check for valid header s = size(hdr) ;Check header for proper attributes. if ( s[0] NE 1 ) or ( s[2] NE 7 ) then $ message,'FITS Header (first parameter) must be a string array' nam = strtrim( strupcase(name) ) ;Copy name, make upper case ; Determine if NAME is of form 'keyword*'. If so, then strip off the '*', and ; set the VECTOR flag. One must consider the possibility that NAM is an empty ; string. namelength1 = (strlen(nam) - 1 ) > 1 if strpos( nam, '*' ) EQ namelength1 then begin nam = strmid( nam, 0, namelength1) vector = 1 ;Flag for vector output name_length = strlen(nam) ;Length of name num_length = 8 - name_length ;Max length of number portion if num_length LE 0 then $ message, 'Keyword length must be 8 characters or less' ; Otherwise, extend NAME with blanks to eight characters. endif else begin while strlen(nam) LT 8 do nam = nam + ' ' ;Make 8 chars long vector = 0 endelse ; If of the form 'keyword*', then find all instances of 'keyword' followed by ; a number. Store the positions of the located keywords in NFOUND, and the ; value of the number field in NUMBER. histnam = (nam eq 'HISTORY ') or (nam eq 'COMMENT ') or (nam eq '') if N_elements(start) EQ 0 then start = -1l start = long(start[0]) if (not vector) and (start GE 0) then begin if N_elements(precheck) EQ 0 then precheck = 5 if N_elements(postcheck) EQ 0 then postcheck = 20 nheader = N_elements(hdr) mn = (start - precheck) > 0 mx = (start + postcheck) < nheader-1 keyword = strmid(hdr[mn:mx], 0, 8) endif else begin restart: start = -1l keyword = strmid( hdr, 0, 8) endelse if vector then begin nfound = where(strpos(keyword,nam) GE 0, matches) if ( matches gt 0 ) then begin numst= strmid( hdr[nfound], name_length, num_length) number = replicate(-1, matches) for i = 0, matches-1 do $ if VALID_NUM( numst[i], num) then number[i] = num igood = where(number GE 0, matches) if matches GT 0 then begin nfound = nfound[igood] number = number[igood] endif endif ; Otherwise, find all the instances of the requested keyword. If more than ; one is found, and NAME is not one of the special cases, then print an error ; message. endif else begin nfound = where(keyword EQ nam, matches) if (matches EQ 0) and (start GE 0) then goto, RESTART if (start GE 0) then nfound = nfound + mn if (matches GT 1) and (not histnam) then $ message,/informational, 'Warning - keyword ' + $ nam + 'located more than once in ' + abort if (matches GT 0) then start = nfound[matches-1] endelse ; Process string parameter if matches GT 0 then begin line = hdr[nfound] svalue = strtrim( strmid(line,9,71),2) if histnam then $ value = strtrim(strmid(line,8,71),2) else for i = 0,matches-1 do begin if ( strmid(svalue[i],0,1) EQ "'" ) then begin ;Is it a string? test = strmid( svalue[i],1,strlen( svalue[i] )-1) next_char = 0 off = 0 value = '' NEXT_APOST: endap = strpos(test, "'", next_char) ;Ending apostrophe if endap LT 0 then $ MESSAGE,'Value of '+name+' invalid in '+abort value = value + strmid( test, next_char, endap-next_char ) ; Test to see if the next character is also an apostrophe. If so, then the ; string isn't completed yet. Apostrophes in the text string are signalled as ; two apostrophes in a row. if strmid( test, endap+1, 1) EQ "'" then begin value = value + "'" next_char = endap+2 goto, NEXT_APOST endif ; Extract the comment, if any slash = strpos( test, "/", endap ) if slash LT 0 then comment = '' else $ comment = strmid( test, slash+1, strlen(test)-slash-1 ) ; This is a string that could be continued on the next line. Check this ; possibility with the following four criteria: *1) Ends with '&' ; (2) Next line is CONTINUE (3) LONGSTRN keyword is present (recursive call to ; SXPAR) 4. /NOCONTINE is not set if not keyword_set(nocontinue) then begin off = off + 1 val = strtrim(value,2) if (strlen(val) gt 0) and $ (strmid(val, strlen(val)-1, 1) EQ '&') and $ (strmid(hdr[nfound[i]+off],0,8) EQ 'CONTINUE') then begin if (size(sxpar(hdr, 'LONGSTRN',/NoCONTINUE)))[1] EQ 7 then begin value = strmid(val, 0, strlen(val)-1) test = hdr[nfound[i]+off] test = strmid(test, 8, strlen(test)-8) test = strtrim(test, 2) if strmid(test, 0, 1) NE "'" then message, $ 'ERROR: Invalidly CONTINUEd string in '+ abort next_char = 1 GOTO, NEXT_APOST ENDIF ENDIF ENDIF ; Process non-string value endif else begin test = svalue[i] slash = strpos( test, "/" ) if slash GT 0 then begin comment = strmid( test, slash+1, strlen(test)-slash-1 ) test = strmid( test, 0, slash ) end else comment = '' ; Find the first word in TEST. Is it a logical value ('T' or 'F') test2 = test value = gettok(test2,' ') if ( value EQ 'T' ) then value = 1b else $ if ( value EQ 'F' ) then value = 0b else begin ; Test to see if a complex number. It's a complex number if the value and ; the next word, if any, are both valid values. if strlen(test2) EQ 0 then goto, NOT_COMPLEX value2 = gettok( test2, ' ') if value2 EQ '' then goto, NOT_COMPLEX On_ioerror, NOT_COMPLEX value2 = float(value2) value = complex(value,value2) goto, GOT_VALUE ; Not a complex number. Decide if it is a floating point, double precision, ; or integer number. NOT_COMPLEX: On_IOerror, GOT_VALUE if (strpos(value,'.') GE 0) or (strpos(value,'E') GT 0) $ or (strpos(value,'D') GE 0) then begin ;Floating or double? if ( strpos(value,'D') GT 0 ) or $ ;Double? ( strlen(value) GE 8 ) then value = double(value) $ else value = float(value) endif else begin ;Long integer lmax = 2.0d^31 - 1.0d lmin = -2.0d31 value = double(value) if (value GE lmin) and (value LE lmax) then $ value = long(value) endelse GOT_VALUE: On_IOerror, NULL endelse endelse; if c eq apost ; Add to vector if required if vector then begin maxnum = max(number) if ( i EQ 0 ) then begin sz_value = size(value) result = make_array( maxnum, TYPE = sz_value[1] ) comments = strarr( maxnum ) endif result[ number[i]-1 ] = value comments[ number[i]-1 ] = comment endif else $ comments = comment endfor if vector then begin !ERR = matches return, result endif else !ERR = 0 endif else begin if abort_return then message,'Keyword '+nam+' not found in '+abort !ERR = -1 endelse return, value END