pro tbinfo,h,tb_str, errmsg = errmsg, NOSCALE= noscale ;+ ; NAME: ; TBINFO ; PURPOSE: ; Return an informational IDL structure from a FITS binary table header. ; ; CALLING SEQUENCE: ; tbinfo, h, tb_str, [ERRMSG = ] ; INPUTS: ; h - FITS binary table header, e.g. as returned by READFITS() ; ; OUTPUTS: ; tb_str - IDL structure with extracted info from the FITS binary table ; header. Tags include ; .tbcol - starting column position in bytes, integer vector ; .width - width of the field in bytes, integer vector ; .idltype - idltype of field, byte vector ; 7 - string, 4- real*4, 3-integer*4, 5-real*8 ; .numval - repeat count, longword vector ; .tunit - string unit numbers, string vector ; .tnull - integer null value for the field, stored as a string vector ; so that an empty string indicates that TNULL is not present ; .tform - format for the field, string vector ; .ttype - field name, string vector ; .maxval- maximum number of elements in a variable length array, long ; vector ; .tscal - pointer array giving the scale factor for converting to ; physical values, default 1.0 ; .tzero - pointer array giving the additive offset for converting to ; physical values, default 0.0 ; .tdisp - recommended output display format ; ; All of the output vectors will have same number of elements, equal ; to the number of columns in the binary table. ; ; The .tscal and .tzero values are stored as pointers so as to preserve ; the individual data types (e.g. float or double) which may differ ; in different columns. For example, to obtain the value of TSCAL for ; the third column use *tab_str.tscal[2] ; OPTIONAL INPUT KEYWORD: ; /NOSCALE - if set, then the TSCAL* and TZERO* keywords are not extracted ; from the FITS header, and the .tscal and .tzero pointers do not ; appear in the output structure. ; OPTIONAL OUTPUT KEYWORD: ; ERRMSG = if present, then error messages are returned in this keyword ; rather than displayed using the MESSAGE facility ; PROCEDURES USED: ; SXPAR() ; NOTES: ; For variable length ('P' format) column, TBINFO returns values for ; reading the 2 element longward array of pointers (numval=2, ; idltype = 3, width=4) ; HISTORY: ; Major rewrite to return a structure W. Landsman August 1997 ; Added "unofficial" 64 bit integer "K" format W. Landsamn Feb. 2003 ; Store .tscal and .tzero tags as pointers, so as to preserve ; type information W. Landsman April 2003 ; Treat repeat count for string as specifying string length, not number ; of elements, added ERRMSG W. Landsman July 2006 ; Treat logical as character string 'T' or 'F' W. Landsman October 2006 ; Added NOSCALE keyword W. Landsman March 2007 ;- ;---------------------------------------------------------------------------- On_error,2 compile_opt idl2 if N_params() LT 2 then begin print,'Syntax - TBINFO, h, tb_str, [ERRMSG=, /NOSCALE]' return endif save_err = arg_present(errmsg) ; get number of fields tfields = sxpar( h, 'TFIELDS', COUNT = N_TFields) if N_TFields EQ 0 then begin ;Legal Binary Table Header? errmsg = 'Invalid FITS binary table header. keyword TFIELDS is missing' if not save_err then message,errmsg else return endif if tfields EQ 0 then begin ;Any fields in table? errmsg = 'No Columns in FITS binary table, keyword TFIELDS = 0' if not save_err then message,errmsg else return endif ; Create output arrays with default values idltype = intarr(tfields) & tnull = idltype numval = lonarr(tfields) & tbcol = numval & width = numval & maxval = numval tunit = replicate('',tfields) & ttype = tunit & tdisp = tunit & tnull = tunit type = sxpar(h,'TTYPE*', COUNT = N_ttype) if N_ttype GT 0 then ttype[0] = strtrim(type,2) tform = strtrim( sxpar(h,'tform*', COUNT = N_tform), 2) ; column format if N_tform EQ 0 then $ message,'Invalid FITS table header -- keyword TFORM not present' tform = strupcase(strtrim(tform,2)) unit = strtrim(sxpar(h, 'TUNIT*', COUNT = N_tunit),2) ;physical units if N_tunit GT 0 then tunit[0] = unit null = sxpar(h, 'TNULL*', COUNT = N_tnull) ;null data value if N_tnull GT 0 then tnull[0] = null if not keyword_set(noscale) then begin tscal = ptrarr(tfields,/all) tzero = ptrarr(tfields,/all) index = strtrim(indgen(tfields)+1,2) for i=0,tfields-1 do begin scale = sxpar(h,'TSCAL' + index[i], COUNT = N_tscal) ;Scale factor if N_tscal GT 0 then *tscal[i] = scale else *tscal[i] = 1.0 zero = sxpar(h,'TZERO' + index[i], Count = N_tzero) if N_tzero GT 0 then *tzero[i] = zero else *tzero[i] = 0 endfor endif disp = sxpar(h,'TDISP*', COUNT = N_tdisp) ;Display format string if N_tdisp GT 0 then tdisp[0] = disp ; determine idl data type from format len = strlen(tform) for i = 0, N_elements(tform)-1 do begin ; Step through each character in the format, until a non-numerical character ; is encountered ichar = 0 NEXT_CHAR: if ichar GE len[i] then message, $ 'Invalid format specification for keyword TFORM ' + strtrim(i+1) char = strupcase( strmid(tform[i],ichar,1) ) if ( (char GE '0') and ( char LE '9')) then begin ichar = ichar + 1 goto, NEXT_CHAR endif if ichar EQ 0 then numval[i] = 1 else $ numval[i] = strmid( tform[i], 0, ichar ) if char EQ "P" then begin ;Variable length array? char = strupcase( strmid(tform[i],ichar+1,1) ) maxval[i] = long( strmid(tform[i],ichar+3, len[i]-ichar-4) ) width[i] = 4 & numval[i] = 2 & idltype[i] = 3 endif else begin tform[i] = char case strupcase( tform[i] ) of 'A' : begin idltype[i] = 7 & width[i] = numval[i] & numval[i]=1 end 'I' : begin & idltype[i] = 2 & width[i] = 2 & end 'J' : begin & idltype[i] = 3 & width[i] = 4 & end 'E' : begin & idltype[i] = 4 & width[i] = 4 & end 'D' : begin & idltype[i] = 5 & width[i] = 8 & end 'L' : begin & idltype[i] = 7 & width[i] = 1 & end 'B' : begin & idltype[i] = 1 & width[i] = 1 & end 'C' : begin & idltype[i] = 6 & width[i] = 8 & end 'M' : begin & idltype[i] = 9 & width[i] =16 & end 'K' : begin & idltype[i] = 14 & width[i] = 8 & end ; Treat bit arrays as byte arrays with 1/8 the number of elements. 'X' : begin idltype[i] = 1 numval[i] = long((numval[i]+7)/8) width[i] = 1 end else : message,'Invalid format specification for keyword ' + $ 'TFORM'+ strtrim(i+1,2) endcase endelse if i ge 1 then tbcol[i] = tbcol[i-1] + width[i-1]*numval[i-1] endfor if keyword_set(noscale) then $ tb_str = {TBCOL:tbcol,WIDTH:width,IDLTYPE:idltype,NUMVAL:numval,TUNIT:tunit,$ TNULL:tnull,TFORM:tform,TTYPE:ttype,MAXVAL:maxval, TDISP:tdisp} $ else $ tb_str = {TBCOL:tbcol,WIDTH:width,IDLTYPE:idltype,NUMVAL:numval,TUNIT:tunit,$ TNULL:tnull,TFORM:tform,TTYPE:ttype,MAXVAL:maxval, TSCAL:tscal, $ TZERO:tzero, TDISP:tdisp} return end