pro norh_rd_tcx,arg0,arg1,arg2,arg3,freq=freq,integer=integer $
  ,event=event,infil=infil

;+
; NAME:
;       NORH_RD_TCX
;
; PURPOSE:
;       This procedure reads the NORH 'tca' or 'tcz' file.
;
; CALLING SEQUENCE:
;       norh_rd_tcx,infil,index,cor
;       norh_rd_tcx,st_day,ed_day,index,cor
;       norh_rd_tcx,day,index,cor
;
; INPUTS:
;       infil: list of 'tca' or 'tcz' files to be read
;       st_day: start day to be read
;       ed_day: end day to be read
;       day: day to be read
; OPTIONAL INPUTS:
;       freq: observing frequency, 17 or 34
;
; OPTIONAL INPUT KEYWORDS:
;       event: if set, read event-mode data
;       integer: if set, give the correration in longword integer
;                 with max. of 2^{15}=32768.
;
; OUTPUTS:
;       index: index structure
;       cor: Correlation. 
;
; HISTORY:
;       Writtern 1998-09-04 TY
;       Modified 1999-01-02 TY for norh_tcx2idx
;       Modified 1999-01-13 TY max. cor becomes unity
;       Modified 1999-04-14 TY event
;       Modified 1999-11-15 TY bug fix for no event-file date
;       Modified 1999-12-27 TY bug fix for event (JST & UT confuse)
;       Modified 2014-02-03 MS bug fix for SDAS.
;
;-

if (n_elements(freq) eq 0) then freq=17
if (freq eq 34) then freqst='tcz' else freqst='tca'

if ((strpos(arg0(0),'bf') ne -1) or $
    (strpos(arg0(0),'cf') ne -1) or $
    (strpos(arg0(0),'tc') ne -1)) then begin
  infil=arg0 
endif else begin
  case n_params() of
    4 : begin
      st_time=arg0
      ed_time=arg1
      st_daytim=anytim(st_time,/ints)
      ed_daytim=anytim(ed_time,/ints)
    end
    3 : begin
      st_time=arg0
      st_daytim=anytim(st_time,/ints)
      ed_daytim=st_daytim
;     ed_daytim.day=st_daytim.day
    end
    else : message, 'Too small number of arguments'
  endcase

ndayx=ed_daytim.day-st_daytim.day+1
ex=anytim(transpose([[lonarr(ndayx)],[st_daytim.day+lindgen(ndayx)]]),/ex)
yyyy=reform(ex(6,*))
mm=reform(ex(5,*))
dd=reform(ex(4,*))
yy=yyyy-yyyy/100*100
yymmdd=$
  string(transpose([[yy],[mm],[dd]]),format="(i2.2,i2.2,i2.2)")
year=strtrim(string(yyyy),2)

dir0=getenv('DIR_NORH_TCX')

if not keyword_set(event) then begin

    files=freqst+yymmdd+'*'
    dir=[dir0+'/'+year+'/'+string(mm,format="(i2.2)")]
    dir=dir(uniq(dir))
    infil=file_list(dir, files, files = lfiles)
    infil=infil(where(strlen(lfiles) le 10))

endif else begin

  pr_ex=anytim([0,st_daytim.day-1],/ex)
  pr_yyyy=reform(pr_ex(6,*))
  pr_mm=reform(pr_ex(5,*))
  pr_dd=reform(pr_ex(4,*))
  pr_yy=pr_yyyy-pr_yyyy/100*100
  pr_yymmdd=$
    string(pr_yy,pr_mm,pr_dd,format="(i2.2,i2.2,i2.2)")

  files=freqst+[pr_yymmdd+'_2*',yymmdd+'_0*']
dir=[dir0+'/'+year+'/'+string(mm,format="(i2.2)")]
  if (n_elements(dir) ge 2) then dir=dir(uniq(dir))
  infil=file_list(dir,files)

endelse

endelse


if (n_elements(infil) eq 1) then begin
if (infil(0) eq '') then begin
    print,'No files found'
    return
endif
endif

mx=n_elements(infil)
case mx of
  1: begin
  file=infil(0)
  cor_el=readfits(file,header,/silent)
  index_el=norh_tcx2idx(header)

  cor=cor_el
  index=index_el
  end
  else : begin
  m=0
    file=infil(m)
    cor_el=readfits(file,header,/silent)
    index_el=norh_tcx2idx(header)

    cor=cor_el
    index=index_el
  for m=1,mx-1 do begin
    file=infil(m)
    cor_el=readfits(file,header,/silent)
    index_el=norh_tcx2idx(header)

    cor=[cor,cor_el]
    index=[index,index_el]
  endfor
  end
endcase
if keyword_set(integer) then cor=fix(cor*32760)

case n_params() of
  4 : begin
    arg2=index
    arg3=cor
  end
  3 : begin
    arg1=index
    arg2=cor
  end
endcase

end