FUNCTION dustem_read_size,file,silent=silent,help=help


;+
; NAME:
;   dustem_read_size
;
; PURPOSE:
;   reads information relating to the grain size distribution
;   from the corresponding .DAT file
;
; CATEGORY:
;    DustEMWrap, Distributed, LowLevel, Initialization
;
; CALLING SEQUENCE:
;   st=dustem_read_size(file)
;
; INPUTS:
;    file  : input file to be read
;
; OPTIONAL INPUT PARAMETERS:
;
; OUTPUTS:
;    st   : dustem data structure
;
; OPTIONAL OUTPUT PARAMETERS:
;
; ACCEPTED KEY-WORDS:
;    help     : writes this help
;
; COMMON BLOCKS:
;    None
;
; SIDE EFFECTS:
;
; RESTRICTIONS:
;    The DustEM fortran code must be installed
;    The DustEMWrap IDL code must be installed
;
; PROCEDURES AND SUBROUTINES USED:  
;
; EXAMPLES:
;
; MODIFICATION HISTORY:
;    Evolution details on the DustEMWrap gitlab.
;    See http://dustemwrap.irap.omp.eu/ for FAQ and help.  
;-
  
IF keyword_set(help) THEN BEGIN
   doc_library,'dustem_read_size'
   full_st=0.
   goto,the_end
ENDIF
  
  
st=''
Nmax=10000L
sts=strarr(Nmax)
openr,unit,file,/get_lun

;==read comments
str='' & first_char='#'
WHILE first_char EQ '#' DO BEGIN
  readf,unit,str
  first_char=strmid(str,0,1)
ENDWHILE

;read number of bulk materials
Nbulk=fix(str)

readf,unit,density
readf,unit,mass_frac
readf,unit,Nsize
Nsize=fix(Nsize)

a=fltarr(Nsize) & dloga=fltarr(Nsize) & a4dnda=fltarr(Nsize)
f_mix=fltarr(nsize) & f_pol=fltarr(nsize) & rho_eff=fltarr(nsize) & fv=fltarr(Nsize)
FOR i=0L,Nsize-1 DO BEGIN
  readf,unit,st
  stv=str_sep(strtrim(strcompress(st),2),' ')
  a(i)=float(stv(0))
  dloga(i)=float(stv(1))
  a4dnda(i)=float(stv(2))
  f_mix(i)=float(stv(3))
  f_pol(i)=float(stv(4))
  rho_eff(i)=float(stv(5))
  fv(i)=float(stv(6))
ENDFOR

close,unit
free_lun,unit

one_size_st={a:0.,dloga:0.,a4dnda:0.,f_mix:0.,f_pol:0.,rho_eff:0.,fv:0.}
size_st=replicate(one_size_st,Nsize)

size_st.a=a
size_st.dloga=dloga
size_st.a4dnda=a4dnda
size_st.f_mix=f_mix
size_st.f_pol=f_pol
size_st.rho_eff=rho_eff
size_st.fv=fv

full_st={file:file,Nbulk:Nbulk,density:density,mass_frac:mass_frac,Nsize:Nsize,size_st:size_st}

the_end:
return,full_st

END