;------------------------------------------------------------
;------------------------------------------------------------
;------------------------------------------------------------
;+
;
; @file_comments 
; Allows to pass from a 2d depth array to a corresponding 2d level array.
;
; @categories
; Without loop
;
; @param TAB 
; 2d depth array (or a structure respecting litchamp critrions)
;
; @keyword UPPER
; (activated by default) We select the level just above the depth
;
; @keyword LOWER
; We select the level just below the depth 
;
; @keyword CLOSER 
; We select the depth's closer level 
;
; @keyword NOMASK 
; To do not mask land points
;
; @returns 
; It is a 2d array containing level's values.
;
; @uses
; common.pro
;
; @restrictions 
; For depthes out of gdep's values, the value !values.f_nan is sent back.
; if the depth is superior to this one of the bottom, we send back jpk-1 in 
; the upper case, and !values.f_nan in the lower case.
;
; @history
; Sebastien Masson (smasson@lodyc.jussieu.fr)
;                       17/6/1999
;                       15/6/2000 accepte !values.f_nan
;
; @version
; $Id$
;-
;------------------------------------------------------------
;------------------------------------------------------------
;------------------------------------------------------------
FUNCTION depth2level, tab, LOWER = lower, UPPER = upper, CLOSER = closer $
                      , NOMASK = nomask, _extra = ex
;
  compile_opt idl2, strictarrsubs
;
   tempsun = systime(1)         ; for key_performance
@common
;------------------------------------------------------------
   upper = 1
   if keyword_set(lower) THEN upper = 0
;------------------------------------------------------------
; Reading of the input field and recuperation of the used subdomain's size
;------------------------------------------------------------
   in = litchamp(tab)
   grille,mask,-1,-1,gdep,nx,ny,nz,firstx,firsty,firstz,lastx,lasty,lastz
;---------------------------------------------------------------
; Verification of the coherence between array's size and the defined by domdef domain
;---------------------------------------------------------------
   IF ny EQ 1 THEN in = reform(in, nx, ny, /over)
   taille = size(in)
   if taille[0] NE 2 then return, report('le champ en entree doit contenir un tableau 2d')
   case 1 of
      taille[1] eq jpi and taille[2] eq jpj:in=in[firstx:lastx, firsty:lasty]
      taille[1] eq  nx and taille[2] eq  ny:
      else:return, report('Probleme d''adequation entre les tailles du domaine et celle du champ.')
   endcase
;------------------------------------------------------------
;------------------------------------------------------------
;------------------------------------------------------------
; delete points at !values.f_nan
   notanumber = where(finite(in, /nan) EQ 1)
   if notanumber[0] NE -1 then in[notanumber] = 0
;------------------------------------------------------------
; We transform the 2d deth value in a 2d array of levels corresponding to depthes
;------------------------------------------------------------
; We go on array who have the size of 3d arrays
   prof=replicate(1,nx*ny)#gdep[firstz:lastz] 
   in = in[*]#replicate(1, nz)
;
   mask01 = (prof[*] LT in[*])
   mask01 = reform(mask01, nx, ny, nz)
   levels = total(mask01, 3)
   notvalid = where(levels EQ nz)
   if keyword_set(upper) then begin
      levels = levels-1
      notvalid = where(levels EQ -1)
   ENDIF ELSE notvalid = where(levels EQ nz)
   IF notvalid[0] NE -1 THEN levels[notvalid] = !values.f_nan

; If closer is activated
   if keyword_set(closer) then begin
      test = [ [[litchamp(tab)-level2depth(levels)]] $
               , [[level2depth( (levels+1)<(jpk-1) )-litchamp(tab)]] ]
      test = test[*, *, 0]-test[*, *, 1]
      changer = where(test GE 0)
      if changer[0] NE -1 then levels[changer] = (levels[changer]+1) < (jpk-1)
   endif
;------------------------------------------------------------
; We put back points at !values.f_nan
   if notanumber[0] NE -1 then levels[notanumber] = !values.f_nan
; We mask land points at valmask
   if NOT keyword_set(nomask) then begin
      if n_elements(valmask) EQ 0 then valmask = 1e20
      terre = where(mask[*, *, 0] EQ 0)
      if terre[0] NE -1 then levels[terre] = valmask
   endif
;------------------------------------------------------------
;------------------------------------------------------------
;------------------------------------------------------------
   if keyword_set(key_performance) THEN print, 'temps depth2level', systime(1)-tempsun 
   return, levels
end