subroutine charlineparser(longchar,nmax,charvars,n)
      implicit none
!7 Sept 2013, revised version
!parse a long line of chars into char variables with the following assumptions:
!1. Each cell is separated by a separating character which can be either a ',', blank space(s) or anything 
!with the ASCII code less than and including 032 or larger than and including 127
!2. Any separating characters at the end of the line are discarded, i.e.
!  '1,2,3,4,a,b,c,,,,,,,,,,       ,'='1,2,3,4,a,b,c'
!3. If there is no entry between two non-comma separating characters,these two separating characters are treated as one.
!   i.e. '1   2   3 4 a           b c'='1,2,3,4,a,b,c'
!4. If there is no entry between two commas that are not positioned in the end of the line, a missing value is assumed to
!exist between these two commas and this missing value is denoted with -9999, i.e.
!     i.e. '1,,3,4,a,b,c'='1,-9999,3,4,a,b,c'
!5. Comma has priotity as a separating characer. E.g commas and blank spaces are not used simultaneously as
!   separating characters in a single line. When both commas and blank spaces appear in the line, comma is 
!   the saparating character and blank spaces are repalced with '_'
      integer nmax,n
      character(*)::longchar
      character charvars(nmax+100)*50
      integer i,k,pos1,pos2,leng,posindex(0:nmax+100),itiscomma
!
      leng=LEN_TRIM(longchar)
      i=leng
5     k=ichar(longchar(i:i))
      if(k.eq.44.or.k.le.32.or.k.ge.127)then
        longchar(i:i)=char(32)
        i=i-1
        if(i.gt.1)goto 5
!empty line
        n=0
        return
      endif
      leng=i

      itiscomma=0
      do i=1,leng
        if(ichar(longchar(i:i)).eq.44)itiscomma=itiscomma+1
      enddo
      if(itiscomma.ge.nmax)then
        n=0
        return
      endif
      if(itiscomma.gt.0)then
!If the line contains at least one comma, it is assumed a comma separated line
        n=0
        do i=1,leng
          if(ichar(longchar(i:i)).eq.44)then
            n=n+1
            posindex(n)=i
          endif
        enddo
        n=n+1
        posindex(0)=0
        posindex(n)=leng+1
        do i=1,n
          pos1=posindex(i-1)+1
          pos2=posindex(i)-1
          If(pos1.gt.pos2)goto 50
30        if(ichar(longchar(pos1:pos1)).ge.33.and.
     &ichar(longchar(pos1:pos1)).le.126)goto 40
          if(pos1.lt.pos2)then
            pos1=pos1+1
            goto 30
          endif
!pos1=pos2 and missing entry
          pos1=pos2+1
          goto 50
40        if(ichar(longchar(pos2:pos2)).ge.33.and.
     &ichar(longchar(pos2:pos2)).le.126)goto 50
          if(pos2.gt.pos1)then
            pos2=pos2-1
            goto 40
          endif
          pos1=pos2+1
50        If(pos1.gt.pos2)then
            charvars(i)='-9999'
          else
            do k=pos1+1,pos2-1
              if(ichar(longchar(k:k)).le.32.or.
     &ichar(longchar(k:k)).ge.127)longchar(k:k)='_'
            enddo
            charvars(i)=longchar(pos1:pos2)
          endif
        enddo
        return
      endif
!non-comma separated file
      n=0
      pos1=0
10    pos1=pos1+1
      if(pos1.gt.leng)return
      if(ichar(longchar(pos1:pos1)).le.32.or.
     &ichar(longchar(pos1:pos1)).ge.127)goto 10
!pos1 is the first character in the character variable.
!now locate the end character
      pos2=pos1
20    pos2=pos2+1
      if(ichar(longchar(pos2:pos2)).ge.33.and.
     &ichar(longchar(pos2:pos2)).le.126)then
        if(pos2.le.leng)goto 20
      endif
      pos2=pos2-1
      n=n+1
      charvars(n)=longchar(pos1:pos2)
      pos1=pos2
      goto 10
      return
      end subroutine charlineparser