!! string handling
!!
	subroutine STR_TRIM(RETSTR, STR, RETLEN) !!
!!
!! if RETSTR=STR then RETSTR is not touched
!!
!! Arguments:
	character*(*) STR, RETSTR !! in,out
	integer RETLEN    	!! out
	integer i

	i=len(str)
	if (str(1:1) .gt. ' ') then
10	  if (str(i:i) .le. ' ') then
	    i=i-1
	    goto 10
	  endif
	else
20	  if (str(i:i) .le. ' ') then
	    if (i .gt. 1) then
	      i=i-1
	      goto 20
	    endif
	  endif
	endif
	retlen=min(len(retstr),i)
	if (retstr .ne. str) then ! avoid copy to retstr if equal
	  retstr=str(1:i)
	endif
	end

!!
	subroutine STR_UPCASE(RETSTR, STR) !!
!!
!! Arguments:
	character STR*(*), RETSTR*(*)	!! in,out
	integer i, ch

	retstr=str
	do i=1,len(retstr)
	  ch=ichar(retstr(i:i))
	  if (ch .ge. ichar('a') .and. ch .le. ichar('z')) then
	    retstr(i:i)=char(ch-(ichar('a')-ichar('A')))
	  endif
	enddo
	end

!!
	subroutine STR_LOWCASE(RETSTR, STR) !!
!!
!! Arguments:
	character STR*(*), RETSTR*(*)	!! in,out
	integer i, ch

	retstr=str
	do i=1,len(retstr)
	  ch=ichar(retstr(i:i))
	  if (ch .ge. ichar('A') .and. ch .le. ichar('Z')) then
	    retstr(i:i)=char(ch+(ichar('a')-ichar('A')))
	  endif
	enddo
	end

!!
	subroutine STR_APPEND(str, length, add) !!
!!
	implicit none

	character*(*) str, add !!
	integer length         !!

	if (len(add)+length .gt. len(str)) then
	  if (length .lt. len(str)) then
	    str(length+1:)=add
	    length=len(str)
	  endif
	else
	  str(length+1:length+len(add))=add
	  length=length+len(add)
	endif
	end

!!
	integer function STR_CMP(str1, str2) !!
!!
!! if strings are equal: return 0
!! else return position of first different character

	character str1*(*), str2*(*) !!

	integer i

	do i=0,min(len(str1),len(str2))-1
	  if (str1(i+1:i+1) .ne. str2(i+1:i+1)) then
	    str_cmp=i+1
	    return
	  endif
	enddo
	do i=len(str1),len(str2)-1
	  if (str2(i+1:i+1) .ne. ' ') then
	    str_cmp=i+1
	    return
	  endif
	enddo
	do i=len(str2),len(str1)-1
	  if (str1(i+1:i+1) .ne. ' ') then
	    str_cmp=i+1
	    return
	  endif
	enddo
	str_cmp=0
	return
	end

!!
	subroutine STR_FIRST_NONBLANK(STR, POS) !!
!!
!! Arguments:
	character*(*) STR       !! in
	integer POS             !! out
	integer i

	do i=1,len(str)
	  if (str(i:i) .gt. ' ') then
	    pos=i
	    return
	  endif
	enddo
	pos=0
	end