map_find Function

  function map_find(map, target) result(idx)
    !! Check if target pointer exists in single-array map
    implicit none
    type(array_ptr), allocatable :: map(:)
    type(array_type), intent(in), target :: target
    integer :: idx, n, i

    idx = 0
    if(.not. allocated(map)) return
    n = size(map)
    do i = 1, n
       if(associated(map(i)%p, target))then
          idx = i
          return
       end if
    end do
  end function map_find