Returns a child in the object or array given the index.
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| class(json_core), | intent(inout) | :: | json | |||
| type(json_value), | intent(in), | pointer | :: | p | object or array JSON data |
|
| integer(kind=IK), | intent(in) | :: | idx | index of the child (this is a 1-based Fortran style array index). |
||
| type(json_value), | pointer | :: | child | pointer to the child |
||
| logical(kind=LK), | intent(out), | optional | :: | found | true if the value was found (if not present, an exception will be thrown if it was not found. If present and not found, no exception will be thrown). |
subroutine json_value_get_child_by_index(json, p, idx, child, found)
implicit none
class(json_core),intent(inout) :: json
type(json_value),pointer,intent(in) :: p !! object or array JSON data
integer(IK),intent(in) :: idx !! index of the child
!! (this is a 1-based Fortran
!! style array index).
type(json_value),pointer :: child !! pointer to the child
logical(LK),intent(out),optional :: found !! true if the value was found
!! (if not present, an exception
!! will be thrown if it was not
!! found. If present and not
!! found, no exception will be
!! thrown).
integer(IK) :: i !! counter
nullify(child)
if (.not. json%exception_thrown) then
if (associated(p%children)) then
! If getting first or last child, we can do this quickly.
! Otherwise, traverse the list.
if (idx==1) then
child => p%children ! first one
elseif (idx==p%n_children) then
if (associated(p%tail)) then
child => p%tail ! last one
else
call json%throw_exception('Error in json_value_get_child_by_index:'//&
' child%tail is not associated.',found)
end if
elseif (idx<1 .or. idx>p%n_children) then
call json%throw_exception('Error in json_value_get_child_by_index:'//&
' idx is out of range.',found)
else
! if idx is closer to the end, we traverse the list backward from tail,
! otherwise we traverse it forward from children:
if (p%n_children-idx < idx) then ! traverse backward
child => p%tail
do i = 1, p%n_children - idx
if (associated(child%previous)) then
child => child%previous
else
call json%throw_exception('Error in json_value_get_child_by_index:'//&
' child%previous is not associated.',found)
nullify(child)
exit
end if
end do
else ! traverse forward
child => p%children
do i = 1, idx - 1
if (associated(child%next)) then
child => child%next
else
call json%throw_exception('Error in json_value_get_child_by_index:'//&
' child%next is not associated.',found)
nullify(child)
exit
end if
end do
end if
end if
else
call json%throw_exception('Error in json_value_get_child_by_index:'//&
' p%children is not associated.',found)
end if
! found output:
if (json%exception_thrown) then
if (present(found)) then
call json%clear_exceptions()
found = .false.
end if
else
if (present(found)) found = .true.
end if
else
if (present(found)) found = .false.
end if
end subroutine json_value_get_child_by_index