Inserts element after p, and updates the JSON structure accordingly.
program test
use json_module
implicit none
logical(json_LK) :: found
type(json_core) :: json
type(json_value),pointer :: p,new,element
call json%load(file='myfile.json', p=p)
call json%get(p,'x(3)',element,found) ! get pointer to an array element in the file
call json%create_integer(new,1,'') ! create a new element
call json%insert_after(element,new) ! insert new element after x(3)
call json%print(p,'myfile2.json') ! write it to a file
call json%destroy(p) ! cleanup
end program test
element are carried along. p
[1] - [2] - [3] - [4]
|
[5] - [6] - [7] n=3 elements inserted
element last
Result is:
[1] - [2] - [5] - [6] - [7] - [3] - [4]
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| class(json_core), | intent(inout) | :: | json | |||
| type(json_value), | pointer | :: | p | a value from a JSON structure (presumably, this is a child of an object or array). |
||
| type(json_value), | pointer | :: | element | the element to insert after |
subroutine json_value_insert_after(json,p,element)
implicit none
class(json_core),intent(inout) :: json
type(json_value),pointer :: p !! a value from a JSON structure
!! (presumably, this is a child of
!! an object or array).
type(json_value),pointer :: element !! the element to insert after `p`
type(json_value),pointer :: parent !! the parent of `p`
type(json_value),pointer :: next !! temp pointer for traversing structure
type(json_value),pointer :: last !! the last of the items being inserted
integer :: n !! number of items being inserted
if (.not. json%exception_thrown) then
parent => p%parent
! set first parent of inserted list:
element%parent => parent
! Count the number of inserted elements.
! and set their parents.
n = 1 ! initialize counter
next => element%next
last => element
do
if (.not. associated(next)) exit
n = n + 1
next%parent => parent
last => next
next => next%next
end do
if (associated(parent)) then
! update parent's child counter:
parent%n_children = parent%n_children + n
! if p is last of parents children then
! also have to update parent tail pointer:
if (associated(parent%tail,p)) then
parent%tail => last
end if
end if
if (associated(element%previous)) then
! element is apparently part of an existing list,
! so have to update that as well.
if (associated(element%previous%parent)) then
element%previous%parent%n_children = &
element%previous%parent%n_children - n
element%previous%parent%tail => &
element%previous ! now the last one in the list
else
! this would be a memory leak if the previous entries
! are not otherwise being pointed too
! [throw an error in this case???]
end if
!remove element from the other list:
element%previous%next => null()
end if
element%previous => p
if (associated(p%next)) then
! if there are any in the list after p:
last%next => p%next
last%next%previous => element
else
last%next => null()
end if
p%next => element
end if
end subroutine json_value_insert_after