Singly Linked List

July 27, 2023 · View on GitHub

Simple generic singly linked list module for in-memory storage of small amounts of data. sll provides the ability to reuse linked list space to avoid the time-consuming duplication of memory allocation and destruction in certain application scenarios.

Suggestions and code contributions are welcome.

Usage

Only FPM is supported, other build systems can copy source files directly, and ifort/ifx and gfortran compilers are tested.

To use slinked-list within your fpm project, add the following lines to your fpm.toml file:

[dependencies]
slinked-list = { git="https://github.com/zoziha/slinked-list" }

Example

> fpm run --example --all  # run the example

program main

    use sll_module, only: sll, iterator, sll_storage, sll_finalizer, iterator_finalizer
    use display_module, only: display
    implicit none
    type(sll) :: list  !! singly linked list
    type(iterator) :: iter  !! iterator for sll
    class(*), pointer :: ptr  !! generic pointer

    call list%push_back(1.0)
    call list%push_back(2)
    call display(list%size(), "size:", inline=.true.)
    call display(list%size(.true.), "capacity:", inline=.true.)

    call list%empty()
    call list%push_back(3.0)
    call display(list%size(), "size:", inline=.true.)
    call display(list%size(.true.), "capacity:", inline=.true.)

    if (.not. list%is_empty()) then

        iter = iterator(list)
        do while (iter%next(ptr))

            select type (ptr)
            type is (real)
                call display(ptr, "v:", inline=.true.)
            type is (integer)
                call display(ptr, "v:", inline=.true.)
            end select

        end do

    end if

    call display(sll_storage(list) + storage_size(list), "storage size (bit):", inline=.true.)
    call sll_finalizer(list)  ! free memory
    call iterator_finalizer(iter)  ! free memory

end program main
!> [scalar] size: 2
!> [scalar] capacity: 2
!> [scalar] size: 1
!> [scalar] capacity: 2
!> [scalar] v:  3.000E+00
!> [scalar] storage size (bit): 1664

Note: Due to the type conversion of class(*), sll is not efficient, so it is only used for storing small datasets.