linked-list/llist.c

#include "llist.h"
#include <stdio.h>

List *create_list(void *data)
{
    ListNode *new_node;

    List *new_list = (List *) malloc(sizeof(List));
    *new_list = (ListNode *) malloc(sizeof(ListNode));

    new_node = *new_list;
    new_node->data = data;
    new_node->next = NULL;

    return new_list;
}

List *list_remove(List *list, uint32_t position)
{
    ListNode *head;
    ListNode *current;
    ListNode *tmp;

    if (list == NULL || *list == NULL)
    {
        return list;
    }

    if (position == 0)
    {
        head = *list;
        head = head->next;
        *list = head;
        return list;
    }

    if (position >= list_size(list))
    {
        current = *list;
        while(current->next)
        {
            tmp = current;
            current=current->next;
        }

        tmp->next = NULL;
        free(current);

        return list;
    }

    current = *list;
    tmp = current;
    while (current && position > 0)
    {
        tmp = current;
        current = current->next;
        position--;
    }

    tmp->next = current->next;
    free(current);

    return list;
}

List *list_add(List *list, void *data, uint32_t position)
{
    ListNode *new_node;
    ListNode *head;
    ListNode *current;

    if (list == NULL || *list == NULL)
    {
        return NULL;
    }

    head = *list;

    if (head == NULL)
    {
        head->data = data;
        head->next = NULL;
        return list;
    }

    new_node = (ListNode*) malloc(sizeof(ListNode));
    new_node->data = data;

    if (position == 0)
    {
        new_node->next = *list;
        *list = new_node;
        return list;
    }

    if (position >= list_size(list))
    {
        current = *list;
        while (current->next)
        {
            current = current->next;
        }
        current->next = new_node;
        return list;
    }

    /* add at any position */
    current = *list;
    while (current && position-- >1)
    {
        current = current->next;
    }

    ListNode *tmp = current->next;
    current->next = new_node;
    new_node->next = tmp;

    return list;
}

void print_list(List *list)
{
    ListNode *current;
    uint32_t index = 0;

    if (list == NULL || *list == NULL)
        return;

    current = *list;

    while (current)
    {
        printf("At %d value = %p\n", index, current);
        index++;
        current = current->next;
    }
}

void list_delete(List *list)
{
    ListNode *current;
    ListNode *next;

    if (list == NULL || *list == NULL)
        return;

    current = *list;
    while (current->next)
    {
        next = current->next;
        free(current);
        current = next;
    }

    free(list);
}

uint32_t list_size(List *list)
{
    uint32_t size = 0;
    ListNode *current;

    if (list == NULL || *list == NULL)
        return size;

    current = *list;
    while (current)
    {
        size++;
        current = current->next;
    }

    return size;
}

void print_size_and_list(List *list)
{
    printf("size = %d\n", list_size(list));
    print_list(list);
}

int main(int argc, char **argv)
{
    void *new_data  = (void *) malloc(sizeof(void));
    void *new_data2 = (void *) malloc(sizeof(void));
    void *new_data3 = (void *) malloc(sizeof(void));
    void *new_data4 = (void *) malloc(sizeof(void));

    List *new_list = create_list(new_data);
    print_size_and_list(new_list);

    list_add(new_list, new_data2, 0);
    print_size_and_list(new_list);

    list_add(new_list, new_data3, 3);
    print_size_and_list(new_list);

    list_add(new_list, new_data4, 2);
    print_size_and_list(new_list);

    list_remove(new_list, 2);
    print_size_and_list(new_list);

    list_delete(new_list);
    new_list = NULL;

    print_size_and_list(new_list);

   return 0;
}