Function sort_list

cJSON_Utils.c:484–593

sort lists using mergesort */

/* sort lists using mergesort */
static cJSON *sort_list(cJSON *list, const cJSON_bool case_sensitive)
{
    cJSON *first = list;
    cJSON *second = list;
    cJSON *current_item = list;
    cJSON *result = list;
    cJSON *result_tail = NULL;

    if ((list == NULL) || (list->next == NULL))
    {
        /* One entry is sorted already. */
        return result;
    }

    while ((current_item != NULL) && (current_item->next != NULL) && (compare_strings((unsigned char*)current_item->string, (unsigned char*)current_item->next->string, case_sensitive) < 0))
    {
        /* Test for list sorted. */
        current_item = current_item->next;
    }
    if ((current_item == NULL) || (current_item->next == NULL))
    {
        /* Leave sorted lists unmodified. */
        return result;
    }

    /* reset pointer to the beginning */
    current_item = list;
    while (current_item != NULL)
    {
        /* Walk two pointers to find the middle. */
        second = second->next;
        current_item = current_item->next;
        /* advances current_item two steps at a time */
        if (current_item != NULL)
        {
            current_item = current_item->next;
        }
    }
    if ((second != NULL) && (second->prev != NULL))
    {
        /* Split the lists */
        second->prev->next = NULL;
        second->prev = NULL;
    }

    /* Recursively sort the sub-lists. */
    first = sort_list(first, case_sensitive);
    second = sort_list(second, case_sensitive);
    result = NULL;

    /* Merge the sub-lists */
    while ((first != NULL) && (second != NULL))
    {
        cJSON *smaller = NULL;
        if (compare_strings((unsigned char*)first->string, (unsigned char*)second->string, case_sensitive) < 0)
        {
            smaller = first;
        }