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/**
 * @file datatop_linked_list.c
 * @brief Necessary linked_list functions created.
 *
 * Holds function which adds to or creates a linked list
 * used for storing dtop_data_point_gatherer's (dpg's).
 * Datapoints are stored in linked list for ability to
 * iteratively poll and print efficiently. Handles creation
 * and deletion of memory for linked list nodes.
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "datatop_linked_list.h"

/**
 * @brief Adds a node to the beginning of a linked list.
 *
 * @param data A void pointer which can hold any data in the node.
 * @param list The list that is added to.
 * @return Updated linked list struct.
 */
struct dtop_linked_list *dtop_add_linked_list(void *data,
				struct dtop_linked_list *list)
{
	struct dtop_linked_list *list_node;
	list_node = malloc(sizeof(struct dtop_linked_list));

	if (!list_node) {
		fprintf(stderr, "failed to allocate memory.\n");
		exit(EXIT_FAILURE);
	}

	list_node->data = data;
	list_node->next_ptr = list;
	list = list_node;
	return list;
}

/**
 * @brief Deletes a linked list.
 *
 * @param head_ptr Pointer to the first node in the linked list that is to be deleted.
 */
void dtop_rem_linked_list(struct dtop_linked_list *head_ptr)
{
	struct dtop_linked_list *tmp_ptr = NULL;
	while (head_ptr) {
		tmp_ptr = head_ptr;
		head_ptr = head_ptr->next_ptr;
		free(tmp_ptr);
	}
}