simple_shell/SS_lists.c at master · Stephen842/simple_shell · GitHub

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#include "shell.h"

/**
 * add_node - this function adds a node to the start of the list
 * @head: parameter showing the address of pointer to head node
 * @str: function parameter showing str field of node
 * @num: parameter indicating the node index used by history
 * Return: 0 if successful
 */

list_t *add_node(list_t **head, const char *str, int num)
{
	list_t *new_node;

	if (!head)
		return (NULL);
	new_node = malloc(sizeof(list_t));
	if (!new_node)
		return (NULL);
	_memset((void *)new_node, 0, sizeof(list_t));
	new_node->num = num;
	if (str)
	{
		new_node->str = _strdup(str);
		if (!new_node->str)
		{
			free(new_node);
			return (NULL);
		}
	}
	new_node->next = *head;
	*head = new_node;
	return (new_node);

}

/**
 * add_node_end - this function adds a node to the end of the list
 * @head: parameter showing the address of pointer to head node
 * @str: function parameter showing str field of node
 * @num: parameter indicating the node index used by history
 * Return: 0 if successful
 */

list_t *add_node_end(list_t **head, const char *str, int num)
{
	list_t *new_head;
	list_t *node;

	if (!head)
		return (NULL);

	node = *head;
	new_head = malloc(sizeof(list_t));
	if (!new_head)
		return (NULL);
	_memset((void *)new_head, 0, sizeof(list_t));
	new_head->num = num;
	if (str)
	{
		new_head->str = _strdup(str);
		if (!new_head->str)
		{
			free(new_head);
			return (NULL);
		}
	}
	if (node)
	{
		while (node->next)
			node = node->next;
		node->next = new_head;
	}
	else
	{
		*head = new_head;
	}

	return (new_head);
}

/**
 * print_list_str - this function prints the str element of a linked list
 * @h: function parameter showing pointer to first node
 * Return: 0 if successful
 */
size_t print_list_str(const list_t *h)
{
	size_t count = 0;

	while (h)
	{
		_puts((h->str) ? h->str : "(nil)");
		_puts("\n");
		h = h->next;
		count++;
	}

	return (count);
}
/**
 * delete_node_at_index - this function deletes node at given indexin the list
 * @head: parameter indicating the address of pointer to first node
 * @index: this parameter shows index of node to delete
 * Return: 1 if successful
 */
int delete_node_at_index(list_t **head, unsigned int index)
{
	list_t *node;
	unsigned int a = 0;
	list_t *prev;


	if (!head || !*head)
		return (0);

	if (!index)
	{
		node = *head;
		*head = (*head)->next;
		free(node->str);
		free(node);
		return (1);
	}
	node = *head;
	while (node)
	{
		if (a == index)
		{
			prev->next = node->next;
			free(node->str);
			free(node);
			return (1);
		}
		a++;
		prev = node;
		node = node->next;
	}
	return (0);

}

/**
 * free_list - this function frees allocated memory for a node in the link list
 * @head_ptr: function parameter indicating the address of pointer to head node
 * Return: void
 */
void free_list(list_t **head_ptr)
{
	list_t *node;
	list_t *next_nodes;
	list_t *header;

	if (!head_ptr || !*head_ptr)
		return;
	header = *head_ptr;
	node = header;
	while (node)
	{
		next_nodes = node->next;
		free(node->str);
		free(node);
		node = next_nodes;
	}
	*head_ptr = NULL;

}