ft_strnstr.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_strnstr.c                                       :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: rakama <rui20030415@gmail.com>             +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2022/04/05 18:03:01 by rakama            #+#    #+#             */
/*   Updated: 2022/05/13 14:29:10 by rakama           ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "libft.h"

char	*ft_result(const char	*big, const char	*little, size_t len)
{
	size_t	i;
	size_t	j;

	i = 0;
	j = 0;
	while (i < len)
	{
		if (big[i] == little[j])
		{
			i++;
			j++;
			if (little[j] == '\0')
				return ((char *)&big[i - j]);
		}
		else
		{
			i -= j;
			i++;
			j = 0;
		}
		if (big[i] == '\0' || little[j] == '\0')
			break ;
	}
	return (NULL);
}

char	*ft_strnstr(const char	*big, const char	*little, size_t len)
{
	if (little[0] == '\0')
		return ((char *)big);
	return (ft_result(big, little, len));
}