ft_strnstr.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_strnstr.c                                       :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: apuchill <apuchill@student.42sp.org.br>    +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2019/12/04 14:36:51 by apuchill          #+#    #+#             */
/*   Updated: 2020/02/19 15:13:39 by apuchill         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

/*
** LIBRARY: <string.h>
** SYNOPSIS: locate a substring in a string (size-bounded)
**
** DESCRIPTION:
** 		The strnstr() function locates the first occurrence of the null-termi-
**	nated string s2 in the string s1, where not more than n characters are
**	searched.  Characters that appear after a `\0' character are not
**	searched.
*/

#include "libft.h"

char	*ft_strnstr(const char *haystack, const char *needle, size_t len)
{
	size_t h;
	size_t n;

	h = 0;
	if (needle[0] == '\0')
		return ((char *)haystack);
	while (haystack[h] != '\0')
	{
		n = 0;
		while (haystack[h + n] == needle[n] && (h + n) < len)
		{
			if (haystack[h + n] == '\0' && needle[n] == '\0')
				return ((char *)&haystack[h]);
			n++;
		}
		if (needle[n] == '\0')
			return ((char *)haystack + h);
		h++;
	}
	return (0);
}