ft_strnstr.c

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/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_strnstr.c                                       :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: kfujita <kfujita@student.42tokyo.jp>       +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2022/04/10 16:52:18 by kfujita           #+#    #+#             */
/*   Updated: 2022/04/19 06:34:37 by kfujita          ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */
 
#include <stddef.h>
 
char    *ft_strnstr(const char *haystack, const char *needle, size_t len)
{
    size_t  pos;
 
    if (*needle == '\0')
        return ((char *)haystack);
    while (len > 0 && *haystack != '\0')
    {
        if (*haystack == *needle)
        {
            pos = 0;
            while (needle[pos] != '\0'
                && len > pos && haystack[pos] == needle[pos])
                pos++;
            if (needle[pos] == '\0')
                return ((char *)haystack);
        }
        haystack++;
        len--;
    }
    return (NULL);
}