ft_substr.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_substr.c                                        :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: mcombeau <mcombeau@student.42.fr>          +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2021/11/26 16:50:44 by mcombeau          #+#    #+#             */
/*   Updated: 2021/12/02 16:53:34 by mcombeau         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "libft.h"

/*
	DESCRIPTION :
	The function ft_substr extracts a substring from the given string by
	allocating sufficient memory for the new string starting at index start
	and ending at len characters.

	RETURN VALUE :
	A pointer to the new string.
	NULL if the memory allocation fails.
*/

char	*ft_substr(char const *s, unsigned int start, size_t len)
{
	char	*res;
	char	*src;
	size_t	reslen;

	if (!s)
		return (NULL);
	if (ft_strlen(s) < (size_t)start)
		return (ft_strdup(""));
	src = (char *)s + start;
	if (ft_strlen(src) < len)
		reslen = ft_strlen(src) + 1;
	else
		reslen = len + 1;
	res = malloc(reslen * sizeof(char));
	if (!res)
		return (NULL);
	ft_strlcpy(res, src, reslen);
	return (res);
}