/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_substr.c                                        :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: thrieg <thrieg@student.42mulhouse.fr>      +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2024/10/15 11:27:50 by thrieg            #+#    #+#             */
/*   Updated: 2025/02/16 19:05:22 by thrieg           ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "libft.h"

static void	ft_memcpy_with_nullchar(char *substring, char const *s, size_t len)
{
	ft_memcpy(substring, s, len);
	substring[len] = '\0';
}

//check for out of bound access and return NULL if s is NULL or allocation fails
//len 0 or out of bound start just returns a null character
char	*ft_substr(char const *s, unsigned int start, size_t len)
{
	char	*substring;
	size_t	slen;

	if (!s)
		return (NULL);
	slen = ft_strlen(s);
	if (slen <= start)
		return (ft_strdup(""));
	s = &s[start];
	slen -= start;
	if (slen > len)
		substring = malloc(sizeof(char) * (len + 1));
	else
		substring = malloc(sizeof(char) * (slen + 1));
	if (!substring)
		return (NULL);
	if (slen > len)
		ft_memcpy_with_nullchar(substring, s, len);
	else
		ft_memcpy_with_nullchar(substring, s, slen);
	return (substring);
}