ft_split.c

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/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_split.c                                         :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: rmikhayl <rmikhayl@student.42london.c      +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2023/12/17 17:25:26 by rmikhayl          #+#    #+#             */
/*   Updated: 2023/12/17 17:25:26 by rmikhayl         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */
 
#include "libft.h"
 
/* *************************** ft_split ************************************* */
/*   Splits the input string 's' into an array of substrings using the        */
/*   delimiter character 'c'. Returns the array, with a NULL-terminated       */
/*   element marking the end.                                                 */
/*                                                                            */
/*   Edge Cases:                                                              */
/*   - If 's' is NULL, returns NULL.                                          */
/*   - If 'c' is '\0', returns an array with 's' as the only element.         */
/*   - If 's' does not contain 'c', returns an array with 's' as the only     */
/*     element.                                                               */
/*                                                                            */
/*   Behavior:                                                                */
/*   - The function splits 's' into substrings wherever 'c' is encountered.   */
/*   - Consecutive 'c' characters result in empty strings in the array.       */
/*   - Leading and trailing 'c' characters are ignored.                       */
/* ************************************************************************** */
 
static int  count_words(const char *s, char c)
{
    int count;
    int in_word;
 
    count = 0;
    in_word = 0;
    while (*s)
    {
        if (*s != c)
        {
            if (!in_word)
            {
                in_word = 1;
                count++;
            }
        }
        else
            in_word = 0;
        s++;
    }
    return (count);
}
 
static char *strndup(const char *s, size_t n)
{
    char    *dup;
 
    dup = malloc(n + 1);
    if (!dup)
        return (NULL);
    ft_memcpy(dup, s, n);
    dup[n] = '\0';
    return (dup);
}
 
static void split_into_words(char **result, const char *s, char c)
{
    int         i;
    int         in_word;
    const char  *start;
 
    i = 0;
    in_word = 0;
    while (*s)
    {
        if (*s != c && !in_word)
        {
            start = s;
            in_word = 1;
        }
        else if (*s == c && in_word)
        {
            result[i++] = strndup(start, s - start);
            in_word = 0;
        }
        s++;
    }
    if (in_word)
        result[i++] = strndup(start, s - start);
    result[i] = NULL;
}
 
char    **ft_split(const char *s, char c)
{
    char    **result;
    int     word_count;
 
    if (!s)
        return (NULL);
    word_count = count_words(s, c);
    result = malloc(sizeof(char *) * (word_count + 1));
    if (!result)
        return (NULL);
    split_into_words(result, s, c);
    return (result);
}