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/* ************************************************************************** */
/* */
/* ::: :::::::: */
/* ft_atoi.c :+: :+: :+: */
/* +:+ +:+ +:+ */
/* By: cacharle <marvin@42.fr> +#+ +:+ +#+ */
/* +#+#+#+#+#+ +#+ */
/* Created: 2019/10/07 09:46:16 by cacharle #+# #+# */
/* Updated: 2019/10/07 11:34:37 by cacharle ### ########.fr */
/* */
/* ************************************************************************** */
#define MIN_INT (1 << 31)
#define MAX_INT (~(1 << 31))
static int precheck(const char **nptr)
{
int is_negative;
while (**nptr == ' ' || **nptr == '\t' || **nptr == '\n'
|| **nptr == '\v' || **nptr == '\f' || **nptr == '\r')
(*nptr)++;
is_negative = 0;
if (**nptr == '-' || **nptr == '+')
{
if (**nptr == '-')
is_negative = 1;
(*nptr)++;
}
return (is_negative);
}
int ft_atoi(const char *nptr)
{
unsigned int nb;
int i;
int is_negative;
is_negative = precheck(&nptr);
i = 0;
nb = 0;
while (nptr[i] >= '0' && nptr[i] <= '9')
{
if (!is_negative && nb > (unsigned int)MAX_INT)
return (-1);
else if (nb > (unsigned int)MIN_INT)
return (0);
nb *= 10;
nb += nptr[i] - '0';
i++;
}
return ((int)(is_negative ? -nb : nb));
}
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