ref: 2a61dfcd596b6da4d31379663a20e4fe0566cc17
dir: /src/libc/stdlib/atoll.c/
#include <ctype.h>
#include <stdlib.h>
#include "../libc.h"
#undef atoll
long long
atoll(const char *s)
{
	int d, sign = -1;
	long long n;
	while (isspace(*s))
		++s;
	switch (*s) {
	case '-':
		sign = 1;
	case '+':
		++s;
	}
	/* Compute n as a negative number to avoid overflow on LLONG_MIN */
	for (n = 0; (d = _dtoi(*s)) < 10; ++s)
		n = n*10 - d;
	return sign * n;
}