ref: e26a37a4c28c2427015a2972a34787c38103736a
dir: /lib/c/atoi.c/
#include <ctype.h>
#include <stdlib.h>
#undef atoi
int
atoi(const char *s)
{
	int n, sign = -1;
	while (isspace(*s))
		++s;
	switch (*s) {
	case '-':
		sign = 1;
	case '+':
		++s;
	}
	/* Compute n as a negative number to avoid overflow on INT_MIN */
	for (n = 0; isdigit(*s); ++s)
		n = 10*n - (*s - '0');
	return sign * n;
}