easy string format without runtime memory allocation, example of IP address

gistfile1.c

#include <stdio.h>
#include <string.h>

#define BUF_NUM 32
#define BUF_LEN 16

static char *format(int val)
{
	static char buf[BUF_NUM][BUF_LEN];
	static int buf_i;
	int i;
	char *ret, *b = buf[buf_i++];

	ret = b;
	bzero(b, BUF_LEN);
	for (i = 0; i < 3; i++) {
		b += sprintf(b, "%d.", val & 0xff);
		val >>= 8;
	}
	sprintf(b, "%d", val & 0xff);

	buf_i %= BUF_NUM;
	return ret;
}

int main(void)
{
	printf("255.255.255.255: %s, 127.0.0.1: %s, 10.0.0.1: %s\n",
		format(0xffffffff), format(0x0100007f), format(0x0100000a));
	return 0;
}