inetaddr.c

来自「Intel PXA270的bootloader程序,在linux环境下运行的.」· C语言 代码 · 共 40 行

#include <stdio.h>
#include <stdbool.h>
#include <ctype.h>
#include <netinet/in.h>


unsigned long inet_addr(const char *ip){
	int i, ndots;
	char ch;
	bool valid;
	unsigned long retval, val;

	i = val = retval = ndots = 0;
	valid = false;
	while ((ch = ip[i++])){
		if (isdigit(ch)){
			val = (val * 10) + (ch & 0x0F);	// '0' -> 0.
			valid = true;
		} else if (ch == '.'){
			if (val > 0xFF) return 0;
			retval = (retval << 8) | val;
			val = 0;
			ndots++;
			valid = false;
		} else return 0;
	}
	if (!valid || ndots != 3) return 0;
	retval = (retval << 8) | val;
	return htonl(retval);
}


int main(int argc, char **argv){
	if (argc != 2) return -1;
	printf("0x%08lx\n", inet_addr(argv[1]));
	return 0;
}