#include <u.h>
#include <libc.h>
#include "fns.h"

int
getmsg(int fd, char *buf, int n)
{
	char num[4+1+1];	/* four digits, newline, nul */
	int len, r;

	if(readn(fd, num, 5) != 5) {
		werrstr("read length: %r");
		return -1;
	}
	num[5] = '\0';
	len = strtoul(num, nil, 10);

	if(len < 0) {
		werrstr("unusual length");
		return -1;
	}
	if(len >= n) {
		werrstr("too big for buffer: %d/%d", len, n);
		return -1;
	}

	r = readn(fd, buf, len);
	if(r < 0)
		return -1;
	if(r < len) {
		werrstr("short read: %d/%d", r, len);
		return -1;
	}
	buf[r] = '\0';

	return len;
}

int
sendmsg(int fd, char *s)
{
	int n;

	n = strlen(s);
	if(fprint(fd, "%.4d\n", n) < 0
	|| write(fd, s, n) != n )
		return -1;
	return n;
}