Cheaper airspy matching

adsbus.c

@@ -131,7 +131,6 @@ int loop(int bfd) {
 				buf_alias(&tmp, &buf);
 				while (airspy_adsb_parse(&tmp, &packet)) {
 					buf_alias(&buf, &tmp);
-					fprintf(stderr, "packet!\n");
 				}
 
 				if (buf.length == BUF_LEN) {

airspy_adsb.c

@@ -1,20 +1,20 @@
+#include <stdio.h>
 #include <string.h>
 
 #include "common.h"
 #include "airspy_adsb.h"
 
 bool airspy_adsb_parse(struct buf *buf, struct packet *packet) {
-	if (buf->length < 35) {
-		// Minimum frame length
+	if (buf->length < 1 || *buf_at(buf, 0) != '*') {
 		return false;
 	}
-	if (buf->buf[buf->start] != '*') {
-		return false;
+  if (buf->length >= 35 && *buf_at(buf, 34) == '\n') {
+		buf_consume(buf, 35);
+		return true;
 	}
-	char *last = memchr(&buf->buf[buf->start], '\n', buf->length);
-	if (!last) {
-		return false;
+	if (buf->length >= 49 && *buf_at(buf, 48) == '\n') {
+		buf_consume(buf, 49);
+		return true;
 	}
-	buf_consume(buf, last - &buf->buf[buf->start] + 1);
-	return true;
+	return false;
 }

common.c

@@ -21,13 +21,12 @@ void buf_alias(struct buf *to, struct buf *from) {
 ssize_t buf_fill(struct buf *buf, int fd) {
 	if (buf->start + buf->length == BUF_LEN) {
 		assert(buf->start > 0);
-		memmove(buf->buf, &buf->buf[buf->start], buf->length);
+		memmove(buf->buf, buf_at(buf, 0), buf->length);
 		buf->start = 0;
 	}
 
 	size_t space = BUF_LEN - buf->length - buf->start;
-	size_t end = buf->start + buf->length;
-	ssize_t in = read(fd, &buf->buf[end], space);
+	ssize_t in = read(fd, buf_at(buf, buf->length), space);
 	if (in < 0) {
 		return in;
 	}

common.h

@@ -25,6 +25,8 @@ struct packet {
 };
 
 
+#define buf_at(buff, at) (&(buff)->buf[(buff)->start + (at)])
+
 void buf_init(struct buf *, char *, char *);
 void buf_alias(struct buf *, struct buf *);