From 93558c0a23e752b2b43c8c473cb404a266c9c3e9 Mon Sep 17 00:00:00 2001
From: Ian Gulliver <flamingcow@gmail.com>
Date: Sun, 14 Feb 2016 20:35:43 +0000
Subject: [PATCH] Clean up buf silliness.

---
 adsbus.c      | 20 +++++++++-----------
 airspy_adsb.c | 13 ++++++++++---
 common.c      | 11 -----------
 common.h      | 21 ++++++++++++---------
 4 files changed, 31 insertions(+), 34 deletions(-)

diff --git a/adsbus.c b/adsbus.c
index 6f9582e..161ba60 100644
--- a/adsbus.c
+++ b/adsbus.c
@@ -19,7 +19,7 @@ struct opts {
 };
 
 
-int parse_opts(int argc, char *argv[], struct opts *opts) {
+static int parse_opts(int argc, char *argv[], struct opts *opts) {
 	int opt;
 	while ((opt = getopt(argc, argv, "h:p:")) != -1) {
 		switch (opt) {
@@ -39,7 +39,7 @@ int parse_opts(int argc, char *argv[], struct opts *opts) {
 }
 
 
-int connect_backend(struct opts *opts) {
+static int connect_backend(struct opts *opts) {
 	struct addrinfo hints = {
 		.ai_family = AF_UNSPEC,
 		.ai_socktype = SOCK_STREAM,
@@ -86,7 +86,7 @@ int connect_backend(struct opts *opts) {
 }
 
 
-int loop(int bfd) {
+static int loop(int bfd) {
 	int efd = epoll_create(10);
   if (efd == -1) {
 		perror("epoll_create");
@@ -106,9 +106,10 @@ int loop(int bfd) {
 		}
 	}
 
-	struct buf buf;
-	char buf_main[BUF_LEN], buf_temp[BUF_LEN];
-	buf_init(&buf, buf_main, buf_temp);
+	struct buf buf = {
+		.start = 0,
+		.length = 0,
+	};
 
 	while (1) {
 #define MAX_EVENTS 10
@@ -126,15 +127,12 @@ int loop(int bfd) {
 					return -1;
 				}
 
-				struct buf tmp;
 				struct packet packet;
-				buf_alias(&tmp, &buf);
-				while (airspy_adsb_parse(&tmp, &packet)) {
-					buf_alias(&buf, &tmp);
+				while (airspy_adsb_parse(&buf, &packet)) {
 				}
 
 				if (buf.length == BUF_LEN) {
-					fprintf(stderr, "Input buffer overrun\n");
+					fprintf(stderr, "Input buffer overrun. This probably means that adsbus doesn't understand the protocol that this source is speaking.\n");
 					return -1;
 				}
 			}
diff --git a/airspy_adsb.c b/airspy_adsb.c
index e636dbb..ea64312 100644
--- a/airspy_adsb.c
+++ b/airspy_adsb.c
@@ -5,14 +5,21 @@
 #include "airspy_adsb.h"
 
 bool airspy_adsb_parse(struct buf *buf, struct packet *packet) {
-	if (buf->length < 1 || *buf_at(buf, 0) != '*') {
+	if (buf->length < 35 ||
+	    buf_chr(buf, 0) != '*') {
 		return false;
 	}
-	if (buf->length >= 35 && *buf_at(buf, 34) == '\n') {
+	if (buf->length >= 35 &&
+	    buf_chr(buf, 34) == '\n' &&
+			buf_chr(buf, 15) == ';') {
+		packet->type = MODE_S_SHORT;
 		buf_consume(buf, 35);
 		return true;
 	}
-	if (buf->length >= 49 && *buf_at(buf, 48) == '\n') {
+	if (buf->length >= 49 &&
+	    buf_chr(buf, 48) == '\n' &&
+			buf_chr(buf, 29) == ';') {
+		packet->type = MODE_S_LONG;
 		buf_consume(buf, 49);
 		return true;
 	}
diff --git a/common.c b/common.c
index 83ec336..e0e25fd 100644
--- a/common.c
+++ b/common.c
@@ -7,17 +7,6 @@
 #include "common.h"
 
 
-void buf_init(struct buf *buf, char *main, char *tmp) {
-	buf->buf = main;
-	buf->tmp = tmp;
-	buf->start = 0;
-	buf->length = 0;
-}
-
-void buf_alias(struct buf *to, struct buf *from) {
-	memcpy(to, from, sizeof(*to));
-}
-
 ssize_t buf_fill(struct buf *buf, int fd) {
 	if (buf->start + buf->length == BUF_LEN) {
 		assert(buf->start > 0);
diff --git a/common.h b/common.h
index 417a40e..7e7a7af 100644
--- a/common.h
+++ b/common.h
@@ -2,14 +2,23 @@
 #include <unistd.h>
 
 
+//////// buf
+
 #define BUF_LEN 4096
 struct buf {
-	char *buf;
-	char *tmp;
+	char buf[BUF_LEN];
 	size_t start;
 	size_t length;
 };
 
+#define buf_chr(buff, at) ((buff)->buf[(buff)->start + (at)])
+#define buf_at(buff, at) (&buf_chr(buff, at))
+
+ssize_t buf_fill(struct buf *, int);
+void buf_consume(struct buf *, size_t);
+
+
+//////// packet
 
 #define MLAT_HZ 60000000
 #define DATA_MAX 14
@@ -25,10 +34,4 @@ 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 *);
-
-ssize_t buf_fill(struct buf *, int);
-void buf_consume(struct buf *, size_t);
+//////// hex