Move adsbus into its own dir.

adsbus/json.c

@@ -0,0 +1,81 @@
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+#include <jansson.h>
+
+#include "receive.h"
+#include "send.h"
+#include "json.h"
+
+static void json_serialize_to_buf(json_t *obj, struct buf *buf) {
+	assert(json_dump_callback(obj, json_buf_append_callback, buf, 0) == 0);
+	json_decref(obj);
+	buf_chr(buf, buf->length++) = '\n';
+}
+
+static void json_hello(struct buf *buf) {
+	json_t *hello = json_pack("{sIsIsI}",
+			"mlat_timestamp_mhz", (json_int_t) MLAT_MHZ,
+			"mlat_timestamp_max", (json_int_t) MLAT_MAX,
+			"rssi_max", (json_int_t) RSSI_MAX);
+	json_serialize_to_buf(hello, buf);
+}
+
+static void json_add_common(struct packet *packet, json_t *obj) {
+	json_object_set_new(obj, "type", json_string(packet_type_names[packet->type]));
+	if (packet->mlat_timestamp) {
+		json_object_set_new(obj, "mlat_timestamp", json_integer(packet->mlat_timestamp));
+	}
+	if (packet->rssi) {
+		json_object_set_new(obj, "rssi", json_integer(packet->rssi));
+	}
+}
+
+static void json_serialize_mode_s_short(struct packet *packet, struct buf *buf) {
+	assert(packet->mlat_timestamp < MLAT_MAX);
+	char hexbuf[14];
+	hex_from_bin(hexbuf, packet->payload, 7);
+	json_t *out = json_pack("{ss#}", "payload", hexbuf, 14);
+	json_add_common(packet, out);
+	json_serialize_to_buf(out, buf);
+}
+
+static void json_serialize_mode_s_long(struct packet *packet, struct buf *buf) {
+	assert(packet->mlat_timestamp < MLAT_MAX);
+	char hexbuf[28];
+	hex_from_bin(hexbuf, packet->payload, 14);
+	json_t *out = json_pack("{ss#}", "payload", hexbuf, 28);
+	json_add_common(packet, out);
+	json_serialize_to_buf(out, buf);
+}
+
+void json_init() {
+	assert(JSON_INTEGER_IS_LONG_LONG);
+}
+
+void json_serialize(struct packet *packet, struct buf *buf) {
+	if (!packet) {
+		json_hello(buf);
+		return;
+	}
+
+	switch (packet->type) {
+		case MODE_S_SHORT:
+			json_serialize_mode_s_short(packet, buf);
+			break;
+
+		case MODE_S_LONG:
+			json_serialize_mode_s_long(packet, buf);
+			break;
+	}
+}
+
+int json_buf_append_callback(const char *buffer, size_t size, void *data) {
+	struct buf *buf = data;
+	if (buf->length + size + 1 > BUF_LEN_MAX) {
+		return -1;
+	}
+	memcpy(buf_at(buf, buf->length), buffer, size);
+	buf->length += size;
+	return 0;
+}