feat: Track consecutive frame index

4 files changed, 20 insertions, 3 deletions

diff --git a/src/frame.cpp b/src/frame.cpp
index bfa9daf..fe96308 100644
--- a/src/frame.cpp
+++ b/src/frame.cpp
@@ -49,8 +49,10 @@ void Frame::parse_frame_str(const unsigned char* iso_tp_frame) {
 		         break;
 
 		// Consecutive frame
-		case CF: this->data_size = 7; // Message objects track total amount of data
+		case CF: this->index = this->size;
+		         this->data_size = 7; // Message objects track total amount of data
 		                              // from multipart messages
+		         this->size = data_size;
 		         break;
 
 		// Flow control frame
@@ -72,6 +74,7 @@ void Frame::free() {
 
 void Frame::copyFrom(const Frame& other) {
 	this->type = other.type;
+	this->index = other.index;
 	this->size = other.size;
 	this->data_size = other.data_size;
 
@@ -81,7 +84,7 @@ void Frame::copyFrom(const Frame& other) {
 
 /* Public */
 
-Frame::Frame(const char* iso_tp_frame) {
+Frame::Frame(const char* iso_tp_frame) : index(0) {
 	this->parse_frame_str((const unsigned char*)iso_tp_frame);
 }
 
@@ -105,6 +108,10 @@ FrameType Frame::get_type() const {
 	return this->type;
 }
 
+unsigned char Frame::get_index() const {
+	return this->index;
+}
+
 unsigned int Frame::get_size() const {
 	return this->size;
 }
diff --git a/src/frame.h b/src/frame.h
index c928edd..07ddab2 100644
--- a/src/frame.h
+++ b/src/frame.h
@@ -10,6 +10,7 @@ enum FrameType {
 
 class Frame {
 	FrameType type;
+	unsigned char index;
 	unsigned int size;
 	unsigned int data_size;
 	unsigned char* data;
@@ -30,6 +31,7 @@ public:
 
 	/* Getters */
 	FrameType get_type() const;
+	unsigned char get_index() const;
 	unsigned int get_size() const;
 	unsigned int get_data_size() const;
 	const unsigned char* get_data() const;
diff --git a/src/message.cpp b/src/message.cpp
index 834fd87..0769533 100644
--- a/src/message.cpp
+++ b/src/message.cpp
@@ -11,6 +11,7 @@ void Message::copyFrom(const Message& other) {
 	this->can_id = other.can_id;
 	this->size = other.size;
 	this->received = other.received;
+	this->latest_index = other.latest_index;
 
 	this->msg = new unsigned char[this->size];
 	std::memcpy(this->msg, other.msg, this->size);
@@ -18,7 +19,7 @@ void Message::copyFrom(const Message& other) {
 
 /* Public */
 
-Message::Message(unsigned int can_id, const Frame& first_frame) : can_id(can_id), received(0) {
+Message::Message(unsigned int can_id, const Frame& first_frame) : can_id(can_id), received(0), latest_index(0) {
 	this->size = first_frame.get_size();
 	this->msg = new unsigned char[this->size];
 	this->receive_frame(first_frame);
@@ -41,6 +42,12 @@ Message& Message::operator=(const Message& other) {
 }
 
 void Message::receive_frame(const Frame& f) {
+	// This logic isn't really necessary, but I like to be thorough
+	if ((this->latest_index + 1) % 16 < f.get_index()) {
+		throw std::invalid_argument("A consecutive frame was lost!");
+	}
+	this->latest_index = f.get_index();
+
 	// For CFs we set the data size to 7 (the maximum), however, we may be expecting
 	// to receive less data (in the last CF).
 	size_t expects = std::min(this->size - this->received, f.get_data_size());
diff --git a/src/message.h b/src/message.h
index fcc8258..764cf69 100644
--- a/src/message.h
+++ b/src/message.h
@@ -8,6 +8,7 @@ class Message {
 	unsigned int can_id;
 	unsigned int size;
 	unsigned int received;
+	unsigned char latest_index;
 	unsigned char* msg;
 
 	void free();