From 6a9e00f6c7abd74d037fd210b6670d3cdb313049 Mon Sep 17 00:00:00 2001
From: Alex Barney <thealexbarney@gmail.com>
Date: Wed, 17 Oct 2018 15:12:06 -0500
Subject: [PATCH] Check that the superframe flag is set properly

---
 C/src/structures.h |  1 +
 C/src/unpack.c     | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/C/src/structures.h b/C/src/structures.h
index ba705ce..67363cf 100644
--- a/C/src/structures.h
+++ b/C/src/structures.h
@@ -130,6 +130,7 @@ struct Block {
 };
 
 struct Frame {
+	int IndexInSuperframe;
 	ConfigData* Config;
 	Channel* Channels[MAX_CHANNEL_COUNT];
 	Block Blocks[MAX_BLOCK_COUNT];
diff --git a/C/src/unpack.c b/C/src/unpack.c
index e2cbf61..8b66e49 100644
--- a/C/src/unpack.c
+++ b/C/src/unpack.c
@@ -32,7 +32,20 @@ At9Status UnpackFrame(Frame* frame, BitReaderCxt* br)
 	for (int i = 0; i < blockCount; i++)
 	{
 		ERROR_CHECK(UnpackBlock(&frame->Blocks[i], br));
+
+		if (frame->Blocks[i].FirstInSuperframe && frame->IndexInSuperframe)
+		{
+			return ERR_UNPACK_SUPERFRAME_FLAG_INVALID;
+		}
+	}
+
+	frame->IndexInSuperframe++;
+
+	if (frame->IndexInSuperframe == frame->Config->FramesPerSuperframe)
+	{
+		frame->IndexInSuperframe = 0;
 	}
+
 	return ERR_SUCCESS;
 }