From 32319ddf9f778a2a72b66bf093655bb2da24e026 Mon Sep 17 00:00:00 2001
From: Jared Boone <jboone@earfeast.com>
Date: Tue, 1 Dec 2015 16:05:23 -0800
Subject: [PATCH] Manchester decoder bounds checking.

Return error symbol if reading past source data.
---
 firmware/application/ui_receiver.cpp | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/firmware/application/ui_receiver.cpp b/firmware/application/ui_receiver.cpp
index a135d424..75be6dce 100644
--- a/firmware/application/ui_receiver.cpp
+++ b/firmware/application/ui_receiver.cpp
@@ -562,9 +562,14 @@ public:
 	}
 
 	DecodedSymbol operator[](const size_t index) const {
-		const auto value = encoded[index * 2 + sense];
-		const auto error = encoded[index * 2 + 0] == encoded[index * 2 + 1];
-		return { value, error };
+		const size_t encoded_index = index * 2;
+		if( (encoded_index + 1) < count ) {
+			const auto value = encoded[encoded_index + sense];
+			const auto error = encoded[encoded_index + 0] == encoded[encoded_index + 1];
+			return { value, error };
+		} else {
+			return { 0, 1 };
+		}
 	}
 
 	size_t symbols_count() const {