From 38cb7c71c52b1b710dd0a8a8883713617b713035 Mon Sep 17 00:00:00 2001
From: marshmellow42 <marshmellowrf@gmail.com>
Date: Wed, 1 Feb 2017 15:39:10 -0500
Subject: [PATCH] add check for no wave in graphbuffer prior to...

hitag lf search check
---
 client/cmdlf.c | 12 ++++++++----
 client/graph.c | 10 ++++++++++
 client/graph.h |  1 +
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/client/cmdlf.c b/client/cmdlf.c
index 2000f6d0..59f6cd0d 100644
--- a/client/cmdlf.c
+++ b/client/cmdlf.c
@@ -1180,10 +1180,14 @@ int CmdLFfind(const char *Cmd)
 		return 1;
 	}
 
-	if (!offline && (cmdp != '1')){
-		ans=CmdLFHitagReader("26");
-		if (ans==0) {
-			return 1;
+	size_t testLen = (GraphTraceLen < 500) ? GraphTraceLen : 500;
+	// only run if graphbuffer is just noise as it should be for hitag
+	if (graphJustNoise(GraphBuffer, testLen)) { 
+		if (!offline && (cmdp != '1')){
+			ans=CmdLFHitagReader("26");
+			if (ans==0) {
+				return 1;
+			}
 		}
 	}
 
diff --git a/client/graph.c b/client/graph.c
index 319cde39..ab10a446 100644
--- a/client/graph.c
+++ b/client/graph.c
@@ -268,3 +268,13 @@ uint8_t fskClocks(uint8_t *fc1, uint8_t *fc2, uint8_t *rf1, bool verbose)
 	}
 	return 1;
 }
+bool graphJustNoise(int *BitStream, int size)
+{
+	static const uint8_t THRESHOLD = 10; //might not be high enough for noisy environments
+	//test samples are not just noise
+	bool justNoise1 = 1;
+	for(int idx=0; idx < size && justNoise1 ;idx++){
+		justNoise1 = BitStream[idx] < THRESHOLD;
+	}
+	return justNoise1;
+}
diff --git a/client/graph.h b/client/graph.h
index 8deeb386..6f3f600d 100644
--- a/client/graph.h
+++ b/client/graph.h
@@ -22,6 +22,7 @@ uint8_t GetPskCarrier(const char str[], bool printAns, bool verbose);
 uint8_t GetNrzClock(const char str[], bool printAns, bool verbose);
 uint8_t GetFskClock(const char str[], bool printAns, bool verbose);
 uint8_t fskClocks(uint8_t *fc1, uint8_t *fc2, uint8_t *rf1, bool verbose);
+bool graphJustNoise(int *BitStream, int size);
 void setGraphBuf(uint8_t *buff, size_t size);
 void save_restoreGB(uint8_t saveOpt);
 
-- 
2.39.5