Minor fixes: Array inits, some array bounds checks.

ADD: some extra help text for lf snoop
ADD: HasGraphData - function in graph.c
ADD: DetectHighLowInGraph  - function in graph.c

client/cmddata.c

@@ -511,10 +511,6 @@ int CmdBitstream(const char *Cmd)
       bit ^= 1;
 
     AppendGraph(0, clock, bit);
-	//    for (j = 0; j < (int)(clock/2); j++)
-	//      GraphBuffer[(i * clock) + j] = bit ^ 1;
-	//    for (j = (int)(clock/2); j < clock; j++)
-	//      GraphBuffer[(i * clock) + j] = bit;
   }
 
   RepaintGraphWindow();
@@ -800,8 +796,7 @@ int CmdFSKdemod(const char *Cmd) //old CmdFSKdemod needs updating
   PrintAndLog("actual data bits start at sample %d", maxPos);
   PrintAndLog("length %d/%d", highLen, lowLen);
 
-	uint8_t bits[46];
+  uint8_t bits[46] = {0x00};
-	bits[sizeof(bits)-1] = '\0';
 
   // find bit pairs and manchester decode them
   for (i = 0; i < arraylen(bits) - 1; ++i) {
@@ -1054,7 +1049,7 @@ int CmdHpf(const char *Cmd)
 
 int CmdSamples(const char *Cmd)
 {
-	uint8_t got[40000];
+	uint8_t got[40000] = {0x00};
 
 	int n = strtol(Cmd, NULL, 0);
 	if (n == 0)

client/cmdlf.c

@@ -467,6 +467,9 @@ int CmdLFSnoop(const char *Cmd)
 		PrintAndLog("usage 1:  snoop");
 		PrintAndLog("      2:  snoop <l|h> [trigger threshold]");
 		PrintAndLog("      3:  snoop <divisor> [trigger threshold]");
+		PrintAndLog("");
+		PrintAndLog("Sample: lf snoop l 200");
+		PrintAndLog("      : lf snoop 95 200");
     return 0;
   }
 

client/graph.c

@@ -9,6 +9,7 @@
 //-----------------------------------------------------------------------------
 
 #include <stdio.h>
+#include <stdbool.h>
 #include <string.h>
 #include "ui.h"
 #include "graph.h"
@@ -50,7 +51,11 @@ int ClearGraph(int redraw)
 
 void setGraphBuf(uint8_t *buff, size_t size)
 {
-  int i=0;
+	if ( buff == NULL ) return;
+	
+	uint16_t i = 0;  
+	if ( size > MAX_GRAPH_TRACE_LEN )
+		size = MAX_GRAPH_TRACE_LEN;
   ClearGraph(0);
   for (; i < size; ++i){
 		GraphBuffer[i]=buff[i]-128;
@@ -61,6 +66,8 @@ void setGraphBuf(uint8_t *buff, size_t size)
 }
 size_t getFromGraphBuf(uint8_t *buff)
 {
+	if ( buff == NULL ) return -1;
+	
   uint32_t i;
   for (i=0;i<GraphTraceLen;++i){
     if (GraphBuffer[i]>127) GraphBuffer[i]=127; //trim
@@ -82,14 +89,48 @@ int GetClock(const char *str, int peak, int verbose)
   {
     uint8_t grph[MAX_GRAPH_TRACE_LEN]={0};
 		size_t size = getFromGraphBuf(grph);
+		if ( size < 0 ) {
+			PrintAndLog("Failed to copy from graphbuffer");
+			return -1;
+		}
     clock = DetectASKClock(grph,size,0);
 		// Only print this message if we're not looping something
     if (!verbose){
       PrintAndLog("Auto-detected clock rate: %d", clock);
     }
+  return clock;
+}
+
+// A simple test to see if there is any data inside Graphbuffer. 
+bool HasGraphData(){
+
+	if ( GraphTraceLen <= 0) {
+		PrintAndLog("No data available, try reading something first");
+		return false;
+	}
+	return true;	
+}
+
+// Detect high and lows in Grapbuffer.
+// Only loops the first 256 values. 
+void DetectHighLowInGraph(int *high, int *low, bool addFuzz) {
+
+	uint8_t loopMax = 255;
+	if ( loopMax > GraphTraceLen)
+		loopMax = GraphTraceLen;
+  
+	for (uint8_t i = 0; i < loopMax; ++i) {
+		if (GraphBuffer[i] > *high)
+			*high = GraphBuffer[i];
+		else if (GraphBuffer[i] < *low)
+			*low = GraphBuffer[i];
 	}
 	
-  return clock;
+	//12% fuzz in case highs and lows aren't clipped
+	if (addFuzz) {
+		*high = (int)(*high * .88);
+		*low  = (int)(*low  * .88);
+	}
 }
 
 int GetNRZpskClock(const char *str, int peak, int verbose)

client/graph.h

@@ -20,8 +20,10 @@ int GetClock(const char *str, int peak, int verbose);
 int GetNRZpskClock(const char *str, int peak, int verbose);
 void setGraphBuf(uint8_t *buff, size_t size);
 
+bool HasGraphData();
+void DetectHighLowInGraph(int *high, int *low, bool addFuzz); 
+
 #define MAX_GRAPH_TRACE_LEN (1024*128)
 extern int GraphBuffer[MAX_GRAPH_TRACE_LEN];
 extern int GraphTraceLen;
-
 #endif