Revision 5:e00cc0dab1c7, committed 2016-06-28

Comitter:

Electrotiger

Date:

Tue Jun 28 01:24:36 2016 +0000

Parent:

4:2d38ad348e0d

Child:

6:076fcae78bac

Commit message:

Added checks to ensure that buffer overflow will not occur in the HC-06 Bluetooth module when receiving data.

Changed in this revision

--- a/HC06Bluetooth.cpp	Sat Jun 25 00:37:31 2016 +0000
+++ b/HC06Bluetooth.cpp	Tue Jun 28 01:24:36 2016 +0000
@@ -105,24 +105,28 @@
             charCallbackFunc(receivedChar);
         }
 
-        // If the character is a newline or carriage return, then call the line callback function.
-        if ((receivedChar == '\n') || (receivedChar == '\r')) {
-            // Terminate the buffer with a null character, since that is what strings end with.
-            receivedChar = '\0';
-            dataReceivedBuffer[dataReceivedBufferPos] = receivedChar;
-            // Copy data from the buffer to a copy.
-            std::copy(dataReceivedBuffer, dataReceivedBuffer + dataReceivedBufferPos, dataReceivedBufferCopy);
-            // Reset the buffer position.
-            dataReceivedBufferPos = 0;
-            // Call the callback function.
-            if (lineCallbackFunc != NULL) {
-                lineCallbackFunc((const char*)dataReceivedBuffer);
+        if (lineCallbackFunc != NULL) {
+            // If the character is a newline or carriage return, then call the line callback function.
+            if ((receivedChar == '\n') || (receivedChar == '\r')) {
+                // Terminate the buffer with a null character, since that is what strings end with.
+                receivedChar = '\0';
+                dataReceivedBuffer[dataReceivedBufferPos] = receivedChar;
+                // Copy data from the buffer to a copy.
+                std::copy(dataReceivedBuffer, dataReceivedBuffer + dataReceivedBufferPos, dataReceivedBufferCopy);
+                // Reset the buffer position.
+                dataReceivedBufferPos = 0;
+                // Call the callback function.
+                if (lineCallbackFunc != NULL) {
+                    lineCallbackFunc((const char*)dataReceivedBuffer);
+                }
             }
-        }
-        // Otherwise, just place it in the buffer and move on.
-        else {
-            dataReceivedBuffer[dataReceivedBufferPos] = receivedChar;
-            dataReceivedBufferPos++;
+            // Otherwise, just place it in the buffer and move on.
+            else {
+                if (dataReceivedBufferPos < dataBufferSize) {
+                    dataReceivedBuffer[dataReceivedBufferPos] = receivedChar;
+                    dataReceivedBufferPos++;
+                }
+            }
         }
     }
 }

--- a/HC06Bluetooth.hpp	Sat Jun 25 00:37:31 2016 +0000
+++ b/HC06Bluetooth.hpp	Tue Jun 28 01:24:36 2016 +0000
@@ -59,6 +59,8 @@
 #include "mbed.h"
 #include <string>
 
+    const int dataBufferSize = 256;
+
 class HC06Bluetooth {
 public: // Public methods.
     /**
@@ -101,9 +103,9 @@
     void (*lineCallbackFunc) (const char*);
     /// Pointer to a callback function the client provides when a character is received.
     void (*charCallbackFunc) (char);
-    char dataReceivedBuffer[256];
+    char dataReceivedBuffer[dataBufferSize];
     int32_t dataReceivedBufferPos;
-    char dataReceivedBufferCopy[256];
+    char dataReceivedBufferCopy[dataBufferSize];
 };
 
 #endif /* HC06BLUETOOTH_H_ */

--- a/QuadEnc.hpp	Sat Jun 25 00:37:31 2016 +0000
+++ b/QuadEnc.hpp	Tue Jun 28 01:24:36 2016 +0000
@@ -3,8 +3,8 @@
  * @date June 2nd, 2016
  * @author Weimen Li
  * @brief Header file for a class which encapsulates a quadrature encoder.
- * @remark The current implementation does not give the Quadrature Encoder maximum
- * priority, but it really should.
+ * @remark The algorith used to read from the encoder may be found at:
+ * http://makeatronics.blogspot.com/2013/02/efficiently-reading-quadrature-with.html
  */
 
 #ifndef QUADENC_H_