Add ::peek for compatibility with trunk Arduino.

git-svn-id: https://arducopter.googlecode.com/svn/trunk@943 f9c3cf11-9bcb-44bc-f272-b75c42450872

libraries/FastSerial/FastSerial.cpp

@@ -209,6 +209,19 @@ FastSerial::read(void)
         return(c);
 }
 
+int
+FastSerial::peek(void)
+{
+
+        // if the head and tail are equal, the buffer is empty
+        if (!_open || (_rxBuffer->head == _rxBuffer->tail))
+                return(-1);
+
+        // pull character from tail
+        return(_rxBuffer->bytes[_rxBuffer->tail]);
+}
+
+
 void
 FastSerial::flush(void)
 {

libraries/FastSerial/FastSerial.h

@@ -100,6 +100,7 @@ public:
         virtual void    end(void);
         virtual int     available(void);
         virtual int     read(void);
+        virtual int     peek(void);
         virtual void    flush(void);
         virtual void    write(uint8_t c);
         using BetterStream::write;