From 9593136bdad1785c451a7d91b24cfd5321ec27da Mon Sep 17 00:00:00 2001
From: Rob Tillaart <rob.tillaart@gmail.com>
Date: Thu, 29 Aug 2013 11:39:24 +0200
Subject: [PATCH] + based upon Print interface + less variables (more local) +
 some comments

---
 libraries/FastShiftOut/FastShiftOut.cpp | 36 +++++++++++++++----------
 libraries/FastShiftOut/FastShiftOut.h   | 23 +++++++---------
 2 files changed, 31 insertions(+), 28 deletions(-)

diff --git a/libraries/FastShiftOut/FastShiftOut.cpp b/libraries/FastShiftOut/FastShiftOut.cpp
index 2bdf8046..b61f0500 100644
--- a/libraries/FastShiftOut/FastShiftOut.cpp
+++ b/libraries/FastShiftOut/FastShiftOut.cpp
@@ -1,8 +1,8 @@
 //
 //    FILE: FastShiftOut.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1
-// PURPOSE: 
+// VERSION: 0.1.03
+// PURPOSE: shiftout that implements the Print interface
 //     URL:
 //
 // Released to the public domain
@@ -10,29 +10,33 @@
 
 #include "FastShiftOut.h"
 
+//
+// Constructor
+// prepares the digitalWrite()
 FastShiftOut::FastShiftOut(uint8_t datapin, uint8_t clockpin, uint8_t bitOrder)
 {
-    _datapin = datapin;
-    _clockpin = clockpin;
     _bitorder = bitOrder;
     _value = -1;
-    pinMode(_datapin, OUTPUT);
-    pinMode(_clockpin, OUTPUT);
+    pinMode(datapin, OUTPUT);
+    pinMode(clockpin, OUTPUT);
     
-    _datatimer  = digitalPinToTimer(_datapin);
-	_databit    = digitalPinToBitMask(_datapin);
-	_dataport   = digitalPinToPort(_datapin);
-    // if (_datatimer != NOT_ON_TIMER) turnOffPWM(_datatimer);
+    // uint8_t _datatimer  = digitalPinToTimer(datapin);
+    // if (_datatimer != NOT_ON_TIMER) turnOffPWM(_datatimer); TODO
+	uint8_t _dataport   = digitalPinToPort(datapin);
     _dataout = portOutputRegister(_dataport);
+	_databit = digitalPinToBitMask(datapin);
     
-    _clocktimer = digitalPinToTimer(_clockpin);
-	_clockbit   = digitalPinToBitMask(_clockpin);
-	_clockport  = digitalPinToPort(_clockpin);
+    // uint8_t _clocktimer = digitalPinToTimer(clockpin);
     // if (_clocktimer != NOT_ON_TIMER) turnOffPWM(_clocktimer);
+	uint8_t _clockport  = digitalPinToPort(clockpin);
     _clockout = portOutputRegister(_clockport);
+	_clockbit   = digitalPinToBitMask(clockpin);
 }
 
-void FastShiftOut::write(uint8_t data)
+//
+// write() must implement the virtual write of Print class
+//
+size_t FastShiftOut::write(uint8_t data)
 {
     _value = data;
     for (uint8_t i = 0; i < 8; i++)  
@@ -49,8 +53,12 @@ void FastShiftOut::write(uint8_t data)
         *_clockout &= ~_clockbit;
         SREG = oldSREG;
     }
+    return 1;
 }
 
+//
+// reads back the last value written.
+//
 int FastShiftOut::read()
 {
     return _value;
diff --git a/libraries/FastShiftOut/FastShiftOut.h b/libraries/FastShiftOut/FastShiftOut.h
index e46ecb17..5f7a4239 100644
--- a/libraries/FastShiftOut/FastShiftOut.h
+++ b/libraries/FastShiftOut/FastShiftOut.h
@@ -1,8 +1,8 @@
 //
 //    FILE: FastShiftOut.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1
-// PURPOSE: 
+// VERSION: 0.1.03
+// PURPOSE: shiftout that implements the Print interface
 //     URL:
 //
 // Released to the public domain
@@ -17,31 +17,26 @@
   #include "WProgram.h"
 #endif
 
-#define FASTSHIFTOUT_LIB_VERSION "0.1.00"
+#define FASTSHIFTOUT_LIB_VERSION "0.1.03"
 
-class FastShiftOut
+#include "Print.h"
+
+class FastShiftOut : public Print
 {
   public:
 	FastShiftOut(uint8_t, uint8_t, uint8_t);
-    void write(uint8_t);
+    size_t write(uint8_t);
     int read(void);
 
   private:
-    uint8_t _datapin;
-    uint8_t _clockpin;
     uint8_t _bitorder;
     int _value;
     
-    uint8_t _datatimer;
 	uint8_t _databit;
-	uint8_t _dataport;
     volatile uint8_t *_dataout;
-        
-    uint8_t _clocktimer;
-	uint8_t _clockbit;
-	uint8_t _clockport;
-    volatile uint8_t *_clockout;
     
+	uint8_t _clockbit;
+    volatile uint8_t *_clockout;
 };
 
 #endif