Introduce EEPROM support (#166)

SampleProjects/TestSomething/test/eeprom.cpp

@@ -0,0 +1,10 @@
+#include <ArduinoUnitTests.h>
+#include <Arduino.h>
+#include <EEPROM.h>
+
+unittest(length)
+{
+  assertEqual(EEPROM_SIZE, EEPROM.length());
+}
+
+unittest_main()

cpp/arduino/EEPROM.h

@@ -0,0 +1,155 @@
+/*
+  EEPROM.h - EEPROM library
+  Original Copyright (c) 2006 David A. Mellis.  All right reserved.
+  New version by Christopher Andrews 2015.
+
+  Copy of https://github.com/arduino/ArduinoCore-megaavr/blob/c8a1dd996c783777ec46167cfd8ad3fd2e6df185/libraries/EEPROM/src/EEPROM.h
+  modified by James Foster 2020 to work with Arduino CI.
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#ifndef EEPROM_h
+#define EEPROM_h
+
+#include <inttypes.h>
+#include <avr/io.h>
+
+// I see EEPROM_SIZE defined in various arv/io*.h files; why isn't it defined here?
+#define EEPROM_SIZE (4096)
+// Is this all the custom code required?
+static uint8_t eeprom[EEPROM_SIZE];
+inline uint8_t eeprom_read_byte( uint8_t* index ) { return eeprom[(unsigned long) index % EEPROM_SIZE]; }
+inline void eeprom_write_byte( uint8_t* index, uint8_t value ) { eeprom[(unsigned long) index % EEPROM_SIZE] = value; }
+
+/***
+    EERef class.
+
+    This object references an EEPROM cell.
+    Its purpose is to mimic a typical byte of RAM, however its storage is the EEPROM.
+    This class has an overhead of two bytes, similar to storing a pointer to an EEPROM cell.
+***/
+
+struct EERef{
+
+    EERef( const int index )
+        : index( index )                 {}
+
+    //Access/read members.
+    uint8_t operator*() const            { return eeprom_read_byte( (uint8_t*) index ); }
+    operator uint8_t() const             { return **this; }
+
+    //Assignment/write members.
+    EERef &operator=( const EERef &ref ) { return *this = *ref; }
+    EERef &operator=( uint8_t in )       { return eeprom_write_byte( (uint8_t*) index, in ), *this;  }
+    EERef &operator +=( uint8_t in )     { return *this = **this + in; }
+    EERef &operator -=( uint8_t in )     { return *this = **this - in; }
+    EERef &operator *=( uint8_t in )     { return *this = **this * in; }
+    EERef &operator /=( uint8_t in )     { return *this = **this / in; }
+    EERef &operator ^=( uint8_t in )     { return *this = **this ^ in; }
+    EERef &operator %=( uint8_t in )     { return *this = **this % in; }
+    EERef &operator &=( uint8_t in )     { return *this = **this & in; }
+    EERef &operator |=( uint8_t in )     { return *this = **this | in; }
+    EERef &operator <<=( uint8_t in )    { return *this = **this << in; }
+    EERef &operator >>=( uint8_t in )    { return *this = **this >> in; }
+
+    EERef &update( uint8_t in )          { return  in != *this ? *this = in : *this; }
+
+    /** Prefix increment/decrement **/
+    EERef& operator++()                  { return *this += 1; }
+    EERef& operator--()                  { return *this -= 1; }
+
+    /** Postfix increment/decrement **/
+    uint8_t operator++ (int){ 
+        uint8_t ret = **this;
+        return ++(*this), ret;
+    }
+
+    uint8_t operator-- (int){ 
+        uint8_t ret = **this;
+        return --(*this), ret;
+    }
+
+    int index; //Index of current EEPROM cell.
+};
+
+/***
+    EEPtr class.
+
+    This object is a bidirectional pointer to EEPROM cells represented by EERef objects.
+    Just like a normal pointer type, this can be dereferenced and repositioned using 
+    increment/decrement operators.
+***/
+
+struct EEPtr{
+
+    EEPtr( const int index )
+        : index( index )                {}
+
+    operator int() const                { return index; }
+    EEPtr &operator=( int in )          { return index = in, *this; }
+
+    //Iterator functionality.
+    bool operator!=( const EEPtr &ptr ) { return index != ptr.index; }
+    EERef operator*()                   { return index; }
+
+    /** Prefix & Postfix increment/decrement **/
+    EEPtr& operator++()                 { return ++index, *this; }
+    EEPtr& operator--()                 { return --index, *this; }
+    EEPtr operator++ (int)              { return index++; }
+    EEPtr operator-- (int)              { return index--; }
+
+    int index; //Index of current EEPROM cell.
+};
+
+/***
+    EEPROMClass class.
+
+    This object represents the entire EEPROM space.
+    It wraps the functionality of EEPtr and EERef into a basic interface.
+    This class is also 100% backwards compatible with earlier Arduino core releases.
+***/
+
+struct EEPROMClass{
+
+    //Basic user access methods.
+    EERef operator[]( const int idx )    { return idx; }
+    uint8_t read( int idx )              { return EERef( idx ); }
+    void write( int idx, uint8_t val )   { (EERef( idx )) = val; }
+    void update( int idx, uint8_t val )  { EERef( idx ).update( val ); }
+
+    //STL and C++11 iteration capability.
+    EEPtr begin()                        { return 0x00; }
+    EEPtr end()                          { return length(); } //Standards requires this to be the item after the last valid entry. The returned pointer is invalid.
+    uint16_t length()                    { return EEPROM_SIZE; }
+
+    //Functionality to 'get' and 'put' objects to and from EEPROM.
+    template< typename T > T &get( int idx, T &t ){
+        EEPtr e = idx;
+        uint8_t *ptr = (uint8_t*) &t;
+        for( int count = sizeof(T) ; count ; --count, ++e )  *ptr++ = *e;
+        return t;
+    }
+
+    template< typename T > const T &put( int idx, const T &t ){
+        EEPtr e = idx;
+        const uint8_t *ptr = (const uint8_t*) &t;
+        for( int count = sizeof(T) ; count ; --count, ++e )  (*e).update( *ptr++ );
+        return t;
+    }
+};
+
+static EEPROMClass EEPROM;
+#endif