From e76f0c7fe7db44203cf2a759bdc48391f7a87172 Mon Sep 17 00:00:00 2001
From: foxblock <foxblock+github@gmail.com>
Date: Mon, 30 May 2022 22:18:32 +0200
Subject: [PATCH] Change to local memory allocation for pin arrays

Add destructor to SevSegShift with proper memory cleanup

Fixes issues #7 and #9

Instead of copying just the pointer of the shiftRegisterMapDigits and
shiftRegisterMapSegments arrays passed to begin, we allocate the memory
for them in SegSevShift and copy the values manually.
This removes the implicit need for passing global/static variables, so
begin can be called with local/temporary memory.
---
 SevSegShift.cpp | 37 +++++++++++++++++++++++++++++++++----
 SevSegShift.h   |  1 +
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/SevSegShift.cpp b/SevSegShift.cpp
index 5d525f6..3c684a4 100644
--- a/SevSegShift.cpp
+++ b/SevSegShift.cpp
@@ -23,7 +23,6 @@
  */
 #include <SevSegShift.h>
 
-
 // constructor implementation
 SevSegShift::SevSegShift(
   byte pinDS, 
@@ -46,6 +45,16 @@ SevSegShift::SevSegShift(
   _shiftRegisterMap = new byte[8*numberOfShiftRegisters];
   _numberOfShiftRegisters = numberOfShiftRegisters;
   _isDigitsOnController = isDigitsOnController;
+
+  _shiftRegisterMapDigits = nullptr;
+  _shiftRegisterMapSegments = nullptr;
+}
+
+SevSegShift::~SevSegShift()
+{
+  delete _shiftRegisterMap;
+  delete _shiftRegisterMapDigits;
+  delete _shiftRegisterMapSegments;
 }
 
 void SevSegShift::begin(
@@ -58,12 +67,33 @@ void SevSegShift::begin(
   bool leadingZerosIn,
   bool disableDecPoint
 ) {
+  // NOTE: Code duplication to SevSeg::begin
+  // We need to calculate numDigits and numSegments here for allocating the maps
+  // We cannot move the SevSeg::begin call up, since it calls segmentOff, which in
+  // turn relies on everything being setup (incl. _shiftRegisterMapSegments)
+  numDigits = numDigitsIn;
+  numSegments = disableDecPoint ? 7 : 8; // Ternary 'if' statement
+  //Limit the max number of digits to prevent overflowing
+  if (numDigits > MAXNUMDIGITS) numDigits = MAXNUMDIGITS;
+
+  // Remove old data if begin is called multiple times on same object
+  delete _shiftRegisterMapDigits;
+  delete _shiftRegisterMapSegments;
+
   // here the digit"pins" of the Shift register is stored
   // pins are here the OUTPUT PINs of the Shift Register
-  _shiftRegisterMapDigits = shiftRegisterMapDigits;
+  _shiftRegisterMapDigits = new byte[numDigitsIn];
+  for (int i = 0; i < numDigitsIn; ++i)
+  {
+    _shiftRegisterMapDigits[i] = shiftRegisterMapDigits[i];
+  }
   // here the segment"pins" of the Shift register is stored
   // pins are here the OUTPUT PINs of the Shift Register
-  _shiftRegisterMapSegments = shiftRegisterMapSegments;
+  _shiftRegisterMapSegments = new byte[numSegments];
+  for (int i = 0; i < numSegments; ++i)
+  {
+    _shiftRegisterMapSegments[i] = shiftRegisterMapSegments[i];
+  }
 
   // dummy port for initialization (pin of DS is used - and will be set for OUTPUT multiple times ;) )
   byte dummyDigitPINs[8] = {_pinDS,_pinDS,_pinDS,_pinDS,_pinDS,_pinDS,_pinDS,_pinDS};
@@ -85,7 +115,6 @@ void SevSegShift::begin(
     updateWithDelaysIn,
     leadingZerosIn,
     disableDecPoint);
-
 }
 
 // segmentOn
diff --git a/SevSegShift.h b/SevSegShift.h
index caa571f..498a612 100644
--- a/SevSegShift.h
+++ b/SevSegShift.h
@@ -39,6 +39,7 @@ class SevSegShift: public SevSeg {
     const byte numberOfShiftRegisters = 2, // currently const value (not changeable) - maybe in future
     bool isDigitsOnController=false // only Segments are on ShiftRegister - DigitPins are connected to controller
   );
+  virtual ~SevSegShift();
 
   /*
     prepare the SevenSeg-Shift-Register lib