+ prevent overflow; refactor memory usage;

libraries/DistanceTable/DistanceTable.cpp

@@ -1,24 +1,30 @@
 //
 //    FILE: DistanceTable.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.01
+// VERSION: 0.1.2
 // PURPOSE: library for a memory efficient DistanceTable for Arduino
 //     URL:
 //
 // Released to the public domain
 //
 
-// 0.1.00 - initial version
+// 0.1.2 - prevent overflow; refactor memory usage;
 // 0.1.01 - refactor
+// 0.1.00 - initial version
 
 #include "DistanceTable.h"
 
 DistanceTable::DistanceTable(uint8_t size)
 {
+    // MUST: size > 1
+    // ATMEL 328 has 2000 bytes mem,
+    // so roughly 30X30 = 900 floats(4Bytes) => 1740 bytes is max feasible
     _size = size;
-    uint16_t s = size * (size-1)/2;
-    _distanceTable = (double*) malloc(s * sizeof(double));
+    _store = _size;
+    _store *= (_size-1)/2;
+    _distanceTable = (double *) malloc(_store * sizeof(double));
     if (_distanceTable == NULL) _size = 0;
+    clear();
 }
 
 DistanceTable::~DistanceTable()
@@ -28,33 +34,28 @@ DistanceTable::~DistanceTable()
 
 void DistanceTable::clear()
 {
-    uint16_t s = _size * (_size-1)/2;
-    for (uint16_t index = 0; index < s; index++)
-    {
-        _distanceTable[index] = 0;
-    }
+    for (uint16_t index = 0; index <_store; index++) _distanceTable[index] = 0;
 };
 
 void DistanceTable::set(uint8_t x, uint8_t y, double value )
 {
-    if ( x >= _size || y >= _size) return;
     if ( x == y ) return;
-    // need swap?
-    if ( x < y ) 
+    if ( x >= _size || y >= _size) return;
+    if ( x < y )
     {
         uint8_t t = x; x = y; y = t;
     }
+    // prevent overflow by moving to 16 bit
     uint16_t index = x;
     index = index * (index-1)/2 + y;
     _distanceTable[index] = value;
 };
 
-double DistanceTable::get(uint8_t x, uint8_t y)
+double DistanceTable::get (uint8_t x, uint8_t y)
 {
-    if ( x >= _size || y >= _size) return -1;
     if ( x == y ) return 0;
-    // need swap?
-    if ( x < y ) 
+    if ( x >= _size || y >= _size) return -1;
+    if ( x < y )
     {
         uint8_t t = x; x = y; y = t;
     }
@@ -63,19 +64,19 @@ double DistanceTable::get(uint8_t x, uint8_t y)
     return _distanceTable[index];
 };
 
-
+// triangular dump
 void DistanceTable::dump()
 {
     uint16_t index = 0;
-    for (uint16_t i = 0; i < _size-1; i++)
+    for (uint8_t i = 0; i < _size-1; i++)
     {
-        for (uint16_t j = 0; j <= i; j++)
+        for (uint8_t j = 0; j <= i; j++)
         {
             Serial.print(_distanceTable[index++]);
             Serial.print("\t");
         }
         Serial.println();
-    }     
+    }
     Serial.println();
 };
 

libraries/DistanceTable/DistanceTable.h

@@ -1,7 +1,7 @@
 //
 //    FILE: DistanceTable.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.01
+// VERSION: 0.1.2
 // PURPOSE: memory efficient DistanceTable for Arduino
 //     URL: 
 //
@@ -13,12 +13,12 @@
 
 #include "Arduino.h"
 
-#define DISTANCETABLE_LIB_VERSION "0.1.01"
+#define DISTANCETABLE_LIB_VERSION "0.1.2"
 
 class DistanceTable
 {
 public:
-    DistanceTable(uint8_t);
+    explicit DistanceTable(uint8_t);
     ~DistanceTable();
 
     void clear();
@@ -27,8 +27,8 @@ public:
     void dump();
 
 protected:
-    int _error;
     uint8_t _size;
+    uint16_t _store;
     double * _distanceTable;
 };
 

libraries/DistanceTable/library.properties

@@ -1,5 +1,5 @@
 name=DistanceTable
-version=0.1.1
+version=0.1.2
 author=Rob Tillaart <rob.tillaart@gmail.com>
 maintainer=Rob Tillaart <rob.tillaart@gmail.com>
 sentence=Library for a memory efficient DistanceTable for Arduino.