+ version 0.1.05 (0.1.04 experimental only)

+ added back function to "reverse map"
+ fastMapDemo2 shows usage of 2 FastMaps
+ fastMapDemo3 shows usage of back function
+ FASTMAP_LIB_VERSION in PROGMEM

libraries/FastMap/FastMap.cpp

@@ -1,11 +1,14 @@
 //
 //    FILE: FastMap.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.03
+// VERSION: 0.1.05
 // PURPOSE: class implementation of map function - library for Arduino
 //     URL: http://forum.arduino.cc/index.php?topic=276194
 //
 // HISTORY:
+// 0.1.05 stripped of bit mask experimental code
+// 0.1.04 add back() - the inverse map
+//        tested with bit mask for constrain code (Perfomance was killed)
 // 0.1.03 proper name
 // 0.1.02 squized the code (first public version)
 // 0.1.01 refactor
@@ -18,17 +21,20 @@
 //
 // PUBLIC
 //
-
 void FastMap::init(float in_min, float in_max, float out_min, float out_max)
 {
     _in_min = in_min;
     _in_max = in_max;
     _out_min = out_min;
     _out_max = out_max;
+
     _factor = (out_max - out_min)/(in_max - in_min);
     _base = out_min - in_min * _factor;
+
+    _backfactor = 1/_factor;
+    _backbase = in_min - out_min * _backfactor;
 }
-    
+
 float FastMap::constrainedMap(float value)
 {
     if (value <= _in_min) return _out_min;

libraries/FastMap/FastMap.h

@@ -1,12 +1,12 @@
 //
 //    FILE: FastMap.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.03
+// VERSION: 0.1.05
 // PURPOSE: class implementation of map function - library for Arduino
 //     URL: http://forum.arduino.cc/index.php?topic=276194
 //
 // HISTORY:
-// see fastMap.cpp file
+// see FastMap.cpp file
 //
 
 #ifndef FastMap_h
@@ -18,9 +18,7 @@
 #include <Arduino.h>
 #endif
 
-#define FASTMAP_LIB_VERSION "0.1.03"
-
-#define USE_CONSTRAINED_MAP
+#define FASTMAP_LIB_VERSION (F("0.1.05"))
 
 class FastMap
 {
@@ -28,6 +26,8 @@ public:
     void init(float in_min, float in_max, float out_min, float out_max);
 
     float inline map(float value) { return _base + value * _factor; }
+    float inline back(float value) { return _backbase + value * _backfactor; }
+
     float constrainedMap(float value);
     float lowerConstrainedMap(float value);
     float upperConstrainedMap(float value);
@@ -35,6 +35,7 @@ public:
 private:
     float _in_min, _in_max, _out_min, _out_max;
     float _factor, _base;
+    float _backfactor, _backbase;
 };
 
 #endif

libraries/FastMap/examples/fastMapDemo2/fastMapDemo2.ino

@@ -0,0 +1,44 @@
+//
+//    FILE: fastMapDemo2.ino
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.1.02
+// PURPOSE: demo of FastMap class ==> a faster map function
+//    DATE: 2014-11-02
+//     URL:
+//
+// Released to the public domain
+//
+
+#include "FastMap.h"
+
+FastMap CtoF;
+FastMap FtoC;
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.print("Start fastMapDemo2\nlib version: ");
+  Serial.println(FASTMAP_LIB_VERSION);
+  Serial.println();
+
+  CtoF.init(0, 100, 32, 212);
+  FtoC.init(32, 212, 0, 100);
+
+  float f = FtoC.map(163);
+  Serial.print(f);
+  Serial.print(char(223));
+  Serial.println('C');
+  
+  float c = CtoF.map(f);
+  Serial.print(c);
+  Serial.print(char(223));
+  Serial.println('F');
+}
+
+void loop()
+{
+}
+//
+// END OF FILE
+//
+

libraries/FastMap/examples/fastMapDemo3/fastMapDemo3.ino

@@ -0,0 +1,52 @@
+//    FILE: fastMapDemo3.ino
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.1.00
+// PURPOSE: demo of FastMap class ==> a faster map function
+//    DATE: 2014-11-02
+//     URL: http://forum.arduino.cc/index.php?topic=276194
+//
+// Released to the public domain
+//
+
+#include "FastMap.h"
+
+FastMap CtoF;
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.print("Start fastMapDemo3\nlib version: ");
+  Serial.println(FASTMAP_LIB_VERSION);
+  Serial.println();
+
+  CtoF.init(0, 100, 32, 212);
+
+  float f = CtoF.map(163);
+  Serial.print(f);
+  Serial.print(char(176));
+  Serial.println('F');
+
+  float c = CtoF.back(f);
+  Serial.print(c);
+  Serial.print(char(176));
+  Serial.println('C');
+
+  f = CtoF.map(163, CONSTRAIN_UPPER);
+  Serial.print(f);
+  Serial.print(char(176));
+  Serial.println('F');
+
+  c = CtoF.back(f, CONSTRAIN_BOTH);
+  Serial.print(c);
+  Serial.print(char(176));
+  Serial.println('C');
+
+}
+
+void loop()
+{
+}
+//
+// END OF FILE
+//
+