refs #478 refs #488, utils / free functions

* seed for random numbers per thread
* added function to get all user metatypes as string
* added new read file function per path/name
* removed DBus operators for pixmap
* JSON operators for byte array
* util function for JSON string

src/blackmisc/math/mathutils.cpp

@@ -8,6 +8,8 @@
  */
 
 #include "blackmisc/math/mathutils.h"
+#include <QThreadStorage>
+#include <QTime>
 #include <algorithm>
 #include <cmath>
 
@@ -77,5 +79,19 @@ namespace BlackMisc
             return (result >= 0.0) ? result : result + 360.0;
         }
 
+        int CMathUtils::randomInteger(int low, int high)
+        {
+            static QThreadStorage<uint> seeds;
+            if (!seeds.hasLocalData())
+            {
+                // seed is per thread!
+                uint seed = static_cast<uint>(QTime::currentTime().msec());
+                qsrand(seed);
+                seeds.setLocalData(seed);
+            }
+            int r(qrand());
+            return r % ((high + 1) - low) + low;
+        }
+
     } // namespace
 } // namespace

src/blackmisc/math/mathutils.h

@@ -100,10 +100,7 @@ namespace BlackMisc
             static double normalizeDegrees(double degrees);
 
             //! Random number between low and high
-            static int randomInteger(int low, int high)
-            {
-                return qrand() % ((high + 1) - low) + low;
-            }
+            static int randomInteger(int low, int high);
         };
 
     } // namespace