MeasurementArea.cc better randmomId

src/MeasurementComplexItem/geometry/MeasurementArea.cc

@@ -19,7 +19,7 @@
 #define MAX_TILES 1000
 #endif
 
-QString randomId();
+QString randomId(std::size_t length = 10);
 
 using namespace geometry;
 namespace trans = bg::strategy::transform;
@@ -726,13 +726,24 @@ bool getTiles(const FPolygon &area, Length tileHeight, Length tileWidth,
   return true;
 }
 
-QString randomId() {
-  std::srand(std::time(nullptr));
-  std::int64_t r = 0;
+QString randomId(std::size_t length) {
+  static const QString values(
+      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789");
+  static std::uint64_t counter = 0;
+  static auto firstCall = std::chrono::high_resolution_clock::now();
+
+  auto delta = std::chrono::duration_cast<std::chrono::nanoseconds>(
+                   std::chrono::high_resolution_clock::now() - firstCall)
+                   .count();
 
-  for (int i = 0; i < 10; ++i) {
-    r ^= std::rand();
+  std::srand((unsigned int)delta ^ counter);
+  QString str;
+  for (int i = 0; i < length; ++i) {
+    int index = std::rand() % values.length();
+    QChar c = values.at(index);
+    str.append(c);
   }
 
-  return QString::number(r);
+  ++counter;
+  return str;
 }