Utils - combine

- Implemented combine, which takes two integer vectors and combines
  them resulting in a single vector contianing the unique values of
  both.

src/util.cpp

@@ -381,6 +381,27 @@ std::string compressIds (const std::vector <int>& ids)
   return result.str ();
 }
 
+////////////////////////////////////////////////////////////////////////////////
+void combine (std::vector <int>& dest, const std::vector <int>& source)
+{
+  // Create a map using the sequence elements as keys.  This will create a
+  // unique list, with no duplicates.
+  std::map <int, int> both;
+  std::vector <int>::iterator i1;
+  for (i1 = dest.begin (); i1 != dest.end (); ++i1) both[*i1] = 0;
+
+  std::vector <int>::const_iterator i2;
+  for (i2 = source.begin (); i2 != source.end (); ++i2) both[*i2] = 0;
+
+  // Now make a sequence out of the keys of the map.
+  dest.clear ();
+  std::map <int, int>::iterator i3;
+  for (i3 = both.begin (); i3 != both.end (); ++i3)
+    dest.push_back (i3->first);
+
+  std::sort (dest.begin (), dest.end ());
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // Run an external executable with execvp. This means stdio goes to 
 // the child process, so that it can receive user input (e.g. passwords).

src/util.h

@@ -72,6 +72,7 @@ int execute (const std::string&, std::vector<std::string>);
 #endif
 
 std::string compressIds (const std::vector <int>&);
+void combine (std::vector <int>&, const std::vector <int>&);
 
 #endif
 ////////////////////////////////////////////////////////////////////////////////

test/util.t.cpp

@@ -34,7 +34,7 @@ Context context;
 ////////////////////////////////////////////////////////////////////////////////
 int main (int argc, char** argv)
 {
-  UnitTest t (19);
+  UnitTest t (30);
 
   // TODO bool confirm (const std::string&);
   // TODO int confirm3 (const std::string&);
@@ -85,6 +85,33 @@ int main (int argc, char** argv)
   output = taskDifferences (right, rightAgain);
   t.ok (output.find ("No changes will be made")               != std::string::npos, "No changes detected");
 
+  // void combine (std::vector <int>&, const std::vector <int>&);
+  std::vector <int> vleft;
+  vleft.push_back (1);
+  vleft.push_back (2);
+  vleft.push_back (3);
+
+  std::vector <int> vright;
+  vright.push_back (4);
+
+  combine (vleft, vright);
+  t.is (vleft.size (), (size_t)4, "1,2,3 + 4 -> [4]");
+  t.is (vleft[0], 1,      "1,2,3 + 4 -> 1,2,3,4");
+  t.is (vleft[1], 2,      "1,2,3 + 4 -> 1,2,3,4");
+  t.is (vleft[2], 3,      "1,2,3 + 4 -> 1,2,3,4");
+  t.is (vleft[3], 4,      "1,2,3 + 4 -> 1,2,3,4");
+
+  vright.push_back (3);
+  vright.push_back (5);
+  combine (vleft, vright);
+
+  t.is (vleft.size (), (size_t)5, "1,2,3,4 + 3,4,5 -> [5]");
+  t.is (vleft[0], 1,      "1,2,3,4 + 3,4,5 -> 1,2,3,4,5");
+  t.is (vleft[1], 2,      "1,2,3,4 + 3,4,5 -> 1,2,3,4,5");
+  t.is (vleft[2], 3,      "1,2,3,4 + 3,4,5 -> 1,2,3,4,5");
+  t.is (vleft[3], 4,      "1,2,3,4 + 3,4,5 -> 1,2,3,4,5");
+  t.is (vleft[4], 5,      "1,2,3,4 + 3,4,5 -> 1,2,3,4,5");
+
   return 0;
 }