[gnome-system-monitor] Add generic function to join elements of a collection.

[Benoît Dejean <bdejean src gnome org>]

commit 1ac93e7fe5bdf7c7d43066367a8bcf290404815d
Author: Benoît Dejean <bdejean gmail com>
Date:   Fri Oct 28 15:19:33 2016 +0200

    Add generic function to join elements of a collection.

 src/util.h |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)
---
diff --git a/src/util.h b/src/util.h
index a389b35..8d5fb3d 100644
--- a/src/util.h
+++ b/src/util.h
@@ -136,6 +136,24 @@ namespace procman
         NonCopyable& operator=(const NonCopyable&) /* = delete */;
     };
 
+
+    // join the elements of c with sep
+    template<typename C, typename S>
+        auto join(const C& c, const S& sep) -> decltype(c[0] + sep)
+    {
+        decltype(c[0] + sep) r;
+        bool first = true;
+
+        for(const auto& e : c) {
+            if (!first) {
+                r += sep;
+            }
+            first = false;
+            r += e;
+        }
+
+        return r;
+    }
 }
 
 #endif /* _GSM_UTIL_H_ */