Merge pull request ceph#17265 from zmedico/interval-set-intersection-…

…insert-optimization interval_set: optimize intersect_of insert operations Reviewed-by: Adam Emerson <[email protected]>
amincheloh · Sep 1, 2017 · e59508e · e59508e
2 parents 30a99d4 + b6a0356
commit e59508e
Showing 1 changed file with 16 additions and 2 deletions.
diff --git a/src/include/interval_set.h b/src/include/interval_set.h
@@ -463,17 +463,31 @@ class interval_set {
 
     typename std::map<T,T>::const_iterator pa = a.m.begin();
     typename std::map<T,T>::const_iterator pb = b.m.begin();
-
+    typename decltype(m)::iterator mi = m.begin();
+
     while (pa != a.m.end() && pb != b.m.end()) {
       // passing?
       if (pa->first + pa->second <= pb->first) 
         { pa++;  continue; }
       if (pb->first + pb->second <= pa->first) 
         { pb++;  continue; }
+
+      if (*pa == *pb) {
+        do {
+          mi = m.insert(mi, *pa);
+          _size += pa->second;
+          ++pa;
+          ++pb;
+        } while (pa != a.m.end() && pb != b.m.end() && *pa == *pb);
+        continue;
+      }
+
       T start = MAX(pa->first, pb->first);
       T en = MIN(pa->first+pa->second, pb->first+pb->second);
       assert(en > start);
-      insert(start, en-start);
+      typename decltype(m)::value_type i{start, en - start};
+      mi = m.insert(mi, i);
+      _size += i.second;
       if (pa->first+pa->second > pb->first+pb->second)
         pb++;
       else