2 files changed, 18 insertions, 1 deletions
diff --git a/src/common/memory.h b/src/common/memory.h
index a02ac578..e90bd52c 100644
--- a/src/common/memory.h
+++ b/src/common/memory.h
@@ -145,6 +145,18 @@ class wasteful_vector {
         used_(0) {
   }
 
+  T& back() {
+    return a_[used_ - 1];
+  }
+
+  const T& back() const {
+    return a_[used_ - 1];
+  }
+
+  bool empty() const {
+    return used_ == 0;
+  }
+
   void push_back(const T& new_element) {
     if (used_ == allocated_)
       Realloc(allocated_ * 2);
diff --git a/src/common/memory_unittest.cc b/src/common/memory_unittest.cc
index 8b2ec410..d580c1fe 100644
--- a/src/common/memory_unittest.cc
+++ b/src/common/memory_unittest.cc
@@ -69,6 +69,7 @@ typedef testing::Test WastefulVectorTest;
 TEST(WastefulVectorTest, Setup) {
   PageAllocator allocator_;
   wasteful_vector<int> v(&allocator_);
+  ASSERT_TRUE(v.empty());
   ASSERT_EQ(v.size(), 0u);
 }
 
@@ -76,8 +77,12 @@ TEST(WastefulVectorTest, Simple) {
   PageAllocator allocator_;
   wasteful_vector<unsigned> v(&allocator_);
 
-  for (unsigned i = 0; i < 256; ++i)
+  for (unsigned i = 0; i < 256; ++i) {
     v.push_back(i);
+    ASSERT_EQ(i, v.back());
+    ASSERT_EQ(&v.back(), &v[i]);
+  }
+  ASSERT_FALSE(v.empty());
   ASSERT_EQ(v.size(), 256u);
   for (unsigned i = 0; i < 256; ++i)
     ASSERT_EQ(v[i], i);