X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=folly%2FPadded.h;h=0a772a2d56fceb458d4e9a95b4775960d799bfdc;hb=f65d8d2c92c7259fcfb5b94f3900cc92ca92e732;hp=f4d3b9c7af57d72deb2f644d015bf2e4fbb61ccf;hpb=86d219c38847965714df9eba03b07fa2f6e30ecc;p=folly.git

diff --git a/folly/Padded.h b/folly/Padded.h
index f4d3b9c7..0a772a2d 100644
--- a/folly/Padded.h
+++ b/folly/Padded.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-#ifndef FOLLY_PADDED_H_
-#define FOLLY_PADDED_H_
+#pragma once
 
+#include <algorithm>
 #include <cassert>
 #include <cstdint>
 #include <cstring>
@@ -27,7 +27,8 @@
 
 #include <boost/iterator/iterator_adaptor.hpp>
 
-#include "folly/Portability.h"
+#include <folly/Portability.h>
+#include <folly/ContainerTraits.h>
 
 /**
  * Code that aids in storing data aligned on block (possibly cache-line)
@@ -343,9 +344,15 @@ class Adaptor {
     : c_(std::move(c)),
       lastCount_(lastCount) {
   }
+  explicit Adaptor(size_t n, const value_type& value = value_type())
+    : c_(Node::nodeCount(n), fullNode(value)) {
+    const auto count = n % Node::kElementCount;
+    lastCount_ = count != 0 ? count : Node::kElementCount;
+  }
+
   Adaptor(const Adaptor&) = default;
   Adaptor& operator=(const Adaptor&) = default;
-  Adaptor(Adaptor&& other)
+  Adaptor(Adaptor&& other) noexcept
     : c_(std::move(other.c_)),
       lastCount_(other.lastCount_) {
     other.lastCount_ = Node::kElementCount;
@@ -419,12 +426,13 @@ class Adaptor {
     return c_.back().data()[lastCount_ - 1];
   }
 
+  template <typename... Args>
+  void emplace_back(Args&&... args) {
+    new (allocate_back()) value_type(std::forward<Args>(args)...);
+  }
+
   void push_back(value_type x) {
-    if (lastCount_ == Node::kElementCount) {
-      c_.push_back(Node());
-      lastCount_ = 0;
-    }
-    c_.back().data()[lastCount_++] = std::move(x);
+    emplace_back(std::move(x));
   }
 
   void pop_back() {
@@ -444,6 +452,7 @@ class Adaptor {
     assert(n >= 0);
     c_.reserve(Node::nodeCount(n));
   }
+
   size_type capacity() const {
     return c_.capacity() * Node::kElementCount;
   }
@@ -475,18 +484,31 @@ class Adaptor {
   }
 
   void padToFullNode(const value_type& padValue) {
-    while (lastCount_ != Node::kElementCount) {
-      push_back(padValue);
+    // the if is necessary because c_ may be empty so we can't call c_.back()
+    if (lastCount_ != Node::kElementCount) {
+      auto last = c_.back().data();
+      std::fill(last + lastCount_, last + Node::kElementCount, padValue);
+      lastCount_ = Node::kElementCount;
     }
   }
 
  private:
+  value_type* allocate_back() {
+    if (lastCount_ == Node::kElementCount) {
+      container_emplace_back_or_push_back(c_);
+      lastCount_ = 0;
+    }
+    return &c_.back().data()[lastCount_++];
+  }
+
+  static Node fullNode(const value_type& value) {
+    Node n;
+    std::fill(n.data(), n.data() + kElementsPerNode, value);
+    return n;
+  }
   Container c_;  // container of Nodes
   size_t lastCount_;  // number of elements in last Node
 };
 
 }  // namespace padded
 }  // namespace folly
-
-#endif /* FOLLY_PADDED_H_ */
-