1 files changed, 82 insertions, 0 deletions
diff --git a/chromium/ui/base/sequential_id_generator.cc b/chromium/ui/base/sequential_id_generator.cc
new file mode 100644
index 00000000000..ac3b1a0ed41
--- /dev/null
+++ b/chromium/ui/base/sequential_id_generator.cc
@@ -0,0 +1,82 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/base/sequential_id_generator.h"
+
+#include "base/logging.h"
+
+namespace {
+
+// Removes |key| from |first|, and |first[key]| from |second|.
+template<typename T>
+void Remove(uint32 key, T* first, T* second) {
+  typename T::iterator iter = first->find(key);
+  if (iter == first->end())
+    return;
+
+  uint32 second_key = iter->second;
+  first->erase(iter);
+
+  iter = second->find(second_key);
+  DCHECK(iter != second->end());
+  second->erase(iter);
+}
+
+}  // namespace
+
+namespace ui {
+
+SequentialIDGenerator::SequentialIDGenerator(uint32 min_id)
+    : min_id_(min_id),
+      min_available_id_(min_id) {
+}
+
+SequentialIDGenerator::~SequentialIDGenerator() {
+}
+
+uint32 SequentialIDGenerator::GetGeneratedID(uint32 number) {
+  IDMap::iterator find = number_to_id_.find(number);
+  if (find != number_to_id_.end())
+    return find->second;
+
+  int id = GetNextAvailableID();
+  number_to_id_.insert(std::make_pair(number, id));
+  id_to_number_.insert(std::make_pair(id, number));
+  return id;
+}
+
+bool SequentialIDGenerator::HasGeneratedIDFor(uint32 number) const {
+  return number_to_id_.find(number) != number_to_id_.end();
+}
+
+void SequentialIDGenerator::ReleaseGeneratedID(uint32 id) {
+  UpdateNextAvailableIDAfterRelease(id);
+  Remove(id, &id_to_number_, &number_to_id_);
+}
+
+void SequentialIDGenerator::ReleaseNumber(uint32 number) {
+  DCHECK_GT(number_to_id_.count(number), 0U);
+  UpdateNextAvailableIDAfterRelease(number_to_id_[number]);
+  Remove(number, &number_to_id_, &id_to_number_);
+}
+
+uint32 SequentialIDGenerator::GetNextAvailableID() {
+  const uint32 kMaxID = 128;
+  while (id_to_number_.count(min_available_id_) > 0 &&
+         min_available_id_ < kMaxID) {
+    ++min_available_id_;
+  }
+  if (min_available_id_ >= kMaxID)
+    min_available_id_ = min_id_;
+  return min_available_id_;
+}
+
+void SequentialIDGenerator::UpdateNextAvailableIDAfterRelease(uint32 id) {
+  if (id < min_available_id_) {
+    min_available_id_ = id;
+    DCHECK_GE(min_available_id_, min_id_);
+  }
+}
+
+}  // namespace ui