1// Copyright (c) 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "ui/gfx/sequential_id_generator.h"
6
7#include "base/logging.h"
8
9namespace {
10
11// Removes |key| from |first|, and |first[key]| from |second|.
12template<typename T>
13void Remove(uint32 key, T* first, T* second) {
14  typename T::iterator iter = first->find(key);
15  if (iter == first->end())
16    return;
17
18  uint32 second_key = iter->second;
19  first->erase(iter);
20
21  iter = second->find(second_key);
22  DCHECK(iter != second->end());
23  second->erase(iter);
24}
25
26}  // namespace
27
28namespace ui {
29
30SequentialIDGenerator::SequentialIDGenerator(uint32 min_id)
31    : min_id_(min_id),
32      min_available_id_(min_id) {
33}
34
35SequentialIDGenerator::~SequentialIDGenerator() {
36}
37
38uint32 SequentialIDGenerator::GetGeneratedID(uint32 number) {
39  IDMap::iterator find = number_to_id_.find(number);
40  if (find != number_to_id_.end())
41    return find->second;
42
43  int id = GetNextAvailableID();
44  number_to_id_.insert(std::make_pair(number, id));
45  id_to_number_.insert(std::make_pair(id, number));
46  return id;
47}
48
49bool SequentialIDGenerator::HasGeneratedIDFor(uint32 number) const {
50  return number_to_id_.find(number) != number_to_id_.end();
51}
52
53void SequentialIDGenerator::ReleaseGeneratedID(uint32 id) {
54  UpdateNextAvailableIDAfterRelease(id);
55  Remove(id, &id_to_number_, &number_to_id_);
56}
57
58void SequentialIDGenerator::ReleaseNumber(uint32 number) {
59  DCHECK_GT(number_to_id_.count(number), 0U);
60  UpdateNextAvailableIDAfterRelease(number_to_id_[number]);
61  Remove(number, &number_to_id_, &id_to_number_);
62}
63
64void SequentialIDGenerator::ResetForTest() {
65  number_to_id_.clear();
66  id_to_number_.clear();
67  min_available_id_ = min_id_;
68}
69
70uint32 SequentialIDGenerator::GetNextAvailableID() {
71  const uint32 kMaxID = 128;
72  while (id_to_number_.count(min_available_id_) > 0 &&
73         min_available_id_ < kMaxID) {
74    ++min_available_id_;
75  }
76  if (min_available_id_ >= kMaxID)
77    min_available_id_ = min_id_;
78  return min_available_id_;
79}
80
81void SequentialIDGenerator::UpdateNextAvailableIDAfterRelease(uint32 id) {
82  if (id < min_available_id_) {
83    min_available_id_ = id;
84    DCHECK_GE(min_available_id_, min_id_);
85  }
86}
87
88}  // namespace ui
89