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1 // Copyright (c) 2009 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2009 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 // This file contains the implementation of IdAllocator. | 5 // This file contains the implementation of IdAllocator. |
6 | 6 |
7 #include "../common/id_allocator.h" | 7 #include "../common/id_allocator.h" |
8 #include "../common/logging.h" | 8 #include "../common/logging.h" |
9 | 9 |
10 namespace gpu { | 10 namespace gpu { |
11 | 11 |
12 IdAllocator::IdAllocator() {} | 12 IdAllocator::IdAllocator() {} |
13 | 13 |
14 IdAllocator::~IdAllocator() {} | 14 IdAllocator::~IdAllocator() {} |
15 | 15 |
16 ResourceId IdAllocator::AllocateID() { | 16 ResourceId IdAllocator::AllocateID() { |
17 ResourceId id = FindFirstFree(); | 17 ResourceId id; |
| 18 ResourceIdSet::iterator iter = free_ids_.begin(); |
| 19 if (iter != free_ids_.end()) { |
| 20 id = *iter; |
| 21 } else { |
| 22 id = LastUsedId() + 1; |
| 23 if (!id) { |
| 24 // We wrapped around to 0. |
| 25 id = FindFirstUnusedId(); |
| 26 } |
| 27 } |
18 MarkAsUsed(id); | 28 MarkAsUsed(id); |
19 return id; | 29 return id; |
20 } | 30 } |
21 | 31 |
22 ResourceId IdAllocator::AllocateIDAtOrAbove(ResourceId desired_id) { | 32 ResourceId IdAllocator::AllocateIDAtOrAbove(ResourceId desired_id) { |
23 GPU_DCHECK_LT(static_cast<ResourceId>(used_ids_.size()), | 33 ResourceId id; |
24 static_cast<ResourceId>(-1)); | 34 ResourceIdSet::iterator iter = free_ids_.lower_bound(desired_id); |
25 for (; InUse(desired_id); ++desired_id) {} | 35 if (iter != free_ids_.end()) { |
26 MarkAsUsed(desired_id); | 36 id = *iter; |
27 return desired_id; | 37 } else if (LastUsedId() < desired_id) { |
| 38 id = desired_id; |
| 39 } else { |
| 40 id = LastUsedId() + 1; |
| 41 if (!id) { |
| 42 // We wrapped around to 0. |
| 43 id = FindFirstUnusedId(); |
| 44 } |
| 45 } |
| 46 MarkAsUsed(id); |
| 47 return id; |
28 } | 48 } |
29 | 49 |
30 bool IdAllocator::MarkAsUsed(ResourceId id) { | 50 bool IdAllocator::MarkAsUsed(ResourceId id) { |
| 51 GPU_DCHECK(id); |
| 52 free_ids_.erase(id); |
31 std::pair<ResourceIdSet::iterator, bool> result = used_ids_.insert(id); | 53 std::pair<ResourceIdSet::iterator, bool> result = used_ids_.insert(id); |
32 return result.second; | 54 return result.second; |
33 } | 55 } |
34 | 56 |
35 void IdAllocator::FreeID(ResourceId id) { | 57 void IdAllocator::FreeID(ResourceId id) { |
| 58 GPU_DCHECK(id); |
36 used_ids_.erase(id); | 59 used_ids_.erase(id); |
| 60 std::pair<ResourceIdSet::iterator, bool> result = free_ids_.insert(id); |
| 61 GPU_DCHECK(result.second); |
37 } | 62 } |
38 | 63 |
39 bool IdAllocator::InUse(ResourceId id) const { | 64 bool IdAllocator::InUse(ResourceId id) const { |
40 return id == kInvalidResource || used_ids_.find(id) != used_ids_.end(); | 65 return id == kInvalidResource || used_ids_.find(id) != used_ids_.end(); |
41 } | 66 } |
42 | 67 |
43 ResourceId IdAllocator::FindFirstFree() const { | 68 ResourceId IdAllocator::LastUsedId() const { |
| 69 if (used_ids_.empty()) { |
| 70 return 0u; |
| 71 } else { |
| 72 return *used_ids_.rbegin(); |
| 73 } |
| 74 } |
| 75 |
| 76 ResourceId IdAllocator::FindFirstUnusedId() const { |
44 ResourceId id = 1; | 77 ResourceId id = 1; |
45 for (ResourceIdSet::const_iterator it = used_ids_.begin(); | 78 for (ResourceIdSet::const_iterator it = used_ids_.begin(); |
46 it != used_ids_.end(); ++it) { | 79 it != used_ids_.end(); ++it) { |
47 if ((*it) != id) { | 80 if ((*it) != id) { |
48 return id; | 81 return id; |
49 } | 82 } |
50 ++id; | 83 ++id; |
51 } | 84 } |
52 return id; | 85 return id; |
53 } | 86 } |
54 | 87 |
55 } // namespace gpu | 88 } // namespace gpu |
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