| OLD | NEW |
| 1 // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file |
| 2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
| 3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
| 4 | 4 |
| 5 #ifndef RUNTIME_VM_RING_BUFFER_H_ | 5 #ifndef RUNTIME_VM_RING_BUFFER_H_ |
| 6 #define RUNTIME_VM_RING_BUFFER_H_ | 6 #define RUNTIME_VM_RING_BUFFER_H_ |
| 7 | 7 |
| 8 #include "platform/assert.h" | 8 #include "platform/assert.h" |
| 9 #include "platform/utils.h" | 9 #include "platform/utils.h" |
| 10 | 10 |
| 11 namespace dart { | 11 namespace dart { |
| 12 | 12 |
| 13 // Fixed-capacity ring buffer. | 13 // Fixed-capacity ring buffer. |
| 14 template<typename T, int N> | 14 template <typename T, int N> |
| 15 class RingBuffer { | 15 class RingBuffer { |
| 16 public: | 16 public: |
| 17 RingBuffer() : count_(0) { } | 17 RingBuffer() : count_(0) {} |
| 18 | 18 |
| 19 void Add(const T& t) { | 19 void Add(const T& t) { data_[count_++ & kMask] = t; } |
| 20 data_[count_++ & kMask] = t; | |
| 21 } | |
| 22 | 20 |
| 23 // Returns the i'th most recently added element. Requires 0 <= i < Size(). | 21 // Returns the i'th most recently added element. Requires 0 <= i < Size(). |
| 24 const T& Get(int i) const { | 22 const T& Get(int i) const { |
| 25 ASSERT(0 <= i && i < Size()); | 23 ASSERT(0 <= i && i < Size()); |
| 26 return data_[(count_ - i - 1) & kMask]; | 24 return data_[(count_ - i - 1) & kMask]; |
| 27 } | 25 } |
| 28 | 26 |
| 29 // Returns the number of elements currently stored in this buffer (at most N). | 27 // Returns the number of elements currently stored in this buffer (at most N). |
| 30 int64_t Size() const { | 28 int64_t Size() const { |
| 31 return Utils::Minimum(count_, static_cast<int64_t>(N)); | 29 return Utils::Minimum(count_, static_cast<int64_t>(N)); |
| 32 } | 30 } |
| 33 | 31 |
| 34 private: | 32 private: |
| 35 static const int kMask = N - 1; | 33 static const int kMask = N - 1; |
| 36 COMPILE_ASSERT((N & kMask) == 0); | 34 COMPILE_ASSERT((N & kMask) == 0); |
| 37 T data_[N]; | 35 T data_[N]; |
| 38 int64_t count_; | 36 int64_t count_; |
| 39 }; | 37 }; |
| 40 | 38 |
| 41 } // namespace dart | 39 } // namespace dart |
| 42 | 40 |
| 43 #endif // RUNTIME_VM_RING_BUFFER_H_ | 41 #endif // RUNTIME_VM_RING_BUFFER_H_ |
| OLD | NEW |