| // Copyright 2010-2015, Google Inc. |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef MOZC_BASE_FREELIST_H_ |
| #define MOZC_BASE_FREELIST_H_ |
| |
| #include <vector> |
| #include "base/port.h" |
| |
| namespace mozc { |
| |
| // Note: The program will be crashed in the following code; |
| // FreeList<int> freelist(10); |
| // freelist.Alloc(5); |
| // freelist.set_size(100); |
| // int* array = freelist.Alloc(10); |
| // array[8] = 0; // crashed. |
| // Also this class runs unneeded T's constructor along with the memory chunk |
| // allocation. |
| // Please do take care to use this class. |
| template <class T> class FreeList { |
| public: |
| explicit FreeList(size_t size) |
| : current_index_(0), chunk_index_(0), size_(size) { |
| } |
| |
| ~FreeList() { |
| for (size_t i = 0; i < pool_.size(); ++i) { |
| delete [] pool_[i]; |
| } |
| } |
| |
| void Reset() { |
| chunk_index_ = current_index_ = 0; |
| } |
| |
| void Free() { |
| for (size_t i = 1; i < pool_.size(); ++i) { |
| delete [] pool_[i]; |
| } |
| if (pool_.size() > 1) { |
| pool_.resize(1); |
| } |
| current_index_ = 0; |
| chunk_index_ = 0; |
| } |
| |
| T* Alloc() { |
| return Alloc(static_cast<size_t>(1)); |
| } |
| |
| T* Alloc(size_t len) { |
| if ((current_index_ + len) >= size_) { |
| chunk_index_++; |
| current_index_ = 0; |
| } |
| |
| if (chunk_index_ == pool_.size()) { |
| pool_.push_back(new T[size_]); |
| } |
| |
| T* r = pool_[chunk_index_] + current_index_; |
| current_index_ += len; |
| return r; |
| } |
| |
| void set_size(size_t size) { |
| size_ = size; |
| } |
| |
| private: |
| vector<T *> pool_; |
| size_t current_index_; |
| size_t chunk_index_; |
| size_t size_; |
| |
| DISALLOW_COPY_AND_ASSIGN(FreeList); |
| }; |
| |
| template <class T> class ObjectPool { |
| public: |
| explicit ObjectPool(int size): freelist_(size) { |
| } |
| |
| ~ObjectPool() { |
| } |
| |
| void Free() { |
| released_.clear(); |
| freelist_.Free(); |
| } |
| |
| T* Alloc() { |
| if (!released_.empty()) { |
| T *result = released_.back(); |
| released_.pop_back(); |
| return result; |
| } |
| return freelist_.Alloc(1); |
| } |
| |
| void Release(T *ptr) { |
| released_.push_back(ptr); |
| } |
| |
| void set_size(int size) { |
| freelist_.set_size(size); |
| } |
| |
| private: |
| vector<T *> released_; |
| FreeList<T> freelist_; |
| |
| DISALLOW_COPY_AND_ASSIGN(ObjectPool); |
| }; |
| |
| } // namespace mozc |
| |
| #endif // MOZC_BASE_FREELIST_H_ |