| // Copyright 2010-2014, 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. |
| |
| #include "converter/cached_connector.h" |
| |
| #include "base/logging.h" |
| #include "base/port.h" |
| #include "converter/connector_interface.h" |
| #include "converter/sparse_connector.h" |
| |
| namespace mozc { |
| namespace converter { |
| namespace { |
| const int kInvalidCacheKey = -1; |
| |
| inline int GetHashValue(uint16 rid, uint16 lid, int hash_mask) { |
| return ((3 * rid + lid) & hash_mask); |
| // The above value is equivalent to: |
| // return (3 * rid + lid) % cache_size; |
| // The performance is important here, as this is called so many times. |
| |
| // Multiplying '3' makes the conversion speed faster. |
| // The result hash value becomes reasonalbly random. |
| } |
| |
| inline uint32 EncodeKey(uint16 rid, uint16 lid) { |
| return (static_cast<uint32>(rid) << 16) | lid; |
| } |
| |
| } // namespace |
| |
| CachedConnector::CachedConnector(ConnectorInterface *connector, int cache_size) |
| : connector_(connector), |
| cache_initialized_(false), |
| cache_key_(new int[cache_size]), |
| cache_value_(new int[cache_size]), |
| cache_size_(cache_size), |
| hash_mask_(cache_size - 1) { |
| // Check if the cache_size is 2^k form. |
| DCHECK_EQ(0, cache_size & (cache_size - 1)); |
| } |
| |
| CachedConnector::~CachedConnector() {} |
| |
| int CachedConnector::GetTransitionCost(uint16 rid, uint16 lid) const { |
| InitializeCache(); |
| |
| const uint32 index = EncodeKey(rid, lid); |
| const int bucket = GetHashValue(rid, lid, hash_mask_); |
| if (cache_key_[bucket] != index) { |
| // Simply overwrite previous key/value. |
| cache_key_[bucket] = index; |
| cache_value_[bucket] = connector_->GetTransitionCost(rid, lid); |
| } |
| |
| return cache_value_[bucket]; |
| } |
| |
| void CachedConnector::InitializeCache() const { |
| if (cache_initialized_) { |
| return; |
| } |
| VLOG(2) << "Initializing Cache for CachedConnector."; |
| for (int i = 0; i < cache_size_; ++i) { |
| cache_key_[i] = kInvalidCacheKey; |
| } |
| cache_initialized_ = true; |
| } |
| |
| // Test code can use this method to get acceptable error. |
| int CachedConnector::GetResolution() const { |
| return connector_->GetResolution(); |
| } |
| |
| void CachedConnector::ClearCache() { |
| cache_initialized_ = false; |
| } |
| |
| } // namespace converter |
| } // namespace mozc |