1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef LATINIME_DIC_NODES_CACHE_H
18#define LATINIME_DIC_NODES_CACHE_H
19
20#include <stdint.h>
21
22#include "defines.h"
23#include "suggest/core/dicnode/dic_node_priority_queue.h"
24
25namespace latinime {
26
27class DicNode;
28
29/**
30 * Class for controlling dicNode search priority queue and lexicon trie traversal.
31 */
32class DicNodesCache {
33 public:
34    AK_FORCE_INLINE explicit DicNodesCache(const bool usesLargeCapacityCache)
35            : mUsesLargeCapacityCache(usesLargeCapacityCache),
36              mDicNodePriorityQueue0(getCacheCapacity()),
37              mDicNodePriorityQueue1(getCacheCapacity()),
38              mDicNodePriorityQueue2(getCacheCapacity()),
39              mDicNodePriorityQueueForTerminal(MAX_RESULTS),
40              mActiveDicNodes(&mDicNodePriorityQueue0),
41              mNextActiveDicNodes(&mDicNodePriorityQueue1),
42              mCachedDicNodesForContinuousSuggestion(&mDicNodePriorityQueue2),
43              mTerminalDicNodes(&mDicNodePriorityQueueForTerminal),
44              mInputIndex(0), mLastCachedInputIndex(0) {}
45
46    AK_FORCE_INLINE virtual ~DicNodesCache() {}
47
48    AK_FORCE_INLINE void reset(const int nextActiveSize, const int terminalSize) {
49        mInputIndex = 0;
50        mLastCachedInputIndex = 0;
51        // We want to use the max capacity for the current active dic node queue.
52        mActiveDicNodes->clearAndResizeToCapacity();
53        // nextActiveSize is used to limit the next iteration's active dic node size.
54        const int nextActiveSizeFittingToTheCapacity = min(nextActiveSize, getCacheCapacity());
55        mNextActiveDicNodes->clearAndResize(nextActiveSizeFittingToTheCapacity);
56        mTerminalDicNodes->clearAndResize(terminalSize);
57        // We want to use the max capacity for the cached dic nodes that will be used for the
58        // continuous suggestion.
59        mCachedDicNodesForContinuousSuggestion->clearAndResizeToCapacity();
60    }
61
62    AK_FORCE_INLINE void continueSearch() {
63        resetTemporaryCaches();
64        restoreActiveDicNodesFromCache();
65    }
66
67    AK_FORCE_INLINE void advanceActiveDicNodes() {
68        if (DEBUG_DICT) {
69            AKLOGI("Advance active %d nodes.", mNextActiveDicNodes->getSize());
70        }
71        if (DEBUG_DICT_FULL) {
72            mNextActiveDicNodes->dump();
73        }
74        mNextActiveDicNodes =
75                moveNodesAndReturnReusableEmptyQueue(mNextActiveDicNodes, &mActiveDicNodes);
76    }
77
78    DicNode *setCommitPoint(int commitPoint);
79
80    int activeSize() const { return mActiveDicNodes->getSize(); }
81    int terminalSize() const { return mTerminalDicNodes->getSize(); }
82    bool isLookAheadCorrectionInputIndex(const int inputIndex) const {
83        return inputIndex == mInputIndex - 1;
84    }
85    void advanceInputIndex(const int inputSize) {
86        if (mInputIndex < inputSize) {
87            mInputIndex++;
88        }
89    }
90
91    AK_FORCE_INLINE void copyPushTerminal(DicNode *dicNode) {
92        mTerminalDicNodes->copyPush(dicNode);
93    }
94
95    AK_FORCE_INLINE void copyPushActive(DicNode *dicNode) {
96        mActiveDicNodes->copyPush(dicNode);
97    }
98
99    AK_FORCE_INLINE bool copyPushContinue(DicNode *dicNode) {
100        return mCachedDicNodesForContinuousSuggestion->copyPush(dicNode);
101    }
102
103    AK_FORCE_INLINE void copyPushNextActive(DicNode *dicNode) {
104        DicNode *pushedDicNode = mNextActiveDicNodes->copyPush(dicNode);
105        if (!pushedDicNode) {
106            if (dicNode->isCached()) {
107                dicNode->remove();
108            }
109            // We simply drop any dic node that was not cached, ignoring the slim chance
110            // that one of its children represents what the user really wanted.
111        }
112    }
113
114    void popTerminal(DicNode *dest) {
115        mTerminalDicNodes->copyPop(dest);
116    }
117
118    void popActive(DicNode *dest) {
119        mActiveDicNodes->copyPop(dest);
120    }
121
122    bool hasCachedDicNodesForContinuousSuggestion() const {
123        return mCachedDicNodesForContinuousSuggestion
124                && mCachedDicNodesForContinuousSuggestion->getSize() > 0;
125    }
126
127    AK_FORCE_INLINE bool isCacheBorderForTyping(const int inputSize) const {
128        // TODO: Move this variable to header
129        static const int CACHE_BACK_LENGTH = 3;
130        const int cacheInputIndex = inputSize - CACHE_BACK_LENGTH;
131        const bool shouldCache = (cacheInputIndex == mInputIndex)
132                && (cacheInputIndex != mLastCachedInputIndex);
133        return shouldCache;
134    }
135
136    AK_FORCE_INLINE void updateLastCachedInputIndex() {
137        mLastCachedInputIndex = mInputIndex;
138    }
139
140 private:
141    DISALLOW_COPY_AND_ASSIGN(DicNodesCache);
142
143    AK_FORCE_INLINE void restoreActiveDicNodesFromCache() {
144        if (DEBUG_DICT) {
145            AKLOGI("Restore %d nodes. inputIndex = %d.",
146                    mCachedDicNodesForContinuousSuggestion->getSize(), mLastCachedInputIndex);
147        }
148        if (DEBUG_DICT_FULL || DEBUG_CACHE) {
149            mCachedDicNodesForContinuousSuggestion->dump();
150        }
151        mInputIndex = mLastCachedInputIndex;
152        mCachedDicNodesForContinuousSuggestion = moveNodesAndReturnReusableEmptyQueue(
153                mCachedDicNodesForContinuousSuggestion, &mActiveDicNodes);
154    }
155
156    AK_FORCE_INLINE static DicNodePriorityQueue *moveNodesAndReturnReusableEmptyQueue(
157            DicNodePriorityQueue *src, DicNodePriorityQueue **dest) {
158        const int srcMaxSize = src->getMaxSize();
159        const int destMaxSize = (*dest)->getMaxSize();
160        DicNodePriorityQueue *tmp = *dest;
161        *dest = src;
162        (*dest)->setMaxSize(destMaxSize);
163        tmp->clearAndResize(srcMaxSize);
164        return tmp;
165    }
166
167    AK_FORCE_INLINE int getCacheCapacity() const {
168        return mUsesLargeCapacityCache ?
169                LARGE_PRIORITY_QUEUE_CAPACITY : SMALL_PRIORITY_QUEUE_CAPACITY;
170    }
171
172    AK_FORCE_INLINE void resetTemporaryCaches() {
173        mActiveDicNodes->clear();
174        mNextActiveDicNodes->clear();
175        mTerminalDicNodes->clear();
176    }
177
178    static const int LARGE_PRIORITY_QUEUE_CAPACITY;
179    static const int SMALL_PRIORITY_QUEUE_CAPACITY;
180
181    const bool mUsesLargeCapacityCache;
182    // Instances
183    DicNodePriorityQueue mDicNodePriorityQueue0;
184    DicNodePriorityQueue mDicNodePriorityQueue1;
185    DicNodePriorityQueue mDicNodePriorityQueue2;
186    DicNodePriorityQueue mDicNodePriorityQueueForTerminal;
187
188    // Active dicNodes currently being expanded.
189    DicNodePriorityQueue *mActiveDicNodes;
190    // Next dicNodes to be expanded.
191    DicNodePriorityQueue *mNextActiveDicNodes;
192    // Cached dicNodes used for continuous suggestion.
193    DicNodePriorityQueue *mCachedDicNodesForContinuousSuggestion;
194    // Current top terminal dicNodes.
195    DicNodePriorityQueue *mTerminalDicNodes;
196    int mInputIndex;
197    int mLastCachedInputIndex;
198};
199} // namespace latinime
200#endif // LATINIME_DIC_NODES_CACHE_H
201