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      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 #include "suggest/core/dicnode/dic_node_utils.h"
     18 
     19 #include "dictionary/interface/dictionary_structure_with_buffer_policy.h"
     20 #include "suggest/core/dicnode/dic_node.h"
     21 #include "suggest/core/dicnode/dic_node_vector.h"
     22 
     23 namespace latinime {
     24 
     25 ///////////////////////////////
     26 // Node initialization utils //
     27 ///////////////////////////////
     28 
     29 /* static */ void DicNodeUtils::initAsRoot(
     30         const DictionaryStructureWithBufferPolicy *const dictionaryStructurePolicy,
     31         const WordIdArrayView prevWordIds, DicNode *const newRootDicNode) {
     32     newRootDicNode->initAsRoot(dictionaryStructurePolicy->getRootPosition(), prevWordIds);
     33 }
     34 
     35 /*static */ void DicNodeUtils::initAsRootWithPreviousWord(
     36         const DictionaryStructureWithBufferPolicy *const dictionaryStructurePolicy,
     37         const DicNode *const prevWordLastDicNode, DicNode *const newRootDicNode) {
     38     newRootDicNode->initAsRootWithPreviousWord(
     39             prevWordLastDicNode, dictionaryStructurePolicy->getRootPosition());
     40 }
     41 
     42 /* static */ void DicNodeUtils::initByCopy(const DicNode *const srcDicNode,
     43         DicNode *const destDicNode) {
     44     destDicNode->initByCopy(srcDicNode);
     45 }
     46 
     47 ///////////////////////////////////
     48 // Traverse node expansion utils //
     49 ///////////////////////////////////
     50 /* static */ void DicNodeUtils::getAllChildDicNodes(const DicNode *dicNode,
     51         const DictionaryStructureWithBufferPolicy *const dictionaryStructurePolicy,
     52         DicNodeVector *const childDicNodes) {
     53     if (dicNode->isTotalInputSizeExceedingLimit()) {
     54         return;
     55     }
     56     if (!dicNode->isLeavingNode()) {
     57         childDicNodes->pushPassingChild(dicNode);
     58     } else {
     59         dictionaryStructurePolicy->createAndGetAllChildDicNodes(dicNode, childDicNodes);
     60     }
     61 }
     62 
     63 ///////////////////
     64 // Scoring utils //
     65 ///////////////////
     66 /**
     67  * Computes the combined bigram / unigram cost for the given dicNode.
     68  */
     69 /* static */ float DicNodeUtils::getBigramNodeImprobability(
     70         const DictionaryStructureWithBufferPolicy *const dictionaryStructurePolicy,
     71         const DicNode *const dicNode, MultiBigramMap *const multiBigramMap) {
     72     if (dicNode->hasMultipleWords() && !dicNode->isValidMultipleWordSuggestion()) {
     73         return static_cast<float>(MAX_VALUE_FOR_WEIGHTING);
     74     }
     75     const WordAttributes wordAttributes = dictionaryStructurePolicy->getWordAttributesInContext(
     76             dicNode->getPrevWordIds(), dicNode->getWordId(), multiBigramMap);
     77     if (wordAttributes.getProbability() == NOT_A_PROBABILITY
     78             || (dicNode->hasMultipleWords()
     79                     && (wordAttributes.isBlacklisted() || wordAttributes.isNotAWord()))) {
     80         return static_cast<float>(MAX_VALUE_FOR_WEIGHTING);
     81     }
     82     // TODO: This equation to calculate the improbability looks unreasonable.  Investigate this.
     83     const float cost = static_cast<float>(MAX_PROBABILITY - wordAttributes.getProbability())
     84             / static_cast<float>(MAX_PROBABILITY);
     85     return cost;
     86 }
     87 
     88 } // namespace latinime
     89