Add spellcheck and word suggestion to the prediction service

third_party/prediction/suggest/core/dicnode/dic_node_utils.cpp

Index: third_party/prediction/suggest/core/dicnode/dic_node_utils.cpp
diff --git a/third_party/prediction/suggest/core/dicnode/dic_node_utils.cpp b/third_party/prediction/suggest/core/dicnode/dic_node_utils.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..f7d21fdde9be5c4bdc041f15baac136ec5041284
--- /dev/null
+++ b/third_party/prediction/suggest/core/dicnode/dic_node_utils.cpp
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "third_party/prediction/suggest/core/dicnode/dic_node_utils.h"
+
+#include "third_party/prediction/suggest/core/dicnode/dic_node.h"
+#include "third_party/prediction/suggest/core/dicnode/dic_node_vector.h"
+#include "third_party/prediction/suggest/core/dictionary/multi_bigram_map.h"
+#include "third_party/prediction/suggest/core/policy/dictionary_structure_with_buffer_policy.h"
+
+namespace latinime {
+
+///////////////////////////////
+// Node initialization utils //
+///////////////////////////////
+
+/* static */ void DicNodeUtils::initAsRoot(
+    const DictionaryStructureWithBufferPolicy* const dictionaryStructurePolicy,
+    const int* const prevWordsPtNodePos,
+    DicNode* const newRootDicNode) {
+  newRootDicNode->initAsRoot(dictionaryStructurePolicy->getRootPosition(),
+                             prevWordsPtNodePos);
+}
+
+/*static */ void DicNodeUtils::initAsRootWithPreviousWord(
+    const DictionaryStructureWithBufferPolicy* const dictionaryStructurePolicy,
+    const DicNode* const prevWordLastDicNode,
+    DicNode* const newRootDicNode) {
+  newRootDicNode->initAsRootWithPreviousWord(
+      prevWordLastDicNode, dictionaryStructurePolicy->getRootPosition());
+}
+
+/* static */ void DicNodeUtils::initByCopy(const DicNode* const srcDicNode,
+                                           DicNode* const destDicNode) {
+  destDicNode->initByCopy(srcDicNode);
+}
+
+///////////////////////////////////
+// Traverse node expansion utils //
+///////////////////////////////////
+/* static */ void DicNodeUtils::getAllChildDicNodes(
+    const DicNode* dicNode,
+    const DictionaryStructureWithBufferPolicy* const dictionaryStructurePolicy,
+    DicNodeVector* const childDicNodes) {
+  if (dicNode->isTotalInputSizeExceedingLimit()) {
+    return;
+  }
+  if (!dicNode->isLeavingNode()) {
+    childDicNodes->pushPassingChild(dicNode);
+  } else {
+    dictionaryStructurePolicy->createAndGetAllChildDicNodes(dicNode,
+                                                            childDicNodes);
+  }
+}
+
+///////////////////
+// Scoring utils //
+///////////////////
+/**
+ * Computes the combined bigram / unigram cost for the given dicNode.
+ */
+/* static */ float DicNodeUtils::getBigramNodeImprobability(
+    const DictionaryStructureWithBufferPolicy* const dictionaryStructurePolicy,
+    const DicNode* const dicNode,
+    MultiBigramMap* const multiBigramMap) {
+  if (dicNode->hasMultipleWords() &&
+      !dicNode->isValidMultipleWordSuggestion()) {
+    return static_cast<float>(MAX_VALUE_FOR_WEIGHTING);
+  }
+  const int probability = getBigramNodeProbability(dictionaryStructurePolicy,
+                                                   dicNode, multiBigramMap);
+  // TODO: This equation to calculate the improbability looks unreasonable.
+  // Investigate this.
+  const float cost = static_cast<float>(MAX_PROBABILITY - probability) /
+                     static_cast<float>(MAX_PROBABILITY);
+  return cost;
+}
+
+/* static */ int DicNodeUtils::getBigramNodeProbability(
+    const DictionaryStructureWithBufferPolicy* const dictionaryStructurePolicy,
+    const DicNode* const dicNode,
+    MultiBigramMap* const multiBigramMap) {
+  const int unigramProbability = dicNode->getProbability();
+  if (multiBigramMap) {
+    const int* const prevWordsPtNodePos =
+        dicNode->getPrevWordsTerminalPtNodePos();
+    return multiBigramMap->getBigramProbability(
+        dictionaryStructurePolicy, prevWordsPtNodePos, dicNode->getPtNodePos(),
+        unigramProbability);
+  }
+  return dictionaryStructurePolicy->getProbability(unigramProbability,
+                                                   NOT_A_PROBABILITY);
+}
+
+}  // namespace latinime