Add spellcheck and word suggestion to the prediction service

third_party/prediction/suggest/core/dictionary/digraph_utils.cpp

Index: third_party/prediction/suggest/core/dictionary/digraph_utils.cpp
diff --git a/third_party/prediction/suggest/core/dictionary/digraph_utils.cpp b/third_party/prediction/suggest/core/dictionary/digraph_utils.cpp
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+++ b/third_party/prediction/suggest/core/dictionary/digraph_utils.cpp
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+/*
+ * Copyright (C) 2013 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/dictionary/digraph_utils.h"
+
+#include <cstdlib>
+
+#include "third_party/prediction/defines.h"
+#include "third_party/prediction/suggest/core/policy/dictionary_header_structure_policy.h"
+#include "third_party/prediction/utils/char_utils.h"
+
+namespace latinime {
+
+const DigraphUtils::digraph_t DigraphUtils::GERMAN_UMLAUT_DIGRAPHS[] = {
+    {'a', 'e', 0x00E4},   // U+00E4 : LATIN SMALL LETTER A WITH DIAERESIS
+    {'o', 'e', 0x00F6},   // U+00F6 : LATIN SMALL LETTER O WITH DIAERESIS
+    {'u', 'e', 0x00FC}};  // U+00FC : LATIN SMALL LETTER U WITH DIAERESIS
+const DigraphUtils::DigraphType DigraphUtils::USED_DIGRAPH_TYPES[] = {
+    DIGRAPH_TYPE_GERMAN_UMLAUT};
+
+/* static */ bool DigraphUtils::hasDigraphForCodePoint(
+    const DictionaryHeaderStructurePolicy* const headerPolicy,
+    const int compositeGlyphCodePoint) {
+  const DigraphUtils::DigraphType digraphType =
+      getDigraphTypeForDictionary(headerPolicy);
+  if (DigraphUtils::getDigraphForDigraphTypeAndCodePoint(
+          digraphType, compositeGlyphCodePoint)) {
+    return true;
+  }
+  return false;
+}
+
+// Returns the digraph type associated with the given dictionary.
+/* static */ DigraphUtils::DigraphType
+DigraphUtils::getDigraphTypeForDictionary(
+    const DictionaryHeaderStructurePolicy* const headerPolicy) {
+  if (headerPolicy->requiresGermanUmlautProcessing()) {
+    return DIGRAPH_TYPE_GERMAN_UMLAUT;
+  }
+  return DIGRAPH_TYPE_NONE;
+}
+
+// Returns the digraph codepoint for the given composite glyph codepoint and
+// digraph codepoint index
+// (which specifies the first or second codepoint in the digraph).
+/* static */ int DigraphUtils::getDigraphCodePointForIndex(
+    const int compositeGlyphCodePoint,
+    const DigraphCodePointIndex digraphCodePointIndex) {
+  if (digraphCodePointIndex == NOT_A_DIGRAPH_INDEX) {
+    return NOT_A_CODE_POINT;
+  }
+  const DigraphUtils::digraph_t* const digraph =
+      DigraphUtils::getDigraphForCodePoint(compositeGlyphCodePoint);
+  if (!digraph) {
+    return NOT_A_CODE_POINT;
+  }
+  if (digraphCodePointIndex == FIRST_DIGRAPH_CODEPOINT) {
+    return digraph->first;
+  } else if (digraphCodePointIndex == SECOND_DIGRAPH_CODEPOINT) {
+    return digraph->second;
+  }
+  ASSERT(false);
+  return NOT_A_CODE_POINT;
+}
+
+// Retrieves the set of all digraphs associated with the given digraph type.
+// Returns the size of the digraph array, or 0 if none exist.
+/* static */ int DigraphUtils::getAllDigraphsForDigraphTypeAndReturnSize(
+    const DigraphUtils::DigraphType digraphType,
+    const DigraphUtils::digraph_t** const digraphs) {
+  if (digraphType == DigraphUtils::DIGRAPH_TYPE_GERMAN_UMLAUT) {
+    *digraphs = GERMAN_UMLAUT_DIGRAPHS;
+    return NELEMS(GERMAN_UMLAUT_DIGRAPHS);
+  }
+  return 0;
+}
+
+/**
+ * Returns the digraph for the input composite glyph codepoint, or nullptr if
+ * none exists.
+ * compositeGlyphCodePoint: the method returns the digraph corresponding to this
+ * codepoint.
+ */
+/* static */ const DigraphUtils::digraph_t*
+DigraphUtils::getDigraphForCodePoint(const int compositeGlyphCodePoint) {
+  for (size_t i = 0; i < NELEMS(USED_DIGRAPH_TYPES); i++) {
+    const DigraphUtils::digraph_t* const digraph =
+        getDigraphForDigraphTypeAndCodePoint(USED_DIGRAPH_TYPES[i],
+                                             compositeGlyphCodePoint);
+    if (digraph) {
+      return digraph;
+    }
+  }
+  return nullptr;
+}
+
+/**
+ * Returns the digraph for the input composite glyph codepoint, or nullptr if
+ * none exists.
+ * digraphType: the type of digraphs supported.
+ * compositeGlyphCodePoint: the method returns the digraph corresponding to this
+ * codepoint.
+ */
+/* static */ const DigraphUtils::digraph_t*
+DigraphUtils::getDigraphForDigraphTypeAndCodePoint(
+    const DigraphUtils::DigraphType digraphType,
+    const int compositeGlyphCodePoint) {
+  const DigraphUtils::digraph_t* digraphs = nullptr;
+  const int compositeGlyphLowerCodePoint =
+      CharUtils::toLowerCase(compositeGlyphCodePoint);
+  const int digraphsSize =
+      DigraphUtils::getAllDigraphsForDigraphTypeAndReturnSize(digraphType,
+                                                              &digraphs);
+  for (int i = 0; i < digraphsSize; i++) {
+    if (digraphs[i].compositeGlyph == compositeGlyphLowerCodePoint) {
+      return &digraphs[i];
+    }
+  }
+  return nullptr;
+}
+
+}  // namespace latinime