Add spellcheck and word suggestion to the prediction service

third_party/android_prediction/suggest/core/session/prev_words_info.h

Index: third_party/android_prediction/suggest/core/session/prev_words_info.h
diff --git a/third_party/android_prediction/suggest/core/session/prev_words_info.h b/third_party/android_prediction/suggest/core/session/prev_words_info.h
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index 0000000000000000000000000000000000000000..fddac8c415c834060319cb61db6f83782858558c
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+/*
+ * Copyright (C) 2014 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.
+ */
+
+#ifndef LATINIME_PREV_WORDS_INFO_H
+#define LATINIME_PREV_WORDS_INFO_H
+
+#include "third_party/android_prediction/defines.h"
+#include "third_party/android_prediction/suggest/core/dictionary/binary_dictionary_bigrams_iterator.h"
+#include "third_party/android_prediction/suggest/core/policy/dictionary_structure_with_buffer_policy.h"
+#include "third_party/android_prediction/utils/char_utils.h"
+
+namespace latinime {
+
+// TODO: Support n-gram.
+class PrevWordsInfo {
+ public:
+    // No prev word information.
+    PrevWordsInfo() {
+        clear();
+    }
+
+    PrevWordsInfo(PrevWordsInfo &&prevWordsInfo) {
+        for (size_t i = 0; i < NELEMS(mPrevWordCodePoints); ++i) {
+            mPrevWordCodePointCount[i] = prevWordsInfo.mPrevWordCodePointCount[i];
+            memmove(mPrevWordCodePoints[i], prevWordsInfo.mPrevWordCodePoints[i],
+                    sizeof(mPrevWordCodePoints[i][0]) * mPrevWordCodePointCount[i]);
+            mIsBeginningOfSentence[i] = prevWordsInfo.mIsBeginningOfSentence[i];
+        }
+    }
+
+    // Construct from previous words.
+    PrevWordsInfo(const int prevWordCodePoints[][MAX_WORD_LENGTH],
+            const int *const prevWordCodePointCount, const bool *const isBeginningOfSentence,
+            const size_t prevWordCount) {
+        clear();
+        for (size_t i = 0; i < std::min(NELEMS(mPrevWordCodePoints), prevWordCount); ++i) {
+            if (prevWordCodePointCount[i] < 0 || prevWordCodePointCount[i] > MAX_WORD_LENGTH) {
+                continue;
+            }
+            memmove(mPrevWordCodePoints[i], prevWordCodePoints[i],
+                    sizeof(mPrevWordCodePoints[i][0]) * prevWordCodePointCount[i]);
+            mPrevWordCodePointCount[i] = prevWordCodePointCount[i];
+            mIsBeginningOfSentence[i] = isBeginningOfSentence[i];
+        }
+    }
+
+    // Construct from a previous word.
+    PrevWordsInfo(const int *const prevWordCodePoints, const int prevWordCodePointCount,
+            const bool isBeginningOfSentence) {
+        clear();
+        if (prevWordCodePointCount > MAX_WORD_LENGTH || !prevWordCodePoints) {
+            return;
+        }
+        memmove(mPrevWordCodePoints[0], prevWordCodePoints,
+                sizeof(mPrevWordCodePoints[0][0]) * prevWordCodePointCount);
+        mPrevWordCodePointCount[0] = prevWordCodePointCount;
+        mIsBeginningOfSentence[0] = isBeginningOfSentence;
+    }
+
+    bool isValid() const {
+        if (mPrevWordCodePointCount[0] > 0) {
+            return true;
+        }
+        if (mIsBeginningOfSentence[0]) {
+            return true;
+        }
+        return false;
+    }
+
+    void getPrevWordsTerminalPtNodePos(
+            const DictionaryStructureWithBufferPolicy *const dictStructurePolicy,
+            int *const outPrevWordsTerminalPtNodePos, const bool tryLowerCaseSearch) const {
+        for (size_t i = 0; i < NELEMS(mPrevWordCodePoints); ++i) {
+            outPrevWordsTerminalPtNodePos[i] = getTerminalPtNodePosOfWord(dictStructurePolicy,
+                    mPrevWordCodePoints[i], mPrevWordCodePointCount[i],
+                    mIsBeginningOfSentence[i], tryLowerCaseSearch);
+        }
+    }
+
+    // n is 1-indexed.
+    const int *getNthPrevWordCodePoints(const int n) const {
+        if (n <= 0 || n > MAX_PREV_WORD_COUNT_FOR_N_GRAM) {
+            return nullptr;
+        }
+        return mPrevWordCodePoints[n - 1];
+    }
+
+    // n is 1-indexed.
+    int getNthPrevWordCodePointCount(const int n) const {
+        if (n <= 0 || n > MAX_PREV_WORD_COUNT_FOR_N_GRAM) {
+            return 0;
+        }
+        return mPrevWordCodePointCount[n - 1];
+    }
+
+    // n is 1-indexed.
+    bool isNthPrevWordBeginningOfSentence(const int n) const {
+        if (n <= 0 || n > MAX_PREV_WORD_COUNT_FOR_N_GRAM) {
+            return false;
+        }
+        return mIsBeginningOfSentence[n - 1];
+    }
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(PrevWordsInfo);
+
+    static int getTerminalPtNodePosOfWord(
+            const DictionaryStructureWithBufferPolicy *const dictStructurePolicy,
+            const int *const wordCodePoints, const int wordCodePointCount,
+            const bool isBeginningOfSentence, const bool tryLowerCaseSearch) {
+        if (!dictStructurePolicy || !wordCodePoints || wordCodePointCount > MAX_WORD_LENGTH) {
+            return NOT_A_DICT_POS;
+        }
+        int codePoints[MAX_WORD_LENGTH];
+        int codePointCount = wordCodePointCount;
+        memmove(codePoints, wordCodePoints, sizeof(int) * codePointCount);
+        if (isBeginningOfSentence) {
+            codePointCount = CharUtils::attachBeginningOfSentenceMarker(codePoints,
+                    codePointCount, MAX_WORD_LENGTH);
+            if (codePointCount <= 0) {
+                return NOT_A_DICT_POS;
+            }
+        }
+        const int wordPtNodePos = dictStructurePolicy->getTerminalPtNodePositionOfWord(
+                codePoints, codePointCount, false /* forceLowerCaseSearch */);
+        if (wordPtNodePos != NOT_A_DICT_POS || !tryLowerCaseSearch) {
+            // Return the position when when the word was found or doesn't try lower case
+            // search.
+            return wordPtNodePos;
+        }
+        // Check bigrams for lower-cased previous word if original was not found. Useful for
+        // auto-capitalized words like "The [current_word]".
+        return dictStructurePolicy->getTerminalPtNodePositionOfWord(
+                codePoints, codePointCount, true /* forceLowerCaseSearch */);
+    }
+
+    void clear() {
+        for (size_t i = 0; i < NELEMS(mPrevWordCodePoints); ++i) {
+            mPrevWordCodePointCount[i] = 0;
+            mIsBeginningOfSentence[i] = false;
+        }
+    }
+
+    int mPrevWordCodePoints[MAX_PREV_WORD_COUNT_FOR_N_GRAM][MAX_WORD_LENGTH];
+    int mPrevWordCodePointCount[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
+    bool mIsBeginningOfSentence[MAX_PREV_WORD_COUNT_FOR_N_GRAM];
+};
+} // namespace latinime
+#endif // LATINIME_PREV_WORDS_INFO_H