Add spellcheck and word suggestion to the prediction service

third_party/android_prediction/suggest/policyimpl/dictionary/utils/trie_map.h

+/*
+ * 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_TRIE_MAP_H
+#define LATINIME_TRIE_MAP_H
+
+#include <climits>
+#include <cstdint>
+#include <cstdio>
+#include <vector>
+
+#include "third_party/android_prediction/defines.h"
+#include "third_party/android_prediction/suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "third_party/android_prediction/utils/byte_array_view.h"
+
+namespace latinime {
+
+/**
+ * Trie map derived from Phil Bagwell's Hash Array Mapped Trie.
+ * key is int and value is uint64_t.
+ * This supports multiple level map. Terminal entries can have a bitmap for the next level map.
+ * This doesn't support root map resizing.
+ */
+class TrieMap {
+ public:
+    struct Result {
+        const uint64_t mValue;
+        const bool mIsValid;
+        const int mNextLevelBitmapEntryIndex;
+
+        Result(const uint64_t value, const bool isValid, const int nextLevelBitmapEntryIndex)
+                : mValue(value), mIsValid(isValid),
+                  mNextLevelBitmapEntryIndex(nextLevelBitmapEntryIndex) {}
+    };
+
+    /**
+     * Struct to record iteration state in a table.
+     */
+    struct TableIterationState {
+        int mTableSize;
+        int mTableIndex;
+        int mCurrentIndex;
+
+        TableIterationState(const int tableSize, const int tableIndex)
+                : mTableSize(tableSize), mTableIndex(tableIndex), mCurrentIndex(0) {}
+    };
+
+    class TrieMapRange;
+    class TrieMapIterator {
+     public:
+        class IterationResult {
+         public:
+            IterationResult(const TrieMap *const trieMap, const int key, const uint64_t value,
+                    const int nextLeveBitmapEntryIndex)
+                    : mTrieMap(trieMap), mKey(key), mValue(value),
+                      mNextLevelBitmapEntryIndex(nextLeveBitmapEntryIndex) {}
+
+            const TrieMapRange getEntriesInNextLevel() const {
+                return TrieMapRange(mTrieMap, mNextLevelBitmapEntryIndex);
+            }
+
+            bool hasNextLevelMap() const {
+                return mNextLevelBitmapEntryIndex != INVALID_INDEX;
+            }
+
+            AK_FORCE_INLINE int key() const {
+                return mKey;
+            }
+
+            AK_FORCE_INLINE uint64_t value() const {
+                return mValue;
+            }
+
+         private:
+            const TrieMap *const mTrieMap;
+            const int mKey;
+            const uint64_t mValue;
+            const int mNextLevelBitmapEntryIndex;
+        };
+
+        TrieMapIterator(const TrieMap *const trieMap, const int bitmapEntryIndex)
+                : mTrieMap(trieMap), mStateStack(), mBaseBitmapEntryIndex(bitmapEntryIndex),
+                  mKey(0), mValue(0), mIsValid(false), mNextLevelBitmapEntryIndex(INVALID_INDEX) {
+            if (!trieMap) {
+                return;
+            }
+            const Entry bitmapEntry = mTrieMap->readEntry(mBaseBitmapEntryIndex);
+            mStateStack.emplace_back(
+                    mTrieMap->popCount(bitmapEntry.getBitmap()), bitmapEntry.getTableIndex());
+            this->operator++();
+        }
+
+        const IterationResult operator*() const {
+            return IterationResult(mTrieMap, mKey, mValue, mNextLevelBitmapEntryIndex);
+        }
+
+        bool operator!=(const TrieMapIterator &other) const {
+            // Caveat: This works only for for loops.
+            return mIsValid || other.mIsValid;
+        }
+
+        const TrieMapIterator &operator++() {
+            const Result result = mTrieMap->iterateNext(&mStateStack, &mKey);
+            mValue = result.mValue;
+            mIsValid = result.mIsValid;
+            mNextLevelBitmapEntryIndex = result.mNextLevelBitmapEntryIndex;
+            return *this;
+        }
+
+     private:
+        DISALLOW_DEFAULT_CONSTRUCTOR(TrieMapIterator);
+        DISALLOW_ASSIGNMENT_OPERATOR(TrieMapIterator);
+
+        const TrieMap *const mTrieMap;
+        std::vector<TrieMap::TableIterationState> mStateStack;
+        const int mBaseBitmapEntryIndex;
+        int mKey;
+        uint64_t mValue;
+        bool mIsValid;
+        int mNextLevelBitmapEntryIndex;
+    };
+
+    /**
+     * Class to support iterating entries in TrieMap by range base for loops.
+     */
+    class TrieMapRange {
+     public:
+        TrieMapRange(const TrieMap *const trieMap, const int bitmapEntryIndex)
+                : mTrieMap(trieMap), mBaseBitmapEntryIndex(bitmapEntryIndex) {};
+
+        TrieMapIterator begin() const {
+            return TrieMapIterator(mTrieMap, mBaseBitmapEntryIndex);
+        }
+
+        const TrieMapIterator end() const {
+            return TrieMapIterator(nullptr, INVALID_INDEX);
+        }
+
+     private:
+        DISALLOW_DEFAULT_CONSTRUCTOR(TrieMapRange);
+        DISALLOW_ASSIGNMENT_OPERATOR(TrieMapRange);
+
+        const TrieMap *const mTrieMap;
+        const int mBaseBitmapEntryIndex;
+    };
+
+    static const int INVALID_INDEX;
+    static const uint64_t MAX_VALUE;
+
+    TrieMap();
+    // Construct TrieMap using existing data in the memory region written by save().
+    TrieMap(const ReadWriteByteArrayView buffer);
+    void dump(const int from = 0, const int to = 0) const;
+
+    bool isNearSizeLimit() const {
+        return mBuffer.isNearSizeLimit();
+    }
+
+    int getRootBitmapEntryIndex() const {
+        return ROOT_BITMAP_ENTRY_INDEX;
+    }
+
+    // Returns bitmapEntryIndex. Create the next level map if it doesn't exist.
+    int getNextLevelBitmapEntryIndex(const int key) {
+        return getNextLevelBitmapEntryIndex(key, ROOT_BITMAP_ENTRY_INDEX);
+    }
+
+    int getNextLevelBitmapEntryIndex(const int key, const int bitmapEntryIndex);
+
+    const Result getRoot(const int key) const {
+        return get(key, ROOT_BITMAP_ENTRY_INDEX);
+    }
+
+    const Result get(const int key, const int bitmapEntryIndex) const;
+
+    bool putRoot(const int key, const uint64_t value) {
+        return put(key, value, ROOT_BITMAP_ENTRY_INDEX);
+    }
+
+    bool put(const int key, const uint64_t value, const int bitmapEntryIndex);
+
+    const TrieMapRange getEntriesInRootLevel() const {
+        return getEntriesInSpecifiedLevel(ROOT_BITMAP_ENTRY_INDEX);
+    }
+
+    const TrieMapRange getEntriesInSpecifiedLevel(const int bitmapEntryIndex) const {
+        return TrieMapRange(this, bitmapEntryIndex);
+    }
+
+    bool save(FILE *const file) const;
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(TrieMap);
+
+    /**
+     * Struct represents an entry.
+     *
+     * Entry is one of these entry types. All entries are fixed size and have 2 fields FIELD_0 and
+     * FIELD_1.
+     * 1. bitmap entry. bitmap entry contains bitmap and the link to hash table.
+     *   FIELD_0(bitmap) FIELD_1(LINK_TO_HASH_TABLE)
+     * 2. terminal entry. terminal entry contains hashed key and value or terminal link. terminal
+     * entry have terminal link when the value is not fit to FIELD_1 or there is a next level map
+     * for the key.
+     *   FIELD_0(hashed key) (FIELD_1(VALUE_FLAG VALUE) | FIELD_1(TERMINAL_LINK_FLAG TERMINAL_LINK))
+     * 3. value entry. value entry represents a value. Upper order bytes are stored in FIELD_0 and
+     * lower order bytes are stored in FIELD_1.
+     *   FIELD_0(value (upper order bytes)) FIELD_1(value (lower order bytes))
+     */
+    struct Entry {
+        const uint32_t mData0;
+        const uint32_t mData1;
+
+        Entry(const uint32_t data0, const uint32_t data1) : mData0(data0), mData1(data1) {}
+
+        AK_FORCE_INLINE bool isBitmapEntry() const {
+            return (mData1 & VALUE_FLAG) == 0 && (mData1 & TERMINAL_LINK_FLAG) == 0;
+        }
+
+        AK_FORCE_INLINE bool hasTerminalLink() const {
+            return (mData1 & TERMINAL_LINK_FLAG) != 0;
+        }
+
+        // For terminal entry.
+        AK_FORCE_INLINE uint32_t getKey() const {
+            return mData0;
+        }
+
+        // For terminal entry.
+        AK_FORCE_INLINE uint32_t getValue() const {
+            return mData1 & VALUE_MASK;
+        }
+
+        // For terminal entry.
+        AK_FORCE_INLINE uint32_t getValueEntryIndex() const {
+            return mData1 & TERMINAL_LINK_MASK;
+        }
+
+        // For bitmap entry.
+        AK_FORCE_INLINE uint32_t getBitmap() const {
+            return mData0;
+        }
+
+        // For bitmap entry.
+        AK_FORCE_INLINE int getTableIndex() const {
+            return static_cast<int>(mData1);
+        }
+
+        // For value entry.
+        AK_FORCE_INLINE uint64_t getValueOfValueEntry() const {
+            return ((static_cast<uint64_t>(mData0) << (FIELD1_SIZE * CHAR_BIT)) ^ mData1);
+        }
+    };
+
+    BufferWithExtendableBuffer mBuffer;
+
+    static const int FIELD0_SIZE;
+    static const int FIELD1_SIZE;
+    static const int ENTRY_SIZE;
+    static const uint32_t VALUE_FLAG;
+    static const uint32_t VALUE_MASK;
+    static const uint32_t TERMINAL_LINK_FLAG;
+    static const uint32_t TERMINAL_LINK_MASK;
+    static const int NUM_OF_BITS_USED_FOR_ONE_LEVEL;
+    static const uint32_t LABEL_MASK;
+    static const int MAX_NUM_OF_ENTRIES_IN_ONE_LEVEL;
+    static const int ROOT_BITMAP_ENTRY_INDEX;
+    static const int ROOT_BITMAP_ENTRY_POS;
+    static const Entry EMPTY_BITMAP_ENTRY;
+    static const int MAX_BUFFER_SIZE;
+
+    uint32_t getBitShuffledKey(const uint32_t key) const;
+    bool writeValue(const uint64_t value, const int terminalEntryIndex);
+    bool updateValue(const Entry &terminalEntry, const uint64_t value,
+            const int terminalEntryIndex);
+    bool freeTable(const int tableIndex, const int entryCount);
+    int allocateTable(const int entryCount);
+    int getTerminalEntryIndex(const uint32_t key, const uint32_t hashedKey,
+            const Entry &bitmapEntry, const int level) const;
+    const Result getInternal(const uint32_t key, const uint32_t hashedKey,
+            const int bitmapEntryIndex, const int level) const;
+    bool putInternal(const uint32_t key, const uint64_t value, const uint32_t hashedKey,
+            const int bitmapEntryIndex, const Entry &bitmapEntry, const int level);
+    bool addNewEntryByResolvingConflict(const uint32_t key, const uint64_t value,
+            const uint32_t hashedKey, const Entry &conflictedEntry, const int conflictedEntryIndex,
+            const int level);
+    bool addNewEntryByExpandingTable(const uint32_t key, const uint64_t value,
+            const int tableIndex, const uint32_t bitmap, const int bitmapEntryIndex,
+            const int label);
+    const Result iterateNext(std::vector<TableIterationState> *const iterationState,
+            int *const outKey) const;
+
+    AK_FORCE_INLINE const Entry readEntry(const int entryIndex) const {
+        return Entry(readField0(entryIndex), readField1(entryIndex));
+    }
+
+    // Returns whether an entry for the index is existing by testing if the index-th bit in the
+    // bitmap is set or not.
+    AK_FORCE_INLINE bool exists(const uint32_t bitmap, const int index) const {
+        return (bitmap & (1 << index)) != 0;
+    }
+
+    // Set index-th bit in the bitmap.
+    AK_FORCE_INLINE uint32_t setExist(const uint32_t bitmap, const int index) const {
+        return bitmap | (1 << index);
+    }
+
+    // Count set bits before index in the bitmap.
+    AK_FORCE_INLINE int popCount(const uint32_t bitmap, const int index) const {
+        return popCount(bitmap & ((1 << index) - 1));
+    }
+
+    // Count set bits in the bitmap.
+    AK_FORCE_INLINE int popCount(const uint32_t bitmap) const {
+        return __builtin_popcount(bitmap);
+        // int v = bitmap - ((bitmap >> 1) & 0x55555555);
+        // v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
+        // return (((v + (v >> 4)) & 0x0F0F0F0F) * 0x01010101) >> 24;
+    }
+
+    AK_FORCE_INLINE int getLabel(const uint32_t hashedKey, const int level) const {
+        return (hashedKey >> (level * NUM_OF_BITS_USED_FOR_ONE_LEVEL)) & LABEL_MASK;
+    }
+
+    AK_FORCE_INLINE uint32_t readField0(const int entryIndex) const {
+        return mBuffer.readUint(FIELD0_SIZE, ROOT_BITMAP_ENTRY_POS + entryIndex * ENTRY_SIZE);
+    }
+
+    AK_FORCE_INLINE uint32_t readField1(const int entryIndex) const {
+        return mBuffer.readUint(FIELD1_SIZE,
+                ROOT_BITMAP_ENTRY_POS + entryIndex * ENTRY_SIZE + FIELD0_SIZE);
+    }
+
+    AK_FORCE_INLINE int readEmptyTableLink(const int entryCount) const {
+        return mBuffer.readUint(FIELD1_SIZE, (entryCount - 1) * FIELD1_SIZE);
+    }
+
+    AK_FORCE_INLINE bool writeEmptyTableLink(const int tableIndex, const int entryCount) {
+        return mBuffer.writeUint(tableIndex, FIELD1_SIZE, (entryCount - 1) * FIELD1_SIZE);
+    }
+
+    AK_FORCE_INLINE bool writeField0(const uint32_t data, const int entryIndex) {
+        return mBuffer.writeUint(data, FIELD0_SIZE,
+                ROOT_BITMAP_ENTRY_POS + entryIndex * ENTRY_SIZE);
+    }
+
+    AK_FORCE_INLINE bool writeField1(const uint32_t data, const int entryIndex) {
+        return mBuffer.writeUint(data, FIELD1_SIZE,
+                ROOT_BITMAP_ENTRY_POS + entryIndex * ENTRY_SIZE + FIELD0_SIZE);
+    }
+
+    AK_FORCE_INLINE bool writeEntry(const Entry &entry, const int entryIndex) {
+        return writeField0(entry.mData0, entryIndex) && writeField1(entry.mData1, entryIndex);
+    }
+
+    AK_FORCE_INLINE bool writeTerminalEntry(const uint32_t key, const uint64_t value,
+            const int entryIndex) {
+        return writeField0(key, entryIndex) && writeValue(value, entryIndex);
+    }
+
+    AK_FORCE_INLINE bool copyEntry(const int originalEntryIndex, const int newEntryIndex) {
+        return writeEntry(readEntry(originalEntryIndex), newEntryIndex);
+    }
+
+    AK_FORCE_INLINE int getTailEntryIndex() const {
+        return (mBuffer.getTailPosition() - ROOT_BITMAP_ENTRY_POS) / ENTRY_SIZE;
+    }
+};
+
+} // namespace latinime
+#endif /* LATINIME_TRIE_MAP_H */