Add spellcheck and word suggestion to the prediction service

third_party/android_prediction/suggest/policyimpl/dictionary/utils/sparse_table.cpp

+/*
+ * 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/android_prediction/suggest/policyimpl/dictionary/utils/sparse_table.h"
+
+namespace latinime {
+
+const int SparseTable::NOT_EXIST = -1;
+const int SparseTable::INDEX_SIZE = 4;
+
+bool SparseTable::contains(const int id) const {
+    const int readingPos = getPosInIndexTable(id);
+    if (id < 0 || mIndexTableBuffer->getTailPosition() <= readingPos) {
+        return false;
+    }
+    const int index = mIndexTableBuffer->readUint(INDEX_SIZE, readingPos);
+    return index != NOT_EXIST;
+}
+
+uint32_t SparseTable::get(const int id) const {
+    const int indexTableReadingPos = getPosInIndexTable(id);
+    const int index = mIndexTableBuffer->readUint(INDEX_SIZE, indexTableReadingPos);
+    const int contentTableReadingPos = getPosInContentTable(id, index);
+    if (contentTableReadingPos < 0
+            || contentTableReadingPos >= mContentTableBuffer->getTailPosition()) {
+        AKLOGE("contentTableReadingPos(%d) is invalid. id: %d, index: %d",
+                contentTableReadingPos, id, index);
+        return NOT_A_DICT_POS;
+    }
+    const int contentValue = mContentTableBuffer->readUint(mDataSize, contentTableReadingPos);
+    return contentValue == NOT_EXIST ? NOT_A_DICT_POS : contentValue;
+}
+
+bool SparseTable::set(const int id, const uint32_t value) {
+    const int posInIndexTable = getPosInIndexTable(id);
+    // Extends the index table if needed.
+    int tailPos = mIndexTableBuffer->getTailPosition();
+    while (tailPos <= posInIndexTable) {
+        if (!mIndexTableBuffer->writeUintAndAdvancePosition(NOT_EXIST, INDEX_SIZE, &tailPos)) {
+            AKLOGE("cannot extend index table. tailPos: %d to: %d", tailPos, posInIndexTable);
+            return false;
+        }
+    }
+    if (contains(id)) {
+        // The entry is already in the content table.
+        const int index = mIndexTableBuffer->readUint(INDEX_SIZE, posInIndexTable);
+        if (!mContentTableBuffer->writeUint(value, mDataSize, getPosInContentTable(id, index))) {
+            AKLOGE("cannot update value %d. pos: %d, tailPos: %d, mDataSize: %d", value,
+                    getPosInContentTable(id, index), mContentTableBuffer->getTailPosition(),
+                    mDataSize);
+            return false;
+        }
+        return true;
+    }
+    // The entry is not in the content table.
+    // Create new entry in the content table.
+    const int index = getIndexFromContentTablePos(mContentTableBuffer->getTailPosition());
+    if (!mIndexTableBuffer->writeUint(index, INDEX_SIZE, posInIndexTable)) {
+        AKLOGE("cannot write index %d. pos %d", index, posInIndexTable);
+        return false;
+    }
+    // Write a new block that containing the entry to be set.
+    int writingPos = getPosInContentTable(0 /* id */, index);
+    for (int i = 0; i < mBlockSize; ++i) {
+        if (!mContentTableBuffer->writeUintAndAdvancePosition(NOT_EXIST, mDataSize,
+                &writingPos)) {
+            AKLOGE("cannot write content table to extend. writingPos: %d, tailPos: %d, "
+                    "mDataSize: %d", writingPos, mContentTableBuffer->getTailPosition(), mDataSize);
+            return false;
+        }
+    }
+    return mContentTableBuffer->writeUint(value, mDataSize, getPosInContentTable(id, index));
+}
+
+int SparseTable::getIndexFromContentTablePos(const int contentTablePos) const {
+    return contentTablePos / mDataSize / mBlockSize;
+}
+
+int SparseTable::getPosInIndexTable(const int id) const {
+    return (id / mBlockSize) * INDEX_SIZE;
+}
+
+int SparseTable::getPosInContentTable(const int id, const int index) const {
+    const int offset = id % mBlockSize;
+    return (index * mBlockSize + offset) * mDataSize;
+}
+
+} // namespace latinime