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      1 /*
      2  * Copyright (C) 2013, The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *     http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "dictionary/structure/v4/ver4_patricia_trie_node_reader.h"
     18 
     19 #include "dictionary/header/header_policy.h"
     20 #include "dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
     21 #include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
     22 #include "dictionary/structure/v4/content/language_model_dict_content.h"
     23 #include "dictionary/structure/v4/content/probability_entry.h"
     24 #include "dictionary/structure/v4/ver4_patricia_trie_reading_utils.h"
     25 #include "dictionary/utils/buffer_with_extendable_buffer.h"
     26 #include "dictionary/utils/forgetting_curve_utils.h"
     27 
     28 namespace latinime {
     29 
     30 const PtNodeParams Ver4PatriciaTrieNodeReader::fetchPtNodeInfoFromBufferAndProcessMovedPtNode(
     31         const int ptNodePos, const int siblingNodePos) const {
     32     if (ptNodePos < 0 || ptNodePos >= mBuffer->getTailPosition()) {
     33         // Reading invalid position because of bug or broken dictionary.
     34         AKLOGE("Fetching PtNode info from invalid dictionary position: %d, dictionary size: %d",
     35                 ptNodePos, mBuffer->getTailPosition());
     36         ASSERT(false);
     37         return PtNodeParams();
     38     }
     39     const bool usesAdditionalBuffer = mBuffer->isInAdditionalBuffer(ptNodePos);
     40     const uint8_t *const dictBuf = mBuffer->getBuffer(usesAdditionalBuffer);
     41     int pos = ptNodePos;
     42     const int headPos = ptNodePos;
     43     if (usesAdditionalBuffer) {
     44         pos -= mBuffer->getOriginalBufferSize();
     45     }
     46     const PatriciaTrieReadingUtils::NodeFlags flags =
     47             PatriciaTrieReadingUtils::getFlagsAndAdvancePosition(dictBuf, &pos);
     48     const int parentPosOffset =
     49             DynamicPtReadingUtils::getParentPtNodePosOffsetAndAdvancePosition(
     50                     dictBuf, &pos);
     51     const int parentPos =
     52             DynamicPtReadingUtils::getParentPtNodePos(parentPosOffset, headPos);
     53     int codePoints[MAX_WORD_LENGTH];
     54     // Code point table is not used for ver4 dictionaries.
     55     const int codePointCount = PatriciaTrieReadingUtils::getCharsAndAdvancePosition(
     56             dictBuf, flags, MAX_WORD_LENGTH, nullptr /* codePointTable */, codePoints, &pos);
     57     int terminalIdFieldPos = NOT_A_DICT_POS;
     58     int terminalId = Ver4DictConstants::NOT_A_TERMINAL_ID;
     59     if (PatriciaTrieReadingUtils::isTerminal(flags)) {
     60         terminalIdFieldPos = pos;
     61         if (usesAdditionalBuffer) {
     62             terminalIdFieldPos += mBuffer->getOriginalBufferSize();
     63         }
     64         terminalId = Ver4PatriciaTrieReadingUtils::getTerminalIdAndAdvancePosition(dictBuf, &pos);
     65     }
     66     int childrenPosFieldPos = pos;
     67     if (usesAdditionalBuffer) {
     68         childrenPosFieldPos += mBuffer->getOriginalBufferSize();
     69     }
     70     int childrenPos = DynamicPtReadingUtils::readChildrenPositionAndAdvancePosition(
     71             dictBuf, &pos);
     72     if (usesAdditionalBuffer && childrenPos != NOT_A_DICT_POS) {
     73         childrenPos += mBuffer->getOriginalBufferSize();
     74     }
     75     if (usesAdditionalBuffer) {
     76         pos += mBuffer->getOriginalBufferSize();
     77     }
     78     // Sibling position is the tail position of original PtNode.
     79     int newSiblingNodePos = (siblingNodePos == NOT_A_DICT_POS) ? pos : siblingNodePos;
     80     // Read destination node if the read node is a moved node.
     81     if (DynamicPtReadingUtils::isMoved(flags)) {
     82         // The destination position is stored at the same place as the parent position.
     83         return fetchPtNodeInfoFromBufferAndProcessMovedPtNode(parentPos, newSiblingNodePos);
     84     } else {
     85         return PtNodeParams(headPos, flags, parentPos, codePointCount, codePoints,
     86                 terminalIdFieldPos, terminalId, NOT_A_PROBABILITY, childrenPosFieldPos, childrenPos,
     87                 newSiblingNodePos);
     88     }
     89 }
     90 
     91 } // namespace latinime
     92