1 /*
2  * Copyright (C) 2014, 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_pt_node_array_reader.h"
18 
19 #include "dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
20 #include "dictionary/structure/pt_common/patricia_trie_reading_utils.h"
21 #include "dictionary/utils/buffer_with_extendable_buffer.h"
22 
23 namespace latinime {
24 
readPtNodeArrayInfoAndReturnIfValid(const int ptNodeArrayPos,int * const outPtNodeCount,int * const outFirstPtNodePos) const25 bool Ver4PtNodeArrayReader::readPtNodeArrayInfoAndReturnIfValid(const int ptNodeArrayPos,
26         int *const outPtNodeCount, int *const outFirstPtNodePos) const {
27     if (ptNodeArrayPos < 0 || ptNodeArrayPos >= mBuffer->getTailPosition()) {
28         // Reading invalid position because of a bug or a broken dictionary.
29         AKLOGE("Reading PtNode array info from invalid dictionary position: %d, dict size: %d",
30                 ptNodeArrayPos, mBuffer->getTailPosition());
31         ASSERT(false);
32         return false;
33     }
34     const bool usesAdditionalBuffer = mBuffer->isInAdditionalBuffer(ptNodeArrayPos);
35     const uint8_t *const dictBuf = mBuffer->getBuffer(usesAdditionalBuffer);
36     int readingPos = ptNodeArrayPos;
37     if (usesAdditionalBuffer) {
38         readingPos -= mBuffer->getOriginalBufferSize();
39     }
40     const int ptNodeCountInArray = PatriciaTrieReadingUtils::getPtNodeArraySizeAndAdvancePosition(
41             dictBuf, &readingPos);
42     if (usesAdditionalBuffer) {
43         readingPos += mBuffer->getOriginalBufferSize();
44     }
45     if (ptNodeCountInArray < 0) {
46         AKLOGE("Invalid PtNode count in an array: %d.", ptNodeCountInArray);
47         return false;
48     }
49     *outPtNodeCount = ptNodeCountInArray;
50     *outFirstPtNodePos = readingPos;
51     return true;
52 }
53 
readForwardLinkAndReturnIfValid(const int forwordLinkPos,int * const outNextPtNodeArrayPos) const54 bool Ver4PtNodeArrayReader::readForwardLinkAndReturnIfValid(const int forwordLinkPos,
55         int *const outNextPtNodeArrayPos) const {
56     if (forwordLinkPos < 0 || forwordLinkPos >= mBuffer->getTailPosition()) {
57         // Reading invalid position because of bug or broken dictionary.
58         AKLOGE("Reading forward link from invalid dictionary position: %d, dict size: %d",
59                 forwordLinkPos, mBuffer->getTailPosition());
60         ASSERT(false);
61         return false;
62     }
63     const bool usesAdditionalBuffer = mBuffer->isInAdditionalBuffer(forwordLinkPos);
64     const uint8_t *const dictBuf = mBuffer->getBuffer(usesAdditionalBuffer);
65     int readingPos = forwordLinkPos;
66     if (usesAdditionalBuffer) {
67         readingPos -= mBuffer->getOriginalBufferSize();
68     }
69     const int nextPtNodeArrayOffset =
70             DynamicPtReadingUtils::getForwardLinkPosition(dictBuf, readingPos);
71     if (DynamicPtReadingUtils::isValidForwardLinkPosition(nextPtNodeArrayOffset)) {
72         *outNextPtNodeArrayPos = forwordLinkPos + nextPtNodeArrayOffset;
73     } else {
74         *outNextPtNodeArrayPos = NOT_A_DICT_POS;
75     }
76     return true;
77 }
78 
79 } // namespace latinime
80