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/utils/sparse_table.h"
18
19 namespace latinime {
20
21 const int SparseTable::NOT_EXIST = -1;
22 const int SparseTable::INDEX_SIZE = 4;
23
contains(const int id) const24 bool SparseTable::contains(const int id) const {
25 const int readingPos = getPosInIndexTable(id);
26 if (id < 0 || mIndexTableBuffer->getTailPosition() <= readingPos) {
27 return false;
28 }
29 const int index = mIndexTableBuffer->readUint(INDEX_SIZE, readingPos);
30 return index != NOT_EXIST;
31 }
32
get(const int id) const33 uint32_t SparseTable::get(const int id) const {
34 const int indexTableReadingPos = getPosInIndexTable(id);
35 const int index = mIndexTableBuffer->readUint(INDEX_SIZE, indexTableReadingPos);
36 const int contentTableReadingPos = getPosInContentTable(id, index);
37 if (contentTableReadingPos < 0
38 || contentTableReadingPos >= mContentTableBuffer->getTailPosition()) {
39 AKLOGE("contentTableReadingPos(%d) is invalid. id: %d, index: %d",
40 contentTableReadingPos, id, index);
41 return NOT_A_DICT_POS;
42 }
43 const int contentValue = mContentTableBuffer->readUint(mDataSize, contentTableReadingPos);
44 return contentValue == NOT_EXIST ? NOT_A_DICT_POS : contentValue;
45 }
46
set(const int id,const uint32_t value)47 bool SparseTable::set(const int id, const uint32_t value) {
48 const int posInIndexTable = getPosInIndexTable(id);
49 // Extends the index table if needed.
50 int tailPos = mIndexTableBuffer->getTailPosition();
51 while (tailPos <= posInIndexTable) {
52 if (!mIndexTableBuffer->writeUintAndAdvancePosition(NOT_EXIST, INDEX_SIZE, &tailPos)) {
53 AKLOGE("cannot extend index table. tailPos: %d to: %d", tailPos, posInIndexTable);
54 return false;
55 }
56 }
57 if (contains(id)) {
58 // The entry is already in the content table.
59 const int index = mIndexTableBuffer->readUint(INDEX_SIZE, posInIndexTable);
60 if (!mContentTableBuffer->writeUint(value, mDataSize, getPosInContentTable(id, index))) {
61 AKLOGE("cannot update value %d. pos: %d, tailPos: %d, mDataSize: %d", value,
62 getPosInContentTable(id, index), mContentTableBuffer->getTailPosition(),
63 mDataSize);
64 return false;
65 }
66 return true;
67 }
68 // The entry is not in the content table.
69 // Create new entry in the content table.
70 const int index = getIndexFromContentTablePos(mContentTableBuffer->getTailPosition());
71 if (!mIndexTableBuffer->writeUint(index, INDEX_SIZE, posInIndexTable)) {
72 AKLOGE("cannot write index %d. pos %d", index, posInIndexTable);
73 return false;
74 }
75 // Write a new block that containing the entry to be set.
76 int writingPos = getPosInContentTable(0 /* id */, index);
77 for (int i = 0; i < mBlockSize; ++i) {
78 if (!mContentTableBuffer->writeUintAndAdvancePosition(NOT_EXIST, mDataSize,
79 &writingPos)) {
80 AKLOGE("cannot write content table to extend. writingPos: %d, tailPos: %d, "
81 "mDataSize: %d", writingPos, mContentTableBuffer->getTailPosition(), mDataSize);
82 return false;
83 }
84 }
85 return mContentTableBuffer->writeUint(value, mDataSize, getPosInContentTable(id, index));
86 }
87
getIndexFromContentTablePos(const int contentTablePos) const88 int SparseTable::getIndexFromContentTablePos(const int contentTablePos) const {
89 return contentTablePos / mDataSize / mBlockSize;
90 }
91
getPosInIndexTable(const int id) const92 int SparseTable::getPosInIndexTable(const int id) const {
93 return (id / mBlockSize) * INDEX_SIZE;
94 }
95
getPosInContentTable(const int id,const int index) const96 int SparseTable::getPosInContentTable(const int id, const int index) const {
97 const int offset = id % mBlockSize;
98 return (index * mBlockSize + offset) * mDataSize;
99 }
100
101 } // namespace latinime
102