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 "suggest/policyimpl/dictionary/dynamic_patricia_trie_reading_utils.h"
18
19#include "defines.h"
20#include "suggest/policyimpl/dictionary/utils/byte_array_utils.h"
21
22namespace latinime {
23
24typedef DynamicPatriciaTrieReadingUtils DptReadingUtils;
25
26const DptReadingUtils::NodeFlags DptReadingUtils::MASK_MOVED = 0xC0;
27const DptReadingUtils::NodeFlags DptReadingUtils::FLAG_IS_NOT_MOVED = 0xC0;
28const DptReadingUtils::NodeFlags DptReadingUtils::FLAG_IS_MOVED = 0x40;
29const DptReadingUtils::NodeFlags DptReadingUtils::FLAG_IS_DELETED = 0x80;
30
31// TODO: Make DICT_OFFSET_ZERO_OFFSET = 0.
32// Currently, DICT_OFFSET_INVALID is 0 in Java side but offset can be 0 during GC. So, the maximum
33// value of offsets, which is 0x7FFFFF is used to represent 0 offset.
34const int DptReadingUtils::DICT_OFFSET_INVALID = 0;
35const int DptReadingUtils::DICT_OFFSET_ZERO_OFFSET = 0x7FFFFF;
36
37/* static */ int DptReadingUtils::getForwardLinkPosition(const uint8_t *const buffer,
38        const int pos) {
39    int linkAddressPos = pos;
40    return ByteArrayUtils::readSint24AndAdvancePosition(buffer, &linkAddressPos);
41}
42
43/* static */ int DptReadingUtils::getParentPtNodePosOffsetAndAdvancePosition(
44        const uint8_t *const buffer, int *const pos) {
45    return ByteArrayUtils::readSint24AndAdvancePosition(buffer, pos);
46}
47
48/* static */ int DptReadingUtils::getParentPtNodePos(const int parentOffset, const int ptNodePos) {
49    if (parentOffset == DICT_OFFSET_INVALID) {
50        return NOT_A_DICT_POS;
51    } else if (parentOffset == DICT_OFFSET_ZERO_OFFSET) {
52        return ptNodePos;
53    } else {
54        return parentOffset + ptNodePos;
55    }
56}
57
58/* static */ int DptReadingUtils::readChildrenPositionAndAdvancePosition(
59        const uint8_t *const buffer, int *const pos) {
60    const int base = *pos;
61    const int offset = ByteArrayUtils::readSint24AndAdvancePosition(buffer, pos);
62    if (offset == DICT_OFFSET_INVALID) {
63        // The PtNode does not have children.
64        return NOT_A_DICT_POS;
65    } else if (offset == DICT_OFFSET_ZERO_OFFSET) {
66        return base;
67    } else {
68        return base + offset;
69    }
70}
71
72} // namespace latinime
73