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#ifndef LATINIME_FORMAT_UTILS_H
18#define LATINIME_FORMAT_UTILS_H
19
20#include <cstdint>
21
22#include "defines.h"
23#include "utils/byte_array_view.h"
24
25namespace latinime {
26
27/**
28 * Methods to handle binary dictionary format version.
29 */
30class FormatUtils {
31 public:
32    enum FORMAT_VERSION {
33        // These MUST have the same values as the relevant constants in FormatSpec.java.
34        // TODO: Remove VERSION_2 and VERSION_201 when we:
35        // * Confirm that old versions of LatinIME download old-format dictionaries
36        // * We no longer need the corresponding constants on the Java side for dicttool
37        VERSION_2 = 2,
38        VERSION_201 = 201,
39        VERSION_202 = 202,
40        VERSION_4_ONLY_FOR_TESTING = 399,
41        VERSION_402 = 402,
42        VERSION_403 = 403,
43        UNKNOWN_VERSION = -1
44    };
45
46    // 32 bit magic number is stored at the beginning of the dictionary header to reject
47    // unsupported or obsolete dictionary formats.
48    static const uint32_t MAGIC_NUMBER;
49
50    static FORMAT_VERSION getFormatVersion(const int formatVersion);
51    static FORMAT_VERSION detectFormatVersion(const ReadOnlyByteArrayView dictBuffer);
52
53 private:
54    DISALLOW_IMPLICIT_CONSTRUCTORS(FormatUtils);
55
56    static const size_t DICTIONARY_MINIMUM_SIZE;
57};
58} // namespace latinime
59#endif /* LATINIME_FORMAT_UTILS_H */
60