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 
25 namespace latinime {
26 
27 /**
28  * Methods to handle binary dictionary format version.
29  */
30 class 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