blob: 7bd4861746a6cae51c49ab565e0a280f4c61437a (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
#pragma once
#include "coding/file_container.hpp"
#include "coding/mmap_reader.hpp"
#include "defines.hpp"
#include "std/cstdint.hpp"
#include "std/unique_ptr.hpp"
#include "std/vector.hpp"
#include "3party/succinct/elias_fano.hpp"
#include "3party/succinct/mapper.hpp"
namespace platform
{
class LocalCountryFile;
}
namespace feature
{
/// This class is a wrapper around elias-fano encoder, which allows
/// to efficiently encode a sequence of strictly increasing features
/// offsets in a MWM file and access them by feature's index.
class FeaturesOffsetsTable
{
public:
/// This class is used to accumulate strictly increasing features
/// offsets and then build FeaturesOffsetsTable.
class Builder
{
public:
/// Adds offset to the end of the sequence of already
/// accumulated offsets. Note that offset must be strictly
/// greater than all previously added offsets.
///
/// \param offset a feature's offset in a MWM file
void PushOffset(uint32_t offset);
/// \return number of already accumulated offsets
inline size_t size() const { return m_offsets.size(); }
private:
friend class FeaturesOffsetsTable;
vector<uint32_t> m_offsets;
};
/// Builds FeaturesOffsetsTable from the strictly increasing
/// sequence of file offsets.
///
/// \param builder Builder containing sequence of offsets.
/// \return a pointer to an instance of FeaturesOffsetsTable
static unique_ptr<FeaturesOffsetsTable> Build(Builder & builder);
/// Load table by full path to the table file.
static unique_ptr<FeaturesOffsetsTable> Load(string const & filePath);
static unique_ptr<FeaturesOffsetsTable> Load(FilesContainerR const & cont);
static unique_ptr<FeaturesOffsetsTable> Build(FilesContainerR const & cont,
string const & storePath);
/// Get table for the MWM map, represented by localFile and cont.
static unique_ptr<FeaturesOffsetsTable> CreateIfNotExistsAndLoad(
platform::LocalCountryFile const & localFile, FilesContainerR const & cont);
/// @todo The easiest solution for now. Need to be removed in future.
//@{
static unique_ptr<FeaturesOffsetsTable> CreateIfNotExistsAndLoad(platform::LocalCountryFile const & localFile);
static unique_ptr<FeaturesOffsetsTable> CreateIfNotExistsAndLoad(FilesContainerR const & cont);
//@}
FeaturesOffsetsTable(FeaturesOffsetsTable const &) = delete;
FeaturesOffsetsTable const & operator=(FeaturesOffsetsTable const &) = delete;
/// Serializes current instance to a section in container.
///
/// \param filePath a full path of the file to store data
void Save(string const & filePath);
/// \param index index of a feature
/// \return offset a feature
uint32_t GetFeatureOffset(size_t index) const;
/// \param offset offset of a feature
/// \return index of a feature
size_t GetFeatureIndexbyOffset(uint32_t offset) const;
/// \return number of features offsets in a table.
inline size_t size() const { return static_cast<size_t>(m_table.num_ones()); }
/// \return byte size of a table, may be slightly different from a
/// real byte size in memory or on disk due to alignment, but
/// can be used in benchmarks, logging, etc.
//inline size_t byte_size() { return static_cast<size_t>(succinct::mapper::size_of(m_table)); }
private:
FeaturesOffsetsTable(succinct::elias_fano::elias_fano_builder & builder);
FeaturesOffsetsTable(string const & filePath);
FeaturesOffsetsTable() = default;
static unique_ptr<FeaturesOffsetsTable> LoadImpl(string const & filePath);
static unique_ptr<FeaturesOffsetsTable> CreateImpl(platform::LocalCountryFile const & localFile,
FilesContainerR const & cont,
string const & storePath);
succinct::elias_fano m_table;
unique_ptr<MmapReader> m_pReader;
detail::MappedFile m_file;
detail::MappedFile::Handle m_handle;
};
// Builds feature offsets table in an mwm or rebuilds an existing
// one.
bool BuildOffsetsTable(string const & filePath);
} // namespace feature
|
