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
|
#pragma once
#include <Core/Block.h>
#include <Processors/Formats/IRowInputFormat.h>
#include <Processors/Formats/ISchemaReader.h>
#include <Formats/FormatSettings.h>
#include <Common/HashTable/HashMap.h>
namespace DB
{
class ReadBuffer;
/** Stream for reading data in TSKV format.
* TSKV is a very inefficient data format.
* Similar to TSV, but each field is written as key=value.
* Fields can be listed in any order (including, in different lines there may be different order),
* and some fields may be missing.
* An equal sign can be escaped in the field name.
* Also, as an additional element there may be a useless tskv fragment - it needs to be ignored.
*/
class TSKVRowInputFormat final : public IRowInputFormat
{
public:
TSKVRowInputFormat(ReadBuffer & in_, Block header_, Params params_, const FormatSettings & format_settings_);
String getName() const override { return "TSKVRowInputFormat"; }
void resetParser() override;
private:
void readPrefix() override;
bool readRow(MutableColumns & columns, RowReadExtension &) override;
bool allowSyncAfterError() const override { return true; }
void syncAfterError() override;
bool supportsCountRows() const override { return true; }
size_t countRows(size_t max_block_size) override;
const FormatSettings format_settings;
/// Buffer for the read from the stream the field name. Used when you have to copy it.
String name_buf;
/// Hash table matching `field name -> position in the block`. NOTE You can use perfect hash map.
using NameMap = HashMap<StringRef, size_t, StringRefHash>;
NameMap name_map;
/// Set of columns for which the values were read. The rest will be filled with default values.
std::vector<UInt8> read_columns;
/// Set of columns which already met in row. Exception is thrown if there are more than one column with the same name.
std::vector<UInt8> seen_columns;
/// These sets may be different, because if null_as_default=1 read_columns[i] will be false and seen_columns[i] will be true
/// for row like ..., non-nullable column name=\N, ...
};
class TSKVSchemaReader : public IRowWithNamesSchemaReader
{
public:
TSKVSchemaReader(ReadBuffer & in_, const FormatSettings & format_settings_);
private:
NamesAndTypesList readRowAndGetNamesAndDataTypes(bool & eof) override;
bool first_row = true;
};
}
|
