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78 lines
2.9 KiB
C++
78 lines
2.9 KiB
C++
#pragma once
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#include <vector>
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#include <memory>
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#include <cstddef>
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#include <string>
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#include <Core/Field.h>
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#include <Core/SettingsEnums.h>
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class Collator;
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namespace DB
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{
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struct FillColumnDescription
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{
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/// All missed values in range [FROM, TO) will be filled
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/// Range [FROM, TO) respects sorting direction
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Field fill_from; /// Fill value >= FILL_FROM
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Field fill_to; /// Fill value + STEP < FILL_TO
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Field fill_step; /// Default = 1 or -1 according to direction
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};
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/// Description of the sorting rule by one column.
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struct SortColumnDescription
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{
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std::string column_name; /// The name of the column.
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size_t column_number; /// Column number (used if no name is given).
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int direction; /// 1 - ascending, -1 - descending.
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int nulls_direction; /// 1 - NULLs and NaNs are greater, -1 - less.
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/// To achieve NULLS LAST, set it equal to direction, to achieve NULLS FIRST, set it opposite.
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std::shared_ptr<Collator> collator; /// Collator for locale-specific comparison of strings
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bool with_fill;
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FillColumnDescription fill_description;
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SortColumnDescription(
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size_t column_number_, int direction_, int nulls_direction_,
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const std::shared_ptr<Collator> & collator_ = nullptr,
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bool with_fill_ = false, const FillColumnDescription & fill_description_ = {})
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: column_number(column_number_), direction(direction_), nulls_direction(nulls_direction_), collator(collator_)
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, with_fill(with_fill_), fill_description(fill_description_) {}
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SortColumnDescription(
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const std::string & column_name_, int direction_, int nulls_direction_,
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const std::shared_ptr<Collator> & collator_ = nullptr,
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bool with_fill_ = false, const FillColumnDescription & fill_description_ = {})
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: column_name(column_name_), column_number(0), direction(direction_), nulls_direction(nulls_direction_)
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, collator(collator_), with_fill(with_fill_), fill_description(fill_description_) {}
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bool operator == (const SortColumnDescription & other) const
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{
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return column_name == other.column_name && column_number == other.column_number
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&& direction == other.direction && nulls_direction == other.nulls_direction;
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}
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bool operator != (const SortColumnDescription & other) const
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{
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return !(*this == other);
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}
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std::string dump() const
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{
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std::stringstream ss;
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ss << column_name << ":" << column_number << ":dir " << direction << "nulls " << nulls_direction;
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return ss.str();
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}
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};
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/// Description of the sorting rule for several columns.
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using SortDescription = std::vector<SortColumnDescription>;
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class Block;
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/// Outputs user-readable description into `out`.
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void dumpSortDescription(const SortDescription & description, const Block & header, WriteBuffer & out);
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}
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