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52 lines
1.1 KiB
C++
52 lines
1.1 KiB
C++
#ifndef DBMS_STORAGES_STORAGE_SYSTEM_NUMBERS_H
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#define DBMS_STORAGES_STORAGE_SYSTEM_NUMBERS_H
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#include <Poco/SharedPtr.h>
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#include <DB/Storages/IStorage.h>
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namespace DB
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{
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using Poco::SharedPtr;
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class NumbersBlockInputStream : public IBlockInputStream
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{
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public:
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NumbersBlockInputStream(size_t block_size_);
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Block read();
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private:
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size_t block_size;
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UInt64 next;
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};
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/** Реализует хранилище для системной таблицы Numbers.
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* Таблица содержит единственный столбец number UInt64.
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* Из этой таблицы можно прочитать все натуральные числа, начиная с 0 (до 2^64 - 1, а потом заново).
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*/
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class StorageSystemNumbers : public IStorage
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{
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public:
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StorageSystemNumbers();
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std::string getName() const { return "SystemNumbers"; }
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std::string getTableName() const { return "Numbers"; }
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const NamesAndTypes & getColumns() const { return columns; }
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SharedPtr<IBlockInputStream> read(
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const Names & column_names,
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ASTPtr query,
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size_t max_block_size = DEFAULT_BLOCK_SIZE);
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private:
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NamesAndTypes columns;
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};
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}
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#endif
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