1#include <TableFunctions/ITableFunction.h>
2#include <TableFunctions/TableFunctionNumbers.h>
3#include <TableFunctions/TableFunctionFactory.h>
4#include <Parsers/ASTFunction.h>
5#include <Parsers/ASTLiteral.h>
6#include <Common/typeid_cast.h>
7#include <Storages/System/StorageSystemNumbers.h>
8#include <Interpreters/evaluateConstantExpression.h>
9#include "registerTableFunctions.h"
10
11
12namespace DB
13{
14
15namespace ErrorCodes
16{
17 extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
18}
19
20template <bool multithreaded>
21StoragePtr TableFunctionNumbers<multithreaded>::executeImpl(const ASTPtr & ast_function, const Context & context, const std::string & table_name) const
22{
23 if (const auto * function = ast_function->as<ASTFunction>())
24 {
25 auto arguments = function->arguments->children;
26
27 if (arguments.size() != 1 && arguments.size() != 2)
28 throw Exception("Table function '" + getName() + "' requires 'length' or 'offset, length'.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
29
30
31 UInt64 offset = arguments.size() == 2 ? evaluateArgument(context, arguments[0]) : 0;
32 UInt64 length = arguments.size() == 2 ? evaluateArgument(context, arguments[1]) : evaluateArgument(context, arguments[0]);
33
34 auto res = StorageSystemNumbers::create(table_name, multithreaded, length, offset, false);
35 res->startup();
36 return res;
37 }
38 throw Exception("Table function '" + getName() + "' requires 'limit' or 'offset, limit'.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
39}
40
41void registerTableFunctionNumbers(TableFunctionFactory & factory)
42{
43 factory.registerFunction<TableFunctionNumbers<true>>();
44 factory.registerFunction<TableFunctionNumbers<false>>();
45}
46
47template <bool multithreaded>
48UInt64 TableFunctionNumbers<multithreaded>::evaluateArgument(const Context & context, ASTPtr & argument) const
49{
50 return evaluateConstantExpressionOrIdentifierAsLiteral(argument, context)->as<ASTLiteral &>().value.safeGet<UInt64>();
51}
52
53}
54