1#include <Functions/FunctionFactory.h>
2#include <Functions/FunctionsVisitParam.h>
3#include <Functions/FunctionsStringSearch.h>
4
5
6namespace DB
7{
8
9struct ExtractString
10{
11 static void extract(const UInt8 * pos, const UInt8 * end, ColumnString::Chars & res_data)
12 {
13 size_t old_size = res_data.size();
14 ReadBufferFromMemory in(pos, end - pos);
15 if (!tryReadJSONStringInto(res_data, in))
16 res_data.resize(old_size);
17 }
18};
19
20struct NameVisitParamExtractString { static constexpr auto name = "visitParamExtractString"; };
21using FunctionVisitParamExtractString = FunctionsStringSearchToString<ExtractParamToStringImpl<ExtractString>, NameVisitParamExtractString>;
22
23
24void registerFunctionVisitParamExtractString(FunctionFactory & factory)
25{
26 factory.registerFunction<FunctionVisitParamExtractString>();
27}
28
29}
30