ClickHouse/src/Functions/FunctionsTextClassification.h

#pragma once

#include <Columns/ColumnString.h>
#include <Columns/ColumnVector.h>
#include <DataTypes/DataTypesNumber.h>
#include <Functions/FunctionHelpers.h>
#include <Functions/IFunction.h>
#include <Interpreters/Context_fwd.h>
#include <Functions/FunctionFactory.h>
#include <Interpreters/Context.h>

namespace DB
{
/// Functions for text classification with different result types

namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
extern const int ILLEGAL_COLUMN;
extern const int SUPPORT_IS_DISABLED;
}

template <typename Impl, typename Name>
class FunctionTextClassificationString : public IFunction
{
public:
    static constexpr auto name = Name::name;

    static FunctionPtr create(ContextPtr context)
    {
        if (!context->getSettingsRef().allow_experimental_nlp_functions)
            throw Exception(ErrorCodes::SUPPORT_IS_DISABLED,
                            "Natural language processing function '{}' is experimental. "
                            "Set `allow_experimental_nlp_functions` setting to enable it", name);

        return std::make_shared<FunctionTextClassificationString>();
    }

    String getName() const override { return name; }

    size_t getNumberOfArguments() const override { return 1; }

    bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return true; }

    bool useDefaultImplementationForConstants() const override { return true; }

    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
    {
        if (!isString(arguments[0]))
            throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
                "Illegal type {} of argument of function {}. Must be String.",
                arguments[0]->getName(), getName());

        return arguments[0];
    }

    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & /*result_type*/, size_t /*input_rows_count*/) const override
    {
        const ColumnPtr & column = arguments[0].column;
        const ColumnString * col = checkAndGetColumn<ColumnString>(column.get());

        if (!col)
            throw Exception(ErrorCodes::ILLEGAL_COLUMN, "Illegal column {} of argument of function {}",
                arguments[0].column->getName(), getName());

        auto col_res = ColumnString::create();
        Impl::vector(col->getChars(), col->getOffsets(), col_res->getChars(), col_res->getOffsets());
        return col_res;
    }
};

template <typename Impl, typename Name>
class FunctionTextClassificationFloat : public IFunction
{
public:
    static constexpr auto name = Name::name;

    static FunctionPtr create(ContextPtr context)
    {
        if (!context->getSettingsRef().allow_experimental_nlp_functions)
            throw Exception(ErrorCodes::SUPPORT_IS_DISABLED,
                            "Natural language processing function '{}' is experimental. "
                            "Set `allow_experimental_nlp_functions` setting to enable it", name);

        return std::make_shared<FunctionTextClassificationFloat>();
    }

    String getName() const override { return name; }

    size_t getNumberOfArguments() const override { return 1; }

    bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return true; }

    bool useDefaultImplementationForConstants() const override { return true; }

    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
    {
        if (!isString(arguments[0]))
            throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
                "Illegal type {} of argument of function {}. Must be String.",
                arguments[0]->getName(), getName());

        return std::make_shared<DataTypeFloat32>();
    }

    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & /*result_type*/, size_t /*input_rows_count*/) const override
    {
        const ColumnPtr & column = arguments[0].column;
        const ColumnString * col = checkAndGetColumn<ColumnString>(column.get());

        if (!col)
            throw Exception(ErrorCodes::ILLEGAL_COLUMN, "Illegal column {} of argument of function {}",
                arguments[0].column->getName(), getName());

        auto col_res = ColumnVector<Float32>::create();
        ColumnVector<Float32>::Container & vec_res = col_res->getData();
        vec_res.resize(col->size());

        Impl::vector(col->getChars(), col->getOffsets(), vec_res);
        return col_res;
    }
};

}