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#pragma once
#include <Columns/ColumnConst.h>
#include <Columns/ColumnString.h>
#include <Columns/ColumnTuple.h>
#include <Columns/ColumnVector.h>
#include <DataTypes/DataTypeFactory.h>
#include <DataTypes/DataTypeTuple.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypeString.h>
#include <Functions/FunctionHelpers.h>
#include <Functions/IFunction.h>
#include <Interpreters/Context_fwd.h>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
extern const int TOO_MANY_ARGUMENTS_FOR_FUNCTION;
extern const int TOO_FEW_ARGUMENTS_FOR_FUNCTION;
extern const int ARGUMENT_OUT_OF_BOUND;
}
// FunctionStringHash
// Simhash: String -> UInt64
// Minhash: String -> (UInt64, UInt64)
template <typename Impl, typename Name, bool is_simhash, bool is_arg = false>
class FunctionsStringHash : public IFunction
{
public:
static constexpr auto name = Name::name;
static constexpr size_t default_shingle_size = 3;
static constexpr size_t default_num_hashes = 6;
static constexpr size_t max_shingle_size = 25;
static constexpr size_t max_num_hashes = 25;
static FunctionPtr create(ContextPtr) { return std::make_shared<FunctionsStringHash>(); }
String getName() const override { return name; }
size_t getNumberOfArguments() const override { return 0; }
bool isVariadic() const override { return true; }
bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return true; }
ColumnNumbers getArgumentsThatAreAlwaysConstant() const override
{
if constexpr (is_simhash)
return {1};
else
return {1, 2};
}
DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
{
if (arguments.empty())
throw Exception(ErrorCodes::TOO_FEW_ARGUMENTS_FOR_FUNCTION, "Function {} expect at least one argument", getName());
if (!isString(arguments[0].type))
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
"First argument of function {} must be String, got {}", getName(), arguments[0].type->getName());
size_t shingle_size = default_shingle_size;
if (arguments.size() > 1)
{
if (!isUnsignedInteger(arguments[1].type))
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
"Second argument (shingle size) of function {} must be unsigned integer, got {}",
getName(), arguments[1].type->getName());
if (!arguments[1].column)
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
"Second argument (shingle size) of function {} must be constant", getName());
shingle_size = arguments[1].column->getUInt(0);
}
size_t num_hashes = default_num_hashes;
if (arguments.size() > 2)
{
if constexpr (is_simhash)
throw Exception(ErrorCodes::TOO_MANY_ARGUMENTS_FOR_FUNCTION,
"Function {} expect no more than two arguments (text, shingle size), got {}",
getName(), arguments.size());
if (!isUnsignedInteger(arguments[2].type))
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
"Third argument (num hashes) of function {} must be unsigned integer, got {}",
getName(), arguments[2].type->getName());
if (!arguments[2].column)
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
"Third argument (num hashes) of function {} must be constant", getName());
num_hashes = arguments[2].column->getUInt(0);
}
if (arguments.size() > 3)
{
throw Exception(ErrorCodes::TOO_MANY_ARGUMENTS_FOR_FUNCTION,
"Function {} expect no more than three arguments (text, shingle size, num hashes), got {}",
getName(), arguments.size());
}
if (shingle_size == 0)
throw Exception(ErrorCodes::ARGUMENT_OUT_OF_BOUND, "Second argument (shingle size) of function {} cannot be zero", getName());
if (num_hashes == 0)
throw Exception(ErrorCodes::ARGUMENT_OUT_OF_BOUND, "Third argument (num hashes) of function {} cannot be zero", getName());
if (shingle_size > max_shingle_size)
throw Exception(ErrorCodes::ARGUMENT_OUT_OF_BOUND,
"Second argument (shingle size) of function {} cannot be greater then {}",
getName(), max_shingle_size);
if (num_hashes > max_num_hashes)
throw Exception(ErrorCodes::ARGUMENT_OUT_OF_BOUND,
"Third argument (num hashes) of function {} cannot be greater then {}",
getName(), max_num_hashes);
auto type = std::make_shared<DataTypeUInt64>();
if constexpr (is_simhash)
return type;
if constexpr (is_arg)
{
DataTypePtr string_type = std::make_shared<DataTypeString>();
DataTypes types(num_hashes, string_type);
auto tuple_type = std::make_shared<DataTypeTuple>(types);
return std::make_shared<DataTypeTuple>(DataTypes{tuple_type, tuple_type});
}
return std::make_shared<DataTypeTuple>(DataTypes{type, type});
}
bool useDefaultImplementationForConstants() const override { return true; }
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t) const override
{
const ColumnPtr & column = arguments[0].column;
size_t shingle_size = default_shingle_size;
size_t num_hashes = default_num_hashes;
if (arguments.size() > 1)
shingle_size = arguments[1].column->getUInt(0);
if (arguments.size() > 2)
num_hashes = arguments[2].column->getUInt(0);
if constexpr (is_simhash)
{
auto col_res = ColumnVector<UInt64>::create();
auto & vec_res = col_res->getData();
vec_res.resize(column->size());
const ColumnString * col_str_vector = checkAndGetColumn<ColumnString>(&*column);
Impl::apply(col_str_vector->getChars(), col_str_vector->getOffsets(), shingle_size, vec_res);
return col_res;
}
else if constexpr (is_arg) // Min hash arg
{
MutableColumns min_columns(num_hashes);
MutableColumns max_columns(num_hashes);
for (size_t i = 0; i < num_hashes; ++i)
{
min_columns[i] = ColumnString::create();
max_columns[i] = ColumnString::create();
}
auto min_tuple = ColumnTuple::create(std::move(min_columns));
auto max_tuple = ColumnTuple::create(std::move(max_columns));
const ColumnString * col_str_vector = checkAndGetColumn<ColumnString>(&*column);
Impl::apply(col_str_vector->getChars(), col_str_vector->getOffsets(), shingle_size, num_hashes, nullptr, nullptr, min_tuple.get(), max_tuple.get());
MutableColumns tuple_columns;
tuple_columns.emplace_back(std::move(min_tuple));
tuple_columns.emplace_back(std::move(max_tuple));
return ColumnTuple::create(std::move(tuple_columns));
}
else // Min hash
{
auto col_h1 = ColumnVector<UInt64>::create();
auto col_h2 = ColumnVector<UInt64>::create();
auto & vec_h1 = col_h1->getData();
auto & vec_h2 = col_h2->getData();
vec_h1.resize(column->size());
vec_h2.resize(column->size());
const ColumnString * col_str_vector = checkAndGetColumn<ColumnString>(&*column);
Impl::apply(col_str_vector->getChars(), col_str_vector->getOffsets(), shingle_size, num_hashes, &vec_h1, &vec_h2, nullptr, nullptr);
MutableColumns tuple_columns;
tuple_columns.emplace_back(std::move(col_h1));
tuple_columns.emplace_back(std::move(col_h2));
return ColumnTuple::create(std::move(tuple_columns));
}
}
};
}
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