ClickHouse/dbms/include/DB/Functions/FunctionsConditional.h

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#pragma once
#include <DB/DataTypes/DataTypesNumberFixed.h>
#include <DB/Columns/ColumnVector.h>
#include <DB/Columns/ColumnString.h>
#include <DB/Columns/ColumnConst.h>
#include <DB/Columns/ColumnArray.h>
#include <DB/Functions/IFunction.h>
namespace DB
{
/** Функция выбора по условию: if(cond, then, else).
* cond - UInt8
* then, else - одинакового типа - либо числа/даты/даты-с-временем, либо строки.
*/
template <typename T>
struct NumIfImpl
{
static void vector_vector(
const std::vector<UInt8> & cond,
const std::vector<T> & a, const std::vector<T> & b,
std::vector<T> & res)
{
size_t size = cond.size();
for (size_t i = 0; i < size; ++i)
res[i] = cond[i] ? a[i] : b[i];
}
static void vector_constant(
const std::vector<UInt8> & cond,
const std::vector<T> & a, T b,
std::vector<T> & res)
{
size_t size = cond.size();
for (size_t i = 0; i < size; ++i)
res[i] = cond[i] ? a[i] : b;
}
static void constant_vector(
const std::vector<UInt8> & cond,
T a, const std::vector<T> & b,
std::vector<T> & res)
{
size_t size = cond.size();
for (size_t i = 0; i < size; ++i)
res[i] = cond[i] ? a : b[i];
}
static void constant_constant(
const std::vector<UInt8> & cond,
T a, T b,
std::vector<T> & res)
{
size_t size = cond.size();
for (size_t i = 0; i < size; ++i)
res[i] = cond[i] ? a : b;
}
};
struct StringIfImpl
{
static void vector_vector(
const std::vector<UInt8> & cond,
const std::vector<UInt8> & a_data, const ColumnString::Offsets_t & a_offsets,
const std::vector<UInt8> & b_data, const ColumnString::Offsets_t & b_offsets,
std::vector<UInt8> & c_data, ColumnString::Offsets_t & c_offsets)
{
size_t size = cond.size();
c_offsets.resize(size);
c_data.reserve(std::max(a_data.size(), b_data.size()));
ColumnString::Offset_t a_prev_offset = 0;
ColumnString::Offset_t b_prev_offset = 0;
ColumnString::Offset_t c_prev_offset = 0;
for (size_t i = 0; i < size; ++i)
{
if (cond[i])
{
size_t size_to_write = a_offsets[i] - a_prev_offset;
c_data.resize(c_data.size() + size_to_write);
memcpy(&c_data[c_prev_offset], &a_data[a_prev_offset], size_to_write);
c_prev_offset += size_to_write;
c_offsets[i] = c_prev_offset;
}
else
{
size_t size_to_write = b_offsets[i] - b_prev_offset;
c_data.resize(c_data.size() + size_to_write);
memcpy(&c_data[c_prev_offset], &b_data[b_prev_offset], size_to_write);
c_prev_offset += size_to_write;
c_offsets[i] = c_prev_offset;
}
a_prev_offset = a_offsets[i];
b_prev_offset = b_offsets[i];
}
}
static void vector_constant(
const std::vector<UInt8> & cond,
const std::vector<UInt8> & a_data, const ColumnString::Offsets_t & a_offsets,
const String & b,
std::vector<UInt8> & c_data, ColumnString::Offsets_t & c_offsets)
{
size_t size = cond.size();
c_offsets.resize(size);
c_data.reserve(a_data.size());
ColumnString::Offset_t a_prev_offset = 0;
ColumnString::Offset_t c_prev_offset = 0;
for (size_t i = 0; i < size; ++i)
{
if (cond[i])
{
size_t size_to_write = a_offsets[i] - a_prev_offset;
c_data.resize(c_data.size() + size_to_write);
memcpy(&c_data[c_prev_offset], &a_data[a_prev_offset], size_to_write);
c_prev_offset += size_to_write;
c_offsets[i] = c_prev_offset;
}
else
{
size_t size_to_write = b.size() + 1;
c_data.resize(c_data.size() + size_to_write);
memcpy(&c_data[c_prev_offset], b.data(), size_to_write);
c_prev_offset += size_to_write;
c_offsets[i] = c_prev_offset;
}
a_prev_offset = a_offsets[i];
}
}
static void constant_vector(
const std::vector<UInt8> & cond,
const String & a,
const std::vector<UInt8> & b_data, const ColumnString::Offsets_t & b_offsets,
std::vector<UInt8> & c_data, ColumnString::Offsets_t & c_offsets)
{
size_t size = cond.size();
c_offsets.resize(size);
c_data.reserve(b_data.size());
ColumnString::Offset_t b_prev_offset = 0;
ColumnString::Offset_t c_prev_offset = 0;
for (size_t i = 0; i < size; ++i)
{
if (cond[i])
{
size_t size_to_write = a.size() + 1;
c_data.resize(c_data.size() + size_to_write);
memcpy(&c_data[c_prev_offset], a.data(), size_to_write);
c_prev_offset += size_to_write;
c_offsets[i] = c_prev_offset;
}
else
{
size_t size_to_write = b_offsets[i] - b_prev_offset;
c_data.resize(c_data.size() + size_to_write);
memcpy(&c_data[c_prev_offset], &b_data[b_prev_offset], size_to_write);
c_prev_offset += size_to_write;
c_offsets[i] = c_prev_offset;
}
b_prev_offset = b_offsets[i];
}
}
static void constant_constant(
const std::vector<UInt8> & cond,
const String & a, const String & b,
std::vector<UInt8> & c_data, ColumnString::Offsets_t & c_offsets)
{
size_t size = cond.size();
c_offsets.resize(size);
c_data.reserve((std::max(a.size(), b.size()) + 1) * size);
ColumnString::Offset_t c_prev_offset = 0;
for (size_t i = 0; i < size; ++i)
{
if (cond[i])
{
size_t size_to_write = a.size() + 1;
c_data.resize(c_data.size() + size_to_write);
memcpy(&c_data[c_prev_offset], a.data(), size_to_write);
c_prev_offset += size_to_write;
c_offsets[i] = c_prev_offset;
}
else
{
size_t size_to_write = b.size() + 1;
c_data.resize(c_data.size() + size_to_write);
memcpy(&c_data[c_prev_offset], b.data(), size_to_write);
c_prev_offset += size_to_write;
c_offsets[i] = c_prev_offset;
}
}
}
};
class FunctionIf : public IFunction
{
private:
template <typename T>
bool executeType(const ColumnVector<UInt8> * cond_col, Block & block, const ColumnNumbers & arguments, size_t result)
{
ColumnVector<T> * col_then_vec = dynamic_cast<ColumnVector<T> *>(&*block.getByPosition(arguments[1]).column);
ColumnVector<T> * col_else_vec = dynamic_cast<ColumnVector<T> *>(&*block.getByPosition(arguments[2]).column);
ColumnConst<T> * col_then_const = dynamic_cast<ColumnConst<T> *>(&*block.getByPosition(arguments[1]).column);
ColumnConst<T> * col_else_const = dynamic_cast<ColumnConst<T> *>(&*block.getByPosition(arguments[2]).column);
ColumnVector<T> * col_res = new ColumnVector<T>;
block.getByPosition(result).column = col_res;
typename ColumnVector<T>::Container_t & vec_res = col_res->getData();
vec_res.resize(block.getByPosition(arguments[0]).column->size());
if (col_then_vec && col_else_vec)
NumIfImpl<T>::vector_vector(cond_col->getData(), col_then_vec->getData(), col_else_vec->getData(), vec_res);
else if (col_then_vec && col_else_const)
NumIfImpl<T>::vector_constant(cond_col->getData(), col_then_vec->getData(), col_else_const->getData(), vec_res);
else if (col_then_const && col_else_vec)
NumIfImpl<T>::constant_vector(cond_col->getData(), col_then_const->getData(), col_else_vec->getData(), vec_res);
else if (col_then_const && col_else_const)
NumIfImpl<T>::constant_constant(cond_col->getData(), col_then_const->getData(), col_else_const->getData(), vec_res);
else
return false;
return true;
}
bool executeString(const ColumnVector<UInt8> * cond_col, Block & block, const ColumnNumbers & arguments, size_t result)
{
ColumnString * col_then = dynamic_cast<ColumnString *>(&*block.getByPosition(arguments[1]).column);
ColumnString * col_else = dynamic_cast<ColumnString *>(&*block.getByPosition(arguments[2]).column);
ColumnConstString * col_then_const = dynamic_cast<ColumnConstString *>(&*block.getByPosition(arguments[1]).column);
ColumnConstString * col_else_const = dynamic_cast<ColumnConstString *>(&*block.getByPosition(arguments[2]).column);
ColumnString * col_res = new ColumnString;
block.getByPosition(result).column = col_res;
ColumnString::Chars_t & res_vec = col_res->getChars();
ColumnString::Offsets_t & res_offsets = col_res->getOffsets();
if (col_then && col_else)
StringIfImpl::vector_vector(
cond_col->getData(),
col_then->getChars(), col_then->getOffsets(),
col_else->getChars(), col_else->getOffsets(),
res_vec, res_offsets);
else if (col_then && col_else_const)
StringIfImpl::vector_constant(
cond_col->getData(),
col_then->getChars(), col_then->getOffsets(),
col_else_const->getData(),
res_vec, res_offsets);
else if (col_then_const && col_else)
StringIfImpl::constant_vector(
cond_col->getData(),
col_then_const->getData(),
col_else->getChars(), col_else->getOffsets(),
res_vec, res_offsets);
else if (col_then_const && col_else_const)
StringIfImpl::constant_constant(
cond_col->getData(),
col_then_const->getData(),
col_else_const->getData(),
res_vec, res_offsets);
else
return false;
return true;
}
public:
/// Получить имя функции.
String getName() const
{
return "if";
}
/// Получить тип результата по типам аргументов. Если функция неприменима для данных аргументов - кинуть исключение.
DataTypePtr getReturnType(const DataTypes & arguments) const
{
if (arguments.size() != 3)
throw Exception("Number of arguments for function " + getName() + " doesn't match: passed "
+ Poco::NumberFormatter::format(arguments.size()) + ", should be 3.",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
if (!dynamic_cast<const DataTypeUInt8 *>(&*arguments[0]))
throw Exception("Illegal type of first argument (condition) of function if. Must be UInt8.",
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
if (arguments[1]->getName() != arguments[2]->getName())
throw Exception("Second and third arguments for function " + getName() + " must have same type. Passed: "
+ arguments[1]->getName() + " and " + arguments[2]->getName() + ".",
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return arguments[1];
}
/// Выполнить функцию над блоком.
void execute(Block & block, const ColumnNumbers & arguments, size_t result)
{
const ColumnVector<UInt8> * cond_col = dynamic_cast<const ColumnVector<UInt8> *>(&*block.getByPosition(arguments[0]).column);
const ColumnConst<UInt8> * cond_const_col = dynamic_cast<const ColumnConst<UInt8> *>(&*block.getByPosition(arguments[0]).column);
if (cond_const_col)
{
block.getByPosition(result).column = cond_const_col->getData()
? block.getByPosition(arguments[1]).column
: block.getByPosition(arguments[2]).column;
}
else if (cond_col)
{
if (!( executeType<UInt8>(cond_col, block, arguments, result)
|| executeType<UInt16>(cond_col, block, arguments, result)
|| executeType<UInt32>(cond_col, block, arguments, result)
|| executeType<UInt64>(cond_col, block, arguments, result)
|| executeType<Int8>(cond_col, block, arguments, result)
|| executeType<Int16>(cond_col, block, arguments, result)
|| executeType<Int32>(cond_col, block, arguments, result)
|| executeType<Int64>(cond_col, block, arguments, result)
|| executeType<Float32>(cond_col, block, arguments, result)
|| executeType<Float64>(cond_col, block, arguments, result)
|| executeString(cond_col, block, arguments, result)))
throw Exception("Illegal columns " + block.getByPosition(arguments[1]).column->getName()
+ " and " + block.getByPosition(arguments[2]).column->getName()
+ " of second (then) and third (else) arguments of function " + getName(),
ErrorCodes::ILLEGAL_COLUMN);
}
else
throw Exception("Illegal column " + cond_col->getName() + " of first argument of function " + getName() + ". Must be ColumnUInt8 or ColumnConstUInt8.",
ErrorCodes::ILLEGAL_COLUMN);
}
};
}