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

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2012-07-15 21:43:04 +00:00
#pragma once
#include <openssl/md5.h>
#include <city.h>
#include <Poco/ByteOrder.h>
#include <DB/DataTypes/DataTypesNumberFixed.h>
#include <DB/DataTypes/DataTypeString.h>
#include <DB/DataTypes/DataTypeDate.h>
#include <DB/DataTypes/DataTypeDateTime.h>
#include <DB/Columns/ColumnString.h>
#include <DB/Columns/ColumnConst.h>
#include <DB/Functions/IFunction.h>
#include <stats/IntHash.h>
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namespace DB
{
/** Функции хэширования.
*
* Половинка MD5:
* halfMD5: String -> UInt64
*
* Быстрая некриптографическая хэш функция для строк:
* cityHash64: String -> UInt64
*
* Быстрая некриптографическая хэш функция от любого целого числа:
* intHash32: number -> UInt32
*/
struct HalfMD5Impl
{
static UInt64 apply(const char * begin, size_t size)
{
union
{
unsigned char char_data[16];
Poco::UInt64 uint64_data;
} buf;
MD5_CTX ctx;
MD5_Init(&ctx);
MD5_Update(&ctx, reinterpret_cast<const unsigned char *>(begin), size);
MD5_Final(buf.char_data, &ctx);
return Poco::ByteOrder::flipBytes(buf.uint64_data); /// Совместимость с существующим кодом.
}
};
struct CityHash64Impl
{
static UInt64 apply(const char * begin, size_t size)
{
return CityHash64(begin, size);
}
};
struct IntHash32Impl
{
typedef UInt32 ReturnType;
static UInt32 apply(UInt64 x)
{
/// seed взят из /dev/urandom.
return intHash32<0x75D9543DE018BF45ULL>(x);
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}
};
template <typename Impl, typename Name>
class FunctionStringHash64 : public IFunction
{
public:
/// Получить имя функции.
String getName() const
{
return Name::get();
}
/// Получить тип результата по типам аргументов. Если функция неприменима для данных аргументов - кинуть исключение.
DataTypePtr getReturnType(const DataTypes & arguments) const
{
if (arguments.size() != 1)
throw Exception("Number of arguments for function " + getName() + " doesn't match: passed "
+ Poco::NumberFormatter::format(arguments.size()) + ", should be 1.",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
if (!dynamic_cast<const DataTypeString *>(&*arguments[0]))
throw Exception("Illegal type " + arguments[0]->getName() + " of argument of function " + getName(),
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return new DataTypeUInt64;
}
/// Выполнить функцию над блоком.
void execute(Block & block, const ColumnNumbers & arguments, size_t result)
{
if (const ColumnString * col_from = dynamic_cast<const ColumnString *>(&*block.getByPosition(arguments[0]).column))
{
ColumnUInt64 * col_to = new ColumnUInt64;
block.getByPosition(result).column = col_to;
const typename ColumnString::Chars_t & data = col_from->getChars();
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const typename ColumnString::Offsets_t & offsets = col_from->getOffsets();
typename ColumnUInt64::Container_t & vec_to = col_to->getData();
size_t size = offsets.size();
vec_to.resize(size);
for (size_t i = 0; i < size; ++i)
vec_to[i] = Impl::apply(
reinterpret_cast<const char *>(&data[i == 0 ? 0 : offsets[i - 1]]),
i == 0 ? offsets[i] - 1 : (offsets[i] - 1 - offsets[i - 1]));
}
else if (const ColumnConstString * col_from = dynamic_cast<const ColumnConstString *>(&*block.getByPosition(arguments[0]).column))
{
block.getByPosition(result).column = new ColumnConstUInt64(
col_from->size(),
Impl::apply(col_from->getData().data(), col_from->getData().size()));
}
else
throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
+ " of first argument of function " + Name::get(),
ErrorCodes::ILLEGAL_COLUMN);
}
};
template <typename Impl, typename Name>
class FunctionIntHash : public IFunction
{
private:
typedef typename Impl::ReturnType ToType;
template <typename FromType>
void executeType(Block & block, const ColumnNumbers & arguments, size_t result)
{
if (ColumnVector<FromType> * col_from = dynamic_cast<ColumnVector<FromType> *>(&*block.getByPosition(arguments[0]).column))
{
ColumnVector<ToType> * col_to = new ColumnVector<ToType>;
block.getByPosition(result).column = col_to;
const typename ColumnVector<FromType>::Container_t & vec_from = col_from->getData();
typename ColumnVector<ToType>::Container_t & vec_to = col_to->getData();
size_t size = vec_from.size();
vec_to.resize(size);
for (size_t i = 0; i < size; ++i)
vec_to[i] = Impl::apply(vec_from[i]);
}
else if (ColumnConst<FromType> * col_from = dynamic_cast<ColumnConst<FromType> *>(&*block.getByPosition(arguments[0]).column))
{
block.getByPosition(result).column = new ColumnConst<ToType>(col_from->size(), Impl::apply(col_from->getData()));
}
else
throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
+ " of first argument of function " + Name::get(),
ErrorCodes::ILLEGAL_COLUMN);
}
public:
/// Получить имя функции.
String getName() const
{
return Name::get();
}
/// Получить тип результата по типам аргументов. Если функция неприменима для данных аргументов - кинуть исключение.
DataTypePtr getReturnType(const DataTypes & arguments) const
{
if (arguments.size() != 1)
throw Exception("Number of arguments for function " + getName() + " doesn't match: passed "
+ Poco::NumberFormatter::format(arguments.size()) + ", should be 1.",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
if (!arguments[0]->isNumeric())
throw Exception("Illegal type " + arguments[0]->getName() + " of argument of function " + getName(),
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return new typename DataTypeFromFieldType<typename Impl::ReturnType>::Type;
}
/// Выполнить функцию над блоком.
void execute(Block & block, const ColumnNumbers & arguments, size_t result)
{
IDataType * from_type = &*block.getByPosition(arguments[0]).type;
if (dynamic_cast<const DataTypeUInt8 * >(from_type)) executeType<UInt8 >(block, arguments, result);
else if (dynamic_cast<const DataTypeUInt16 * >(from_type)) executeType<UInt16>(block, arguments, result);
else if (dynamic_cast<const DataTypeUInt32 * >(from_type)) executeType<UInt32>(block, arguments, result);
else if (dynamic_cast<const DataTypeUInt64 * >(from_type)) executeType<UInt64>(block, arguments, result);
else if (dynamic_cast<const DataTypeInt8 * >(from_type)) executeType<Int8 >(block, arguments, result);
else if (dynamic_cast<const DataTypeInt16 * >(from_type)) executeType<Int16 >(block, arguments, result);
else if (dynamic_cast<const DataTypeInt32 * >(from_type)) executeType<Int32 >(block, arguments, result);
else if (dynamic_cast<const DataTypeInt64 * >(from_type)) executeType<Int64 >(block, arguments, result);
else if (dynamic_cast<const DataTypeDate * >(from_type)) executeType<UInt16>(block, arguments, result);
else if (dynamic_cast<const DataTypeDateTime * >(from_type)) executeType<UInt32>(block, arguments, result);
else
throw Exception("Illegal type " + block.getByPosition(arguments[0]).type->getName() + " of argument of function " + getName(),
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
}
};
struct NameHalfMD5 { static const char * get() { return "halfMD5"; } };
struct NameCityHash64 { static const char * get() { return "cityHash64"; } };
struct NameIntHash32 { static const char * get() { return "intHash32"; } };
typedef FunctionStringHash64<HalfMD5Impl, NameHalfMD5> FunctionHalfMD5;
typedef FunctionStringHash64<CityHash64Impl, NameCityHash64> FunctionCityHash64;
typedef FunctionIntHash<IntHash32Impl, NameIntHash32> FunctionIntHash32;
}