ClickHouse/dbms/Functions/geohashEncode.cpp

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#include <Functions/FunctionFactory.h>
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#include <Functions/GeoHash.h>
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#include <Functions/FunctionHelpers.h>
#include <Columns/ColumnString.h>
#include <DataTypes/DataTypeString.h>
#include <string>
#define GEOHASH_MAX_TEXT_LENGTH 16
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
extern const int ILLEGAL_COLUMN;
extern const int TOO_MANY_ARGUMENTS_FOR_FUNCTION;
}
// geohashEncode(lon float32/64, lat float32/64, length UInt8) => string
class FunctionGeohashEncode : public IFunction
{
public:
static constexpr auto name = "geohashEncode";
static FunctionPtr create(const Context &) { return std::make_shared<FunctionGeohashEncode>(); }
String getName() const override
{
return name;
}
bool isVariadic() const override { return true; }
size_t getNumberOfArguments() const override { return 0; }
ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return {2}; }
bool useDefaultImplementationForConstants() const override { return true; }
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
validateArgumentType(*this, arguments, 0, isFloat, "float");
validateArgumentType(*this, arguments, 1, isFloat, "float");
if (arguments.size() == 3)
{
validateArgumentType(*this, arguments, 2, isInteger, "integer");
}
if (arguments.size() > 3)
{
throw Exception("Too many arguments for function " + getName() +
" expected at most 3",
ErrorCodes::TOO_MANY_ARGUMENTS_FOR_FUNCTION);
}
return std::make_shared<DataTypeString>();
}
template <typename LonType, typename LatType>
bool tryExecute(const IColumn * lon_column, const IColumn * lat_column, UInt64 precision_value, ColumnPtr & result)
{
const ColumnVector<LonType> * longitude = checkAndGetColumn<ColumnVector<LonType>>(lon_column);
const ColumnVector<LatType> * latitude = checkAndGetColumn<ColumnVector<LatType>>(lat_column);
if (!latitude || !longitude)
return false;
auto col_str = ColumnString::create();
ColumnString::Chars & out_vec = col_str->getChars();
ColumnString::Offsets & out_offsets = col_str->getOffsets();
const size_t size = lat_column->size();
out_offsets.resize(size);
out_vec.resize(size * (GEOHASH_MAX_TEXT_LENGTH + 1));
char * begin = reinterpret_cast<char *>(out_vec.data());
char * pos = begin;
for (size_t i = 0; i < size; ++i)
{
const Float64 longitude_value = longitude->getElement(i);
const Float64 latitude_value = latitude->getElement(i);
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const size_t encoded_size = geohashEncode(longitude_value, latitude_value, precision_value, pos);
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pos += encoded_size;
*pos = '\0';
out_offsets[i] = ++pos - begin;
}
out_vec.resize(pos - begin);
if (!out_offsets.empty() && out_offsets.back() != out_vec.size())
throw Exception("Column size mismatch (internal logical error)", ErrorCodes::LOGICAL_ERROR);
result = std::move(col_str);
return true;
}
void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/) override
{
const IColumn * longitude = block.getByPosition(arguments[0]).column.get();
const IColumn * latitude = block.getByPosition(arguments[1]).column.get();
const UInt64 precision_value = std::min<UInt64>(GEOHASH_MAX_TEXT_LENGTH,
arguments.size() == 3 ? block.getByPosition(arguments[2]).column->get64(0) : GEOHASH_MAX_TEXT_LENGTH);
ColumnPtr & res_column = block.getByPosition(result).column;
if (tryExecute<Float32, Float32>(longitude, latitude, precision_value, res_column) ||
tryExecute<Float64, Float32>(longitude, latitude, precision_value, res_column) ||
tryExecute<Float32, Float64>(longitude, latitude, precision_value, res_column) ||
tryExecute<Float64, Float64>(longitude, latitude, precision_value, res_column))
return;
std::string arguments_description;
for (size_t i = 0; i < arguments.size(); ++i)
{
if (i != 0)
arguments_description += ", ";
arguments_description += block.getByPosition(arguments[i]).column->getName();
}
throw Exception("Unsupported argument types: " + arguments_description +
+ " for function " + getName(),
ErrorCodes::ILLEGAL_COLUMN);
}
};
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void registerFunctionGeohashEncode(FunctionFactory & factory)
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{
factory.registerFunction<FunctionGeohashEncode>();
}
}