ClickHouse/dbms/src/Functions/bar.cpp
2019-12-29 04:14:21 +03:00

171 lines
6.3 KiB
C++

#include <Functions/IFunctionImpl.h>
#include <Functions/FunctionHelpers.h>
#include <Functions/FunctionFactory.h>
#include <DataTypes/DataTypeString.h>
#include <Columns/ColumnString.h>
#include <Columns/ColumnVector.h>
#include <Common/UnicodeBar.h>
#include <Common/FieldVisitors.h>
#include <IO/WriteHelpers.h>
namespace DB
{
namespace ErrorCodes
{
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
extern const int ARGUMENT_OUT_OF_BOUND;
extern const int ILLEGAL_COLUMN;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
/** bar(x, min, max, width) - draws a strip from the number of characters proportional to (x - min) and equal to width for x == max.
* Returns a string with nice Unicode-art bar with resolution of 1/8 part of symbol.
*/
class FunctionBar : public IFunction
{
public:
static constexpr auto name = "bar";
static FunctionPtr create(const Context &)
{
return std::make_shared<FunctionBar>();
}
String getName() const override
{
return name;
}
bool isVariadic() const override
{
return true;
}
size_t getNumberOfArguments() const override
{
return 0;
}
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
if (arguments.size() != 3 && arguments.size() != 4)
throw Exception("Function " + getName()
+ " requires from 3 or 4 parameters: value, min_value, max_value, [max_width_of_bar = 80]. Passed "
+ toString(arguments.size())
+ ".",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
if (!isNativeNumber(arguments[0]) || !isNativeNumber(arguments[1]) || !isNativeNumber(arguments[2])
|| (arguments.size() == 4 && !isNativeNumber(arguments[3])))
throw Exception("All arguments for function " + getName() + " must be numeric.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return std::make_shared<DataTypeString>();
}
bool useDefaultImplementationForConstants() const override { return true; }
ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return {1, 2, 3}; }
void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/) override
{
Int64 min = extractConstant<Int64>(block, arguments, 1, "Second"); /// The level at which the line has zero length.
Int64 max = extractConstant<Int64>(block, arguments, 2, "Third"); /// The level at which the line has the maximum length.
/// The maximum width of the bar in characters, by default.
Float64 max_width = arguments.size() == 4 ? extractConstant<Float64>(block, arguments, 3, "Fourth") : 80;
if (max_width < 1)
throw Exception("Max_width argument must be >= 1.", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
if (max_width > 1000)
throw Exception("Too large max_width.", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
const auto & src = *block.getByPosition(arguments[0]).column;
auto res_column = ColumnString::create();
if (executeNumber<UInt8>(src, *res_column, min, max, max_width)
|| executeNumber<UInt16>(src, *res_column, min, max, max_width)
|| executeNumber<UInt32>(src, *res_column, min, max, max_width)
|| executeNumber<UInt64>(src, *res_column, min, max, max_width)
|| executeNumber<Int8>(src, *res_column, min, max, max_width)
|| executeNumber<Int16>(src, *res_column, min, max, max_width)
|| executeNumber<Int32>(src, *res_column, min, max, max_width)
|| executeNumber<Int64>(src, *res_column, min, max, max_width)
|| executeNumber<Float32>(src, *res_column, min, max, max_width)
|| executeNumber<Float64>(src, *res_column, min, max, max_width))
{
block.getByPosition(result).column = std::move(res_column);
}
else
throw Exception(
"Illegal column " + block.getByPosition(arguments[0]).column->getName() + " of argument of function " + getName(),
ErrorCodes::ILLEGAL_COLUMN);
}
private:
template <typename T>
T extractConstant(Block & block, const ColumnNumbers & arguments, size_t argument_pos, const char * which_argument) const
{
const auto & column = *block.getByPosition(arguments[argument_pos]).column;
if (!isColumnConst(column))
throw Exception(
which_argument + String(" argument for function ") + getName() + " must be constant.", ErrorCodes::ILLEGAL_COLUMN);
return applyVisitor(FieldVisitorConvertToNumber<T>(), column[0]);
}
template <typename T>
static void fill(const PaddedPODArray<T> & src,
ColumnString::Chars & dst_chars,
ColumnString::Offsets & dst_offsets,
Int64 min,
Int64 max,
Float64 max_width)
{
size_t size = src.size();
size_t current_offset = 0;
dst_offsets.resize(size);
dst_chars.reserve(size * (UnicodeBar::getWidthInBytes(max_width) + 1)); /// lines 0-terminated.
for (size_t i = 0; i < size; ++i)
{
Float64 width = UnicodeBar::getWidth(src[i], min, max, max_width);
size_t next_size = current_offset + UnicodeBar::getWidthInBytes(width) + 1;
dst_chars.resize(next_size);
UnicodeBar::render(width, reinterpret_cast<char *>(&dst_chars[current_offset]));
current_offset = next_size;
dst_offsets[i] = current_offset;
}
}
template <typename T>
static void fill(T src, String & dst_chars, Int64 min, Int64 max, Float64 max_width)
{
Float64 width = UnicodeBar::getWidth(src, min, max, max_width);
dst_chars.resize(UnicodeBar::getWidthInBytes(width));
UnicodeBar::render(width, dst_chars.data());
}
template <typename T>
static bool executeNumber(const IColumn & src, ColumnString & dst, Int64 min, Int64 max, Float64 max_width)
{
if (const ColumnVector<T> * col = checkAndGetColumn<ColumnVector<T>>(&src))
{
fill(col->getData(), dst.getChars(), dst.getOffsets(), min, max, max_width);
return true;
}
else
return false;
}
};
void registerFunctionBar(FunctionFactory & factory)
{
factory.registerFunction<FunctionBar>();
}
}