mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-25 00:52:02 +00:00
113 lines
3.4 KiB
C++
113 lines
3.4 KiB
C++
#include <Functions/FunctionFactory.h>
|
|
#include <Functions/FunctionUnaryArithmetic.h>
|
|
#include <DataTypes/NumberTraits.h>
|
|
#include <Common/FieldVisitorConvertToNumber.h>
|
|
|
|
namespace DB
|
|
{
|
|
|
|
namespace ErrorCodes
|
|
{
|
|
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
|
|
extern const int BAD_ARGUMENTS;
|
|
}
|
|
|
|
template <typename A>
|
|
struct FactorialImpl
|
|
{
|
|
using ResultType = UInt64;
|
|
static const constexpr bool allow_decimal = false;
|
|
static const constexpr bool allow_string_or_fixed_string = false;
|
|
|
|
static NO_SANITIZE_UNDEFINED ResultType apply(A a)
|
|
{
|
|
if constexpr (is_floating_point<A> || is_over_big_int<A>)
|
|
throw Exception(
|
|
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
|
|
"Illegal type of argument of function factorial, should not be floating point or big int");
|
|
|
|
if constexpr (is_integer<A>)
|
|
{
|
|
if (a > 20)
|
|
throw Exception(ErrorCodes::BAD_ARGUMENTS, "The maximum value for the input argument of function factorial is 20");
|
|
|
|
if constexpr (is_unsigned_v<A>)
|
|
return factorials[a];
|
|
else if constexpr (is_signed_v<A>)
|
|
return a >= 0 ? factorials[a] : 1;
|
|
}
|
|
}
|
|
|
|
#if USE_EMBEDDED_COMPILER
|
|
static constexpr bool compilable = false; /// special type handling, some other time
|
|
#endif
|
|
|
|
private:
|
|
static const constexpr ResultType factorials[21]
|
|
= {1,
|
|
1,
|
|
2,
|
|
6,
|
|
24,
|
|
120,
|
|
720,
|
|
5040,
|
|
40320,
|
|
362880,
|
|
3628800,
|
|
39916800,
|
|
479001600,
|
|
6227020800L,
|
|
87178291200L,
|
|
1307674368000L,
|
|
20922789888000L,
|
|
355687428096000L,
|
|
6402373705728000L,
|
|
121645100408832000L,
|
|
2432902008176640000L};
|
|
};
|
|
|
|
struct NameFactorial { static constexpr auto name = "factorial"; };
|
|
using FunctionFactorial = FunctionUnaryArithmetic<FactorialImpl, NameFactorial, false>;
|
|
|
|
template <> struct FunctionUnaryArithmeticMonotonicity<NameFactorial>
|
|
{
|
|
static bool has() { return true; }
|
|
|
|
static IFunction::Monotonicity get(const Field & left, const Field & right)
|
|
{
|
|
bool is_strict = false;
|
|
if (!left.isNull() && !right.isNull())
|
|
{
|
|
auto left_value = applyVisitor(FieldVisitorConvertToNumber<Int128>(), left);
|
|
auto right_value = applyVisitor(FieldVisitorConvertToNumber<Int128>(), left);
|
|
if (1 <= left_value && left_value <= right_value && right_value <= 20)
|
|
is_strict = true;
|
|
}
|
|
|
|
return {
|
|
.is_monotonic = true,
|
|
.is_positive = true,
|
|
.is_always_monotonic = true,
|
|
.is_strict = is_strict,
|
|
};
|
|
}
|
|
};
|
|
|
|
|
|
REGISTER_FUNCTION(Factorial)
|
|
{
|
|
factory.registerFunction<FunctionFactorial>(FunctionDocumentation
|
|
{
|
|
.description=R"(
|
|
Computes the factorial of an integer value. It works with any native integer type including UInt(8|16|32|64) and Int(8|16|32|64). The return type is UInt64.
|
|
|
|
The factorial of 0 is 1. Likewise, the factorial() function returns 1 for any negative value. The maximum positive value for the input argument is 20, a value of 21 or greater will cause exception throw.
|
|
)",
|
|
.examples{{"factorial", "SELECT factorial(10)", ""}},
|
|
.categories{"Mathematical"}},
|
|
FunctionFactory::Case::Insensitive);
|
|
}
|
|
|
|
}
|