From 813742e5d736f1bdc04586524451b0c5660a244e Mon Sep 17 00:00:00 2001
From: Andrey Mironov <hertz@yandex-team.ru>
Date: Fri, 21 Nov 2014 17:28:39 +0300
Subject: [PATCH] dbms: add intDivOrZero function. [#METR-13159]

---
 .../DB/Functions/FunctionsArithmetic.h        | 30 +++++++++++++++++++
 dbms/src/Functions/FunctionsArithmetic.cpp    |  1 +
 .../00081_int_div_or_zero.reference           |  5 ++++
 .../0_stateless/00081_int_div_or_zero.sql     |  5 ++++
 4 files changed, 41 insertions(+)
 create mode 100644 dbms/tests/queries/0_stateless/00081_int_div_or_zero.reference
 create mode 100644 dbms/tests/queries/0_stateless/00081_int_div_or_zero.sql

diff --git a/dbms/include/DB/Functions/FunctionsArithmetic.h b/dbms/include/DB/Functions/FunctionsArithmetic.h
index 72dcf215602..9fd2d7856dc 100644
--- a/dbms/include/DB/Functions/FunctionsArithmetic.h
+++ b/dbms/include/DB/Functions/FunctionsArithmetic.h
@@ -139,6 +139,22 @@ inline void throwIfDivisionLeadsToFPE(A a, B b)
 		throw Exception("Division of minimal signed number by minus one", ErrorCodes::ILLEGAL_DIVISION);
 }
 
+template <typename A, typename B>
+inline bool divisionLeadsToFPE(A a, B b)
+{
+	/// Возможно, лучше вместо проверок использовать siglongjmp?
+
+	if (unlikely(b == 0))
+		return true;
+
+	/// http://avva.livejournal.com/2548306.html
+	if (unlikely(std::is_signed<A>::value && std::is_signed<B>::value && a == std::numeric_limits<A>::min() && b == -1))
+		return true;
+
+	return false;
+}
+
+
 #pragma GCC diagnostic pop
 
 
@@ -155,6 +171,18 @@ struct DivideIntegralImpl
 	}
 };
 
+template<typename A, typename B>
+struct DivideIntegralOrZeroImpl
+{
+	typedef typename NumberTraits::ResultOfIntegerDivision<A, B>::Type ResultType;
+
+	template <typename Result = ResultType>
+	static inline Result apply(A a, B b)
+	{
+		return unlikely(divisionLeadsToFPE(a, b)) ? 0 : static_cast<Result>(a) / b;
+	}
+};
+
 template<typename A, typename B>
 struct ModuloImpl
 {
@@ -752,6 +780,7 @@ struct NameMinus 			{ static constexpr auto name = "minus"; };
 struct NameMultiply 		{ static constexpr auto name = "multiply"; };
 struct NameDivideFloating	{ static constexpr auto name = "divide"; };
 struct NameDivideIntegral	{ static constexpr auto name = "intDiv"; };
+struct NameDivideIntegralOrZero	{ static constexpr auto name = "intDivOrZero"; };
 struct NameModulo			{ static constexpr auto name = "modulo"; };
 struct NameNegate			{ static constexpr auto name = "negate"; };
 struct NameBitAnd			{ static constexpr auto name = "bitAnd"; };
@@ -766,6 +795,7 @@ typedef FunctionBinaryArithmetic<MinusImpl, 			NameMinus> 				FunctionMinus;
 typedef FunctionBinaryArithmetic<MultiplyImpl,			NameMultiply> 			FunctionMultiply;
 typedef FunctionBinaryArithmetic<DivideFloatingImpl, 	NameDivideFloating>	 	FunctionDivideFloating;
 typedef FunctionBinaryArithmetic<DivideIntegralImpl, 	NameDivideIntegral> 	FunctionDivideIntegral;
+typedef FunctionBinaryArithmetic<DivideIntegralOrZeroImpl, 	NameDivideIntegralOrZero> 	FunctionDivideIntegralOrZero;
 typedef FunctionBinaryArithmetic<ModuloImpl, 			NameModulo> 			FunctionModulo;
 typedef FunctionUnaryArithmetic<NegateImpl, 			NameNegate> 			FunctionNegate;
 typedef FunctionBinaryArithmetic<BitAndImpl,			NameBitAnd> 			FunctionBitAnd;
diff --git a/dbms/src/Functions/FunctionsArithmetic.cpp b/dbms/src/Functions/FunctionsArithmetic.cpp
index b515273a197..dab8dc242eb 100644
--- a/dbms/src/Functions/FunctionsArithmetic.cpp
+++ b/dbms/src/Functions/FunctionsArithmetic.cpp
@@ -11,6 +11,7 @@ void registerFunctionsArithmetic(FunctionFactory & factory)
 	factory.registerFunction<FunctionMultiply>();
 	factory.registerFunction<FunctionDivideFloating>();
 	factory.registerFunction<FunctionDivideIntegral>();
+	factory.registerFunction<FunctionDivideIntegralOrZero>();
 	factory.registerFunction<FunctionModulo>();
 	factory.registerFunction<FunctionNegate>();
 	factory.registerFunction<FunctionBitAnd>();
diff --git a/dbms/tests/queries/0_stateless/00081_int_div_or_zero.reference b/dbms/tests/queries/0_stateless/00081_int_div_or_zero.reference
new file mode 100644
index 00000000000..627e1097cda
--- /dev/null
+++ b/dbms/tests/queries/0_stateless/00081_int_div_or_zero.reference
@@ -0,0 +1,5 @@
+1
+1
+1
+1
+1
diff --git a/dbms/tests/queries/0_stateless/00081_int_div_or_zero.sql b/dbms/tests/queries/0_stateless/00081_int_div_or_zero.sql
new file mode 100644
index 00000000000..204cac83ba4
--- /dev/null
+++ b/dbms/tests/queries/0_stateless/00081_int_div_or_zero.sql
@@ -0,0 +1,5 @@
+select intDivOrZero(0, 0) = 0;
+select intDivOrZero(-128, -1) = 0;
+select intDivOrZero(-127, -1) = 127;
+select intDivOrZero(1, 1) = 1;
+select intDivOrZero(4, 2) = 2;