ClickHouse/libs/libcommon/include/common/arithmeticOverflow.h
Alexey Milovidov 14e1dfa0ea Fixed UB #3926
2018-12-26 08:11:53 +03:00

107 lines
2.8 KiB
C++

#pragma once
namespace common
{
template <typename T>
inline bool addOverflow(T x, T y, T & res)
{
return __builtin_add_overflow(x, y, &res);
}
template <>
inline bool addOverflow(int x, int y, int & res)
{
return __builtin_sadd_overflow(x, y, &res);
}
template <>
inline bool addOverflow(long x, long y, long & res)
{
return __builtin_saddl_overflow(x, y, &res);
}
template <>
inline bool addOverflow(long long x, long long y, long long & res)
{
return __builtin_saddll_overflow(x, y, &res);
}
template <>
inline bool addOverflow(__int128 x, __int128 y, __int128 & res)
{
static constexpr __int128 min_int128 = __int128(0x8000000000000000ll) << 64;
static constexpr __int128 max_int128 = (__int128(0x7fffffffffffffffll) << 64) + 0xffffffffffffffffll;
res = x + y;
return (y > 0 && x > max_int128 - y) || (y < 0 && x < min_int128 - y);
}
template <typename T>
inline bool subOverflow(T x, T y, T & res)
{
return __builtin_sub_overflow(x, y, &res);
}
template <>
inline bool subOverflow(int x, int y, int & res)
{
return __builtin_ssub_overflow(x, y, &res);
}
template <>
inline bool subOverflow(long x, long y, long & res)
{
return __builtin_ssubl_overflow(x, y, &res);
}
template <>
inline bool subOverflow(long long x, long long y, long long & res)
{
return __builtin_ssubll_overflow(x, y, &res);
}
template <>
inline bool subOverflow(__int128 x, __int128 y, __int128 & res)
{
static constexpr __int128 min_int128 = __int128(0x8000000000000000ll) << 64;
static constexpr __int128 max_int128 = (__int128(0x7fffffffffffffffll) << 64) + 0xffffffffffffffffll;
res = x - y;
return (y < 0 && x > max_int128 + y) || (y > 0 && x < min_int128 + y);
}
template <typename T>
inline bool mulOverflow(T x, T y, T & res)
{
return __builtin_mul_overflow(x, y, &res);
}
template <>
inline bool mulOverflow(int x, int y, int & res)
{
return __builtin_smul_overflow(x, y, &res);
}
template <>
inline bool mulOverflow(long x, long y, long & res)
{
return __builtin_smull_overflow(x, y, &res);
}
template <>
inline bool mulOverflow(long long x, long long y, long long & res)
{
return __builtin_smulll_overflow(x, y, &res);
}
template <>
inline bool mulOverflow(__int128 x, __int128 y, __int128 & res)
{
res = static_cast<unsigned __int128>(x) * static_cast<unsigned __int128>(y); /// Avoid signed integer overflow.
if (!x || !y)
return false;
unsigned __int128 a = (x > 0) ? x : -x;
unsigned __int128 b = (y > 0) ? y : -y;
return (a * b) / b != a;
}
}