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BAN: Implement will_{addition,multiplication}_overflow

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Bananymous
2024-06-14 11:04:29 +03:00
parent ea7fc7f6c4
commit 05e9d76c77
2 changed files with 25 additions and 24 deletions
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27
libc/stdlib.cpp
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@@ -64,35 +64,14 @@ static constexpr int get_base_digit(char c, int base)
return -1;
}
template<BAN::integral T>
static constexpr bool will_multiplication_overflow(T a, T b)
{
if (a == 0 || b == 0)
return false;
if ((a > 0) == (b > 0))
return a > BAN::numeric_limits<T>::max() / b;
else
return a < BAN::numeric_limits<T>::min() / b;
}
template<BAN::integral T>
static constexpr bool will_addition_overflow(T a, T b)
{
if (a > 0 && b > 0)
return a > BAN::numeric_limits<T>::max() - b;
if (a < 0 && b < 0)
return a < BAN::numeric_limits<T>::min() - b;
return false;
}
template<BAN::integral T>
static constexpr bool will_digit_append_overflow(bool negative, T current, int digit, int base)
{
if (BAN::is_unsigned_v<T> && negative && digit)
return true;
if (will_multiplication_overflow<T>(current, base))
if (BAN::Math::will_multiplication_overflow<T>(current, base))
return true;
if (will_addition_overflow<T>(current * base, current < 0 ? -digit : digit))
if (BAN::Math::will_addition_overflow<T>(current * base, current < 0 ? -digit : digit))
return true;
return false;
}
@@ -286,7 +265,7 @@ static T strtoT(const char* str, char** endp, int& error)
int extra_exponent = strtoT<int>(str + 1, &maybe_end, 10, exp_error);
if (exp_error != EINVAL)
{
if (exp_error == ERANGE || will_addition_overflow(exponent, extra_exponent))
if (exp_error == ERANGE || BAN::Math::will_addition_overflow(exponent, extra_exponent))
exponent = negative ? BAN::numeric_limits<int>::min() : BAN::numeric_limits<int>::max();
else
exponent += extra_exponent;