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AK: Make Checked<T> check for division overflow as well

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Signed integer overflow can occur with division when the RHS is -1,
as the negative values' range is one larger than the positives.
This commit is contained in:
Ali Mohammad Pur 2021-05-07 09:45:54 +04:30 • committed by Andreas Kling
commit da68c4580c
Notes: sideshowbarker 2024-07-18 18:37:25 +09:00
1 changed files with 7 additions and 0 deletions
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7
AK/Checked.h
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@ -183,6 +183,13 @@ public:
constexpr void div(T other) constexpr void div(T other)
{ {
if constexpr (IsSigned<T>) {
// Ensure that the resulting value won't be out of range, this can only happen when dividing by -1.
if (other == -1 && m_value == NumericLimits<T>::min()) {
m_overflow = true;
return;
}
}
m_value /= other; m_value /= other;
} }