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AK: Prevent overflow of the min when clamping unsigned values to signed

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Also, add some tests for the cases that were broken before.
This commit is contained in:
Zaggy1024
2024-06-19 22:04:45 -05:00
committed by Andrew Kaster
parent 172f4588a7
commit bbd8a218a5
2 changed files with 12 additions and 4 deletions
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14
AK/Math.h
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@@ -1008,11 +1008,17 @@ constexpr T pow(T x, T y)
template<Integral I, typename T>
constexpr I clamp_to(T value)
{
if (value >= static_cast<T>(NumericLimits<I>::max()))
return NumericLimits<I>::max();
constexpr auto max = static_cast<T>(NumericLimits<I>::max());
if constexpr (max > 0) {
if (value >= static_cast<T>(NumericLimits<I>::max()))
return NumericLimits<I>::max();
}
if (value <= static_cast<T>(NumericLimits<I>::min()))
return NumericLimits<I>::min();
constexpr auto min = static_cast<T>(NumericLimits<I>::min());
if constexpr (min <= 0) {
if (value <= static_cast<T>(NumericLimits<I>::min()))
return NumericLimits<I>::min();
}
if constexpr (IsFloatingPoint<T>)
return round_to<I>(value);

2
Tests/AK/TestIntegerMath.cpp
View File

@@ -119,9 +119,11 @@ TEST_CASE(ceil_log2)
TEST_CASE(clamp_to)
{
EXPECT_EQ((AK::clamp_to<i32>(1000000u)), 1000000);
EXPECT_EQ((AK::clamp_to<i32>(NumericLimits<u64>::max())), NumericLimits<i32>::max());
EXPECT_EQ((AK::clamp_to<u32>(-10)), 0u);
EXPECT_EQ((AK::clamp_to<u32>(10)), 10u);
EXPECT_EQ((AK::clamp_to<i32>(NumericLimits<i64>::min())), NumericLimits<i32>::min());
EXPECT_EQ((AK::clamp_to<i32>(NumericLimits<i64>::max())), NumericLimits<i32>::max());