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AK: Use correct type when calculating integral exp2()

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Previously, integral `exp2()` would produce the incorrect result for
exponents above 31.
This commit is contained in:
Tim Ledbetter 2023-10-27 22:02:18 +01:00 • committed by Tim Flynn
parent 810bbeaed1
commit e4715aa82a
2 changed files with 19 additions and 1 deletions
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2
AK/IntegralMath.h
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@ -15,7 +15,7 @@ namespace AK {
template<Integral T> template<Integral T>
constexpr T exp2(T exponent) constexpr T exp2(T exponent)
{ {
return 1u << exponent; return static_cast<T>(1) << exponent;
} }
template<Integral T> template<Integral T>

18
Tests/AK/TestIntegerMath.cpp
View file

@ -36,3 +36,21 @@ TEST_CASE(is_power_of)
check_prime.operator()<97>(9); check_prime.operator()<97>(9);
check_prime.operator()<257>(7); check_prime.operator()<257>(7);
} }
TEST_CASE(exp2)
{
EXPECT_EQ(AK::exp2<u64>(0), 1ull);
EXPECT_EQ(AK::exp2<u64>(1), 2ull);
EXPECT_EQ(AK::exp2<i8>(6), 64);
EXPECT_EQ(AK::exp2<u8>(7), 128);
EXPECT_EQ(AK::exp2<u16>(9), 512);
EXPECT_EQ(AK::exp2<i16>(14), 16384);
EXPECT_EQ(AK::exp2<u16>(15), 32768);
EXPECT_EQ(AK::exp2<u32>(17), 131072u);
EXPECT_EQ(AK::exp2<i32>(30), 1073741824);
EXPECT_EQ(AK::exp2<u32>(31), 2147483648);
EXPECT_EQ(AK::exp2<i64>(32), 4294967296);
EXPECT_EQ(AK::exp2<u64>(33), 8589934592ull);
EXPECT_EQ(AK::exp2<i64>(62), 4611686018427387904);
EXPECT_EQ(AK::exp2<u64>(63), 9223372036854775808ull);
}