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Match x86 for every possible float value

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This commit is contained in:
Evil Eye 2025-12-02 22:01:58 +01:00
parent be73f2b019
commit 2c4559e507
1 changed files with 15 additions and 7 deletions
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22
components/esm3/variantimp.cpp
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@ -1,6 +1,7 @@
#include "variantimp.hpp"
#include <cmath>
#include <cstring>
#include <limits>
#include <sstream>
#include <stdexcept>
@ -15,11 +16,21 @@ namespace ESM
template <class T>
T floatCast(float value)
{
constexpr float min = static_cast<float>(std::numeric_limits<T>::lowest());
constexpr float max = static_cast<float>(std::numeric_limits<T>::max());
// float to int conversions for values outside T's valid range are UB. This code produces a result
// equivalent to static_cast<T>(value) on x86 without invoking UB.
constexpr double min = static_cast<double>(std::numeric_limits<int32_t>::lowest());
constexpr double max = static_cast<double>(std::numeric_limits<int32_t>::max());
constexpr uint32_t magic = 0x4fffffffu;
if (std::isnan(value) || value < min || value > max)
{
static_assert(sizeof(float) == sizeof(uint32_t));
uint32_t bits;
std::memcpy(&bits, &value, sizeof(float));
if (bits & magic)
return static_cast<T>(std::numeric_limits<int32_t>::lowest());
return {};
return static_cast<T>(value);
}
return static_cast<T>(static_cast<int32_t>(value));
}
}
@ -70,10 +81,7 @@ namespace ESM
esm.getHNT(value, "FLTV");
if (type == VT_Short)
if (std::isnan(value))
out = 0;
else
out = floatCast<int16_t>(value);
out = floatCast<int16_t>(value);
else if (type == VT_Long)
out = floatCast<int32_t>(value);
else