supercell-wx/wxdata/source/scwx/util/float.cpp
2022-04-08 01:34:36 -05:00

62 lines
1.2 KiB
C++

#include <scwx/util/float.hpp>
#include <cmath>
#ifdef WIN32
# include <WinSock2.h>
#else
# include <arpa/inet.h>
#endif
namespace scwx
{
namespace util
{
float DecodeFloat16(uint16_t hex)
{
static constexpr uint16_t S_MASK = 0x8000;
static constexpr uint16_t S_LSB = 0;
static constexpr uint16_t S_SHIFT = 15 - S_LSB;
static constexpr uint16_t E_MASK = 0x7a00;
static constexpr uint16_t E_LSB = 5;
static constexpr uint16_t E_SHIFT = 15 - E_LSB;
static constexpr uint16_t F_MASK = 0x03ff;
static constexpr uint16_t F_LSB = 15;
static constexpr uint16_t F_SHIFT = 15 - F_LSB;
uint16_t sHex = (hex & S_MASK) >> S_SHIFT;
uint16_t eHex = (hex & E_MASK) >> E_SHIFT;
uint16_t fHex = (hex & F_MASK) >> F_SHIFT;
float value;
float s = std::pow(-1.0f, static_cast<float>(sHex));
float e;
float f;
if (eHex == 0)
{
e = 2.0f;
f = (fHex / std::pow(2.0f, 10.0f));
}
else
{
e = std::pow(2.0f, eHex - 16.0f);
f = (1 + fHex / std::pow(2.0f, 10.0f));
}
value = s * e * f;
return value;
}
float DecodeFloat32(uint16_t msw, uint16_t lsw)
{
uint32_t value = msw << 16 | lsw;
return reinterpret_cast<float&>(value);
}
} // namespace util
} // namespace scwx