assimp/code/qnan.h

#if (!defined AI_QNAN_H_INCLUDED)
#define AI_QNAN_H_INCLUDED

// Data structure for a 32 Bit IEEE 754 floating-point number
union _IEEESingle
{
	float Float;
	struct
	{
		uint32_t Frac : 23;
		uint32_t Exp  : 8;
		uint32_t Sign : 1;
	} IEEE;
} ;

// ---------------------------------------------------------------------------
// check whether a float is NaN
AI_FORCE_INLINE bool is_qnan(float in)
{
	return (in != in);
}

// ---------------------------------------------------------------------------
// check whether a float is NOT NaN. 
AI_FORCE_INLINE bool is_not_qnan(float in)
{
	return (in == in);
}

// ---------------------------------------------------------------------------
// check whether a float is either NaN or (+/-) INF. Denorms return false,
// they're treated like normal values.
AI_FORCE_INLINE bool is_special_float(float in)
{
	return (((_IEEESingle*)&in)->IEEE.Exp == (1u << 8)-1);
}

#endif // !! AI_QNAN_H_INCLUDED