#ifndef INCLUDED_IEEE_FLOAT_H
#define INCLUDED_IEEE_FLOAT_H

#ifndef INCLUDED_STDINT_H
#define INCLUDED_STDINT_H
#include <stdint.h>
#endif /*INCLUDED_STDINT_H*/

#ifndef INCLUDED_FLOAT_H
#define INCLUDED_FLOAT_H
#include <float.h>
#endif /*INCLUDED_FLOAT_H*/

#ifndef INCLUDED_STDBOOL_H
#define INCLUDED_STDBOOL_H
#include <stdbool.h>
#endif /*INCLUDED_STDBOOL_H*/


/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

typedef struct {
    union{
        struct{
            uint32_t sign:1;
            uint32_t exponent:8;
            uint32_t mantissa:23;
        }IEEE754;
        uint32_t uint;
        float f;
    }value;
}ieee_float_t;

typedef struct {
    union{
        struct{
            uint64_t sign:1;
            uint64_t exponent:11;
            uint64_t mantissa:52;
        }IEEE754;
        uint64_t uint;
        double f;
    }value;
}ieee_double_t;

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

#define IEEE_FLOAT_POSITIVE_INFINITY    (1.0f/0.0f)
#define IEEE_FLOAT_NEGATIVE_INFINITY    (-1.0f/0.0f)
#define IEEE_FLOAT_NAN                  (0.0f/0.0f)

#define IEEE_FLOAT_EPSILON              (FLT_EPSILON)
#define IEEE_DOUBLE_EPSILON             (DBL_EPSILON)

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

int ieee_float_cmp(const float a, const float b, const float maxDiff);
int ieee_double_cmp(const double a, const double b, const double maxDiff);

// 当将 float 看作 uint32 时进行比较，maxUlpsDiff 就是作为无符号整数允许的最大差异,一般取 `1` 就可以
// maxFloatDiff 一般取 IEEE_FLOAT_EPSILON, 是将数值作为 float 进行比较，但是如果两个 float 无法完成比较，就可以通过
// 无符号整数的形式来进行比较
int ieee_float_UlpsCmp(const float a, const float b, const float maxFloatDiff, const int maxUlpsDiff);
int ieee_double_UlpsCmp(const double a, const double b, const double maxFloatDiff, const int maxUlpsDiff);

bool ieee_float_is_zero(const float a, const float maxDiff);
bool ieee_double_is_zero(const double a, const double maxDiff);

#endif /*INCLUDED_IEEE_FLOAT_H*/