source: cpp/common/nonstd_math.h

// This file is a part of Framsticks SDK.  http://www.framsticks.com/
// Copyright (C) 1999-2024  Maciej Komosinski and Szymon Ulatowski.
// See LICENSE.txt for details.

#ifndef _NONSTD_MATH_H_
#define _NONSTD_MATH_H_


#ifdef _MSC_VER
 #define _USE_MATH_DEFINES //after this is defined, the next #include <math.h> or <cmath> will define M_PI etc.
 #include <math.h> //in vc2008, <cmath> worked here, but no longer in vc2010 because "something" (some other .h from stl?) earlier includes <cmath> without _USE_MATH_DEFINES, and <cmath> includes <math.h> (just once because it has "include guards" like any other .h)
 #include <float.h>
 //#define isnan(x) _isnan(x) //since 2014 we use std::isnan()
 #define finite(x) _finite(x)
#else //e.g. __BORLANDC__
 #include <math.h>
#endif



//random number generator:
#include "random.h"
RandomGenerator &rndGetInstance();

inline double rndDouble(double limit_exclusive) { return rndGetInstance().getDouble() * limit_exclusive; }
inline unsigned int rndUint(unsigned int limit_exclusive) { return (unsigned int)(rndGetInstance().getDouble() * limit_exclusive); } //returns random from 0..limit_exclusive-1
inline unsigned int rndUint(size_t limit_exclusive) {return rndUint((unsigned int)limit_exclusive);} //just an overload with size_t argument
unsigned int rndUint(int limit_exclusive); //just an overload with int argument
inline void rndSetSeed(unsigned int seed) { rndGetInstance().setSeed(seed); }
inline unsigned int rndRandomizeSeed() { return rndGetInstance().randomize(); }



// precision==-1 for full precision, or positive values for the number of digits to print past the decimal point.
// Allocated buffer with bufferlen=30 is OK.
// Returns the number of chars actually used (not including the ending 0).
int doubleToString(double x, int precision, char *buffer, int bufferlen);

#include <string>
std::string doubleToString(double x, int precision);
double round(const double x, const int precision);
static inline void clipNegativeZeroIfNeeded(double& value, const double range_low)
{
        if (value == 0.0 && range_low == 0.0) // if we have range_low==0.0 and we get value==-0.0 (which is ==0.0)
                value = 0.0; //turn -0.0 to 0.0 so that it does not look like exceeding the allowed range (even though -0.0==0.0). This code unnecessarily also "overwrites" value==0.0 with 0.0, but it is faster and simpler than additionally checking std::signbit(value) just to distinguish -0.0 from 0.0.
        //these conditions are not intended for range_low==-0.0, as we assume nobody would define allowed ranges using -0.0.
}





//floating point specific numbers
#include "stdlib.h"

#ifdef __BORLANDC__
        #include <float.h>
        #define isnan(x) _isnan(x) //http://stackoverflow.com/questions/570669/checking-if-a-double-or-float-is-nan-in-c
        #define finite(x) _finite(x)
#endif

#ifdef LINUX
  #define _isnan(a) isnan(a)
#endif

#ifdef IPHONE
        #define finite(x) (!isinf(x))
  #define _isnan(a) isnan(a)
#endif


#if defined SHP
 //#define __assert_func(a,b,c,d) 0 //Currently, we are sorry to inform you that assert() is not yet supported. We have considered your request for internal discussion. Na szcz�cie jest w�asna (byle by by�a, bo i tak zak�adamy ze assert ktore przeciez dziala tylko w trybie debug nie jest potrzebne na bada) implementacja w "bada-assert.cpp"
 #define isnan(x) false //isnan() sie nie linkuje
 #define finite(x) true //j.w.
 //#include <cstdlib> //RAND_MAX defined incorrectly
 //#ifdef BADA_SIMULATOR //...but only in simulator libs
 // #undef RAND_MAX
 // #define RAND_MAX 32768 //...this is the actual value used by rand()
 //#endif
#endif

#if defined LINUX || defined TIZEN || defined __ANDROID__
#include <fenv.h>
#endif

namespace fpExcept
{
//handling floating point exceptions
#if defined LINUX || defined TIZEN || defined __ANDROID__
        //fenv.h values
        static constexpr unsigned int FPEX_DIV0 = FE_DIVBYZERO;
        static constexpr unsigned int FPEX_INVALID = FE_INVALID;
        static constexpr unsigned int FPEX_OVERFLOW = FE_OVERFLOW;
#elif defined IPHONE
        // (not implemented but these constants are still needed)
        static constexpr unsigned int FPEX_DIV0 = 0;
        static constexpr unsigned int FPEX_INVALID = 0;
        static constexpr unsigned int FPEX_OVERFLOW = 0;
#else
        //_control87() values
        static constexpr unsigned int FPEX_DIV0 = EM_ZERODIVIDE;
        static constexpr unsigned int FPEX_INVALID = EM_INVALID;
        static constexpr unsigned int FPEX_OVERFLOW = EM_OVERFLOW;
#endif
        extern int wanted_exceptions;
        
        void init(); //call once, before ...Enable/Disable
        void enable();
        void disable();
};

// std::lerp can be used since C++20 (and has some guaranteed properties probably better than this basic formula) but apparently it is not a template
template <typename Value, typename Linear> Value universal_lerp(Value a,Value b,Linear t) {return a*(1-t)+b*t;}

template <typename T> T linearTransform(T value, T min_in, T max_in, T min_out, T max_out)
{
        return min_out + (value-min_in)*(max_out-min_out)/(max_in-min_in);
}

//in C++20, related: https://en.cppreference.com/w/cpp/numeric/countl_zero
#ifdef _WIN32 //visual studio is missing ffs()
static inline unsigned ffs(int x)
{
        if (x == 0) return 0u;
        unsigned r = 1;
        while ((x & 1) == 0)
                x >>= 1, ++r;
        return r;
}
#endif


#endif