//
// Copyright 2020 Electronic Arts Inc.
//
// TiberianDawn.DLL and RedAlert.dll and corresponding source code is free
// software: you can redistribute it and/or modify it under the terms of
// the GNU General Public License as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
// TiberianDawn.DLL and RedAlert.dll and corresponding source code is distributed
// in the hope that it will be useful, but with permitted additional restrictions
// under Section 7 of the GPL. See the GNU General Public License in LICENSE.TXT
// distributed with this program. You should have received a copy of the
// GNU General Public License along with permitted additional restrictions
// with this program. If not, see https://github.com/electronicarts/CnC_Remastered_Collection
/* $Header: /CounterStrike/FIXED.H 1 3/03/97 10:24a Joe_bostic $ */
/***********************************************************************************************
*** C O N F I D E N T I A L --- W E S T W O O D S T U D I O S ***
***********************************************************************************************
* *
* Project Name : Command & Conquer *
* *
* File Name : FIXED.H *
* *
* Programmer : Joe L. Bostic *
* *
* Start Date : 06/19/96 *
* *
* Last Update : June 19, 1996 [JLB] *
* *
*---------------------------------------------------------------------------------------------*
* Functions: *
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
#ifndef FIXED_H
#define FIXED_H
/*
** The "bool" integral type was defined by the C++ committee in
** November of '94. Until the compiler supports this, use the following
** definition.
*/
#ifndef __BORLANDC__
#ifndef TRUE_FALSE_DEFINED
#define TRUE_FALSE_DEFINED
enum {false=0,true=1};
typedef int bool;
#endif
#endif
//#pragma warning 604 9
//#pragma warning 595 9
/*
** This is a very simple fixed point class that functions like a regular integral type. However
** it is under certain restrictions. The whole part must not exceed 65535. The fractional part is
** limited to an accuracy of 1/65536. It cannot represent or properly handle negative values. It
** really isn't all that fast (if an FPU is guaranteed to be present than using "float" might be
** more efficient). It doesn't detect overflow or underflow in mathematical or bit-shift operations.
**
** Take careful note that the normal mathematical operators return integers and not fixed point
** values if either of the components is an integer. This is the normal C auto-upcasting rule
** as it would apply presuming that integers are considered to be of higher precision than
** fixed point numbers. This allows the result of these operators to generate values with greater
** magnitude than is normally possible if the result were coerced into a fixed point number.
** If the result should be fixed point, then ensure that both parameters are fixed point.
**
** Note that although integers are used as the parameters in the mathematical operators, this
** does not imply that negative parameters are supported. The use of integers is as a convenience
** to the programmer -- constant integers are presumed signed. If unsigned parameters were
** specified, then the compiler would have ambiguous conversion situation in the case of constant
** integers (e.g. 1, 10, 32, etc). This is most important for the constructor when dealing with the
** "0" parameter case. In that situation the compiler might interpret the "0" as a null pointer rather
** than an unsigned integer. There should be no adverse consequences of using signed integer parameters
** since the precision/magnitude of these integers far exceeds the fixed point component counterparts.
**
** Note that when integer values are returns from the arithmetic operators, the value is rounded
** to the nearest whole integer value. This differs from normal integer math that always rounds down.
*/
class fixed
{
static constexpr unsigned int PRECISION = 1 << 16;
public:
// The default constructor must not touch the data members in any way.
fixed(void) {}
// Copy constructor
fixed(fixed const & rvalue) {Data.Raw = rvalue.Data.Raw;}
// Convenient constructor if numerator and denominator components are known.
fixed(int numerator, int denominator);
// Conversion constructor to get fixed point from integer.
fixed(int value) {Data.Composite.Fraction = 0U;Data.Composite.Whole = (unsigned short)value;}
fixed(unsigned int value) {Data.Composite.Fraction = 0U;Data.Composite.Whole = (unsigned short)value;}
// Conversion constructor to get fixed point from floating-point.
fixed(float value) {value += 1.0f/(PRECISION<<1);Data.Composite.Fraction = (unsigned short)((value - (unsigned short)value) * PRECISION);Data.Composite.Whole = (unsigned short)value;}
// Constructor if ASCII image of number is known.
fixed(char const * ascii);
// Convert to integer when implicitly required.
operator unsigned (void) const {return(unsigned)(((unsigned __int64)Data.Raw+(PRECISION>>1)) / PRECISION);}
/*
** The standard operators as they apply to in-place operation.
*/
fixed & operator *= (fixed const & rvalue) {Data.Raw = (unsigned int)(((unsigned __int64)Data.Raw * rvalue.Data.Raw) / PRECISION);return(*this);}
fixed & operator *= (int rvalue) {Data.Raw *= (unsigned int)rvalue;return(*this);}
fixed & operator /= (fixed const & rvalue) {if (rvalue.Data.Raw != 0U && rvalue.Data.Raw != PRECISION) Data.Raw = (unsigned int)((((unsigned __int64)Data.Raw * PRECISION)+(PRECISION>>1)) / rvalue.Data.Raw);return(*this);}
fixed & operator /= (int rvalue) {if (rvalue) Data.Raw /= (unsigned int)rvalue;return(*this);}
fixed & operator += (fixed const & rvalue) {Data.Raw += rvalue.Data.Raw;return(*this);}
fixed & operator -= (fixed const & rvalue) {Data.Raw -= rvalue.Data.Raw;return(*this);}
/*
** The standard "My Dear Aunt Sally" operators. The integer versions of multiply
** and divide are more efficient than using the fixed point counterparts.
*/
const fixed operator * (fixed const & rvalue) const { return fixed(*this) *= rvalue; }
const int operator * (int rvalue) const { return fixed(*this) *= rvalue; }
const fixed operator / (fixed const & rvalue) const { return fixed(*this) /= rvalue; }
const int operator / (int rvalue) const { return fixed(*this) /= rvalue; }
const fixed operator + (fixed const & rvalue) const { return fixed(*this) += rvalue; }
const int operator + (int rvalue) const { return fixed(*this) += rvalue; }
const fixed operator - (fixed const & rvalue) const { return fixed(*this) -= rvalue; }
const int operator - (int rvalue) const { return fixed(*this) -= rvalue; }
/*
** The Shift operators are more efficient than using multiplies or divides by power-of-2 numbers.
*/
fixed & operator >>= (unsigned rvalue) {Data.Raw >>= rvalue;return(*this);}
fixed & operator <<= (unsigned rvalue) {Data.Raw <<= rvalue;return(*this);}
const fixed operator >> (unsigned rvalue) const {return fixed(*this) >>= rvalue;}
const fixed operator << (unsigned rvalue) const {return fixed(*this) <<= rvalue;}
/*
** The full set of comparison operators.
*/
bool operator == (fixed const & rvalue) const {return(Data.Raw == rvalue.Data.Raw);}
bool operator != (fixed const & rvalue) const {return(Data.Raw != rvalue.Data.Raw);}
bool operator < (fixed const & rvalue) const {return(Data.Raw < rvalue.Data.Raw);}
bool operator > (fixed const & rvalue) const {return(Data.Raw > rvalue.Data.Raw);}
bool operator <= (fixed const & rvalue) const {return(Data.Raw <= rvalue.Data.Raw);}
bool operator >= (fixed const & rvalue) const {return(Data.Raw >= rvalue.Data.Raw);}
bool operator ! (void) const {return(Data.Raw == 0U);}
/*
** Comparison to integers requires consideration of fractional component.
*/
bool operator < (int rvalue) const {return(Data.Raw < ((unsigned int)rvalue*PRECISION));}
bool operator > (int rvalue) const {return(Data.Raw > ((unsigned int)rvalue*PRECISION));}
bool operator <= (int rvalue) const {return(Data.Raw <= ((unsigned int)rvalue*PRECISION));}
bool operator >= (int rvalue) const {return(Data.Raw >= ((unsigned int)rvalue*PRECISION));}
bool operator == (int rvalue) const {return(Data.Raw == ((unsigned int)rvalue*PRECISION));}
bool operator != (int rvalue) const {return(Data.Raw != ((unsigned int)rvalue*PRECISION));}
/*
** Friend functions to handle the alternate positioning of fixed and integer parameters.
*/
friend const int operator * (int lvalue, fixed const & rvalue) { return fixed(lvalue) * rvalue; }
friend const int operator / (int lvalue, fixed const & rvalue) { return fixed(lvalue) / rvalue; }
friend const int operator + (int lvalue, fixed const & rvalue) { return fixed(lvalue) + rvalue; }
friend const int operator - (int lvalue, fixed const & rvalue) { return fixed(lvalue) - rvalue; }
friend bool operator < (unsigned lvalue, fixed const & rvalue) { return fixed(lvalue) < rvalue; }
friend bool operator > (unsigned lvalue, fixed const & rvalue) { return fixed(lvalue) > rvalue; }
friend bool operator <= (unsigned lvalue, fixed const & rvalue) { return fixed(lvalue) <= rvalue; }
friend bool operator >= (unsigned lvalue, fixed const & rvalue) { return fixed(lvalue) >= rvalue; }
friend bool operator == (unsigned lvalue, fixed const & rvalue) { return fixed(lvalue) == rvalue; }
friend bool operator != (unsigned lvalue, fixed const & rvalue) { return fixed(lvalue) != rvalue; }
friend int operator *= (int & lvalue, fixed const & rvalue) { lvalue = lvalue * rvalue; return(lvalue); }
friend int operator /= (int & lvalue, fixed const & rvalue) { lvalue = lvalue / rvalue; return(lvalue); }
friend int operator += (int & lvalue, fixed const & rvalue) { lvalue = lvalue + rvalue; return(lvalue); }
friend int operator -= (int & lvalue, fixed const & rvalue) { lvalue = lvalue - rvalue; return(lvalue); }
/*
** Helper functions to handle simple and common operations on fixed point numbers.
*/
void Round_Up(void) {Data.Raw += (PRECISION-1U);Data.Composite.Fraction = 0U;}
void Round_Down(void) {Data.Composite.Fraction = 0U;}
void Round(void) {if (Data.Composite.Fraction >= PRECISION>>1) Round_Up();Round_Down();}
void Saturate(unsigned capvalue) {if (Data.Raw > (capvalue*PRECISION)) Data.Raw = capvalue*PRECISION;}
void Saturate(fixed const & capvalue) {if (*this > capvalue) *this = capvalue;}
void Sub_Saturate(unsigned capvalue) {if (Data.Raw >= (capvalue*PRECISION)) Data.Raw = (capvalue*PRECISION)-1U;}
void Sub_Saturate(fixed const & capvalue) {if (*this >= capvalue) Data.Raw = capvalue.Data.Raw-1U;}
void Inverse(void) {*this = fixed(1) / *this;}
/*
** Friend helper functions that work in the typical C fashion of passing the object to
** be processed as a parameter to the function.
*/
friend const fixed Round_Up(fixed const & value) {fixed temp = value; temp.Round_Up();return(temp);}
friend const fixed Round_Down(fixed const & value) {fixed temp = value; temp.Round_Down();return(temp);}
friend const fixed Round(fixed const & value) {fixed temp = value; temp.Round();return(temp);}
friend const fixed Saturate(fixed const & value, unsigned capvalue) {fixed temp = value;temp.Saturate(capvalue);return(temp);}
friend const fixed Saturate(fixed const & value, fixed const & capvalue) {fixed temp = value;temp.Saturate(capvalue);return(temp);}
friend const fixed Sub_Saturate(fixed const & value, unsigned capvalue) {fixed temp = value;temp.Sub_Saturate(capvalue);return(temp);}
friend const fixed Sub_Saturate(fixed const & value, fixed const & capvalue) {fixed temp = value;temp.Sub_Saturate(capvalue);return(temp);}
friend const fixed Inverse(fixed const & value) {fixed temp = value;temp.Inverse();return(temp);}
/*
** Conversion of the fixed point number into an ASCII string.
*/
int To_ASCII(char * buffer, int maxlen=-1) const;
char const * As_ASCII(void) const;
/*
** Helper constants that provide some convenient fixed point values.
*/
static const fixed _1_2;
static const fixed _1_3;
static const fixed _1_4;
static const fixed _3_4;
static const fixed _2_3;
private:
union {
struct {
#ifdef BIG_ENDIAN
unsigned short Whole;
unsigned short Fraction;
#else
unsigned short Fraction;
unsigned short Whole;
#endif
} Composite;
unsigned int Raw;
} Data;
};
#endif