233 lines
13 KiB
C++
233 lines
13 KiB
C++
/*
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** Command & Conquer Red Alert(tm)
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** Copyright 2025 Electronic Arts Inc.
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**
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** This program is free software: you can redistribute it and/or modify
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** it under the terms of the GNU General Public License as published by
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** the Free Software Foundation, either version 3 of the License, or
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** (at your option) any later version.
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**
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** This program is distributed in the hope that it will be useful,
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** but WITHOUT ANY WARRANTY; without even the implied warranty of
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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** GNU General Public License for more details.
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**
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** You should have received a copy of the GNU General Public License
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** along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/* $Header: /CounterStrike/FIXED.H 1 3/03/97 10:24a Joe_bostic $ */
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/***********************************************************************************************
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*** 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 ***
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***********************************************************************************************
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* *
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* Project Name : Command & Conquer *
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* *
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* File Name : FIXED.H *
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* *
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* Programmer : Joe L. Bostic *
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* *
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* Start Date : 06/19/96 *
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* *
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* Last Update : June 19, 1996 [JLB] *
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* *
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*---------------------------------------------------------------------------------------------*
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* Functions: *
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* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
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#ifndef FIXED_H
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#define FIXED_H
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/*
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** The "bool" integral type was defined by the C++ committee in
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** November of '94. Until the compiler supports this, use the following
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** definition.
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*/
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#ifndef __BORLANDC__
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#ifndef TRUE_FALSE_DEFINED
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#define TRUE_FALSE_DEFINED
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enum {false=0,true=1};
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typedef int bool;
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#endif
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#endif
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//#pragma warning 604 9
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//#pragma warning 595 9
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/*
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** This is a very simple fixed point class that functions like a regular integral type. However
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** it is under certain restrictions. The whole part must not exceed 255. The fractional part is
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** limited to an accuracy of 1/256. It cannot represent or properly handle negative values. It
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** really isn't all that fast (if an FPU is guaranteed to be present than using "float" might be
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** more efficient). It doesn't detect overflow or underflow in mathematical or bit-shift operations.
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**
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** Take careful note that the normal mathematical operators return integers and not fixed point
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** values if either of the components is an integer. This is the normal C auto-upcasting rule
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** as it would apply presuming that integers are considered to be of higher precision than
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** fixed point numbers. This allows the result of these operators to generate values with greater
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** magnitude than is normally possible if the result were coerced into a fixed point number.
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** If the result should be fixed point, then ensure that both parameters are fixed point.
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**
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** Note that although integers are used as the parameters in the mathematical operators, this
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** does not imply that negative parameters are supported. The use of integers is as a convenience
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** to the programmer -- constant integers are presumed signed. If unsigned parameters were
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** specified, then the compiler would have ambiguous conversion situation in the case of constant
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** integers (e.g. 1, 10, 32, etc). This is most important for the constructor when dealing with the
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** "0" parameter case. In that situation the compiler might interpret the "0" as a null pointer rather
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** than an unsigned integer. There should be no adverse consequences of using signed integer parameters
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** since the precision/magnitude of these integers far exceeds the fixed point component counterparts.
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**
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** Note that when integer values are returns from the arithmetic operators, the value is rounded
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** to the nearest whole integer value. This differs from normal integer math that always rounds down.
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*/
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class fixed
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{
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public:
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// The default constructor must not touch the data members in any way.
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fixed(void) {}
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// Convenient constructor if numerator and denominator components are known.
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fixed(int numerator, int denominator);
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// Conversion constructor to get fixed point from integer.
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fixed(int value) {Data.Composite.Fraction = 0;Data.Composite.Whole = (unsigned char)value;}
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// Constructor if ASCII image of number is known.
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fixed(char const * ascii);
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// Convert to integer when implicitly required.
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operator unsigned (void) const {return(((unsigned)Data.Raw+(256/2)) / 256);}
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/*
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** The standard operators as they apply to in-place operation.
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*/
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fixed & operator *= (fixed const & rvalue) {Data.Raw = (unsigned short)(((int)Data.Raw * rvalue.Data.Raw) / 256);return(*this);}
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fixed & operator *= (int rvalue) {Data.Raw = (unsigned short)(Data.Raw * rvalue);return(*this);}
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fixed & operator /= (fixed const & rvalue) {if (rvalue.Data.Raw != 0 && rvalue.Data.Raw != 256) Data.Raw = (unsigned short)(((int)Data.Raw * 256) / rvalue);return(*this);}
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fixed & operator /= (int rvalue) {if (rvalue) Data.Raw = (unsigned short)((unsigned)Data.Raw / rvalue);return(*this);}
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fixed & operator += (fixed const & rvalue) {Data.Raw += rvalue.Data.Raw;return(*this);}
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fixed & operator -= (fixed const & rvalue) {Data.Raw -= rvalue.Data.Raw;return(*this);}
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/*
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** The standard "My Dear Aunt Sally" operators. The integer versions of multiply
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** and divide are more efficient than using the fixed point counterparts.
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*/
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// const fixed operator * (fixed const & rvalue) const {return(fixed(*this) *= rvalue);}
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const fixed operator * (fixed const & rvalue) const {fixed temp = *this;temp.Data.Raw = (unsigned short)(((int)temp.Data.Raw * (int)rvalue.Data.Raw) / 256);return(temp);}
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const int operator * (int rvalue) const {return ((((unsigned)Data.Raw * rvalue) + (256/2)) / 256);}
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// const fixed operator / (fixed const & rvalue) const {return(fixed(*this) /= rvalue);}
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const fixed operator / (fixed const & rvalue) const {fixed temp = *this;if (rvalue.Data.Raw != 0 && rvalue.Data.Raw != 256) temp.Data.Raw = (unsigned short)(((int)temp.Data.Raw * 256) / rvalue.Data.Raw);return(temp);}
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const int operator / (int rvalue) const {if (rvalue) return(((unsigned)Data.Raw+(256/2)) / ((unsigned)rvalue*256));return(*this);}
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// const fixed operator + (fixed const & rvalue) const {return(fixed(*this) += rvalue);}
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const fixed operator + (fixed const & rvalue) const {fixed temp = *this;temp += rvalue;return(temp);}
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const int operator + (int rvalue) const {return((((unsigned)Data.Raw+(256/2))/256) + rvalue);}
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// const fixed operator - (fixed const & rvalue) const {return(fixed(*this) -= rvalue);}
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const fixed operator - (fixed const & rvalue) const {fixed temp = *this;temp -= rvalue;return(temp);}
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const int operator - (int rvalue) const {return((((unsigned)Data.Raw+(256/2))/256) - rvalue);}
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/*
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** The Shift operators are more efficient than using multiplies or divides by power-of-2 numbers.
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*/
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fixed & operator >>= (unsigned rvalue) {Data.Raw >>= rvalue;return(*this);}
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fixed & operator <<= (unsigned rvalue) {Data.Raw <<= rvalue;return(*this);}
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const fixed operator >> (unsigned rvalue) const {fixed temp = *this;temp >>= rvalue;return(temp);}
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const fixed operator << (unsigned rvalue) const {fixed temp = *this;temp <<= rvalue;return(temp);}
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/*
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** The full set of comparison operators.
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*/
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bool operator == (fixed const & rvalue) const {return(Data.Raw == rvalue.Data.Raw);}
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bool operator != (fixed const & rvalue) const {return(Data.Raw != rvalue.Data.Raw);}
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bool operator < (fixed const & rvalue) const {return(Data.Raw < rvalue.Data.Raw);}
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bool operator > (fixed const & rvalue) const {return(Data.Raw > rvalue.Data.Raw);}
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bool operator <= (fixed const & rvalue) const {return(Data.Raw <= rvalue.Data.Raw);}
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bool operator >= (fixed const & rvalue) const {return(Data.Raw >= rvalue.Data.Raw);}
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bool operator ! (void) const {return(Data.Raw == 0);}
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/*
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** Comparison to integers requires consideration of fractional component.
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*/
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bool operator < (int rvalue) const {return(Data.Raw < (rvalue*256));}
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bool operator > (int rvalue) const {return(Data.Raw > (rvalue*256));}
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bool operator <= (int rvalue) const {return(Data.Raw <= (rvalue*256));}
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bool operator >= (int rvalue) const {return(Data.Raw >= (rvalue*256));}
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bool operator == (int rvalue) const {return(Data.Raw == (rvalue*256));}
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bool operator != (int rvalue) const {return(Data.Raw != (rvalue*256));}
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/*
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** Friend functions to handle the alternate positioning of fixed and integer parameters.
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*/
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friend const int operator * (int lvalue, fixed const & rvalue) {return(rvalue * lvalue);}
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friend const int operator / (int lvalue, fixed const & rvalue) {if (rvalue.Data.Raw == 0 || rvalue.Data.Raw == 256) return (lvalue); return(((unsigned)(lvalue * 256)+(256/2)) / rvalue.Data.Raw);}
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friend const int operator + (int lvalue, fixed const & rvalue) {return(rvalue + lvalue);}
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friend const int operator - (int lvalue, fixed const & rvalue) {return((((lvalue*256) - rvalue.Data.Raw) + (256/2)) / 256);}
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friend bool operator < (unsigned lvalue, fixed const & rvalue) {return((lvalue*256) < rvalue.Data.Raw);}
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friend bool operator > (unsigned lvalue, fixed const & rvalue) {return((lvalue*256) > rvalue.Data.Raw);}
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friend bool operator <= (unsigned lvalue, fixed const & rvalue) {return((lvalue*256) <= rvalue.Data.Raw);}
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friend bool operator >= (unsigned lvalue, fixed const & rvalue) {return((lvalue*256) >= rvalue.Data.Raw);}
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friend bool operator == (unsigned lvalue, fixed const & rvalue) {return((lvalue*256) == rvalue.Data.Raw);}
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friend bool operator != (unsigned lvalue, fixed const & rvalue) {return((lvalue*256) != rvalue.Data.Raw);}
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friend int operator *= (int & lvalue, fixed const & rvalue) {lvalue = lvalue * rvalue;return(lvalue);}
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friend int operator /= (int & lvalue, fixed const & rvalue) {lvalue = lvalue / rvalue;return(lvalue);}
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friend int operator += (int & lvalue, fixed const & rvalue) {lvalue = lvalue + rvalue;return(lvalue);}
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friend int operator -= (int & lvalue, fixed const & rvalue) {lvalue = lvalue - rvalue;return(lvalue);}
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/*
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** Helper functions to handle simple and common operations on fixed point numbers.
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*/
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void Round_Up(void) {Data.Raw += (unsigned short)(256-1);Data.Composite.Fraction = 0;}
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void Round_Down(void) {Data.Composite.Fraction = 0;}
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void Round(void) {if (Data.Composite.Fraction >= 256/2) Round_Up();Round_Down();}
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void Saturate(unsigned capvalue) {if (Data.Raw > (capvalue*256)) Data.Raw = (unsigned short)(capvalue*256);}
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void Saturate(fixed const & capvalue) {if (*this > capvalue) *this = capvalue;}
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void Sub_Saturate(unsigned capvalue) {if (Data.Raw >= (capvalue*256)) Data.Raw = (unsigned short)((capvalue*256)-1);}
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void Sub_Saturate(fixed const & capvalue) {if (*this >= capvalue) Data.Raw = (unsigned short)(capvalue.Data.Raw-1);}
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void Inverse(void) {*this = fixed(1) / *this;}
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/*
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** Friend helper functions that work in the typical C fashion of passing the object to
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** be processed as a parameter to the function.
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*/
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friend const fixed Round_Up(fixed const & value) {fixed temp = value; temp.Round_Up();return(temp);}
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friend const fixed Round_Down(fixed const & value) {fixed temp = value; temp.Round_Down();return(temp);}
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friend const fixed Round(fixed const & value) {fixed temp = value; temp.Round();return(temp);}
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friend const fixed Saturate(fixed const & value, unsigned capvalue) {fixed temp = value;temp.Saturate(capvalue);return(temp);}
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friend const fixed Saturate(fixed const & value, fixed const & capvalue) {fixed temp = value;temp.Saturate(capvalue);return(temp);}
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friend const fixed Sub_Saturate(fixed const & value, unsigned capvalue) {fixed temp = value;temp.Sub_Saturate(capvalue);return(temp);}
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friend const fixed Sub_Saturate(fixed const & value, fixed const & capvalue) {fixed temp = value;temp.Sub_Saturate(capvalue);return(temp);}
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friend const fixed Inverse(fixed const & value) {fixed temp = value;temp.Inverse();return(temp);}
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/*
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** Conversion of the fixed point number into an ASCII string.
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*/
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int To_ASCII(char * buffer, int maxlen=-1) const;
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char const * As_ASCII(void) const;
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/*
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** Helper constants that provide some convenient fixed point values.
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*/
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static const fixed _1_2;
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static const fixed _1_3;
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static const fixed _1_4;
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static const fixed _3_4;
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static const fixed _2_3;
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private:
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union {
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struct {
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#ifdef BIG_ENDIAN
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unsigned char Whole;
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unsigned char Fraction;
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#else
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unsigned char Fraction;
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unsigned char Whole;
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#endif
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} Composite;
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unsigned short Raw;
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} Data;
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};
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#endif
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