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// ==========================================================
// Helper class for rational numbers
//
// Design and implementation by
// - Hervé Drolon <drolon@infonie.fr>
//
// This file is part of FreeImage 3
//
// COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
// THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
// OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED
// CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT
// THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
// SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL
// PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
// THIS DISCLAIMER.
//
// Use at your own risk!
// ==========================================================
#include "FreeImage.h"
#include "Utilities.h"
#include "FIRational.h"
/// Initialize and normalize a rational number
void FIRational::initialize(LONG n, LONG d) {
if(d) {
_numerator = n;
_denominator = d;
// normalize rational
normalize();
} else {
_numerator = 0;
_denominator = 0;
}
}
/// Default constructor
FIRational::FIRational() {
_numerator = 0;
_denominator = 0;
}
/// Constructor with longs
FIRational::FIRational(LONG n, LONG d) {
initialize(n, d);
}
/// Constructor with FITAG
FIRational::FIRational(const FITAG *tag) {
switch(FreeImage_GetTagType((FITAG*)tag)) {
case FIDT_RATIONAL: // 64-bit unsigned fraction
{
DWORD *pvalue = (DWORD*)FreeImage_GetTagValue((FITAG*)tag);
initialize((LONG)pvalue[0], (LONG)pvalue[1]);
break;
}
case FIDT_SRATIONAL: // 64-bit signed fraction
{
LONG *pvalue = (LONG*)FreeImage_GetTagValue((FITAG*)tag);
initialize((LONG)pvalue[0], (LONG)pvalue[1]);
break;
}
}
}
FIRational::FIRational(float value) {
if (value == (float)((LONG)value)) {
_numerator = (LONG)value;
_denominator = 1L;
} else {
int k, count;
LONG n[4];
float x = fabs(value);
int sign = (value > 0) ? 1 : -1;
// make a continued-fraction expansion of x
count = -1;
for(k = 0; k < 4; k++) {
n[k] = (LONG)floor(x);
count++;
x -= (float)n[k];
if(x == 0) break;
x = 1 / x;
}
// compute the rational
_numerator = 1;
_denominator = n[count];
for(int i = count - 1; i >= 0; i--) {
if(n[i] == 0) break;
LONG _num = (n[i] * _numerator + _denominator);
LONG _den = _numerator;
_numerator = _num;
_denominator = _den;
}
_numerator *= sign;
}
}
/// Copy constructor
FIRational::FIRational (const FIRational& r) {
initialize(r._numerator, r._denominator);
}
/// Destructor
FIRational::~FIRational() {
}
/// Assignement operator
FIRational& FIRational::operator=(FIRational& r) {
if(this != &r) {
initialize(r._numerator, r._denominator);
}
return *this;
}
/// Get the numerator
LONG FIRational::getNumerator() {
return _numerator;
}
/// Get the denominator
LONG FIRational::getDenominator() {
return _denominator;
}
/// Calculate GCD
LONG FIRational::gcd(LONG a, LONG b) {
LONG temp;
while (b) { // While non-zero value
temp = b; // Save current value
b = a % b; // Assign remainder of division
a = temp; // Copy old value
}
return a; // Return GCD of numbers
}
/// Normalize numerator / denominator
void FIRational::normalize() {
if (_numerator != 1 && _denominator != 1) { // Is there something to do?
// Calculate GCD
LONG common = gcd(_numerator, _denominator);
if (common != 1) { // If GCD is not one
_numerator /= common; // Calculate new numerator
_denominator /= common; // Calculate new denominator
}
}
if(_denominator < 0) { // If sign is in denominator
_numerator *= -1; // Multiply num and den by -1
_denominator *= -1; // To keep sign in numerator
}
}
/// Checks if this rational number is an Integer, either positive or negative
BOOL FIRational::isInteger() {
if(_denominator == 1 || (_denominator != 0 && (_numerator % _denominator == 0)) || (_denominator == 0 && _numerator == 0))
return TRUE;
return FALSE;
}
/// Convert as "numerator/denominator"
std::string FIRational::toString() {
std::ostringstream s;
if(isInteger()) {
s << intValue();
} else {
s << _numerator << "/" << _denominator;
}
return s.str();
}
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