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Diffstat (limited to 'plugins/FreeImage/Source/Metadata/FIRational.cpp')
| -rw-r--r-- | plugins/FreeImage/Source/Metadata/FIRational.cpp | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/plugins/FreeImage/Source/Metadata/FIRational.cpp b/plugins/FreeImage/Source/Metadata/FIRational.cpp new file mode 100644 index 0000000000..969c06489a --- /dev/null +++ b/plugins/FreeImage/Source/Metadata/FIRational.cpp @@ -0,0 +1,176 @@ +// ==========================================================
+// 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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