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Merge "Camera2: Updated Rational for denom=0." into klp-dev

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This commit is contained in:
Timothy Knight
2013-09-04 20:25:35 +00:00
committed by Android (Google) Code Review
parent 3cd28adc5d 23c8809568
commit 1b039b1d2e
2 changed files with 105 additions and 29 deletions
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83
core/java/android/hardware/camera2/Rational.java
View File

@@ -26,22 +26,17 @@ public final class Rational {
/**
* <p>Create a Rational with a given numerator and denominator.</p>
*
* <p>
* The signs of the numerator and the denominator may be flipped such that the denominator
* is always 0.
* </p>
* <p>The signs of the numerator and the denominator may be flipped such that the denominator
* is always positive.</p>
*
* <p>A rational value with a 0-denominator may be constructed, but will have similar semantics
* as float NaN and INF values. The int getter functions return 0 in this case.</p>
*
* @param numerator the numerator of the rational
* @param denominator the denominator of the rational
*
* @throws IllegalArgumentException if the denominator is 0
*/
public Rational(int numerator, int denominator) {
if (denominator == 0) {
throw new IllegalArgumentException("Argument 'denominator' is 0");
}
if (denominator < 0) {
numerator = -numerator;
denominator = -denominator;
@@ -55,6 +50,9 @@ public final class Rational {
* Gets the numerator of the rational.
*/
public int getNumerator() {
if (mDenominator == 0) {
return 0;
}
return mNumerator;
}
@@ -65,22 +63,41 @@ public final class Rational {
return mDenominator;
}
private boolean isNaN() {
return mDenominator == 0 && mNumerator == 0;
}
private boolean isInf() {
return mDenominator == 0 && mNumerator > 0;
}
private boolean isNegInf() {
return mDenominator == 0 && mNumerator < 0;
}
/**
* <p>Compare this Rational to another object and see if they are equal.</p>
*
* <p>A Rational object can only be equal to another Rational object (comparing against any other
* type will return false).</p>
*
* <p>A Rational object is considered equal to another Rational object if and only if their
* reduced forms have the same numerator and denominator.</p>
* <p>A Rational object is considered equal to another Rational object if and only if one of
* the following holds</p>:
* <ul><li>Both are NaN</li>
* <li>Both are infinities of the same sign</li>
* <li>Both have the same numerator and denominator in their reduced form</li>
* </ul>
*
* <p>A reduced form of a Rational is calculated by dividing both the numerator and the
* denominator by their greatest common divisor.</p>
*
* <pre>
* (new Rational(1, 2)).equals(new Rational(1, 2)) == true // trivially true
* (new Rational(2, 3)).equals(new Rational(1, 2)) == false // trivially false
* (new Rational(1, 2)).equals(new Rational(2, 4)) == true // true after reduction
* (new Rational(1, 2)).equals(new Rational(1, 2)) == true // trivially true
* (new Rational(2, 3)).equals(new Rational(1, 2)) == false // trivially false
* (new Rational(1, 2)).equals(new Rational(2, 4)) == true // true after reduction
* (new Rational(0, 0)).equals(new Rational(0, 0)) == true // NaN.equals(NaN)
* (new Rational(1, 0)).equals(new Rational(5, 0)) == true // both are +infinity
* (new Rational(1, 0)).equals(new Rational(-1, 0)) == false // +infinity != -infinity
* </pre>
*
* @param obj a reference to another object
@@ -91,13 +108,17 @@ public final class Rational {
public boolean equals(Object obj) {
if (obj == null) {
return false;
}
if (this == obj) {
return true;
}
if (obj instanceof Rational) {
} else if (obj instanceof Rational) {
Rational other = (Rational) obj;
if(mNumerator == other.mNumerator && mDenominator == other.mDenominator) {
if (mDenominator == 0 || other.mDenominator == 0) {
if (isNaN() && other.isNaN()) {
return true;
} else if (isInf() && other.isInf() || isNegInf() && other.isNegInf()) {
return true;
} else {
return false;
}
} else if (mNumerator == other.mNumerator && mDenominator == other.mDenominator) {
return true;
} else {
int thisGcd = gcd();
@@ -117,7 +138,25 @@ public final class Rational {
@Override
public String toString() {
return mNumerator + "/" + mDenominator;
if (isNaN()) {
return "NaN";
} else if (isInf()) {
return "Infinity";
} else if (isNegInf()) {
return "-Infinity";
} else {
return mNumerator + "/" + mDenominator;
}
}
/**
* <p>Convert to a floating point representation.</p>
*
* @return The floating point representation of this rational number.
* @hide
*/
public float toFloat() {
return (float) mNumerator / (float) mDenominator;
}
@Override

51
media/tests/MediaFrameworkTest/src/com/android/mediaframeworktest/unit/RationalTest.java
View File

@@ -50,12 +50,20 @@ public class RationalTest extends junit.framework.TestCase {
assertEquals(1, r.getNumerator());
assertEquals(2, r.getDenominator());
// Dividing by zero is not allowed
try {
r = new Rational(1, 0);
fail("Expected Rational constructor to throw an IllegalArgumentException");
} catch(IllegalArgumentException e) {
}
// Infinity.
r = new Rational(1, 0);
assertEquals(0, r.getNumerator());
assertEquals(0, r.getDenominator());
// Negative infinity.
r = new Rational(-1, 0);
assertEquals(0, r.getNumerator());
assertEquals(0, r.getDenominator());
// NaN.
r = new Rational(0, 0);
assertEquals(0, r.getNumerator());
assertEquals(0, r.getDenominator());
}
@SmallTest
@@ -110,5 +118,34 @@ public class RationalTest extends junit.framework.TestCase {
assertEquals(moreComplicated, moreComplicated2);
assertEquals(moreComplicated2, moreComplicated);
Rational nan = new Rational(0, 0);
Rational nan2 = new Rational(0, 0);
assertTrue(nan.equals(nan));
assertTrue(nan.equals(nan2));
assertTrue(nan2.equals(nan));
assertFalse(nan.equals(r));
assertFalse(r.equals(nan));
// Infinities of the same sign are equal.
Rational posInf = new Rational(1, 0);
Rational posInf2 = new Rational(2, 0);
Rational negInf = new Rational(-1, 0);
Rational negInf2 = new Rational(-2, 0);
assertEquals(posInf, posInf);
assertEquals(negInf, negInf);
assertEquals(posInf, posInf2);
assertEquals(negInf, negInf2);
// Infinities aren't equal to anything else.
assertFalse(posInf.equals(negInf));
assertFalse(negInf.equals(posInf));
assertFalse(negInf.equals(r));
assertFalse(posInf.equals(r));
assertFalse(r.equals(negInf));
assertFalse(r.equals(posInf));
assertFalse(posInf.equals(nan));
assertFalse(negInf.equals(nan));
assertFalse(nan.equals(posInf));
assertFalse(nan.equals(negInf));
}
}
}