X-Git-Url: http://gitweb.fperrin.net/?p=GpsPrune.git;a=blobdiff_plain;f=tim%2Fprune%2Fjpeg%2FExifGateway.java;fp=tim%2Fprune%2Fjpeg%2FExifGateway.java;h=9fefadf33c78003248e12e119481346c667166d6;hp=c60afb299822c623f7a4abe77a78e485e50bdc00;hb=f35b6d628f68e3b5ef19965ad8988d0dd1eb8efa;hpb=3745d70b1427bb8ac1a085e47cbdc566936784e1

diff --git a/tim/prune/jpeg/ExifGateway.java b/tim/prune/jpeg/ExifGateway.java
index c60afb2..9fefadf 100644
--- a/tim/prune/jpeg/ExifGateway.java
+++ b/tim/prune/jpeg/ExifGateway.java
@@ -1,9 +1,7 @@
 package tim.prune.jpeg;
 
 import java.io.File;
-
 import javax.swing.JOptionPane;
-
 import tim.prune.I18nManager;
 
 /**
@@ -12,10 +10,8 @@ import tim.prune.I18nManager;
  * to the external libmetadata-extractor-java library
  * instead of the included modified routines.
  *
- * To use the internal routines, set the USE_INTERNAL_LIBRARY flag to true
- * and include the internal classes in the compiled jar.
- * To use the external library, set the USE_INTERNAL_LIBRARY flag to false
- * and do not export the internal classes.
+ * Switching between internal and external libraries is
+ * handled by the ExifLibrarySwitch
  */
 public abstract class ExifGateway
 {
@@ -71,4 +67,25 @@ public abstract class ExifGateway
 		if (_exifLibrary == null || !_exifLibrary.looksOK()) {key = key + ".failed";}
 		return key;
 	}
+
+
+
+	/**
+	 * @param inNumerator numerator from Rational
+	 * @param inDenominator denominator from Rational
+	 * @return the value of the specified number as a positive <code>double</code>.
+	 * Prevents interpretation of 32 bit numbers as negative, and forces a positive answer
+	 */
+	public static final double convertToPositiveValue(int inNumerator, int inDenominator)
+	{
+		if (inDenominator == 0) return 0.0;
+		double numeratorDbl = inNumerator;
+		double denomDbl = inDenominator;
+		if (inNumerator >= 0)
+			return numeratorDbl / denomDbl;
+		final double correction = Math.pow(2.0, 32);
+		numeratorDbl += correction;
+		if (inDenominator < 0) denomDbl += correction;
+		return numeratorDbl / denomDbl;
+	}
 }