X-Git-Url: http://gitweb.fperrin.net/?p=GpsPrune.git;a=blobdiff_plain;f=src%2Ftim%2Fprune%2Ffunction%2Folc%2FCoordPair.java;fp=src%2Ftim%2Fprune%2Ffunction%2Folc%2FCoordPair.java;h=778b46d98c4705ec36f59960246be9077134d4ef;hp=0000000000000000000000000000000000000000;hb=8b20e3e027058cdf6ff52993ee5576193d08667a;hpb=2302358503c38817e19f6e529f6c9e530aac0e86

diff --git a/src/tim/prune/function/olc/CoordPair.java b/src/tim/prune/function/olc/CoordPair.java
new file mode 100644
index 0000000..778b46d
--- /dev/null
+++ b/src/tim/prune/function/olc/CoordPair.java
@@ -0,0 +1,75 @@
+package tim.prune.function.olc;
+
+class ParseException extends Exception {}
+
+/**
+ * Pair of coordinates
+ */
+class CoordPair
+{
+	/** Alphabet of allowed characters */
+	private static final String ALPHABET = "23456789CFGHJMPQRVWX";
+
+	public double lat = 0.0;
+	public double lon = 0.0;
+
+	/** Constructor */
+	public CoordPair(double inLat, double inLon)
+	{
+		lat = inLat;
+		lon = inLon;
+	}
+
+	/** Constant pair to represent padding */
+	public static CoordPair PADDING = new CoordPair(-1.0, -1.0);
+
+	/**
+	 * Try to parse the given pair of characters into a CoordPair
+	 * @param inFirst first character of pair
+	 * @param inSecond second character of pair
+	 * @return CoordPair from (0, 0) to (19/20, 19/20)
+	 * @throws ParseException
+	 */
+	public static CoordPair decode(char inFirst, char inSecond) throws ParseException
+	{
+		final boolean isFirstPadding = (inFirst == '0');
+		final boolean isSecondPadding = (inSecond == '0');
+		if (isFirstPadding && isSecondPadding) {return CoordPair.PADDING;}
+		if (isFirstPadding || isSecondPadding) {throw new ParseException();}
+		// Try to turn these characters into numbers
+		final double lat = decodeChar(inFirst);
+		final double lon = decodeChar(inSecond);
+		return new CoordPair(lat / 20.0, lon / 20.0);
+	}
+
+	/**
+	 * Try to parse the given single character into a CoordPair
+	 * @param inChar single character from level 11
+	 * @return CoordPair from (0, 0) to (19/20, 19/20)
+	 * @throws ParseException
+	 */
+	public static CoordPair decode(char inChar) throws ParseException
+	{
+		// Try to turn this character into a number
+		final int charIndex = decodeChar(inChar);
+		final int lat = charIndex / 4;
+		final int lon = charIndex % 4;
+		return new CoordPair(lat / 5.0, lon / 4.0);
+	}
+
+	/**
+	 * Get the index from the given character
+	 * @param inChar character from OLC
+	 * @return index from 0 to 19
+	 * @throws ParseException if character not found
+	 */
+	private static int decodeChar(char inChar) throws ParseException
+	{
+		final int index = ALPHABET.indexOf(inChar);
+		if (index < 0)
+		{
+			throw new ParseException();
+		}
+		return index;
+	}
+}