X-Git-Url: http://gitweb.fperrin.net/?p=GpsPrune.git;a=blobdiff_plain;f=src%2Ftim%2Fprune%2Ffunction%2Folc%2FOlcDecoder.java;fp=src%2Ftim%2Fprune%2Ffunction%2Folc%2FOlcDecoder.java;h=122f6fe29b5d6d70950b4e1a77290913b7a94ab8;hp=0000000000000000000000000000000000000000;hb=8b20e3e027058cdf6ff52993ee5576193d08667a;hpb=2302358503c38817e19f6e529f6c9e530aac0e86

diff --git a/src/tim/prune/function/olc/OlcDecoder.java b/src/tim/prune/function/olc/OlcDecoder.java
new file mode 100644
index 0000000..122f6fe
--- /dev/null
+++ b/src/tim/prune/function/olc/OlcDecoder.java
@@ -0,0 +1,101 @@
+package tim.prune.function.olc;
+
+
+/**
+ * Decoder of OLC (Open Location Code) strings
+ */
+public class OlcDecoder
+{
+	/**
+	 * Decode the given String into an OlcArea object
+	 * @param inCode code representing an OLC
+	 * @return an OlcArea object, or null if parsing failed
+	 */
+	public static OlcArea decode(String inCode)
+	{
+		if (inCode == null || inCode.length() < 8) {
+			return null;
+		}
+		String code = inCode.trim().toUpperCase();
+		if (code.length() < 8 || code.length() > 12) {
+			return null;
+		}
+		double lat = 0.0, lon = 0.0;
+		double resolution = 400.0;
+		int charPos = 0;
+		int numSteps = 0;
+		boolean amPadding = false;
+		try
+		{
+			while (charPos < inCode.length())
+			{
+				if (charPos == 0 || charPos == 2 || charPos == 4 || charPos == 6 || charPos == 9)
+				{
+					// take next two characters, make pair, position += 2
+					CoordPair pair = CoordPair.decode(code.charAt(charPos), code.charAt(charPos+1));
+					if (pair == CoordPair.PADDING) {
+						amPadding = true;
+					}
+					else if (amPadding)
+					{
+						return null;
+					}
+					else
+					{
+						// Add to current lat, lon
+						lat += (pair.lat * resolution);
+						lon += (pair.lon * resolution);
+						numSteps++;
+						resolution /= 20.0;
+					}
+					charPos += 2;
+				}
+				else if (charPos == 8)
+				{
+					if (code.charAt(charPos) != '+')
+					{
+						return null;
+					}
+					charPos += 1;
+				}
+				else if (charPos == 11)
+				{
+					// take next character, make pair
+					CoordPair pair = CoordPair.decode(code.charAt(charPos));
+					// Add to current lat, lon
+					lat += (pair.lat * resolution);
+					lon += (pair.lon * resolution);
+					charPos += 1;
+					numSteps++;
+					resolution /= 20.0;
+				}
+				else
+				{
+					return null;
+				}
+			}
+
+			// Make OlcArea object and return it
+			if (numSteps < 1)
+			{
+				return null;
+			}
+			else if (numSteps < 6)
+			{
+				// make four points
+				lat -= 90.0;
+				lon -= 180.0;
+				return new OlcArea(lat, lon, lat+resolution, lon+resolution);
+			}
+			else
+			{
+				// make single point:
+				lat -= 90.0;
+				lon -= 180.0;
+				return new OlcArea(lat, lon, lat+resolution*2.5, lon+resolution*2.0);
+			}
+		}
+		catch (ParseException e) {}
+		return null;
+	}
+}
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