From ba4af96c2b771e3984887de0a4d2d7338aed1270 Mon Sep 17 00:00:00 2001 From: Anton Tananaev Date: Sat, 18 Jan 2014 19:07:39 +1300 Subject: Implement KHD protocol --- src/org/traccar/helper/ChannelBufferTools.java | 22 ++++++++++++++++++++++ src/org/traccar/helper/Crc.java | 8 ++++++++ 2 files changed, 30 insertions(+) (limited to 'src/org/traccar/helper') diff --git a/src/org/traccar/helper/ChannelBufferTools.java b/src/org/traccar/helper/ChannelBufferTools.java index c0df86bcd..ef2ebc313 100644 --- a/src/org/traccar/helper/ChannelBufferTools.java +++ b/src/org/traccar/helper/ChannelBufferTools.java @@ -97,6 +97,28 @@ public class ChannelBufferTools { return result.toString(); } + + /** + * Read BCD coded coordinate (first byte has sign bit) + */ + public static double readCoordinate(ChannelBuffer buf) { + int b1 = buf.readUnsignedByte(); + int b2 = buf.readUnsignedByte(); + int b3 = buf.readUnsignedByte(); + int b4 = buf.readUnsignedByte(); + + double value = (b2 & 0xf) * 10 + (b3 >> 4); + value += (((b3 & 0xf) * 10 + (b4 >> 4)) * 10 + (b4 & 0xf)) / 1000.0; + value /= 60; + value += ((b1 >> 4 & 0x7) * 10 + (b1 & 0xf)) * 10 + (b2 >> 4); + + if ((b1 & 0x80) != 0) { + value = -value; + } + + return value; + } + /** * Convert integer array to byte array diff --git a/src/org/traccar/helper/Crc.java b/src/org/traccar/helper/Crc.java index 84224a781..5a668f30a 100644 --- a/src/org/traccar/helper/Crc.java +++ b/src/org/traccar/helper/Crc.java @@ -136,6 +136,14 @@ public class Crc { } return (int) checksum.getValue(); } + + public static int xorChecksum(ByteBuffer buf) { + int checksum = 0; + for (int i = 0; i < buf.remaining(); i++) { + checksum ^= buf.get(i); + } + return checksum; + } public static String nmeaChecksum(String msg) { int checksum = 0; -- cgit v1.2.3