aboutsummaryrefslogtreecommitdiff
path: root/src/main/java/org/traccar/protocol/At2000FrameDecoder.java
diff options
context:
space:
mode:
Diffstat (limited to 'src/main/java/org/traccar/protocol/At2000FrameDecoder.java')
-rw-r--r--src/main/java/org/traccar/protocol/At2000FrameDecoder.java81
1 files changed, 81 insertions, 0 deletions
diff --git a/src/main/java/org/traccar/protocol/At2000FrameDecoder.java b/src/main/java/org/traccar/protocol/At2000FrameDecoder.java
new file mode 100644
index 000000000..5fa82a5f7
--- /dev/null
+++ b/src/main/java/org/traccar/protocol/At2000FrameDecoder.java
@@ -0,0 +1,81 @@
+/*
+ * Copyright 2016 - 2018 Anton Tananaev (anton@traccar.org)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.traccar.protocol;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelHandlerContext;
+import org.traccar.BaseFrameDecoder;
+import org.traccar.NetworkMessage;
+
+public class At2000FrameDecoder extends BaseFrameDecoder {
+
+ private static final int BLOCK_LENGTH = 16;
+ private static final int ACK_LENGTH = 496;
+
+ private boolean firstPacket = true;
+
+ private ByteBuf currentBuffer;
+ private int acknowledgedBytes;
+
+ private void sendResponse(Channel channel) {
+ if (channel != null) {
+ ByteBuf response = Unpooled.buffer(2 * BLOCK_LENGTH);
+ response.writeByte(At2000ProtocolDecoder.MSG_ACKNOWLEDGEMENT);
+ response.writeMedium(1);
+ response.writeByte(0x00); // success
+ response.writerIndex(2 * BLOCK_LENGTH);
+ channel.writeAndFlush(new NetworkMessage(response, channel.remoteAddress()));
+ }
+ }
+
+ @Override
+ protected Object decode(
+ ChannelHandlerContext ctx, Channel channel, ByteBuf buf) throws Exception {
+
+ if (buf.readableBytes() < 5) {
+ return null;
+ }
+
+ int length;
+ if (firstPacket) {
+ firstPacket = false;
+ length = buf.getUnsignedMediumLE(buf.readerIndex() + 2);
+ } else {
+ length = buf.getUnsignedMediumLE(buf.readerIndex() + 1);
+ }
+
+ length += BLOCK_LENGTH;
+ if (length % BLOCK_LENGTH != 0) {
+ length = (length / BLOCK_LENGTH + 1) * BLOCK_LENGTH;
+ }
+
+ if ((buf.readableBytes() >= length || buf.readableBytes() % ACK_LENGTH == 0)
+ && (buf != currentBuffer || buf.readableBytes() > acknowledgedBytes)) {
+ sendResponse(channel);
+ currentBuffer = buf;
+ acknowledgedBytes = buf.readableBytes();
+ }
+
+ if (buf.readableBytes() >= length) {
+ return buf.readRetainedSlice(length);
+ }
+
+ return null;
+ }
+
+}