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author | Anton Tananaev <anton.tananaev@gmail.com> | 2019-03-31 22:35:39 -0700 |
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committer | Anton Tananaev <anton.tananaev@gmail.com> | 2019-03-31 22:35:39 -0700 |
commit | 59416923dcb3a756eaf532cc4259f2f6625c0762 (patch) | |
tree | 9082dae6616deac8fda432b7bfd80e4a52b6d9dc /src/main/java/org/traccar/helper/BitBuffer.java | |
parent | 79a129dd6327d932133d6b9a50190d3f4927bff9 (diff) | |
download | trackermap-server-59416923dcb3a756eaf532cc4259f2f6625c0762.tar.gz trackermap-server-59416923dcb3a756eaf532cc4259f2f6625c0762.tar.bz2 trackermap-server-59416923dcb3a756eaf532cc4259f2f6625c0762.zip |
Convert project to gradle
Diffstat (limited to 'src/main/java/org/traccar/helper/BitBuffer.java')
-rw-r--r-- | src/main/java/org/traccar/helper/BitBuffer.java | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/src/main/java/org/traccar/helper/BitBuffer.java b/src/main/java/org/traccar/helper/BitBuffer.java new file mode 100644 index 000000000..f30a4557b --- /dev/null +++ b/src/main/java/org/traccar/helper/BitBuffer.java @@ -0,0 +1,101 @@ +/* + * 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.helper; + +import io.netty.buffer.ByteBuf; +import io.netty.buffer.Unpooled; + +public class BitBuffer { + + private final ByteBuf buffer; + + private int writeByte; + private int writeCount; + + private int readByte; + private int readCount; + + public BitBuffer() { + buffer = Unpooled.buffer(); + } + + public BitBuffer(ByteBuf buffer) { + this.buffer = buffer; + } + + public void writeEncoded(byte[] bytes) { + for (byte b : bytes) { + b -= 48; + if (b > 40) { + b -= 8; + } + write(b); + } + } + + public void write(int b) { + if (writeCount == 0) { + writeByte |= b; + writeCount = 6; + } else { + int remaining = 8 - writeCount; + writeByte <<= remaining; + writeByte |= b >> (6 - remaining); + buffer.writeByte(writeByte); + writeByte = b & ((1 << (6 - remaining)) - 1); + writeCount = 6 - remaining; + } + } + + public int readUnsigned(int length) { + int result = 0; + + while (length > 0) { + if (readCount == 0) { + readByte = buffer.readUnsignedByte(); + readCount = 8; + } + if (readCount >= length) { + result <<= length; + result |= readByte >> (readCount - length); + readByte &= (1 << (readCount - length)) - 1; + readCount -= length; + length = 0; + } else { + result <<= readCount; + result |= readByte; + length -= readCount; + readByte = 0; + readCount = 0; + } + } + + return result; + } + + public int readSigned(int length) { + int result = readUnsigned(length); + int signBit = 1 << (length - 1); + if ((result & signBit) == 0) { + return result; + } else { + result &= signBit - 1; + result += ~(signBit - 1); + return result; + } + } + +} |