ByteHolder.java
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package com.genersoft.iot.vmp.jtt1078.util;
import java.util.Arrays;
/**
* 字节缓冲区工具类
* Created by matrixy on 2018-06-15.
*/
public class ByteHolder {
int offset = 0;
int size = 0;
byte[] buffer = null;
public ByteHolder(int bufferSize) {
this.buffer = new byte[bufferSize];
}
public int size() {
return this.size;
}
public void write(byte[] data) {
write(data, 0, data.length);
}
public void write(byte[] data, int offset, int length) {
// 防止溢出，简单的扩容策略或抛异常
if (this.offset + length > buffer.length) {
// 简单扩容策略：如果空间不够，扩大两倍 (可选)
// byte[] newBuffer = new byte[Math.max(buffer.length * 2, this.offset + length)];
// System.arraycopy(buffer, 0, newBuffer, 0, this.offset);
// this.buffer = newBuffer;
// 原有逻辑：直接抛异常
throw new RuntimeException(String.format("exceed the max buffer size, max length: %d, data length: %d", buffer.length, length));
}
System.arraycopy(data, offset, buffer, this.offset, length);
this.offset += length;
this.size += length;
}
public byte[] array() {
return array(this.size);
}
public byte[] array(int length) {
return Arrays.copyOf(this.buffer, length);
}
public void write(byte b) {
if (this.offset >= buffer.length) {
throw new RuntimeException("Buffer overflow");
}
this.buffer[offset++] = b;
this.size += 1;
}
/**
* 将数据读入 dest 数组，并从缓冲区移除这些数据
*/
public void sliceInto(byte[] dest, int length) {
if (length > this.size) {
throw new RuntimeException("Buffer underflow: not enough bytes to read");
}
System.arraycopy(this.buffer, 0, dest, 0, length);
// 往前挪 length 个位 (移除已读数据)
System.arraycopy(this.buffer, length, this.buffer, 0, this.size - length);
this.offset -= length;
this.size -= length;
}
/**
* 【新增】读取字节到数组中，并从缓冲区移除
* 配合 Decoder 的搜寻包头逻辑使用
*/
public void read(byte[] dest) {
sliceInto(dest, dest.length);
}
/**
* 丢弃前 length 个字节
*/
public void slice(int length) {
if (length > this.size) {
length = this.size; // 容错处理，最多丢弃所有
}
System.arraycopy(this.buffer, length, this.buffer, 0, this.size - length);
this.offset -= length;
this.size -= length;
}
public byte get(int position) {
return this.buffer[position];
}
public void clear() {
this.offset = 0;
this.size = 0;
}
public int getInt(int offset) {
// 需保证 ByteUtils 存在且逻辑正确
return ByteUtils.getInt(this.buffer, offset, 4);
}
public int getShort(int position) {
int h = this.buffer[position] & 0xff;
int l = this.buffer[position + 1] & 0xff;
return ((h << 8) | l) & 0xffff;
}
}