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Donald_Draper:
Donald_Draper 写道刘落落cici 写道能给我发一 ...
DatagramChannelImpl 解析三(多播) -
Donald_Draper:
刘落落cici 写道能给我发一份这个类的源码吗Datagram ...
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请问楼主,执行消息发送的时候,报错:Transport sch ...
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flyfeifei66:
打算使用xmemcache作为memcache的客户端,由于x ...
Memcached分布式客户端(Xmemcached)
netty 通道接口定义:http://donald-draper.iteye.com/blog/2392740
netty 抽象通道初始化:http://donald-draper.iteye.com/blog/2392801
netty 抽象Unsafe定义:http://donald-draper.iteye.com/blog/2393053
netty 通道Outbound缓冲区:http://donald-draper.iteye.com/blog/2393098
netty 抽象通道后续:http://donald-draper.iteye.com/blog/2393166
netty 抽象nio通道:http://donald-draper.iteye.com/blog/2393269
netty 抽象nio字节通道:http://donald-draper.iteye.com/blog/2393323
netty 抽象nio消息通道:http://donald-draper.iteye.com/blog/2393364
netty NioServerSocketChannel解析:http://donald-draper.iteye.com/blog/2393443
netty 通道配置接口定义:http://donald-draper.iteye.com/blog/2393484
netty 默认通道配置初始化:http://donald-draper.iteye.com/blog/2393504
netty 默认通道配置后续:http://donald-draper.iteye.com/blog/2393510
netty 字节buf定义:http://donald-draper.iteye.com/blog/2393813
netty 资源泄漏探测器:http://donald-draper.iteye.com/blog/2393940
引言
本打算上一文章看一抽象字节buf,但中途遇到了资源泄漏探测器,就简单分析了资源泄漏探测器,今天我们回到抽象字节buf,先来回顾字节buf接口的定义:
对象引用计数器ReferenceCounted,主要记录对象的引用数量,当引用数量为0时,表示可以回收对象,在调试模式下,如果发现对象出现内存泄漏,可以用touch方法记录操作的相关信息,通过ResourceLeakDetector获取操作的相关信息,以便分析内存泄漏的原因。
字节缓存ByteBuf继承了对象引用计数器ReferenceCounted,拥有一个最大容量限制,如果用户尝试用 #capacity(int)和 #ensureWritable(int)方法,增加buf容量超过最大容量,将会抛出非法参数异常;字节buf有两个索引,一个为读索引readerIndex,一个为写索引writerIndex,读索引不能大于写索引,写索引不能小于读索引,buf可读字节数为writerIndex - readerIndex,buf可写字节数为capacity - writerIndex,buf可写的最大字节数为maxCapacity - writerIndex;
可以使用markReader/WriterIndex标记当前buf读写索引位置,resetReader/WriterIndex方法可以重回先前标记的索引位置;
当内存空间负载过度时,我们可以使用discardReadBytes丢弃一些数据,以节省空间;
我们可以使用ensureWritable检测当buf是否有足够的空间写数据;
提供了getBytes方法,可以将buf中的数据转移到目的ByteBuf,Byte数组,Nio字节buf ByteBuffer,OutputStream,聚集字节通道
GatheringByteChannel和文件通道FileChannel中,这些方法不会修改当前buf读写索引,具体是否修改目的对象索引或位置,见java doc 描述。
提供了setBytes方法,可以将源ByteBuf,Byte数组,Nio字节buf ByteBuffer,InputputStream,分散字节通道ScatteringByteChannel和文件通道FileChannel中的数据转移到当前buf中,这些方法不会修改当前buf的读写索引,至于源对象索引或位置,见java doc 描述。
提供了readBytes方法,可以将buf中的数据转移到目的ByteBuf,Byte数组,Nio字节buf ByteBuffer,OutputStream,聚集字节通道GatheringByteChannel和文件通道FileChannel中,这些方法具体会会修改当前buf读索引,至于会不会修改源对象索引或位置,见java doc 描述。
提供了writeBytes方法,可以将源ByteBuf,Byte数组,Nio字节buf ByteBuffer,
InputputStream,分散字节通道ScatteringByteChannel和文件通道FileChannel中的数据写到当前buf中,这些方法会修改当前buf的写索引,至于会不会修改源对象索引或位置,见java
doc 描述。
set*原始类型方法不会修改读写索引;
get*原始类型方法不会修改读写索引;
write*原始类型方法会修改写索引;
read*原始类型方法,会修改读索引;
字节buf中的set/get*方法不会修改当前buf的读写索引,而write*修改写索引,read*会修改读索引;
提供了copy,slice和retainSlice,duplicate和retainedDuplicate方法,用于拷贝,切割,复制当前buf数据,retained*方法会增加buf的
引用计数器;
提供nioBuffer和nioBuffers方法,用于包装当前buf可读数据为java nio ByteBuffer和ByteBuffer数组。
今天我们来看一下抽象字节buf的定义
从上面来看,字节buf内部有两个索引,一个读索引,一个写索引,两个索引标记,即读写索引对应的标记,buf的最大容量为maxCapacity;buf的构造,主要是初始化最大容量。
先来看读写索引相关的操作,很简单,看一下就了。
字节buf,读写索引设值获取、标记重置相关方法:
来看设置读写索引方法
再来看丢弃已经读过的字节数据:
从上面可以看出,丢弃已读数据方法discardReadBytes,丢弃buf数据时,只修改读写索引和相应的标记,
并不删除数据。
再来看,根据负载丢弃数据方法:
来看get*方法:
来看获取一个字节:
检查索引是否越界
//MathUtil
再看获取一个int值:
其他get原始类型方法,思路基本相同;
来看getBytes(*)方法:
字节buf接口定义中:
从上面可以看出,getBytes(...,ByteBuf,...)方法不会修改当前buf读写索引,会修改目的buf的写索引。getBytes(...,byte[],...)方法不会修改当前buf读写索引。
//ByteBufUtil
回到抽象字节buf,来看set方法:
其他set原始类型方法,思路基本相同。
再来看setBytes(*)系列方法:
//ByteBuf
从上面可以看出,setBytes(...,ByteBuf,...)方法不会修改当前buf读写索引,会修改源buf的读索引。setBytes(...,byte[],...)方法不会修改当前buf读写索引。
来set写字符序列
//ByteBufUtil
回到抽象字节buf,来看read*相关方法:
先来看读一个字节数据
其他get*原始类型方法,思路基本相同
来看readBytes(*)相关方法:
从上面来看readBytes(byte[],...),会修改当前buf的读索引
//ByteBuf
//ByteBuf
//ByteBuf
//ByteBuf
从上面可以看出,read*原始类型方法会修改当前buf读索引,readBytes(...,ByteBuf,...)方法会修改当前buf读索引,同时会修改目的buf的写索引,readBytes(...,byte[],...)方法会修改当前buf读索引。read*操作实际委托个get*的相关操作,同时更新buf读索引。
再来看readSlice相关方法
//UnpooledSlicedByteBuf
//AbstractUnpooledSlicedByteBuf,可以理解为字节buf的静态代理
//AbstractDerivedByteBuf,可以理解实现了引用计数器的抽象字节buf
//ByteBuf
从上面可以看出retainedSlice和slice方法返回则的字节buf,实际为字节buf底层unwrap buf,
可以理解为字节buf的快照或引用,数据更改相互影响,retainedSlice方法会增加字节buf的引用计数器。
再来看读部分数据到字节序列
再来看skipBytes方法
再来看write*相关方法:
再来看写int
其他write*原始类型方法,思路基本相同;
再来看writeBytes相关方法
将字节数组数据写到当前buf
将字节buf数据写到当前buf
再来看将nio 字节buf,InputStream,ScatteringByteChannel,FileChannel中的数据写到
当前buf
//ByteBuf
//ByteBuf
//ByteBuf
//ByteBuf
从上面可以看出write*原始类型方法会修改当前buf写索引,writeBytes(...,ByteBuf,...)方法会修改当前buf写索引,同时会修改目的buf的读索引,writeBytes(...,byte[],...)方法会修改当前buf写索引。write*操作实际委托个set*的相关操作,同时更新buf写索引。
再来看复制方法:
//ByteBuf
slice和retainedSlice相关的方法,我们在前面已说,这里仅仅展示一下:
来看完全复制duplicate
//可以理解为buf的静态代理
从上面可以看出:retainedDuplicate和duplicate方法返回则的字节buf,实际为字节buf底层unwrap buf,可以理解为字节buf的快照或引用,数据更改相互影响,retainedDuplicate方法会增加字节buf的引用计数器。
再来看转化nio ByteBuffer
//ByteBuf
public abstract ByteBuffer[] nioBuffers(int index, int length);
总结:
字节buf内部有两个索引,一个读索引,一个写索引,两个索引标记,即读写索引对应的标记,buf的最大容量为maxCapacity;buf的构造,主要是初始化最大容量。
弃已读数据方法discardReadBytes,丢弃buf数据时,只修改读写索引和相应的标记,并不删除数据。
get*原始类型方法不会修改当前buf读写索引,getBytes(...,ByteBuf,...)方法不会修改当前buf读写索引,会修改目的buf的写索引。getBytes(...,byte[],...)方法不会修改当前buf读写索引。
set*原始类型方法不会修改当前buf读写索引,setBytes(...,ByteBuf,...)方法不会修改当前buf读写索引,会修改源buf的读索引。setBytes(...,byte[],...)方法不会修改当前buf读写索引。
read*原始类型方法会修改当前buf读索引,readBytes(...,ByteBuf,...)方法会修改当前buf读索引,同时会修改目的buf的写索引,readBytes(...,byte[],...)方法会修改当前buf读索引。
read*操作实际委托个get*的相关操作,同时更新buf读索引。
跳过length长度的字节,只更新读索引,不删除实际buf数据。
retainedSlice和slice方法返回则的字节buf,实际为字节buf底层unwrap buf,可以理解为字节buf的快照或引用,数据更改相互影响,retainedSlice方法会增加字节buf的引用计数器。
write*原始类型方法会修改当前buf写索引,writeBytes(...,ByteBuf,...)方法会修改当前buf写索引,同时会修改目的buf的读索引,readBytes(...,byte[],...)方法会修改当前buf写索引。
write*操作实际委托个set*的相关操作,同时更新buf写索引。
retainedDuplicate和duplicate方法返回则的字节buf,实际为字节buf底层unwrap buf,可以理解为字节buf的快照或引用,数据更改相互影响,retainedDuplicate方法会增加字节buf的引用计数器。
附:
//ByteBufUtil
/
//ByteProcessor
//遍历buf所有字节,调用处理器,处理
升序方式
倒序方式
netty 抽象通道初始化:http://donald-draper.iteye.com/blog/2392801
netty 抽象Unsafe定义:http://donald-draper.iteye.com/blog/2393053
netty 通道Outbound缓冲区:http://donald-draper.iteye.com/blog/2393098
netty 抽象通道后续:http://donald-draper.iteye.com/blog/2393166
netty 抽象nio通道:http://donald-draper.iteye.com/blog/2393269
netty 抽象nio字节通道:http://donald-draper.iteye.com/blog/2393323
netty 抽象nio消息通道:http://donald-draper.iteye.com/blog/2393364
netty NioServerSocketChannel解析:http://donald-draper.iteye.com/blog/2393443
netty 通道配置接口定义:http://donald-draper.iteye.com/blog/2393484
netty 默认通道配置初始化:http://donald-draper.iteye.com/blog/2393504
netty 默认通道配置后续:http://donald-draper.iteye.com/blog/2393510
netty 字节buf定义:http://donald-draper.iteye.com/blog/2393813
netty 资源泄漏探测器:http://donald-draper.iteye.com/blog/2393940
引言
本打算上一文章看一抽象字节buf,但中途遇到了资源泄漏探测器,就简单分析了资源泄漏探测器,今天我们回到抽象字节buf,先来回顾字节buf接口的定义:
对象引用计数器ReferenceCounted,主要记录对象的引用数量,当引用数量为0时,表示可以回收对象,在调试模式下,如果发现对象出现内存泄漏,可以用touch方法记录操作的相关信息,通过ResourceLeakDetector获取操作的相关信息,以便分析内存泄漏的原因。
字节缓存ByteBuf继承了对象引用计数器ReferenceCounted,拥有一个最大容量限制,如果用户尝试用 #capacity(int)和 #ensureWritable(int)方法,增加buf容量超过最大容量,将会抛出非法参数异常;字节buf有两个索引,一个为读索引readerIndex,一个为写索引writerIndex,读索引不能大于写索引,写索引不能小于读索引,buf可读字节数为writerIndex - readerIndex,buf可写字节数为capacity - writerIndex,buf可写的最大字节数为maxCapacity - writerIndex;
可以使用markReader/WriterIndex标记当前buf读写索引位置,resetReader/WriterIndex方法可以重回先前标记的索引位置;
当内存空间负载过度时,我们可以使用discardReadBytes丢弃一些数据,以节省空间;
我们可以使用ensureWritable检测当buf是否有足够的空间写数据;
提供了getBytes方法,可以将buf中的数据转移到目的ByteBuf,Byte数组,Nio字节buf ByteBuffer,OutputStream,聚集字节通道
GatheringByteChannel和文件通道FileChannel中,这些方法不会修改当前buf读写索引,具体是否修改目的对象索引或位置,见java doc 描述。
提供了setBytes方法,可以将源ByteBuf,Byte数组,Nio字节buf ByteBuffer,InputputStream,分散字节通道ScatteringByteChannel和文件通道FileChannel中的数据转移到当前buf中,这些方法不会修改当前buf的读写索引,至于源对象索引或位置,见java doc 描述。
提供了readBytes方法,可以将buf中的数据转移到目的ByteBuf,Byte数组,Nio字节buf ByteBuffer,OutputStream,聚集字节通道GatheringByteChannel和文件通道FileChannel中,这些方法具体会会修改当前buf读索引,至于会不会修改源对象索引或位置,见java doc 描述。
提供了writeBytes方法,可以将源ByteBuf,Byte数组,Nio字节buf ByteBuffer,
InputputStream,分散字节通道ScatteringByteChannel和文件通道FileChannel中的数据写到当前buf中,这些方法会修改当前buf的写索引,至于会不会修改源对象索引或位置,见java
doc 描述。
set*原始类型方法不会修改读写索引;
get*原始类型方法不会修改读写索引;
write*原始类型方法会修改写索引;
read*原始类型方法,会修改读索引;
字节buf中的set/get*方法不会修改当前buf的读写索引,而write*修改写索引,read*会修改读索引;
提供了copy,slice和retainSlice,duplicate和retainedDuplicate方法,用于拷贝,切割,复制当前buf数据,retained*方法会增加buf的
引用计数器;
提供nioBuffer和nioBuffers方法,用于包装当前buf可读数据为java nio ByteBuffer和ByteBuffer数组。
今天我们来看一下抽象字节buf的定义
package io.netty.buffer; import io.netty.util.ByteProcessor; import io.netty.util.CharsetUtil; import io.netty.util.IllegalReferenceCountException; import io.netty.util.ResourceLeakDetector; import io.netty.util.ResourceLeakDetectorFactory; import io.netty.util.internal.PlatformDependent; import io.netty.util.internal.StringUtil; import io.netty.util.internal.SystemPropertyUtil; import io.netty.util.internal.logging.InternalLogger; import io.netty.util.internal.logging.InternalLoggerFactory; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.nio.channels.FileChannel; import java.nio.channels.GatheringByteChannel; import java.nio.channels.ScatteringByteChannel; import java.nio.charset.Charset; import static io.netty.util.internal.MathUtil.isOutOfBounds; /** * A skeletal implementation of a buffer. */ public abstract class AbstractByteBuf extends ByteBuf { private static final InternalLogger logger = InternalLoggerFactory.getInstance(AbstractByteBuf.class); private static final String PROP_MODE = "io.netty.buffer.bytebuf.checkAccessible"; private static final boolean checkAccessible;//访问buf时,是否可需要检查 static { checkAccessible = SystemPropertyUtil.getBoolean(PROP_MODE, true); if (logger.isDebugEnabled()) { logger.debug("-D{}: {}", PROP_MODE, checkAccessible); } } //内存泄漏探测器 static final ResourceLeakDetector<ByteBuf> leakDetector = ResourceLeakDetectorFactory.instance().newResourceLeakDetector(ByteBuf.class); int readerIndex;//读索引 int writerIndex;//写索引 private int markedReaderIndex;//读索引标记 private int markedWriterIndex;//写索引标记 private int maxCapacity;//最大容量 protected AbstractByteBuf(int maxCapacity) { if (maxCapacity < 0) { throw new IllegalArgumentException("maxCapacity: " + maxCapacity + " (expected: >= 0)"); } this.maxCapacity = maxCapacity; }: }
从上面来看,字节buf内部有两个索引,一个读索引,一个写索引,两个索引标记,即读写索引对应的标记,buf的最大容量为maxCapacity;buf的构造,主要是初始化最大容量。
先来看读写索引相关的操作,很简单,看一下就了。
字节buf,读写索引设值获取、标记重置相关方法:
@Override public boolean isReadOnly() { return false; } @SuppressWarnings("deprecation") @Override public ByteBuf asReadOnly() { if (isReadOnly()) { return this; } return Unpooled.unmodifiableBuffer(this); } @Override public int maxCapacity() { return maxCapacity; } protected final void maxCapacity(int maxCapacity) { this.maxCapacity = maxCapacity; } @Override public int readerIndex() { return readerIndex; } @Override public ByteBuf readerIndex(int readerIndex) { if (readerIndex < 0 || readerIndex > writerIndex) { throw new IndexOutOfBoundsException(String.format( "readerIndex: %d (expected: 0 <= readerIndex <= writerIndex(%d))", readerIndex, writerIndex)); } this.readerIndex = readerIndex; return this; } @Override public int writerIndex() { return writerIndex; } @Override public ByteBuf writerIndex(int writerIndex) { if (writerIndex < readerIndex || writerIndex > capacity()) { throw new IndexOutOfBoundsException(String.format( "writerIndex: %d (expected: readerIndex(%d) <= writerIndex <= capacity(%d))", writerIndex, readerIndex, capacity())); } this.writerIndex = writerIndex; return this; } @Override public ByteBuf clear() { readerIndex = writerIndex = 0; return this; } @Override public boolean isReadable() { return writerIndex > readerIndex; } @Override public boolean isReadable(int numBytes) { return writerIndex - readerIndex >= numBytes; } @Override public boolean isWritable() { return capacity() > writerIndex; } @Override public boolean isWritable(int numBytes) { return capacity() - writerIndex >= numBytes; } @Override public int readableBytes() { return writerIndex - readerIndex; } @Override public int writableBytes() { return capacity() - writerIndex; } @Override public int maxWritableBytes() { return maxCapacity() - writerIndex; } @Override public ByteBuf markReaderIndex() { markedReaderIndex = readerIndex; return this; } @Override public ByteBuf resetReaderIndex() { readerIndex(markedReaderIndex); return this; } @Override public ByteBuf markWriterIndex() { markedWriterIndex = writerIndex; return this; } @Override public ByteBuf resetWriterIndex() { writerIndex = markedWriterIndex; return this; }
来看设置读写索引方法
@Override public ByteBuf setIndex(int readerIndex, int writerIndex) { if (readerIndex < 0 || readerIndex > writerIndex || writerIndex > capacity()) { throw new IndexOutOfBoundsException(String.format( "readerIndex: %d, writerIndex: %d (expected: 0 <= readerIndex <= writerIndex <= capacity(%d))", readerIndex, writerIndex, capacity())); } setIndex0(readerIndex, writerIndex); return this; } final void setIndex0(int readerIndex, int writerIndex) { this.readerIndex = readerIndex; this.writerIndex = writerIndex; }
再来看丢弃已经读过的字节数据:
@Override public ByteBuf discardReadBytes() { ensureAccessible(); if (readerIndex == 0) { return this; } if (readerIndex != writerIndex) { //更新索引 setBytes(0, this, readerIndex, writerIndex - readerIndex); writerIndex -= readerIndex; ////更新读写索引标记 adjustMarkers(readerIndex); readerIndex = 0; } else { adjustMarkers(readerIndex); writerIndex = readerIndex = 0; } return this; } /** * Should be called by every method that tries to access the buffers content to check * if the buffer was released before. 确保buf可以访问 */ protected final void ensureAccessible() { if (checkAccessible && refCnt() == 0) { throw new IllegalReferenceCountException(0); } } //更新读写索引标记 protected final void adjustMarkers(int decrement) { int markedReaderIndex = this.markedReaderIndex; if (markedReaderIndex <= decrement) { this.markedReaderIndex = 0; int markedWriterIndex = this.markedWriterIndex; if (markedWriterIndex <= decrement) { this.markedWriterIndex = 0; } else { this.markedWriterIndex = markedWriterIndex - decrement; } } else { this.markedReaderIndex = markedReaderIndex - decrement; markedWriterIndex -= decrement; } }
从上面可以看出,丢弃已读数据方法discardReadBytes,丢弃buf数据时,只修改读写索引和相应的标记,
并不删除数据。
再来看,根据负载丢弃数据方法:
@Override public ByteBuf discardSomeReadBytes() { ensureAccessible(); if (readerIndex == 0) { return this; } if (readerIndex == writerIndex) { //读写索引相等,则更新读写索引为0 adjustMarkers(readerIndex); writerIndex = readerIndex = 0; return this; } if (readerIndex >= capacity() >>> 1) { //丢弃已读的数据,与discardReadBytes方法作用相同 setBytes(0, this, readerIndex, writerIndex - readerIndex); writerIndex -= readerIndex; adjustMarkers(readerIndex); readerIndex = 0; } return this; }
来看get*方法:
来看获取一个字节:
@Override public byte getByte(int index) { checkIndex(index); return _getByte(index); } //待子类扩展 protected abstract byte _getByte(int index);
检查索引是否越界
protected final void checkIndex(int index) { checkIndex(index, 1); } protected final void checkIndex(int index, int fieldLength) { ensureAccessible(); checkIndex0(index, fieldLength); } final void checkIndex0(int index, int fieldLength) { if (isOutOfBounds(index, fieldLength, capacity())) { throw new IndexOutOfBoundsException(String.format( "index: %d, length: %d (expected: range(0, %d))", index, fieldLength, capacity())); } }
//MathUtil
package io.netty.util.internal; /** * Math utility methods. */ public final class MathUtil { /** * Determine if the requested {@code index} and {@code length} will fit within {@code capacity}. * @param index The starting index. * @param length The length which will be utilized (starting from {@code index}). * @param capacity The capacity that {@code index + length} is allowed to be within. * @return {@code true} if the requested {@code index} and {@code length} will fit within {@code capacity}. * {@code false} if this would result in an index out of bounds exception. */ public static boolean isOutOfBounds(int index, int length, int capacity) { return (index | length | (index + length) | (capacity - (index + length))) < 0; } ... }
再看获取一个int值:
@Override public int getInt(int index) { checkIndex(index, 4); return _getInt(index); } protected abstract int _getInt(int index);
其他get原始类型方法,思路基本相同;
来看getBytes(*)方法:
@Override public ByteBuf getBytes(int index, ByteBuf dst) { getBytes(index, dst, dst.writableBytes()); return this; } @Override public ByteBuf getBytes(int index, ByteBuf dst, int length) { getBytes(index, dst, dst.writerIndex(), length); //更新目的buf索引 dst.writerIndex(dst.writerIndex() + length); return this; } @Override public ByteBuf getBytes(int index, byte[] dst) { getBytes(index, dst, 0, dst.length); return this; }
字节buf接口定义中:
public abstract ByteBuf getBytes(int index, byte[] dst, int dstIndex, int length); public abstract ByteBuf getBytes(int index, ByteBuf dst, int dstIndex, int length);
从上面可以看出,getBytes(...,ByteBuf,...)方法不会修改当前buf读写索引,会修改目的buf的写索引。getBytes(...,byte[],...)方法不会修改当前buf读写索引。
@Override public CharSequence readCharSequence(int length, Charset charset) { CharSequence sequence = getCharSequence(readerIndex, length, charset); readerIndex += length; return sequence; } @Override public CharSequence getCharSequence(int index, int length, Charset charset) { // TODO: We could optimize this for UTF8 and US_ASCII return toString(index, length, charset); } @Override public String toString(Charset charset) { return toString(readerIndex, readableBytes(), charset); } @Override public String toString(int index, int length, Charset charset) { return ByteBufUtil.decodeString(this, index, length, charset); }
//ByteBufUtil
/** * A collection of utility methods that is related with handling {@link ByteBuf}, * such as the generation of hex dump and swapping an integer's byte order. */ public final class ByteBufUtil { //Java nio CharBuffer 线程本地字符buf private static final FastThreadLocal<CharBuffer> CHAR_BUFFERS = new FastThreadLocal<CharBuffer>() { @Override protected CharBuffer initialValue() throws Exception { return CharBuffer.allocate(1024); } }; //根据字符编码解析字节buf为字符串 static String decodeString(ByteBuf src, int readerIndex, int len, Charset charset) { if (len == 0) { return StringUtil.EMPTY_STRING; } //获取字符编码 final CharsetDecoder decoder = CharsetUtil.decoder(charset); final int maxLength = (int) ((double) len * decoder.maxCharsPerByte()); //获取线程本地字符buf CharBuffer dst = CHAR_BUFFERS.get(); if (dst.length() < maxLength) { //重新分配maxLength长度的字符buf dst = CharBuffer.allocate(maxLength); if (maxLength <= MAX_CHAR_BUFFER_SIZE) { //添加buf到线程本地字符buf缓存 CHAR_BUFFERS.set(dst); } } else { //清除线程本地字符buf dst.clear(); } if (src.nioBufferCount() == 1) { // Use internalNioBuffer(...) to reduce object creation. //使用源字节buf的内部nio 字节buf,解码数据 decodeString(decoder, src.internalNioBuffer(readerIndex, len), dst); } else { // We use a heap buffer as CharsetDecoder is most likely able to use a fast-path if src and dst buffers // are both backed by a byte array. //否则分配一个堆buf ByteBuf buffer = src.alloc().heapBuffer(len); try { //将源buf数据写到,写到新的堆buf中 buffer.writeBytes(src, readerIndex, len); // Use internalNioBuffer(...) to reduce object creation. //使用buf的内部nio 字节buf,解码数据 decodeString(decoder, buffer.internalNioBuffer(buffer.readerIndex(), len), dst); } finally { // Release the temporary buffer again. 释放buf buffer.release(); } } //返回解码结果 return dst.flip().toString(); } //根据字符解码器器,解码nio字节buf数据到字符buf private static void decodeString(CharsetDecoder decoder, ByteBuffer src, CharBuffer dst) { try { //委托给字符解码器 CoderResult cr = decoder.decode(src, dst, true); if (!cr.isUnderflow()) { cr.throwException(); } //将解码后的数据写到目的字符buf中 cr = decoder.flush(dst); if (!cr.isUnderflow()) { cr.throwException(); } } catch (CharacterCodingException x) { throw new IllegalStateException(x); } } }
回到抽象字节buf,来看set方法:
@Override public ByteBuf setByte(int index, int value) { checkIndex(index); _setByte(index, value); return this; } //待子类扩展 protected abstract void _setByte(int index, int value); @Override public ByteBuf setInt(int index, int value) { checkIndex(index, 4); _setInt(index, value); return this; } //待子类扩展 protected abstract void _setInt(int index, int value);
其他set原始类型方法,思路基本相同。
再来看setBytes(*)系列方法:
@Override public ByteBuf setBytes(int index, ByteBuf src) { setBytes(index, src, src.readableBytes()); return this; } @Override public ByteBuf setBytes(int index, ByteBuf src, int length) { checkIndex(index, length); if (src == null) { throw new NullPointerException("src"); } if (length > src.readableBytes()) { throw new IndexOutOfBoundsException(String.format( "length(%d) exceeds src.readableBytes(%d) where src is: %s", length, src.readableBytes(), src)); } setBytes(index, src, src.readerIndex(), length); //更新源字节buf的读索引 src.readerIndex(src.readerIndex() + length); return this; } @Override public ByteBuf setBytes(int index, byte[] src) { setBytes(index, src, 0, src.length); return this; }
//ByteBuf
public abstract ByteBuf setBytes(int index, byte[] src, int srcIndex, int length); public abstract ByteBuf setBytes(int index, ByteBuf src, int srcIndex, int length);
从上面可以看出,setBytes(...,ByteBuf,...)方法不会修改当前buf读写索引,会修改源buf的读索引。setBytes(...,byte[],...)方法不会修改当前buf读写索引。
来set写字符序列
@Override public int setCharSequence(int index, CharSequence sequence, Charset charset) { if (charset.equals(CharsetUtil.UTF_8)) { //确保有足有容量可写 ensureWritable(ByteBufUtil.utf8MaxBytes(sequence)); return ByteBufUtil.writeUtf8(this, index, sequence, sequence.length()); } if (charset.equals(CharsetUtil.US_ASCII)) { //ASCII编码,长度为字符序列长度 int len = sequence.length(); ensureWritable(len); return ByteBufUtil.writeAscii(this, index, sequence, len); } //获取字符序列,charset编码对应的字节数组 byte[] bytes = sequence.toString().getBytes(charset); //确保buf容量足够 ensureWritable(bytes.length); //委托给setBytes setBytes(index, bytes); return bytes.length; }
//ByteBufUtil
/** * Returns max bytes length of UTF8 character sequence. 返回字符系列UTF-8编码的长度 */ public static int utf8MaxBytes(CharSequence seq) { return seq.length() * MAX_BYTES_PER_CHAR_UTF8; } // Fast-Path implementation static int writeUtf8(AbstractByteBuf buffer, int writerIndex, CharSequence seq, int len) { int oldWriterIndex = writerIndex; // We can use the _set methods as these not need to do any index checks and reference checks. // This is possible as we called ensureWritable(...) before. for (int i = 0; i < len; i++) { //遍历字符序列,将字符编码成UTF-8字节,写入字节buf中 char c = seq.charAt(i); if (c < 0x80) { buffer._setByte(writerIndex++, (byte) c); } else if (c < 0x800) { buffer._setByte(writerIndex++, (byte) (0xc0 | (c >> 6))); buffer._setByte(writerIndex++, (byte) (0x80 | (c & 0x3f))); } else if (isSurrogate(c)) { if (!Character.isHighSurrogate(c)) { buffer._setByte(writerIndex++, WRITE_UTF_UNKNOWN); continue; } final char c2; try { // Surrogate Pair consumes 2 characters. Optimistically try to get the next character to avoid // duplicate bounds checking with charAt. If an IndexOutOfBoundsException is thrown we will // re-throw a more informative exception describing the problem. c2 = seq.charAt(++i); } catch (IndexOutOfBoundsException e) { buffer._setByte(writerIndex++, WRITE_UTF_UNKNOWN); break; } if (!Character.isLowSurrogate(c2)) { buffer._setByte(writerIndex++, WRITE_UTF_UNKNOWN); buffer._setByte(writerIndex++, Character.isHighSurrogate(c2) ? WRITE_UTF_UNKNOWN : c2); continue; } int codePoint = Character.toCodePoint(c, c2); // See http://www.unicode.org/versions/Unicode7.0.0/ch03.pdf#G2630. buffer._setByte(writerIndex++, (byte) (0xf0 | (codePoint >> 18))); buffer._setByte(writerIndex++, (byte) (0x80 | ((codePoint >> 12) & 0x3f))); buffer._setByte(writerIndex++, (byte) (0x80 | ((codePoint >> 6) & 0x3f))); buffer._setByte(writerIndex++, (byte) (0x80 | (codePoint & 0x3f))); } else { buffer._setByte(writerIndex++, (byte) (0xe0 | (c >> 12))); buffer._setByte(writerIndex++, (byte) (0x80 | ((c >> 6) & 0x3f))); buffer._setByte(writerIndex++, (byte) (0x80 | (c & 0x3f))); } } return writerIndex - oldWriterIndex; } // Fast-Path implementation static int writeAscii(AbstractByteBuf buffer, int writerIndex, CharSequence seq, int len) { // We can use the _set methods as these not need to do any index checks and reference checks. // This is possible as we called ensureWritable(...) before. for (int i = 0; i < len; i++) { buffer._setByte(writerIndex++, (byte) seq.charAt(i)); } return len; }
回到抽象字节buf,来看read*相关方法:
先来看读一个字节数据
@Override public byte readByte() { //检查是否有1个可读字节数据 checkReadableBytes0(1); int i = readerIndex; //获取读索引对应的字节 byte b = _getByte(i); //更新读索引 readerIndex = i + 1; return b; } //检查是否有minimumReadableBytes个可读字节数据 private void checkReadableBytes0(int minimumReadableBytes) { ensureAccessible(); if (readerIndex > writerIndex - minimumReadableBytes) { throw new IndexOutOfBoundsException(String.format( "readerIndex(%d) + length(%d) exceeds writerIndex(%d): %s", readerIndex, minimumReadableBytes, writerIndex, this)); } } @Override public int readInt() { //读一个int值,所以检查是否有4个可读字节数据 checkReadableBytes0(4); //委托给_getInt int v = _getInt(readerIndex); readerIndex += 4; return v; }
其他get*原始类型方法,思路基本相同
来看readBytes(*)相关方法:
//读取当前buf数据,写到字节数组中 @Override public ByteBuf readBytes(byte[] dst) { readBytes(dst, 0, dst.length); return this; } @Override public ByteBuf readBytes(byte[] dst, int dstIndex, int length) { checkReadableBytes(length); //委托getBytes getBytes(readerIndex, dst, dstIndex, length); readerIndex += length;//更新读索引 return this; }
从上面来看readBytes(byte[],...),会修改当前buf的读索引
@Override public ByteBuf readBytes(ByteBuf dst) { readBytes(dst, dst.writableBytes()); return this; } //读当前buf数据,写到目的字节buf中 @Override public ByteBuf readBytes(ByteBuf dst, int length) { if (length > dst.writableBytes()) { throw new IndexOutOfBoundsException(String.format( "length(%d) exceeds dst.writableBytes(%d) where dst is: %s", length, dst.writableBytes(), dst)); } readBytes(dst, dst.writerIndex(), length); dst.writerIndex(dst.writerIndex() + length);//更新目的buf的写索引 return this; } @Override public ByteBuf readBytes(ByteBuf dst, int dstIndex, int length) { checkReadableBytes(length); getBytes(readerIndex, dst, dstIndex, length);//更新目的buf的写索引 readerIndex += length;//更新读索引 return this; }
//读当前buf数据到nio 字节buf @Override public ByteBuf readBytes(ByteBuffer dst) { int length = dst.remaining(); checkReadableBytes(length); getBytes(readerIndex, dst); readerIndex += length; return this; }
//ByteBuf
public abstract ByteBuf getBytes(int index, ByteBuffer dst);
//读当前buf数据到GatheringByteChannel @Override public int readBytes(GatheringByteChannel out, int length) throws IOException { checkReadableBytes(length); int readBytes = getBytes(readerIndex, out, length); readerIndex += readBytes; return readBytes; }
//ByteBuf
public abstract int getBytes(int index, GatheringByteChannel out, int length) throws IOException;
//读当前buf数据到FileChannel @Override public int readBytes(FileChannel out, long position, int length) throws IOException { checkReadableBytes(length); int readBytes = getBytes(readerIndex, out, position, length); readerIndex += readBytes; return readBytes; }
//ByteBuf
public abstract int getBytes(int index, FileChannel out, long position, int length) throws IOException
//读当前buf数据到OutputStream @Override public ByteBuf readBytes(OutputStream out, int length) throws IOException { checkReadableBytes(length); getBytes(readerIndex, out, length); readerIndex += length; return this; }
//ByteBuf
public abstract ByteBuf getBytes(int index, OutputStream out, int length) throws IOException;
从上面可以看出,read*原始类型方法会修改当前buf读索引,readBytes(...,ByteBuf,...)方法会修改当前buf读索引,同时会修改目的buf的写索引,readBytes(...,byte[],...)方法会修改当前buf读索引。read*操作实际委托个get*的相关操作,同时更新buf读索引。
再来看readSlice相关方法
@Override public ByteBuf readSlice(int length) { ByteBuf slice = slice(readerIndex, length); readerIndex += length; return slice; } @Override public ByteBuf readRetainedSlice(int length) { ByteBuf slice = retainedSlice(readerIndex, length); readerIndex += length; return slice; } @Override public ByteBuf slice(int index, int length) { return new UnpooledSlicedByteBuf(this, index, length); } @Override public ByteBuf retainedSlice(int index, int length) { return slice(index, length).retain(); }
//UnpooledSlicedByteBuf
class UnpooledSlicedByteBuf extends AbstractUnpooledSlicedByteBuf { UnpooledSlicedByteBuf(AbstractByteBuf buffer, int index, int length) { super(buffer, index, length); @Override public AbstractByteBuf unwrap() { return (AbstractByteBuf) super.unwrap(); } @Override protected byte _getByte(int index) { return unwrap()._getByte(idx(index)); } //其他get方法思路基本相同 ... }
//AbstractUnpooledSlicedByteBuf,可以理解为字节buf的静态代理
abstract class AbstractUnpooledSlicedByteBuf extends AbstractDerivedByteBuf { private final ByteBuf buffer;//内部字节buf private final int adjustment; //获取内部字节buf @Override public ByteBuf unwrap() { return buffer; } @Override public byte getByte(int index) { checkIndex0(index, 1); return unwrap().getByte(idx(index)); } @Override protected byte _getByte(int index) { return unwrap().getByte(idx(index)); } //其他字节buf的相关方法,都是委托给内部字节buf ... }
//AbstractDerivedByteBuf,可以理解实现了引用计数器的抽象字节buf
public abstract class AbstractDerivedByteBuf extends AbstractByteBuf { protected AbstractDerivedByteBuf(int maxCapacity) { super(maxCapacity); } @Override public final int refCnt() { return refCnt0(); } int refCnt0() { return unwrap().refCnt(); } @Override public final ByteBuf retain() { return retain0(); } ByteBuf retain0() { unwrap().retain(); return this; } ... }
//ByteBuf
/** * Return the underlying buffer instance if this buffer is a wrapper of another buffer. * * @return {@code null} if this buffer is not a wrapper */ public abstract ByteBuf unwrap();
从上面可以看出retainedSlice和slice方法返回则的字节buf,实际为字节buf底层unwrap buf,
可以理解为字节buf的快照或引用,数据更改相互影响,retainedSlice方法会增加字节buf的引用计数器。
再来看读部分数据到字节序列
@Override public CharSequence readCharSequence(int length, Charset charset) { CharSequence sequence = getCharSequence(readerIndex, length, charset); readerIndex += length; return sequence; }
再来看skipBytes方法
//跳过length长度的字节,只更新读索引,不删除实际buf数据 @Override public ByteBuf skipBytes(int length) { checkReadableBytes(length); readerIndex += length; return this; }
再来看write*相关方法:
@Override public ByteBuf writeByte(int value) { ensureAccessible(); //确保buf,足够容下1个字节数据 ensureWritable0(1); //委托给_setByte,并更新写索引 _setByte(writerIndex++, value); return this; } //确保buf,足够容下minWritableBytes个字节数据 @Override public ByteBuf ensureWritable(int minWritableBytes) { if (minWritableBytes < 0) { throw new IllegalArgumentException(String.format( "minWritableBytes: %d (expected: >= 0)", minWritableBytes)); } ensureWritable0(minWritableBytes); return this; } private void ensureWritable0(int minWritableBytes) { if (minWritableBytes <= writableBytes()) { return; } if (minWritableBytes > maxCapacity - writerIndex) { throw new IndexOutOfBoundsException(String.format( "writerIndex(%d) + minWritableBytes(%d) exceeds maxCapacity(%d): %s", writerIndex, minWritableBytes, maxCapacity, this)); } // Normalize the current capacity to the power of 2. 计算新的buf容量 int newCapacity = alloc().calculateNewCapacity(writerIndex + minWritableBytes, maxCapacity); // Adjust to the new capacity. //调整容量 capacity(newCapacity); } @Override public int ensureWritable(int minWritableBytes, boolean force) { if (minWritableBytes < 0) { throw new IllegalArgumentException(String.format( "minWritableBytes: %d (expected: >= 0)", minWritableBytes)); } if (minWritableBytes <= writableBytes()) { //不够写 return 0; } final int maxCapacity = maxCapacity(); final int writerIndex = writerIndex(); if (minWritableBytes > maxCapacity - writerIndex) { if (!force || capacity() == maxCapacity) { return 1; } //扩展至最大容量 capacity(maxCapacity); return 3; } //计算新的容量,并更新 // Normalize the current capacity to the power of 2. int newCapacity = alloc().calculateNewCapacity(writerIndex + minWritableBytes, maxCapacity); // Adjust to the new capacity. capacity(newCapacity); return 2; }
再来看写int
@Override public ByteBuf writeInt(int value) { ensureAccessible(); //确保buf,足够容下4个字节数据 ensureWritable0(4); _setInt(writerIndex, value); writerIndex += 4;//更新写索引 return this; }
其他write*原始类型方法,思路基本相同;
再来看writeBytes相关方法
将字节数组数据写到当前buf
@Override public ByteBuf writeBytes(byte[] src) { writeBytes(src, 0, src.length); return this; } @Override public ByteBuf writeBytes(byte[] src, int srcIndex, int length) { ensureAccessible(); ensureWritable(length); setBytes(writerIndex, src, srcIndex, length); writerIndex += length; return this; }
将字节buf数据写到当前buf
@Override public ByteBuf writeBytes(ByteBuf src) { writeBytes(src, src.readableBytes()); return this; } @Override public ByteBuf writeBytes(ByteBuf src, int length) { if (length > src.readableBytes()) { throw new IndexOutOfBoundsException(String.format( "length(%d) exceeds src.readableBytes(%d) where src is: %s", length, src.readableBytes(), src)); } writeBytes(src, src.readerIndex(), length); src.readerIndex(src.readerIndex() + length); return this; } @Override public ByteBuf writeBytes(ByteBuf src, int srcIndex, int length) { ensureAccessible(); ensureWritable(length); setBytes(writerIndex, src, srcIndex, length); writerIndex += length; return this; }
再来看将nio 字节buf,InputStream,ScatteringByteChannel,FileChannel中的数据写到
当前buf
@Override public ByteBuf writeBytes(ByteBuffer src) { ensureAccessible(); int length = src.remaining(); ensureWritable(length); setBytes(writerIndex, src); writerIndex += length; return this; }
//ByteBuf
public abstract ByteBuf setBytes(int index, ByteBuffer src);
@Override public int writeBytes(InputStream in, int length) throws IOException { ensureAccessible(); ensureWritable(length); int writtenBytes = setBytes(writerIndex, in, length); if (writtenBytes > 0) { writerIndex += writtenBytes; } return writtenBytes; }
//ByteBuf
public abstract int setBytes(int index, InputStream in, int length) throws IOException;
@Override public int writeBytes(ScatteringByteChannel in, int length) throws IOException { ensureAccessible(); ensureWritable(length); int writtenBytes = setBytes(writerIndex, in, length); if (writtenBytes > 0) { writerIndex += writtenBytes; } return writtenBytes; }
//ByteBuf
public abstract int setBytes(int index, ScatteringByteChannel in, int length) throws IOException;
@Override public int writeBytes(FileChannel in, long position, int length) throws IOException { ensureAccessible(); ensureWritable(length); int writtenBytes = setBytes(writerIndex, in, position, length); if (writtenBytes > 0) { writerIndex += writtenBytes; } return writtenBytes; }
//ByteBuf
public abstract int setBytes(int index, FileChannel in, long position, int length) throws IOException;
//写字节序列 @Override public int writeCharSequence(CharSequence sequence, Charset charset) { int written = setCharSequence(writerIndex, sequence, charset); writerIndex += written; return written; }
从上面可以看出write*原始类型方法会修改当前buf写索引,writeBytes(...,ByteBuf,...)方法会修改当前buf写索引,同时会修改目的buf的读索引,writeBytes(...,byte[],...)方法会修改当前buf写索引。write*操作实际委托个set*的相关操作,同时更新buf写索引。
再来看复制方法:
@Override public ByteBuf copy() { return copy(readerIndex, readableBytes()); }
//ByteBuf
public abstract ByteBuf copy(int index, int length);
slice和retainedSlice相关的方法,我们在前面已说,这里仅仅展示一下:
@Override public ByteBuf slice() { return slice(readerIndex, readableBytes()); } @Override public ByteBuf retainedSlice() { return slice().retain(); } @Override public ByteBuf slice(int index, int length) { return new UnpooledSlicedByteBuf(this, index, length); } @Override public ByteBuf retainedSlice(int index, int length) { return slice(index, length).retain(); }
来看完全复制duplicate
@Override public ByteBuf duplicate() { return new UnpooledDuplicatedByteBuf(this); }@Override public ByteBuf retainedDuplicate() { return duplicate().retain(); }
//UnpooledDuplicatedByteBuf
class UnpooledDuplicatedByteBuf extends DuplicatedByteBuf {
UnpooledDuplicatedByteBuf(AbstractByteBuf buffer) {
super(buffer);
}
@Override
public AbstractByteBuf unwrap() {
return (AbstractByteBuf) super.unwrap();
}
@Override
protected byte _getByte(int index) {
return unwrap()._getByte(index);
}
//其他方法思路一样委托给内存的buf
...
}
//可以理解为buf的静态代理
@Deprecated public class DuplicatedByteBuf extends AbstractDerivedByteBuf { private final ByteBuf buffer; public DuplicatedByteBuf(ByteBuf buffer) { this(buffer, buffer.readerIndex(), buffer.writerIndex()); } @Override public byte getByte(int index) { return unwrap().getByte(index); } 其他方法思路一样委托给内存的buf ... }
从上面可以看出:retainedDuplicate和duplicate方法返回则的字节buf,实际为字节buf底层unwrap buf,可以理解为字节buf的快照或引用,数据更改相互影响,retainedDuplicate方法会增加字节buf的引用计数器。
再来看转化nio ByteBuffer
@Override public ByteBuffer nioBuffer() { return nioBuffer(readerIndex, readableBytes()); } @Override public ByteBuffer[] nioBuffers() { return nioBuffers(readerIndex, readableBytes()); }
//ByteBuf
public abstract ByteBuffer[] nioBuffers(int index, int length);
总结:
字节buf内部有两个索引,一个读索引,一个写索引,两个索引标记,即读写索引对应的标记,buf的最大容量为maxCapacity;buf的构造,主要是初始化最大容量。
弃已读数据方法discardReadBytes,丢弃buf数据时,只修改读写索引和相应的标记,并不删除数据。
get*原始类型方法不会修改当前buf读写索引,getBytes(...,ByteBuf,...)方法不会修改当前buf读写索引,会修改目的buf的写索引。getBytes(...,byte[],...)方法不会修改当前buf读写索引。
set*原始类型方法不会修改当前buf读写索引,setBytes(...,ByteBuf,...)方法不会修改当前buf读写索引,会修改源buf的读索引。setBytes(...,byte[],...)方法不会修改当前buf读写索引。
read*原始类型方法会修改当前buf读索引,readBytes(...,ByteBuf,...)方法会修改当前buf读索引,同时会修改目的buf的写索引,readBytes(...,byte[],...)方法会修改当前buf读索引。
read*操作实际委托个get*的相关操作,同时更新buf读索引。
跳过length长度的字节,只更新读索引,不删除实际buf数据。
retainedSlice和slice方法返回则的字节buf,实际为字节buf底层unwrap buf,可以理解为字节buf的快照或引用,数据更改相互影响,retainedSlice方法会增加字节buf的引用计数器。
write*原始类型方法会修改当前buf写索引,writeBytes(...,ByteBuf,...)方法会修改当前buf写索引,同时会修改目的buf的读索引,readBytes(...,byte[],...)方法会修改当前buf写索引。
write*操作实际委托个set*的相关操作,同时更新buf写索引。
retainedDuplicate和duplicate方法返回则的字节buf,实际为字节buf底层unwrap buf,可以理解为字节buf的快照或引用,数据更改相互影响,retainedDuplicate方法会增加字节buf的引用计数器。
附:
//字节查找 @Override public int indexOf(int fromIndex, int toIndex, byte value) { return ByteBufUtil.indexOf(this, fromIndex, toIndex, value); }
//ByteBufUtil
/
** * The default implementation of {@link ByteBuf#indexOf(int, int, byte)}. * This method is useful when implementing a new buffer type. */ public static int indexOf(ByteBuf buffer, int fromIndex, int toIndex, byte value) { if (fromIndex <= toIndex) { return firstIndexOf(buffer, fromIndex, toIndex, value); } else { return lastIndexOf(buffer, fromIndex, toIndex, value); } } private static int firstIndexOf(ByteBuf buffer, int fromIndex, int toIndex, byte value) { fromIndex = Math.max(fromIndex, 0); if (fromIndex >= toIndex || buffer.capacity() == 0) { return -1; } return buffer.forEachByte(fromIndex, toIndex - fromIndex, new ByteProcessor.IndexOfProcessor(value)); } private static int lastIndexOf(ByteBuf buffer, int fromIndex, int toIndex, byte value) { fromIndex = Math.min(fromIndex, buffer.capacity()); if (fromIndex < 0 || buffer.capacity() == 0) { return -1; } return buffer.forEachByteDesc(toIndex, fromIndex - toIndex, new ByteProcessor.IndexOfProcessor(value)); }
//ByteProcessor
public interface ByteProcessor { /** * A {@link ByteProcessor} which finds the first appearance of a specific byte. */ class IndexOfProcessor implements ByteProcessor { private final byte byteToFind; public IndexOfProcessor(byte byteToFind) { this.byteToFind = byteToFind; } @Override public boolean process(byte value) { return value != byteToFind; } } ... }
//获取字节在buf中的第一个索引位置与开始索引之前的长度 @Override public int bytesBefore(byte value) { return bytesBefore(readerIndex(), readableBytes(), value); } @Override public int bytesBefore(int length, byte value) { checkReadableBytes(length); return bytesBefore(readerIndex(), length, value); } @Override public int bytesBefore(int index, int length, byte value) { //委托给indexOf int endIndex = indexOf(index, index + length, value); if (endIndex < 0) { return -1; } return endIndex - index; }
//遍历buf所有字节,调用处理器,处理
升序方式
@Override public int forEachByte(ByteProcessor processor) { ensureAccessible(); try { return forEachByteAsc0(readerIndex, writerIndex, processor); } catch (Exception e) { PlatformDependent.throwException(e); return -1; } } @Override public int forEachByte(int index, int length, ByteProcessor processor) { checkIndex(index, length); try { return forEachByteAsc0(index, index + length, processor); } catch (Exception e) { PlatformDependent.throwException(e); return -1; } } private int forEachByteAsc0(int start, int end, ByteProcessor processor) throws Exception { for (; start < end; ++start) { if (!processor.process(_getByte(start))) { return start; } } return -1; }
倒序方式
@Override public int forEachByteDesc(ByteProcessor processor) { ensureAccessible(); try { return forEachByteDesc0(writerIndex - 1, readerIndex, processor); } catch (Exception e) { PlatformDependent.throwException(e); return -1; } } @Override public int forEachByteDesc(int index, int length, ByteProcessor processor) { checkIndex(index, length); try { return forEachByteDesc0(index + length - 1, index, processor); } catch (Exception e) { PlatformDependent.throwException(e); return -1; } } private int forEachByteDesc0(int rStart, final int rEnd, ByteProcessor processor) throws Exception { for (; rStart >= rEnd; --rStart) { if (!processor.process(_getByte(rStart))) { return rStart; } } return -1; }
@Override public int hashCode() { return ByteBufUtil.hashCode(this); } @Override public boolean equals(Object o) { return this == o || (o instanceof ByteBuf && ByteBufUtil.equals(this, (ByteBuf) o)); } @Override public int compareTo(ByteBuf that) { return ByteBufUtil.compare(this, that); } @Override public String toString() { if (refCnt() == 0) { return StringUtil.simpleClassName(this) + "(freed)"; } StringBuilder buf = new StringBuilder() .append(StringUtil.simpleClassName(this)) .append("(ridx: ").append(readerIndex) .append(", widx: ").append(writerIndex) .append(", cap: ").append(capacity()); if (maxCapacity != Integer.MAX_VALUE) { buf.append('/').append(maxCapacity); } ByteBuf unwrapped = unwrap(); if (unwrapped != null) { buf.append(", unwrapped: ").append(unwrapped); } buf.append(')'); return buf.toString(); }
发表评论
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netty NioSocketChannel解析
2017-09-29 12:50 1320netty 抽象BootStrap定义:http://dona ... -
netty Pooled字节buf分配器
2017-09-28 13:00 2057netty 字节buf定义:http://donald-dra ... -
netty Unpooled字节buf分配器
2017-09-26 22:01 2443netty 字节buf定义:http://donald-dra ... -
netty 抽象字节buf分配器
2017-09-26 08:43 1316netty 字节buf定义:http:// ... -
netty 复合buf概念
2017-09-25 22:31 1310netty 字节buf定义:http://donald-dra ... -
netty 抽象字节buf引用计数器
2017-09-22 12:48 1593netty 字节buf定义:http://donald-dra ... -
netty 资源泄漏探测器
2017-09-21 09:37 1397netty 通道接口定义:http://donald-drap ... -
netty 字节buf定义
2017-09-20 08:31 2833netty 通道接口定义:http://donald-drap ... -
netty 默认通道配置后续
2017-09-18 08:36 2177netty 通道接口定义:http://donald-drap ... -
netty 默认通道配置初始化
2017-09-17 22:51 2036netty 通道接口定义:http://donald-drap ... -
netty 通道配置接口定义
2017-09-17 14:51 1077netty 通道接口定义:http://donald-drap ... -
netty NioServerSocketChannel解析
2017-09-16 13:01 1876netty ServerBootStrap解析:http:// ... -
netty 抽象nio消息通道
2017-09-15 15:30 1217netty 通道接口定义:http:/ ... -
netty 抽象nio字节通道
2017-09-14 22:39 1201netty 通道接口定义:http:/ ... -
netty 抽象nio通道解析
2017-09-14 17:23 957netty 通道接口定义:http://donald-drap ... -
netty 抽象通道后续
2017-09-13 22:40 1309netty Inboudn/Outbound通道Inv ... -
netty 通道Outbound缓冲区
2017-09-13 14:31 2189netty 通道接口定义:http:/ ... -
netty 抽象Unsafe定义
2017-09-12 21:24 1075netty 通道接口定义:http:/ ... -
netty 抽象通道初始化
2017-09-11 12:56 1854netty 管道线定义-ChannelPipeline:htt ... -
netty 通道接口定义
2017-09-10 15:36 1876netty Inboudn/Outbound通道Invoker ...
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