/*
* Copyright 2013 The Netty Project
*
* The Netty Project licenses this file to you 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 io.netty.buffer;
import io.netty.util.internal.EmptyArrays;
import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.StringUtil;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.ReadOnlyBufferException;
import java.nio.channels.GatheringByteChannel;
import java.nio.channels.ScatteringByteChannel;
import java.nio.charset.Charset;
/**
* An empty {@link ByteBuf} whose capacity and maximum capacity are all {@code 0}.
*/
public final class EmptyByteBuf extends ByteBuf {
private static final ByteBuffer EMPTY_BYTE_BUFFER = ByteBuffer.allocateDirect(0);
private static final long EMPTY_BYTE_BUFFER_ADDRESS;
static {
long emptyByteBufferAddress = 0;
try {
if (PlatformDependent.hasUnsafe()) {
emptyByteBufferAddress = PlatformDependent.directBufferAddress(EMPTY_BYTE_BUFFER);
}
} catch (Throwable t) {
// Ignore
}
EMPTY_BYTE_BUFFER_ADDRESS = emptyByteBufferAddress;
}
private final ByteBufAllocator alloc;
private final ByteOrder order;
private final String str;
private EmptyByteBuf swapped;
public EmptyByteBuf(ByteBufAllocator alloc) {
this(alloc, ByteOrder.BIG_ENDIAN);
}
private EmptyByteBuf(ByteBufAllocator alloc, ByteOrder order) {
if (alloc == null) {
throw new NullPointerException("alloc");
}
this.alloc = alloc;
this.order = order;
str = StringUtil.simpleClassName(this) + (order == ByteOrder.BIG_ENDIAN? "BE" : "LE");
}
@Override
public int capacity() {
return 0;
}
@Override
public ByteBuf capacity(int newCapacity) {
throw new ReadOnlyBufferException();
}
@Override
public ByteBufAllocator alloc() {
return alloc;
}
@Override
public ByteOrder order() {
return order;
}
@Override
public ByteBuf unwrap() {
return null;
}
@Override
public boolean isDirect() {
return true;
}
@Override
public int maxCapacity() {
return 0;
}
@Override
public ByteBuf order(ByteOrder endianness) {
if (endianness == null) {
throw new NullPointerException("endianness");
}
if (endianness == order()) {
return this;
}
EmptyByteBuf swapped = this.swapped;
if (swapped != null) {
return swapped;
}
this.swapped = swapped = new EmptyByteBuf(alloc(), endianness);
return swapped;
}
@Override
public int readerIndex() {
return 0;
}
@Override
public ByteBuf readerIndex(int readerIndex) {
return checkIndex(readerIndex);
}
@Override
public int writerIndex() {
return 0;
}
@Override
public ByteBuf writerIndex(int writerIndex) {
return checkIndex(writerIndex);
}
@Override
public ByteBuf setIndex(int readerIndex, int writerIndex) {
checkIndex(readerIndex);
checkIndex(writerIndex);
return this;
}
@Override
public int readableBytes() {
return 0;
}
@Override
public int writableBytes() {
return 0;
}
@Override
public int maxWritableBytes() {
return 0;
}
@Override
public boolean isReadable() {
return false;
}
@Override
public boolean isWritable() {
return false;
}
@Override
public ByteBuf clear() {
return this;
}
@Override
public ByteBuf markReaderIndex() {
return this;
}
@Override
public ByteBuf resetReaderIndex() {
return this;
}
@Override
public ByteBuf markWriterIndex() {
return this;
}
@Override
public ByteBuf resetWriterIndex() {
return this;
}
@Override
public ByteBuf discardReadBytes() {
return this;
}
@Override
public ByteBuf discardSomeReadBytes() {
return this;
}
@Override
public ByteBuf ensureWritable(int minWritableBytes) {
if (minWritableBytes < 0) {
throw new IllegalArgumentException("minWritableBytes: " + minWritableBytes + " (expected: >= 0)");
}
if (minWritableBytes != 0) {
throw new IndexOutOfBoundsException();
}
return this;
}
@Override
public int ensureWritable(int minWritableBytes, boolean force) {
if (minWritableBytes < 0) {
throw new IllegalArgumentException("minWritableBytes: " + minWritableBytes + " (expected: >= 0)");
}
if (minWritableBytes == 0) {
return 0;
}
return 1;
}
@Override
public boolean getBoolean(int index) {
throw new IndexOutOfBoundsException();
}
@Override
public byte getByte(int index) {
throw new IndexOutOfBoundsException();
}
@Override
public short getUnsignedByte(int index) {
throw new IndexOutOfBoundsException();
}
@Override
public short getShort(int index) {
throw new IndexOutOfBoundsException();
}
@Override
public int getUnsignedShort(int index) {
throw new IndexOutOfBoundsException();
}
@Override
public int getMedium(int index) {
throw new IndexOutOfBoundsException();
}
@Override
public int getUnsignedMedium(int index) {
throw new IndexOutOfBoundsException();
}
@Override
public int getInt(int index) {
throw new IndexOutOfBoundsException();
}
@Override
public long getUnsignedInt(int index) {
throw new IndexOutOfBoundsException();
}
@Override
public long getLong(int index) {
throw new IndexOutOfBoundsException();
}
@Override
public char getChar(int index) {
throw new IndexOutOfBoundsException();
}
@Override
public float getFloat(int index) {
throw new IndexOutOfBoundsException();
}
@Override
public double getDouble(int index) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf getBytes(int index, ByteBuf dst) {
return checkIndex(index, dst.writableBytes());
}
@Override
public ByteBuf getBytes(int index, ByteBuf dst, int length) {
return checkIndex(index, length);
}
@Override
public ByteBuf getBytes(int index, ByteBuf dst, int dstIndex, int length) {
return checkIndex(index, length);
}
@Override
public ByteBuf getBytes(int index, byte[] dst) {
return checkIndex(index, dst.length);
}
@Override
public ByteBuf getBytes(int index, byte[] dst, int dstIndex, int length) {
return checkIndex(index, length);
}
@Override
public ByteBuf getBytes(int index, ByteBuffer dst) {
return checkIndex(index, dst.remaining());
}
@Override
public ByteBuf getBytes(int index, OutputStream out, int length) {
return checkIndex(index, length);
}
@Override
public int getBytes(int index, GatheringByteChannel out, int length) {
checkIndex(index, length);
return 0;
}
@Override
public ByteBuf setBoolean(int index, boolean value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf setByte(int index, int value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf setShort(int index, int value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf setMedium(int index, int value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf setInt(int index, int value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf setLong(int index, long value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf setChar(int index, int value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf setFloat(int index, float value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf setDouble(int index, double value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf setBytes(int index, ByteBuf src) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf setBytes(int index, ByteBuf src, int length) {
return checkIndex(index, length);
}
@Override
public ByteBuf setBytes(int index, ByteBuf src, int srcIndex, int length) {
return checkIndex(index, length);
}
@Override
public ByteBuf setBytes(int index, byte[] src) {
return checkIndex(index, src.length);
}
@Override
public ByteBuf setBytes(int index, byte[] src, int srcIndex, int length) {
return checkIndex(index, length);
}
@Override
public ByteBuf setBytes(int index, ByteBuffer src) {
return checkIndex(index, src.remaining());
}
@Override
public int setBytes(int index, InputStream in, int length) {
checkIndex(index, length);
return 0;
}
@Override
public int setBytes(int index, ScatteringByteChannel in, int length) {
checkIndex(index, length);
return 0;
}
@Override
public ByteBuf setZero(int index, int length) {
return checkIndex(index, length);
}
@Override
public boolean readBoolean() {
throw new IndexOutOfBoundsException();
}
@Override
public byte readByte() {
throw new IndexOutOfBoundsException();
}
@Override
public short readUnsignedByte() {
throw new IndexOutOfBoundsException();
}
@Override
public short readShort() {
throw new IndexOutOfBoundsException();
}
@Override
public int readUnsignedShort() {
throw new IndexOutOfBoundsException();
}
@Override
public int readMedium() {
throw new IndexOutOfBoundsException();
}
@Override
public int readUnsignedMedium() {
throw new IndexOutOfBoundsException();
}
@Override
public int readInt() {
throw new IndexOutOfBoundsException();
}
@Override
public long readUnsignedInt() {
throw new IndexOutOfBoundsException();
}
@Override
public long readLong() {
throw new IndexOutOfBoundsException();
}
@Override
public char readChar() {
throw new IndexOutOfBoundsException();
}
@Override
public float readFloat() {
throw new IndexOutOfBoundsException();
}
@Override
public double readDouble() {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf readBytes(int length) {
return checkLength(length);
}
@Override
public ByteBuf readSlice(int length) {
return checkLength(length);
}
@Override
public ByteBuf readBytes(ByteBuf dst) {
return checkLength(dst.writableBytes());
}
@Override
public ByteBuf readBytes(ByteBuf dst, int length) {
return checkLength(length);
}
@Override
public ByteBuf readBytes(ByteBuf dst, int dstIndex, int length) {
return checkLength(length);
}
@Override
public ByteBuf readBytes(byte[] dst) {
return checkLength(dst.length);
}
@Override
public ByteBuf readBytes(byte[] dst, int dstIndex, int length) {
return checkLength(length);
}
@Override
public ByteBuf readBytes(ByteBuffer dst) {
return checkLength(dst.remaining());
}
@Override
public ByteBuf readBytes(OutputStream out, int length) {
return checkLength(length);
}
@Override
public int readBytes(GatheringByteChannel out, int length) {
checkLength(length);
return 0;
}
@Override
public ByteBuf skipBytes(int length) {
return checkLength(length);
}
@Override
public ByteBuf writeBoolean(boolean value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf writeByte(int value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf writeShort(int value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf writeMedium(int value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf writeInt(int value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf writeLong(long value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf writeChar(int value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf writeFloat(float value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf writeDouble(double value) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf writeBytes(ByteBuf src) {
throw new IndexOutOfBoundsException();
}
@Override
public ByteBuf writeBytes(ByteBuf src, int length) {
return checkLength(length);
}
@Override
public ByteBuf writeBytes(ByteBuf src, int srcIndex, int length) {
return checkLength(length);
}
@Override
public ByteBuf writeBytes(byte[] src) {
return checkLength(src.length);
}
@Override
public ByteBuf writeBytes(byte[] src, int srcIndex, int length) {
return checkLength(length);
}
@Override
public ByteBuf writeBytes(ByteBuffer src) {
return checkLength(src.remaining());
}
@Override
public int writeBytes(InputStream in, int length) {
checkLength(length);
return 0;
}
@Override
public int writeBytes(ScatteringByteChannel in, int length) {
checkLength(length);
return 0;
}
@Override
public ByteBuf writeZero(int length) {
return checkLength(length);
}
@Override
public int indexOf(int fromIndex, int toIndex, byte value) {
checkIndex(fromIndex);
checkIndex(toIndex);
return -1;
}
@Override
public int bytesBefore(byte value) {
return -1;
}
@Override
public int bytesBefore(int length, byte value) {
checkLength(length);
return -1;
}
@Override
public int bytesBefore(int index, int length, byte value) {
checkIndex(index, length);
return -1;
}
@Override
public int forEachByte(ByteBufProcessor processor) {
return -1;
}
@Override
public int forEachByte(int index, int length, ByteBufProcessor processor) {
checkIndex(index, length);
return -1;
}
@Override
public int forEachByteDesc(ByteBufProcessor processor) {
return -1;
}
@Override
public int forEachByteDesc(int index, int length, ByteBufProcessor processor) {
checkIndex(index, length);
return -1;
}
@Override
public ByteBuf copy() {
return this;
}
@Override
public ByteBuf copy(int index, int length) {
return checkIndex(index, length);
}
@Override
public ByteBuf slice() {
return this;
}
@Override
public ByteBuf slice(int index, int length) {
return checkIndex(index, length);
}
@Override
public ByteBuf duplicate() {
return this;
}
@Override
public int nioBufferCount() {
return 1;
}
@Override
public ByteBuffer nioBuffer() {
return EMPTY_BYTE_BUFFER;
}
@Override
public ByteBuffer nioBuffer(int index, int length) {
checkIndex(index, length);
return nioBuffer();
}
@Override
public ByteBuffer[] nioBuffers() {
return new ByteBuffer[] { EMPTY_BYTE_BUFFER };
}
@Override
public ByteBuffer[] nioBuffers(int index, int length) {
checkIndex(index, length);
return nioBuffers();
}
@Override
public ByteBuffer internalNioBuffer(int index, int length) {
return EMPTY_BYTE_BUFFER;
}
@Override
public boolean hasArray() {
return true;
}
@Override
public byte[] array() {
return EmptyArrays.EMPTY_BYTES;
}
@Override
public int arrayOffset() {
return 0;
}
@Override
public boolean hasMemoryAddress() {
return EMPTY_BYTE_BUFFER_ADDRESS != 0;
}
@Override
public long memoryAddress() {
if (hasMemoryAddress()) {
return EMPTY_BYTE_BUFFER_ADDRESS;
} else {
throw new UnsupportedOperationException();
}
}
@Override
public String toString(Charset charset) {
return "";
}
@Override
public String toString(int index, int length, Charset charset) {
checkIndex(index, length);
return toString(charset);
}
@Override
public int hashCode() {
return 0;
}
@Override
public boolean equals(Object obj) {
return obj instanceof ByteBuf && !((ByteBuf) obj).isReadable();
}
@Override
public int compareTo(ByteBuf buffer) {
return buffer.isReadable()? -1 : 0;
}
@Override
public String toString() {
return str;
}
@Override
public boolean isReadable(int size) {
return false;
}
@Override
public boolean isWritable(int size) {
return false;
}
@Override
public int refCnt() {
return 1;
}
@Override
public ByteBuf retain() {
return this;
}
@Override
public ByteBuf retain(int increment) {
return this;
}
@Override
public boolean release() {
return false;
}
@Override
public boolean release(int decrement) {
return false;
}
private ByteBuf checkIndex(int index) {
if (index != 0) {
throw new IndexOutOfBoundsException();
}
return this;
}
private ByteBuf checkIndex(int index, int length) {
if (length < 0) {
throw new IllegalArgumentException("length: " + length);
}
if (index != 0 || length != 0) {
throw new IndexOutOfBoundsException();
}
return this;
}
private ByteBuf checkLength(int length) {
if (length < 0) {
throw new IllegalArgumentException("length: " + length + " (expected: >= 0)");
}
if (length != 0) {
throw new IndexOutOfBoundsException();
}
return this;
}
}