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/*
 * Copyright 2012 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 org.jboss.netty.buffer;

import org.jboss.netty.util.CharsetUtil;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.CharBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CoderResult;
import java.util.ArrayList;
import java.util.List;


/**
 * Creates a new {@link ChannelBuffer} by allocating new space or by wrapping
 * or copying existing byte arrays, byte buffers and a string.
 *
 * 

Use static import

* This classes is intended to be used with Java 5 static import statement: * *
 * import static org.jboss.netty.buffer.{@link ChannelBuffers}.*;
 *
 * {@link ChannelBuffer} heapBuffer    = buffer(128);
 * {@link ChannelBuffer} directBuffer  = directBuffer(256);
 * {@link ChannelBuffer} dynamicBuffer = dynamicBuffer(512);
 * {@link ChannelBuffer} wrappedBuffer = wrappedBuffer(new byte[128], new byte[256]);
 * {@link ChannelBuffer} copiedBuffe r = copiedBuffer({@link ByteBuffer}.allocate(128));
 * 
* *

Allocating a new buffer

* * Three buffer types are provided out of the box. * *
    *
  • {@link #buffer(int)} allocates a new fixed-capacity heap buffer.
  • *
  • {@link #directBuffer(int)} allocates a new fixed-capacity direct buffer.
  • *
  • {@link #dynamicBuffer(int)} allocates a new dynamic-capacity heap * buffer, whose capacity increases automatically as needed by a write * operation.
  • *
* *

Creating a wrapped buffer

* * Wrapped buffer is a buffer which is a view of one or more existing * byte arrays and byte buffers. Any changes in the content of the original * array or buffer will be visible in the wrapped buffer. Various wrapper * methods are provided and their name is all {@code wrappedBuffer()}. * You might want to take a look at the methods that accept varargs closely if * you want to create a buffer which is composed of more than one array to * reduce the number of memory copy. * *

Creating a copied buffer

* * Copied buffer is a deep copy of one or more existing byte arrays, byte * buffers or a string. Unlike a wrapped buffer, there's no shared data * between the original data and the copied buffer. Various copy methods are * provided and their name is all {@code copiedBuffer()}. It is also convenient * to use this operation to merge multiple buffers into one buffer. * *

Miscellaneous utility methods

* * This class also provides various utility methods to help implementation * of a new buffer type, generation of hex dump and swapping an integer's * byte order. * * @apiviz.landmark * @apiviz.has org.jboss.netty.buffer.ChannelBuffer oneway - - creates */ public final class ChannelBuffers { /** * Big endian byte order. */ public static final ByteOrder BIG_ENDIAN = ByteOrder.BIG_ENDIAN; /** * Little endian byte order. */ public static final ByteOrder LITTLE_ENDIAN = ByteOrder.LITTLE_ENDIAN; /** * A buffer whose capacity is {@code 0}. */ public static final ChannelBuffer EMPTY_BUFFER = new EmptyChannelBuffer(); private static final char[] HEXDUMP_TABLE = new char[256 * 4]; static { final char[] DIGITS = "0123456789abcdef".toCharArray(); for (int i = 0; i < 256; i ++) { HEXDUMP_TABLE[i << 1] = DIGITS[i >>> 4 & 0x0F]; HEXDUMP_TABLE[(i << 1) + 1] = DIGITS[i & 0x0F]; } } /** * Creates a new big-endian Java heap buffer with the specified * {@code capacity}. The new buffer's {@code readerIndex} and * {@code writerIndex} are {@code 0}. */ public static ChannelBuffer buffer(int capacity) { return buffer(BIG_ENDIAN, capacity); } /** * Creates a new Java heap buffer with the specified {@code endianness} * and {@code capacity}. The new buffer's {@code readerIndex} and * {@code writerIndex} are {@code 0}. */ public static ChannelBuffer buffer(ByteOrder endianness, int capacity) { if (endianness == BIG_ENDIAN) { if (capacity == 0) { return EMPTY_BUFFER; } return new BigEndianHeapChannelBuffer(capacity); } else if (endianness == LITTLE_ENDIAN) { if (capacity == 0) { return EMPTY_BUFFER; } return new LittleEndianHeapChannelBuffer(capacity); } else { throw new NullPointerException("endianness"); } } /** * Creates a new big-endian direct buffer with the specified * {@code capacity}. The new buffer's {@code readerIndex} and * {@code writerIndex} are {@code 0}. */ public static ChannelBuffer directBuffer(int capacity) { return directBuffer(BIG_ENDIAN, capacity); } /** * Creates a new direct buffer with the specified {@code endianness} and * {@code capacity}. The new buffer's {@code readerIndex} and * {@code writerIndex} are {@code 0}. */ public static ChannelBuffer directBuffer(ByteOrder endianness, int capacity) { if (endianness == null) { throw new NullPointerException("endianness"); } if (capacity == 0) { return EMPTY_BUFFER; } ChannelBuffer buffer = new ByteBufferBackedChannelBuffer( ByteBuffer.allocateDirect(capacity).order(endianness)); buffer.clear(); return buffer; } /** * Creates a new big-endian dynamic buffer whose estimated data length is * {@code 256} bytes. The new buffer's {@code readerIndex} and * {@code writerIndex} are {@code 0}. */ public static ChannelBuffer dynamicBuffer() { return dynamicBuffer(BIG_ENDIAN, 256); } public static ChannelBuffer dynamicBuffer(ChannelBufferFactory factory) { if (factory == null) { throw new NullPointerException("factory"); } return new DynamicChannelBuffer(factory.getDefaultOrder(), 256, factory); } /** * Creates a new big-endian dynamic buffer with the specified estimated * data length. More accurate estimation yields less unexpected * reallocation overhead. The new buffer's {@code readerIndex} and * {@code writerIndex} are {@code 0}. */ public static ChannelBuffer dynamicBuffer(int estimatedLength) { return dynamicBuffer(BIG_ENDIAN, estimatedLength); } /** * Creates a new dynamic buffer with the specified endianness and * the specified estimated data length. More accurate estimation yields * less unexpected reallocation overhead. The new buffer's * {@code readerIndex} and {@code writerIndex} are {@code 0}. */ public static ChannelBuffer dynamicBuffer(ByteOrder endianness, int estimatedLength) { return new DynamicChannelBuffer(endianness, estimatedLength); } /** * Creates a new big-endian dynamic buffer with the specified estimated * data length using the specified factory. More accurate estimation yields * less unexpected reallocation overhead. The new buffer's {@code readerIndex} * and {@code writerIndex} are {@code 0}. */ public static ChannelBuffer dynamicBuffer(int estimatedLength, ChannelBufferFactory factory) { if (factory == null) { throw new NullPointerException("factory"); } return new DynamicChannelBuffer(factory.getDefaultOrder(), estimatedLength, factory); } /** * Creates a new dynamic buffer with the specified endianness and * the specified estimated data length using the specified factory. * More accurate estimation yields less unexpected reallocation overhead. * The new buffer's {@code readerIndex} and {@code writerIndex} are {@code 0}. */ public static ChannelBuffer dynamicBuffer( ByteOrder endianness, int estimatedLength, ChannelBufferFactory factory) { return new DynamicChannelBuffer(endianness, estimatedLength, factory); } /** * Creates a new big-endian buffer which wraps the specified {@code array}. * A modification on the specified array's content will be visible to the * returned buffer. */ public static ChannelBuffer wrappedBuffer(byte[] array) { return wrappedBuffer(BIG_ENDIAN, array); } /** * Creates a new buffer which wraps the specified {@code array} with the * specified {@code endianness}. A modification on the specified array's * content will be visible to the returned buffer. */ public static ChannelBuffer wrappedBuffer(ByteOrder endianness, byte[] array) { if (endianness == BIG_ENDIAN) { if (array.length == 0) { return EMPTY_BUFFER; } return new BigEndianHeapChannelBuffer(array); } else if (endianness == LITTLE_ENDIAN) { if (array.length == 0) { return EMPTY_BUFFER; } return new LittleEndianHeapChannelBuffer(array); } else { throw new NullPointerException("endianness"); } } /** * Creates a new big-endian buffer which wraps the sub-region of the * specified {@code array}. A modification on the specified array's * content will be visible to the returned buffer. */ public static ChannelBuffer wrappedBuffer(byte[] array, int offset, int length) { return wrappedBuffer(BIG_ENDIAN, array, offset, length); } /** * Creates a new buffer which wraps the sub-region of the specified * {@code array} with the specified {@code endianness}. A modification on * the specified array's content will be visible to the returned buffer. */ public static ChannelBuffer wrappedBuffer(ByteOrder endianness, byte[] array, int offset, int length) { if (endianness == null) { throw new NullPointerException("endianness"); } if (offset == 0) { if (length == array.length) { return wrappedBuffer(endianness, array); } else { if (length == 0) { return EMPTY_BUFFER; } else { return new TruncatedChannelBuffer(wrappedBuffer(endianness, array), length); } } } else { if (length == 0) { return EMPTY_BUFFER; } else { return new SlicedChannelBuffer(wrappedBuffer(endianness, array), offset, length); } } } /** * Creates a new buffer which wraps the specified NIO buffer's current * slice. A modification on the specified buffer's content will be * visible to the returned buffer. */ public static ChannelBuffer wrappedBuffer(ByteBuffer buffer) { if (!buffer.hasRemaining()) { return EMPTY_BUFFER; } if (buffer.hasArray()) { return wrappedBuffer( buffer.order(), buffer.array(), buffer.arrayOffset() + buffer.position(), buffer.remaining()); } else { return new ByteBufferBackedChannelBuffer(buffer); } } /** * Creates a new buffer which wraps the specified buffer's readable bytes. * A modification on the specified buffer's content will be visible to the * returned buffer. */ public static ChannelBuffer wrappedBuffer(ChannelBuffer buffer) { if (buffer.readable()) { return buffer.slice(); } else { return EMPTY_BUFFER; } } /** * Creates a new big-endian composite buffer which wraps the specified * arrays without copying them. A modification on the specified arrays' * content will be visible to the returned buffer. */ public static ChannelBuffer wrappedBuffer(byte[]... arrays) { return wrappedBuffer(BIG_ENDIAN, arrays); } /** * Creates a new composite buffer which wraps the specified arrays without * copying them. A modification on the specified arrays' content will be * visible to the returned buffer. * * @param endianness the endianness of the new buffer */ public static ChannelBuffer wrappedBuffer(ByteOrder endianness, byte[]... arrays) { switch (arrays.length) { case 0: break; case 1: if (arrays[0].length != 0) { return wrappedBuffer(endianness, arrays[0]); } break; default: // Get the list of the component, while guessing the byte order. final List components = new ArrayList(arrays.length); for (byte[] a: arrays) { if (a == null) { break; } if (a.length > 0) { components.add(wrappedBuffer(endianness, a)); } } return compositeBuffer(endianness, components, false); } return EMPTY_BUFFER; } private static ChannelBuffer compositeBuffer( ByteOrder endianness, List components, boolean gathering) { switch (components.size()) { case 0: return EMPTY_BUFFER; case 1: return components.get(0); default: return new CompositeChannelBuffer(endianness, components, gathering); } } /** * Creates a new composite buffer which wraps the readable bytes of the * specified buffers without copying them. A modification on the content * of the specified buffers will be visible to the returned buffer. * * @throws IllegalArgumentException * if the specified buffers' endianness are different from each * other */ public static ChannelBuffer wrappedBuffer(ChannelBuffer... buffers) { return wrappedBuffer(false, buffers); } /** * Creates a new composite buffer which wraps the readable bytes of the * specified buffers without copying them. A modification on the content * of the specified buffers will be visible to the returned buffer. * If gathering is {@code true} then gathering writes will be used when ever * possible. * * @throws IllegalArgumentException * if the specified buffers' endianness are different from each * other */ public static ChannelBuffer wrappedBuffer(boolean gathering, ChannelBuffer... buffers) { switch (buffers.length) { case 0: break; case 1: if (buffers[0].readable()) { return wrappedBuffer(buffers[0]); } break; default: ByteOrder order = null; final List components = new ArrayList(buffers.length); for (ChannelBuffer c: buffers) { if (c == null) { break; } if (c.readable()) { if (order != null) { if (!order.equals(c.order())) { throw new IllegalArgumentException( "inconsistent byte order"); } } else { order = c.order(); } if (c instanceof CompositeChannelBuffer) { // Expand nested composition. components.addAll( ((CompositeChannelBuffer) c).decompose( c.readerIndex(), c.readableBytes())); } else { // An ordinary buffer (non-composite) components.add(c.slice()); } } } return compositeBuffer(order, components, gathering); } return EMPTY_BUFFER; } /** * Creates a new composite buffer which wraps the slices of the specified * NIO buffers without copying them. A modification on the content of the * specified buffers will be visible to the returned buffer. * * @throws IllegalArgumentException * if the specified buffers' endianness are different from each * other */ public static ChannelBuffer wrappedBuffer(ByteBuffer... buffers) { return wrappedBuffer(false, buffers); } /** * Creates a new composite buffer which wraps the slices of the specified * NIO buffers without copying them. A modification on the content of the * specified buffers will be visible to the returned buffer. * If gathering is {@code true} then gathering writes will be used when ever * possible. * * @throws IllegalArgumentException * if the specified buffers' endianness are different from each * other */ public static ChannelBuffer wrappedBuffer(boolean gathering, ByteBuffer... buffers) { switch (buffers.length) { case 0: break; case 1: if (buffers[0].hasRemaining()) { return wrappedBuffer(buffers[0]); } break; default: ByteOrder order = null; final List components = new ArrayList(buffers.length); for (ByteBuffer b: buffers) { if (b == null) { break; } if (b.hasRemaining()) { if (order != null) { if (!order.equals(b.order())) { throw new IllegalArgumentException( "inconsistent byte order"); } } else { order = b.order(); } components.add(wrappedBuffer(b)); } } return compositeBuffer(order, components, gathering); } return EMPTY_BUFFER; } /** * Creates a new big-endian buffer whose content is a copy of the * specified {@code array}. The new buffer's {@code readerIndex} and * {@code writerIndex} are {@code 0} and {@code array.length} respectively. */ public static ChannelBuffer copiedBuffer(byte[] array) { return copiedBuffer(BIG_ENDIAN, array); } /** * Creates a new buffer with the specified {@code endianness} whose * content is a copy of the specified {@code array}. The new buffer's * {@code readerIndex} and {@code writerIndex} are {@code 0} and * {@code array.length} respectively. */ public static ChannelBuffer copiedBuffer(ByteOrder endianness, byte[] array) { if (endianness == BIG_ENDIAN) { if (array.length == 0) { return EMPTY_BUFFER; } return new BigEndianHeapChannelBuffer(array.clone()); } else if (endianness == LITTLE_ENDIAN) { if (array.length == 0) { return EMPTY_BUFFER; } return new LittleEndianHeapChannelBuffer(array.clone()); } else { throw new NullPointerException("endianness"); } } /** * Creates a new big-endian buffer whose content is a copy of the * specified {@code array}'s sub-region. The new buffer's * {@code readerIndex} and {@code writerIndex} are {@code 0} and * the specified {@code length} respectively. */ public static ChannelBuffer copiedBuffer(byte[] array, int offset, int length) { return copiedBuffer(BIG_ENDIAN, array, offset, length); } /** * Creates a new buffer with the specified {@code endianness} whose * content is a copy of the specified {@code array}'s sub-region. The new * buffer's {@code readerIndex} and {@code writerIndex} are {@code 0} and * the specified {@code length} respectively. */ public static ChannelBuffer copiedBuffer(ByteOrder endianness, byte[] array, int offset, int length) { if (endianness == null) { throw new NullPointerException("endianness"); } if (length == 0) { return EMPTY_BUFFER; } byte[] copy = new byte[length]; System.arraycopy(array, offset, copy, 0, length); return wrappedBuffer(endianness, copy); } /** * Creates a new buffer whose content is a copy of the specified * {@code buffer}'s current slice. The new buffer's {@code readerIndex} * and {@code writerIndex} are {@code 0} and {@code buffer.remaining} * respectively. */ public static ChannelBuffer copiedBuffer(ByteBuffer buffer) { int length = buffer.remaining(); if (length == 0) { return EMPTY_BUFFER; } byte[] copy = new byte[length]; int position = buffer.position(); try { buffer.get(copy); } finally { buffer.position(position); } return wrappedBuffer(buffer.order(), copy); } /** * Creates a new buffer whose content is a copy of the specified * {@code buffer}'s readable bytes. The new buffer's {@code readerIndex} * and {@code writerIndex} are {@code 0} and {@code buffer.readableBytes} * respectively. */ public static ChannelBuffer copiedBuffer(ChannelBuffer buffer) { if (buffer.readable()) { return buffer.copy(); } else { return EMPTY_BUFFER; } } /** * Creates a new big-endian buffer whose content is a merged copy of * the specified {@code arrays}. The new buffer's {@code readerIndex} * and {@code writerIndex} are {@code 0} and the sum of all arrays' * {@code length} respectively. */ public static ChannelBuffer copiedBuffer(byte[]... arrays) { return copiedBuffer(BIG_ENDIAN, arrays); } /** * Creates a new buffer with the specified {@code endianness} whose * content is a merged copy of the specified {@code arrays}. The new * buffer's {@code readerIndex} and {@code writerIndex} are {@code 0} * and the sum of all arrays' {@code length} respectively. */ public static ChannelBuffer copiedBuffer(ByteOrder endianness, byte[]... arrays) { switch (arrays.length) { case 0: return EMPTY_BUFFER; case 1: if (arrays[0].length == 0) { return EMPTY_BUFFER; } else { return copiedBuffer(endianness, arrays[0]); } } // Merge the specified arrays into one array. int length = 0; for (byte[] a: arrays) { if (Integer.MAX_VALUE - length < a.length) { throw new IllegalArgumentException( "The total length of the specified arrays is too big."); } length += a.length; } if (length == 0) { return EMPTY_BUFFER; } byte[] mergedArray = new byte[length]; for (int i = 0, j = 0; i < arrays.length; i ++) { byte[] a = arrays[i]; System.arraycopy(a, 0, mergedArray, j, a.length); j += a.length; } return wrappedBuffer(endianness, mergedArray); } /** * Creates a new buffer whose content is a merged copy of the specified * {@code buffers}' readable bytes. The new buffer's {@code readerIndex} * and {@code writerIndex} are {@code 0} and the sum of all buffers' * {@code readableBytes} respectively. * * @throws IllegalArgumentException * if the specified buffers' endianness are different from each * other */ public static ChannelBuffer copiedBuffer(ChannelBuffer... buffers) { switch (buffers.length) { case 0: return EMPTY_BUFFER; case 1: return copiedBuffer(buffers[0]); } ChannelBuffer[] copiedBuffers = new ChannelBuffer[buffers.length]; for (int i = 0; i < buffers.length; i ++) { copiedBuffers[i] = copiedBuffer(buffers[i]); } return wrappedBuffer(false, copiedBuffers); } /** * Creates a new buffer whose content is a merged copy of the specified * {@code buffers}' slices. The new buffer's {@code readerIndex} and * {@code writerIndex} are {@code 0} and the sum of all buffers' * {@code remaining} respectively. * * @throws IllegalArgumentException * if the specified buffers' endianness are different from each * other */ public static ChannelBuffer copiedBuffer(ByteBuffer... buffers) { switch (buffers.length) { case 0: return EMPTY_BUFFER; case 1: return copiedBuffer(buffers[0]); } ChannelBuffer[] copiedBuffers = new ChannelBuffer[buffers.length]; for (int i = 0; i < buffers.length; i ++) { copiedBuffers[i] = copiedBuffer(buffers[i]); } return wrappedBuffer(false, copiedBuffers); } /** * Creates a new big-endian buffer whose content is the specified * {@code string} encoded in the specified {@code charset}. * The new buffer's {@code readerIndex} and {@code writerIndex} are * {@code 0} and the length of the encoded string respectively. */ public static ChannelBuffer copiedBuffer(CharSequence string, Charset charset) { return copiedBuffer(BIG_ENDIAN, string, charset); } /** * Creates a new big-endian buffer whose content is a subregion of * the specified {@code string} encoded in the specified {@code charset}. * The new buffer's {@code readerIndex} and {@code writerIndex} are * {@code 0} and the length of the encoded string respectively. */ public static ChannelBuffer copiedBuffer( CharSequence string, int offset, int length, Charset charset) { return copiedBuffer(BIG_ENDIAN, string, offset, length, charset); } /** * Creates a new buffer with the specified {@code endianness} whose * content is the specified {@code string} encoded in the specified * {@code charset}. The new buffer's {@code readerIndex} and * {@code writerIndex} are {@code 0} and the length of the encoded string * respectively. */ public static ChannelBuffer copiedBuffer(ByteOrder endianness, CharSequence string, Charset charset) { if (string == null) { throw new NullPointerException("string"); } if (string instanceof CharBuffer) { return copiedBuffer(endianness, (CharBuffer) string, charset); } return copiedBuffer(endianness, CharBuffer.wrap(string), charset); } /** * Creates a new buffer with the specified {@code endianness} whose * content is a subregion of the specified {@code string} encoded in the * specified {@code charset}. The new buffer's {@code readerIndex} and * {@code writerIndex} are {@code 0} and the length of the encoded string * respectively. */ public static ChannelBuffer copiedBuffer( ByteOrder endianness, CharSequence string, int offset, int length, Charset charset) { if (string == null) { throw new NullPointerException("string"); } if (length == 0) { return EMPTY_BUFFER; } if (string instanceof CharBuffer) { CharBuffer buf = (CharBuffer) string; if (buf.hasArray()) { return copiedBuffer( endianness, buf.array(), buf.arrayOffset() + buf.position() + offset, length, charset); } buf = buf.slice(); buf.limit(length); buf.position(offset); return copiedBuffer(endianness, buf, charset); } return copiedBuffer( endianness, CharBuffer.wrap(string, offset, offset + length), charset); } /** * Creates a new big-endian buffer whose content is the specified * {@code array} encoded in the specified {@code charset}. * The new buffer's {@code readerIndex} and {@code writerIndex} are * {@code 0} and the length of the encoded string respectively. */ public static ChannelBuffer copiedBuffer(char[] array, Charset charset) { return copiedBuffer(BIG_ENDIAN, array, 0, array.length, charset); } /** * Creates a new big-endian buffer whose content is a subregion of * the specified {@code array} encoded in the specified {@code charset}. * The new buffer's {@code readerIndex} and {@code writerIndex} are * {@code 0} and the length of the encoded string respectively. */ public static ChannelBuffer copiedBuffer( char[] array, int offset, int length, Charset charset) { return copiedBuffer(BIG_ENDIAN, array, offset, length, charset); } /** * Creates a new buffer with the specified {@code endianness} whose * content is the specified {@code array} encoded in the specified * {@code charset}. The new buffer's {@code readerIndex} and * {@code writerIndex} are {@code 0} and the length of the encoded string * respectively. */ public static ChannelBuffer copiedBuffer(ByteOrder endianness, char[] array, Charset charset) { return copiedBuffer(endianness, array, 0, array.length, charset); } /** * Creates a new buffer with the specified {@code endianness} whose * content is a subregion of the specified {@code array} encoded in the * specified {@code charset}. The new buffer's {@code readerIndex} and * {@code writerIndex} are {@code 0} and the length of the encoded string * respectively. */ public static ChannelBuffer copiedBuffer( ByteOrder endianness, char[] array, int offset, int length, Charset charset) { if (array == null) { throw new NullPointerException("array"); } if (length == 0) { return EMPTY_BUFFER; } return copiedBuffer( endianness, CharBuffer.wrap(array, offset, length), charset); } private static ChannelBuffer copiedBuffer(ByteOrder endianness, CharBuffer buffer, Charset charset) { CharBuffer src = buffer; ByteBuffer dst = encodeString(src, charset); ChannelBuffer result = wrappedBuffer(endianness, dst.array()); result.writerIndex(dst.remaining()); return result; } /** * Creates a read-only buffer which disallows any modification operations * on the specified {@code buffer}. The new buffer has the same * {@code readerIndex} and {@code writerIndex} with the specified * {@code buffer}. */ public static ChannelBuffer unmodifiableBuffer(ChannelBuffer buffer) { if (buffer instanceof ReadOnlyChannelBuffer) { buffer = ((ReadOnlyChannelBuffer) buffer).unwrap(); } return new ReadOnlyChannelBuffer(buffer); } /** * Create a {@link ChannelBuffer} from the given hex dump */ public static ChannelBuffer hexDump(String hexString) { int len = hexString.length(); byte[] hexData = new byte[len / 2]; for (int i = 0; i < len; i += 2) { hexData[i / 2] = (byte) ((Character.digit(hexString.charAt(i), 16) << 4) + Character.digit(hexString.charAt(i + 1), 16)); } return wrappedBuffer(hexData); } /** * Returns a hex dump * of the specified buffer's readable bytes. */ public static String hexDump(ChannelBuffer buffer) { return hexDump(buffer, buffer.readerIndex(), buffer.readableBytes()); } /** * Returns a hex dump * of the specified buffer's sub-region. */ public static String hexDump(ChannelBuffer buffer, int fromIndex, int length) { if (length < 0) { throw new IllegalArgumentException("length: " + length); } if (length == 0) { return ""; } int endIndex = fromIndex + length; char[] buf = new char[length << 1]; int srcIdx = fromIndex; int dstIdx = 0; for (; srcIdx < endIndex; srcIdx ++, dstIdx += 2) { System.arraycopy( HEXDUMP_TABLE, buffer.getUnsignedByte(srcIdx) << 1, buf, dstIdx, 2); } return new String(buf); } /** * Calculates the hash code of the specified buffer. This method is * useful when implementing a new buffer type. */ public static int hashCode(ChannelBuffer buffer) { final int aLen = buffer.readableBytes(); final int intCount = aLen >>> 2; final int byteCount = aLen & 3; int hashCode = 1; int arrayIndex = buffer.readerIndex(); if (buffer.order() == BIG_ENDIAN) { for (int i = intCount; i > 0; i --) { hashCode = 31 * hashCode + buffer.getInt(arrayIndex); arrayIndex += 4; } } else { for (int i = intCount; i > 0; i --) { hashCode = 31 * hashCode + swapInt(buffer.getInt(arrayIndex)); arrayIndex += 4; } } for (int i = byteCount; i > 0; i --) { hashCode = 31 * hashCode + buffer.getByte(arrayIndex ++); } if (hashCode == 0) { hashCode = 1; } return hashCode; } /** * Returns {@code true} if and only if the two specified buffers are * identical to each other as described in {@code ChannelBuffer#equals(Object)}. * This method is useful when implementing a new buffer type. */ public static boolean equals(ChannelBuffer bufferA, ChannelBuffer bufferB) { final int aLen = bufferA.readableBytes(); if (aLen != bufferB.readableBytes()) { return false; } final int longCount = aLen >>> 3; final int byteCount = aLen & 7; int aIndex = bufferA.readerIndex(); int bIndex = bufferB.readerIndex(); if (bufferA.order() == bufferB.order()) { for (int i = longCount; i > 0; i --) { if (bufferA.getLong(aIndex) != bufferB.getLong(bIndex)) { return false; } aIndex += 8; bIndex += 8; } } else { for (int i = longCount; i > 0; i --) { if (bufferA.getLong(aIndex) != swapLong(bufferB.getLong(bIndex))) { return false; } aIndex += 8; bIndex += 8; } } for (int i = byteCount; i > 0; i --) { if (bufferA.getByte(aIndex) != bufferB.getByte(bIndex)) { return false; } aIndex ++; bIndex ++; } return true; } /** * Compares the two specified buffers as described in {@link ChannelBuffer#compareTo(ChannelBuffer)}. * This method is useful when implementing a new buffer type. */ public static int compare(ChannelBuffer bufferA, ChannelBuffer bufferB) { final int aLen = bufferA.readableBytes(); final int bLen = bufferB.readableBytes(); final int minLength = Math.min(aLen, bLen); final int uintCount = minLength >>> 2; final int byteCount = minLength & 3; int aIndex = bufferA.readerIndex(); int bIndex = bufferB.readerIndex(); if (bufferA.order() == bufferB.order()) { for (int i = uintCount; i > 0; i --) { long va = bufferA.getUnsignedInt(aIndex); long vb = bufferB.getUnsignedInt(bIndex); if (va > vb) { return 1; } if (va < vb) { return -1; } aIndex += 4; bIndex += 4; } } else { for (int i = uintCount; i > 0; i --) { long va = bufferA.getUnsignedInt(aIndex); long vb = swapInt(bufferB.getInt(bIndex)) & 0xFFFFFFFFL; if (va > vb) { return 1; } if (va < vb) { return -1; } aIndex += 4; bIndex += 4; } } for (int i = byteCount; i > 0; i --) { short va = bufferA.getUnsignedByte(aIndex); short vb = bufferB.getUnsignedByte(bIndex); if (va > vb) { return 1; } if (va < vb) { return -1; } aIndex ++; bIndex ++; } return aLen - bLen; } /** * The default implementation of {@link ChannelBuffer#indexOf(int, int, byte)}. * This method is useful when implementing a new buffer type. */ public static int indexOf(ChannelBuffer buffer, int fromIndex, int toIndex, byte value) { if (fromIndex <= toIndex) { return firstIndexOf(buffer, fromIndex, toIndex, value); } else { return lastIndexOf(buffer, fromIndex, toIndex, value); } } /** * The default implementation of {@link ChannelBuffer#indexOf(int, int, ChannelBufferIndexFinder)}. * This method is useful when implementing a new buffer type. */ public static int indexOf( ChannelBuffer buffer, int fromIndex, int toIndex, ChannelBufferIndexFinder indexFinder) { if (fromIndex <= toIndex) { return firstIndexOf(buffer, fromIndex, toIndex, indexFinder); } else { return lastIndexOf(buffer, fromIndex, toIndex, indexFinder); } } /** * Toggles the endianness of the specified 16-bit short integer. */ public static short swapShort(short value) { return (short) (value << 8 | value >>> 8 & 0xff); } /** * Toggles the endianness of the specified 24-bit medium integer. */ public static int swapMedium(int value) { return value << 16 & 0xff0000 | value & 0xff00 | value >>> 16 & 0xff; } /** * Toggles the endianness of the specified 32-bit integer. */ public static int swapInt(int value) { return swapShort((short) value) << 16 | swapShort((short) (value >>> 16)) & 0xffff; } /** * Toggles the endianness of the specified 64-bit long integer. */ public static long swapLong(long value) { return (long) swapInt((int) value) << 32 | swapInt((int) (value >>> 32)) & 0xffffffffL; } private static int firstIndexOf(ChannelBuffer buffer, int fromIndex, int toIndex, byte value) { fromIndex = Math.max(fromIndex, 0); if (fromIndex >= toIndex || buffer.capacity() == 0) { return -1; } for (int i = fromIndex; i < toIndex; i ++) { if (buffer.getByte(i) == value) { return i; } } return -1; } private static int lastIndexOf(ChannelBuffer buffer, int fromIndex, int toIndex, byte value) { fromIndex = Math.min(fromIndex, buffer.capacity()); if (fromIndex < 0 || buffer.capacity() == 0) { return -1; } for (int i = fromIndex - 1; i >= toIndex; i --) { if (buffer.getByte(i) == value) { return i; } } return -1; } private static int firstIndexOf( ChannelBuffer buffer, int fromIndex, int toIndex, ChannelBufferIndexFinder indexFinder) { fromIndex = Math.max(fromIndex, 0); if (fromIndex >= toIndex || buffer.capacity() == 0) { return -1; } for (int i = fromIndex; i < toIndex; i ++) { if (indexFinder.find(buffer, i)) { return i; } } return -1; } private static int lastIndexOf( ChannelBuffer buffer, int fromIndex, int toIndex, ChannelBufferIndexFinder indexFinder) { fromIndex = Math.min(fromIndex, buffer.capacity()); if (fromIndex < 0 || buffer.capacity() == 0) { return -1; } for (int i = fromIndex - 1; i >= toIndex; i --) { if (indexFinder.find(buffer, i)) { return i; } } return -1; } static ByteBuffer encodeString(CharBuffer src, Charset charset) { final CharsetEncoder encoder = CharsetUtil.getEncoder(charset); final ByteBuffer dst = ByteBuffer.allocate( (int) ((double) src.remaining() * encoder.maxBytesPerChar())); try { CoderResult cr = encoder.encode(src, dst, true); if (!cr.isUnderflow()) { cr.throwException(); } cr = encoder.flush(dst); if (!cr.isUnderflow()) { cr.throwException(); } } catch (CharacterCodingException x) { throw new IllegalStateException(x); } dst.flip(); return dst; } static String decodeString(ByteBuffer src, Charset charset) { final CharsetDecoder decoder = CharsetUtil.getDecoder(charset); final CharBuffer dst = CharBuffer.allocate( (int) ((double) src.remaining() * decoder.maxCharsPerByte())); try { CoderResult cr = decoder.decode(src, dst, true); if (!cr.isUnderflow()) { cr.throwException(); } cr = decoder.flush(dst); if (!cr.isUnderflow()) { cr.throwException(); } } catch (CharacterCodingException x) { throw new IllegalStateException(x); } return dst.flip().toString(); } private ChannelBuffers() { // Unused } }




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