/* * Copyright 1999-2012 Alibaba Group. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.alibaba.dubbo.remoting.buffer; import java.nio.ByteBuffer; /** * @author <a href="mailto:gang.lvg@alibaba-inc.com">kimi</a> */ public final class ChannelBuffers { public static final ChannelBuffer EMPTY_BUFFER = new HeapChannelBuffer(0); private ChannelBuffers() {} public static ChannelBuffer dynamicBuffer() { return dynamicBuffer(256); } public static ChannelBuffer dynamicBuffer(int capacity) { return new DynamicChannelBuffer(capacity); } public static ChannelBuffer dynamicBuffer(int capacity, ChannelBufferFactory factory) { return new DynamicChannelBuffer(capacity, factory); } public static ChannelBuffer buffer(int capacity) { if (capacity < 0) { throw new IllegalArgumentException("capacity can not be negative"); } if (capacity == 0) { return EMPTY_BUFFER; } return new HeapChannelBuffer(capacity); } public static ChannelBuffer wrappedBuffer(byte[] array, int offset, int length) { if (array == null) { throw new NullPointerException("array == null"); } byte[] dest = new byte[length]; System.arraycopy(array, offset, dest, 0, length); return wrappedBuffer(dest); } public static ChannelBuffer wrappedBuffer(byte[] array) { if (array == null) { throw new NullPointerException("array == null"); } if (array.length == 0) { return EMPTY_BUFFER; } return new HeapChannelBuffer(array); } public static ChannelBuffer wrappedBuffer(ByteBuffer buffer) { if (!buffer.hasRemaining()) { return EMPTY_BUFFER; } if (buffer.hasArray()) { return wrappedBuffer(buffer.array(), buffer.arrayOffset() + buffer.position(), buffer.remaining()); } else { return new ByteBufferBackedChannelBuffer(buffer); } } public static ChannelBuffer directBuffer(int capacity) { if (capacity == 0) { return EMPTY_BUFFER; } ChannelBuffer buffer = new ByteBufferBackedChannelBuffer( ByteBuffer.allocateDirect(capacity)); buffer.clear(); return buffer; } public static boolean equals(ChannelBuffer bufferA, ChannelBuffer bufferB) { final int aLen = bufferA.readableBytes(); if (aLen != bufferB.readableBytes()) { return false; } final int byteCount = aLen & 7; int aIndex = bufferA.readerIndex(); int bIndex = bufferB.readerIndex(); for (int i = byteCount; i > 0; i--) { if (bufferA.getByte(aIndex) != bufferB.getByte(bIndex)) { return false; } aIndex++; bIndex++; } return true; } 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); int aIndex = bufferA.readerIndex(); int bIndex = bufferB.readerIndex(); for (int i = minLength; i > 0; i--) { byte va = bufferA.getByte(aIndex); byte vb = bufferB.getByte(bIndex); if (va > vb) { return 1; } else if (va < vb) { return -1; } aIndex++; bIndex++; } return aLen - bLen; } }