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<pre><span class="source-line-no">001</span><span id="line-1">/*</span>
<span class="source-line-no">002</span><span id="line-2"> * Licensed to the Apache Software Foundation (ASF) under one</span>
<span class="source-line-no">003</span><span id="line-3"> * or more contributor license agreements. See the NOTICE file</span>
<span class="source-line-no">004</span><span id="line-4"> * distributed with this work for additional information</span>
<span class="source-line-no">005</span><span id="line-5"> * regarding copyright ownership. The ASF licenses this file</span>
<span class="source-line-no">006</span><span id="line-6"> * to you under the Apache License, Version 2.0 (the</span>
<span class="source-line-no">007</span><span id="line-7"> * "License"); you may not use this file except in compliance</span>
<span class="source-line-no">008</span><span id="line-8"> * with the License. You may obtain a copy of the License at</span>
<span class="source-line-no">009</span><span id="line-9"> *</span>
<span class="source-line-no">010</span><span id="line-10"> * http://www.apache.org/licenses/LICENSE-2.0</span>
<span class="source-line-no">011</span><span id="line-11"> *</span>
<span class="source-line-no">012</span><span id="line-12"> * Unless required by applicable law or agreed to in writing, software</span>
<span class="source-line-no">013</span><span id="line-13"> * distributed under the License is distributed on an "AS IS" BASIS,</span>
<span class="source-line-no">014</span><span id="line-14"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span>
<span class="source-line-no">015</span><span id="line-15"> * See the License for the specific language governing permissions and</span>
<span class="source-line-no">016</span><span id="line-16"> * limitations under the License.</span>
<span class="source-line-no">017</span><span id="line-17"> */</span>
<span class="source-line-no">018</span><span id="line-18">package org.apache.hadoop.hbase.util;</span>
<span class="source-line-no">019</span><span id="line-19"></span>
<span class="source-line-no">020</span><span id="line-20">import java.io.IOException;</span>
<span class="source-line-no">021</span><span id="line-21">import java.nio.ByteBuffer;</span>
<span class="source-line-no">022</span><span id="line-22">import java.util.ArrayList;</span>
<span class="source-line-no">023</span><span id="line-23">import java.util.Iterator;</span>
<span class="source-line-no">024</span><span id="line-24">import java.util.List;</span>
<span class="source-line-no">025</span><span id="line-25">import java.util.concurrent.ExecutorService;</span>
<span class="source-line-no">026</span><span id="line-26">import java.util.concurrent.Executors;</span>
<span class="source-line-no">027</span><span id="line-27">import java.util.concurrent.Future;</span>
<span class="source-line-no">028</span><span id="line-28">import java.util.function.BiConsumer;</span>
<span class="source-line-no">029</span><span id="line-29">import org.apache.hadoop.hbase.nio.ByteBuff;</span>
<span class="source-line-no">030</span><span id="line-30">import org.apache.hadoop.util.StringUtils;</span>
<span class="source-line-no">031</span><span id="line-31">import org.apache.yetus.audience.InterfaceAudience;</span>
<span class="source-line-no">032</span><span id="line-32">import org.slf4j.Logger;</span>
<span class="source-line-no">033</span><span id="line-33">import org.slf4j.LoggerFactory;</span>
<span class="source-line-no">034</span><span id="line-34"></span>
<span class="source-line-no">035</span><span id="line-35">/**</span>
<span class="source-line-no">036</span><span id="line-36"> * This class manages an array of ByteBuffers with a default size 4MB. These buffers are sequential</span>
<span class="source-line-no">037</span><span id="line-37"> * and could be considered as a large buffer.It supports reading/writing data from this large buffer</span>
<span class="source-line-no">038</span><span id="line-38"> * with a position and offset</span>
<span class="source-line-no">039</span><span id="line-39"> */</span>
<span class="source-line-no">040</span><span id="line-40">@InterfaceAudience.Private</span>
<span class="source-line-no">041</span><span id="line-41">public class ByteBufferArray {</span>
<span class="source-line-no">042</span><span id="line-42"> private static final Logger LOG = LoggerFactory.getLogger(ByteBufferArray.class);</span>
<span class="source-line-no">043</span><span id="line-43"></span>
<span class="source-line-no">044</span><span id="line-44"> public static final int DEFAULT_BUFFER_SIZE = 4 * 1024 * 1024;</span>
<span class="source-line-no">045</span><span id="line-45"> private final int bufferSize;</span>
<span class="source-line-no">046</span><span id="line-46"> private final int bufferCount;</span>
<span class="source-line-no">047</span><span id="line-47"> final ByteBuffer[] buffers;</span>
<span class="source-line-no">048</span><span id="line-48"></span>
<span class="source-line-no">049</span><span id="line-49"> /**</span>
<span class="source-line-no">050</span><span id="line-50"> * We allocate a number of byte buffers as the capacity.</span>
<span class="source-line-no">051</span><span id="line-51"> * @param capacity total size of the byte buffer array</span>
<span class="source-line-no">052</span><span id="line-52"> * @param allocator the ByteBufferAllocator that will create the buffers</span>
<span class="source-line-no">053</span><span id="line-53"> * @throws IOException throws IOException if there is an exception thrown by the allocator</span>
<span class="source-line-no">054</span><span id="line-54"> */</span>
<span class="source-line-no">055</span><span id="line-55"> public ByteBufferArray(long capacity, ByteBufferAllocator allocator) throws IOException {</span>
<span class="source-line-no">056</span><span id="line-56"> this(getBufferSize(capacity), getBufferCount(capacity),</span>
<span class="source-line-no">057</span><span id="line-57"> Runtime.getRuntime().availableProcessors(), capacity, allocator);</span>
<span class="source-line-no">058</span><span id="line-58"> }</span>
<span class="source-line-no">059</span><span id="line-59"></span>
<span class="source-line-no">060</span><span id="line-60"> ByteBufferArray(int bufferSize, int bufferCount, int threadCount, long capacity,</span>
<span class="source-line-no">061</span><span id="line-61"> ByteBufferAllocator alloc) throws IOException {</span>
<span class="source-line-no">062</span><span id="line-62"> this.bufferSize = bufferSize;</span>
<span class="source-line-no">063</span><span id="line-63"> this.bufferCount = bufferCount;</span>
<span class="source-line-no">064</span><span id="line-64"> LOG.info("Allocating buffers total={}, sizePerBuffer={}, count={}",</span>
<span class="source-line-no">065</span><span id="line-65"> StringUtils.byteDesc(capacity), StringUtils.byteDesc(bufferSize), bufferCount);</span>
<span class="source-line-no">066</span><span id="line-66"> this.buffers = new ByteBuffer[bufferCount];</span>
<span class="source-line-no">067</span><span id="line-67"> createBuffers(threadCount, alloc);</span>
<span class="source-line-no">068</span><span id="line-68"> }</span>
<span class="source-line-no">069</span><span id="line-69"></span>
<span class="source-line-no">070</span><span id="line-70"> private void createBuffers(int threadCount, ByteBufferAllocator alloc) throws IOException {</span>
<span class="source-line-no">071</span><span id="line-71"> ExecutorService pool = Executors.newFixedThreadPool(threadCount);</span>
<span class="source-line-no">072</span><span id="line-72"> int perThreadCount = bufferCount / threadCount;</span>
<span class="source-line-no">073</span><span id="line-73"> int reminder = bufferCount % threadCount;</span>
<span class="source-line-no">074</span><span id="line-74"> try {</span>
<span class="source-line-no">075</span><span id="line-75"> List&lt;Future&lt;ByteBuffer[]&gt;&gt; futures = new ArrayList&lt;&gt;(threadCount);</span>
<span class="source-line-no">076</span><span id="line-76"> // Dispatch the creation task to each thread.</span>
<span class="source-line-no">077</span><span id="line-77"> for (int i = 0; i &lt; threadCount; i++) {</span>
<span class="source-line-no">078</span><span id="line-78"> final int chunkSize = perThreadCount + ((i == threadCount - 1) ? reminder : 0);</span>
<span class="source-line-no">079</span><span id="line-79"> futures.add(pool.submit(() -&gt; {</span>
<span class="source-line-no">080</span><span id="line-80"> ByteBuffer[] chunk = new ByteBuffer[chunkSize];</span>
<span class="source-line-no">081</span><span id="line-81"> for (int k = 0; k &lt; chunkSize; k++) {</span>
<span class="source-line-no">082</span><span id="line-82"> chunk[k] = alloc.allocate(bufferSize);</span>
<span class="source-line-no">083</span><span id="line-83"> }</span>
<span class="source-line-no">084</span><span id="line-84"> return chunk;</span>
<span class="source-line-no">085</span><span id="line-85"> }));</span>
<span class="source-line-no">086</span><span id="line-86"> }</span>
<span class="source-line-no">087</span><span id="line-87"> // Append the buffers created by each thread.</span>
<span class="source-line-no">088</span><span id="line-88"> int bufferIndex = 0;</span>
<span class="source-line-no">089</span><span id="line-89"> try {</span>
<span class="source-line-no">090</span><span id="line-90"> for (Future&lt;ByteBuffer[]&gt; f : futures) {</span>
<span class="source-line-no">091</span><span id="line-91"> for (ByteBuffer b : f.get()) {</span>
<span class="source-line-no">092</span><span id="line-92"> this.buffers[bufferIndex++] = b;</span>
<span class="source-line-no">093</span><span id="line-93"> }</span>
<span class="source-line-no">094</span><span id="line-94"> }</span>
<span class="source-line-no">095</span><span id="line-95"> assert bufferIndex == bufferCount;</span>
<span class="source-line-no">096</span><span id="line-96"> } catch (Exception e) {</span>
<span class="source-line-no">097</span><span id="line-97"> LOG.error("Buffer creation interrupted", e);</span>
<span class="source-line-no">098</span><span id="line-98"> throw new IOException(e);</span>
<span class="source-line-no">099</span><span id="line-99"> }</span>
<span class="source-line-no">100</span><span id="line-100"> } finally {</span>
<span class="source-line-no">101</span><span id="line-101"> pool.shutdownNow();</span>
<span class="source-line-no">102</span><span id="line-102"> }</span>
<span class="source-line-no">103</span><span id="line-103"> }</span>
<span class="source-line-no">104</span><span id="line-104"></span>
<span class="source-line-no">105</span><span id="line-105"> static int getBufferSize(long capacity) {</span>
<span class="source-line-no">106</span><span id="line-106"> int bufferSize = DEFAULT_BUFFER_SIZE;</span>
<span class="source-line-no">107</span><span id="line-107"> if (bufferSize &gt; (capacity / 16)) {</span>
<span class="source-line-no">108</span><span id="line-108"> bufferSize = (int) roundUp(capacity / 16, 32768);</span>
<span class="source-line-no">109</span><span id="line-109"> }</span>
<span class="source-line-no">110</span><span id="line-110"> return bufferSize;</span>
<span class="source-line-no">111</span><span id="line-111"> }</span>
<span class="source-line-no">112</span><span id="line-112"></span>
<span class="source-line-no">113</span><span id="line-113"> private static int getBufferCount(long capacity) {</span>
<span class="source-line-no">114</span><span id="line-114"> int bufferSize = getBufferSize(capacity);</span>
<span class="source-line-no">115</span><span id="line-115"> return (int) (roundUp(capacity, bufferSize) / bufferSize);</span>
<span class="source-line-no">116</span><span id="line-116"> }</span>
<span class="source-line-no">117</span><span id="line-117"></span>
<span class="source-line-no">118</span><span id="line-118"> private static long roundUp(long n, long to) {</span>
<span class="source-line-no">119</span><span id="line-119"> return ((n + to - 1) / to) * to;</span>
<span class="source-line-no">120</span><span id="line-120"> }</span>
<span class="source-line-no">121</span><span id="line-121"></span>
<span class="source-line-no">122</span><span id="line-122"> /**</span>
<span class="source-line-no">123</span><span id="line-123"> * Transfers bytes from this buffers array into the given destination {@link ByteBuff}</span>
<span class="source-line-no">124</span><span id="line-124"> * @param offset start position in this big logical array.</span>
<span class="source-line-no">125</span><span id="line-125"> * @param dst the destination ByteBuff. Notice that its position will be advanced.</span>
<span class="source-line-no">126</span><span id="line-126"> * @return number of bytes read</span>
<span class="source-line-no">127</span><span id="line-127"> */</span>
<span class="source-line-no">128</span><span id="line-128"> public int read(long offset, ByteBuff dst) {</span>
<span class="source-line-no">129</span><span id="line-129"> return internalTransfer(offset, dst, READER);</span>
<span class="source-line-no">130</span><span id="line-130"> }</span>
<span class="source-line-no">131</span><span id="line-131"></span>
<span class="source-line-no">132</span><span id="line-132"> /**</span>
<span class="source-line-no">133</span><span id="line-133"> * Transfers bytes from the given source {@link ByteBuff} into this buffer array</span>
<span class="source-line-no">134</span><span id="line-134"> * @param offset start offset of this big logical array.</span>
<span class="source-line-no">135</span><span id="line-135"> * @param src the source ByteBuff. Notice that its position will be advanced.</span>
<span class="source-line-no">136</span><span id="line-136"> * @return number of bytes write</span>
<span class="source-line-no">137</span><span id="line-137"> */</span>
<span class="source-line-no">138</span><span id="line-138"> public int write(long offset, ByteBuff src) {</span>
<span class="source-line-no">139</span><span id="line-139"> return internalTransfer(offset, src, WRITER);</span>
<span class="source-line-no">140</span><span id="line-140"> }</span>
<span class="source-line-no">141</span><span id="line-141"></span>
<span class="source-line-no">142</span><span id="line-142"> /**</span>
<span class="source-line-no">143</span><span id="line-143"> * Transfer bytes from source {@link ByteBuff} to destination {@link ByteBuffer}. Position of both</span>
<span class="source-line-no">144</span><span id="line-144"> * source and destination will be advanced.</span>
<span class="source-line-no">145</span><span id="line-145"> */</span>
<span class="source-line-no">146</span><span id="line-146"> @SuppressWarnings("UnnecessaryLambda")</span>
<span class="source-line-no">147</span><span id="line-147"> private static final BiConsumer&lt;ByteBuffer, ByteBuff&gt; WRITER = (dst, src) -&gt; {</span>
<span class="source-line-no">148</span><span id="line-148"> int off = src.position(), len = dst.remaining();</span>
<span class="source-line-no">149</span><span id="line-149"> src.get(dst, off, len);</span>
<span class="source-line-no">150</span><span id="line-150"> src.position(off + len);</span>
<span class="source-line-no">151</span><span id="line-151"> };</span>
<span class="source-line-no">152</span><span id="line-152"></span>
<span class="source-line-no">153</span><span id="line-153"> /**</span>
<span class="source-line-no">154</span><span id="line-154"> * Transfer bytes from source {@link ByteBuffer} to destination {@link ByteBuff}, Position of both</span>
<span class="source-line-no">155</span><span id="line-155"> * source and destination will be advanced.</span>
<span class="source-line-no">156</span><span id="line-156"> */</span>
<span class="source-line-no">157</span><span id="line-157"> @SuppressWarnings("UnnecessaryLambda")</span>
<span class="source-line-no">158</span><span id="line-158"> private static final BiConsumer&lt;ByteBuffer, ByteBuff&gt; READER = (src, dst) -&gt; {</span>
<span class="source-line-no">159</span><span id="line-159"> int off = dst.position(), len = src.remaining(), srcOff = src.position();</span>
<span class="source-line-no">160</span><span id="line-160"> dst.put(off, ByteBuff.wrap(src), srcOff, len);</span>
<span class="source-line-no">161</span><span id="line-161"> src.position(srcOff + len);</span>
<span class="source-line-no">162</span><span id="line-162"> dst.position(off + len);</span>
<span class="source-line-no">163</span><span id="line-163"> };</span>
<span class="source-line-no">164</span><span id="line-164"></span>
<span class="source-line-no">165</span><span id="line-165"> /**</span>
<span class="source-line-no">166</span><span id="line-166"> * Transferring all remaining bytes from b to the buffers array starting at offset, or</span>
<span class="source-line-no">167</span><span id="line-167"> * transferring bytes from the buffers array at offset to b until b is filled. Notice that</span>
<span class="source-line-no">168</span><span id="line-168"> * position of ByteBuff b will be advanced.</span>
<span class="source-line-no">169</span><span id="line-169"> * @param offset where we start in the big logical array.</span>
<span class="source-line-no">170</span><span id="line-170"> * @param b the ByteBuff to transfer from or to</span>
<span class="source-line-no">171</span><span id="line-171"> * @param transfer the transfer interface.</span>
<span class="source-line-no">172</span><span id="line-172"> * @return the length of bytes we transferred.</span>
<span class="source-line-no">173</span><span id="line-173"> */</span>
<span class="source-line-no">174</span><span id="line-174"> private int internalTransfer(long offset, ByteBuff b, BiConsumer&lt;ByteBuffer, ByteBuff&gt; transfer) {</span>
<span class="source-line-no">175</span><span id="line-175"> int expectedTransferLen = b.remaining();</span>
<span class="source-line-no">176</span><span id="line-176"> if (expectedTransferLen == 0) {</span>
<span class="source-line-no">177</span><span id="line-177"> return 0;</span>
<span class="source-line-no">178</span><span id="line-178"> }</span>
<span class="source-line-no">179</span><span id="line-179"> BufferIterator it = new BufferIterator(offset, expectedTransferLen);</span>
<span class="source-line-no">180</span><span id="line-180"> while (it.hasNext()) {</span>
<span class="source-line-no">181</span><span id="line-181"> ByteBuffer a = it.next();</span>
<span class="source-line-no">182</span><span id="line-182"> transfer.accept(a, b);</span>
<span class="source-line-no">183</span><span id="line-183"> assert !a.hasRemaining();</span>
<span class="source-line-no">184</span><span id="line-184"> }</span>
<span class="source-line-no">185</span><span id="line-185"> assert expectedTransferLen == it.getSum() : "Expected transfer length (=" + expectedTransferLen</span>
<span class="source-line-no">186</span><span id="line-186"> + ") don't match the actual transfer length(=" + it.getSum() + ")";</span>
<span class="source-line-no">187</span><span id="line-187"> return expectedTransferLen;</span>
<span class="source-line-no">188</span><span id="line-188"> }</span>
<span class="source-line-no">189</span><span id="line-189"></span>
<span class="source-line-no">190</span><span id="line-190"> /**</span>
<span class="source-line-no">191</span><span id="line-191"> * Creates a sub-array from a given array of ByteBuffers from the given offset to the length</span>
<span class="source-line-no">192</span><span id="line-192"> * specified. For eg, if there are 4 buffers forming an array each with length 10 and if we call</span>
<span class="source-line-no">193</span><span id="line-193"> * asSubByteBuffers(5, 10) then we will create an sub-array consisting of two BBs and the first</span>
<span class="source-line-no">194</span><span id="line-194"> * one be a BB from 'position' 5 to a 'length' 5 and the 2nd BB will be from 'position' 0 to</span>
<span class="source-line-no">195</span><span id="line-195"> * 'length' 5.</span>
<span class="source-line-no">196</span><span id="line-196"> * @param offset the position in the whole array which is composited by multiple byte buffers.</span>
<span class="source-line-no">197</span><span id="line-197"> * @param len the length of bytes</span>
<span class="source-line-no">198</span><span id="line-198"> * @return the underlying ByteBuffers, each ByteBuffer is a slice from the backend and will have a</span>
<span class="source-line-no">199</span><span id="line-199"> * zero position.</span>
<span class="source-line-no">200</span><span id="line-200"> */</span>
<span class="source-line-no">201</span><span id="line-201"> public ByteBuffer[] asSubByteBuffers(long offset, final int len) {</span>
<span class="source-line-no">202</span><span id="line-202"> BufferIterator it = new BufferIterator(offset, len);</span>
<span class="source-line-no">203</span><span id="line-203"> ByteBuffer[] mbb = new ByteBuffer[it.getBufferCount()];</span>
<span class="source-line-no">204</span><span id="line-204"> for (int i = 0; i &lt; mbb.length; i++) {</span>
<span class="source-line-no">205</span><span id="line-205"> assert it.hasNext();</span>
<span class="source-line-no">206</span><span id="line-206"> mbb[i] = it.next();</span>
<span class="source-line-no">207</span><span id="line-207"> }</span>
<span class="source-line-no">208</span><span id="line-208"> assert it.getSum() == len;</span>
<span class="source-line-no">209</span><span id="line-209"> return mbb;</span>
<span class="source-line-no">210</span><span id="line-210"> }</span>
<span class="source-line-no">211</span><span id="line-211"></span>
<span class="source-line-no">212</span><span id="line-212"> /**</span>
<span class="source-line-no">213</span><span id="line-213"> * Iterator to fetch ByteBuffers from offset with given length in this big logical array.</span>
<span class="source-line-no">214</span><span id="line-214"> */</span>
<span class="source-line-no">215</span><span id="line-215"> private class BufferIterator implements Iterator&lt;ByteBuffer&gt; {</span>
<span class="source-line-no">216</span><span id="line-216"> private final int len;</span>
<span class="source-line-no">217</span><span id="line-217"> private int startBuffer, startOffset, endBuffer, endOffset;</span>
<span class="source-line-no">218</span><span id="line-218"> private int curIndex, sum = 0;</span>
<span class="source-line-no">219</span><span id="line-219"></span>
<span class="source-line-no">220</span><span id="line-220"> private int index(long pos) {</span>
<span class="source-line-no">221</span><span id="line-221"> return (int) (pos / bufferSize);</span>
<span class="source-line-no">222</span><span id="line-222"> }</span>
<span class="source-line-no">223</span><span id="line-223"></span>
<span class="source-line-no">224</span><span id="line-224"> private int offset(long pos) {</span>
<span class="source-line-no">225</span><span id="line-225"> return (int) (pos % bufferSize);</span>
<span class="source-line-no">226</span><span id="line-226"> }</span>
<span class="source-line-no">227</span><span id="line-227"></span>
<span class="source-line-no">228</span><span id="line-228"> public BufferIterator(long offset, int len) {</span>
<span class="source-line-no">229</span><span id="line-229"> assert len &gt;= 0 &amp;&amp; offset &gt;= 0;</span>
<span class="source-line-no">230</span><span id="line-230"> this.len = len;</span>
<span class="source-line-no">231</span><span id="line-231"></span>
<span class="source-line-no">232</span><span id="line-232"> this.startBuffer = index(offset);</span>
<span class="source-line-no">233</span><span id="line-233"> this.startOffset = offset(offset);</span>
<span class="source-line-no">234</span><span id="line-234"></span>
<span class="source-line-no">235</span><span id="line-235"> this.endBuffer = index(offset + len);</span>
<span class="source-line-no">236</span><span id="line-236"> this.endOffset = offset(offset + len);</span>
<span class="source-line-no">237</span><span id="line-237"> if (startBuffer &lt; endBuffer &amp;&amp; endOffset == 0) {</span>
<span class="source-line-no">238</span><span id="line-238"> endBuffer--;</span>
<span class="source-line-no">239</span><span id="line-239"> endOffset = bufferSize;</span>
<span class="source-line-no">240</span><span id="line-240"> }</span>
<span class="source-line-no">241</span><span id="line-241"> assert startBuffer &gt;= 0 &amp;&amp; startBuffer &lt; bufferCount;</span>
<span class="source-line-no">242</span><span id="line-242"> assert endBuffer &gt;= 0 &amp;&amp; endBuffer &lt; bufferCount;</span>
<span class="source-line-no">243</span><span id="line-243"></span>
<span class="source-line-no">244</span><span id="line-244"> // initialize the index to the first buffer index.</span>
<span class="source-line-no">245</span><span id="line-245"> this.curIndex = startBuffer;</span>
<span class="source-line-no">246</span><span id="line-246"> }</span>
<span class="source-line-no">247</span><span id="line-247"></span>
<span class="source-line-no">248</span><span id="line-248"> @Override</span>
<span class="source-line-no">249</span><span id="line-249"> public boolean hasNext() {</span>
<span class="source-line-no">250</span><span id="line-250"> return this.curIndex &lt;= endBuffer;</span>
<span class="source-line-no">251</span><span id="line-251"> }</span>
<span class="source-line-no">252</span><span id="line-252"></span>
<span class="source-line-no">253</span><span id="line-253"> /**</span>
<span class="source-line-no">254</span><span id="line-254"> * The returned ByteBuffer is an sliced one, it won't affect the position or limit of the</span>
<span class="source-line-no">255</span><span id="line-255"> * original one.</span>
<span class="source-line-no">256</span><span id="line-256"> */</span>
<span class="source-line-no">257</span><span id="line-257"> @Override</span>
<span class="source-line-no">258</span><span id="line-258"> public ByteBuffer next() {</span>
<span class="source-line-no">259</span><span id="line-259"> ByteBuffer bb = buffers[curIndex].duplicate();</span>
<span class="source-line-no">260</span><span id="line-260"> if (curIndex == startBuffer) {</span>
<span class="source-line-no">261</span><span id="line-261"> bb.position(startOffset).limit(Math.min(bufferSize, startOffset + len));</span>
<span class="source-line-no">262</span><span id="line-262"> } else if (curIndex == endBuffer) {</span>
<span class="source-line-no">263</span><span id="line-263"> bb.position(0).limit(endOffset);</span>
<span class="source-line-no">264</span><span id="line-264"> } else {</span>
<span class="source-line-no">265</span><span id="line-265"> bb.position(0).limit(bufferSize);</span>
<span class="source-line-no">266</span><span id="line-266"> }</span>
<span class="source-line-no">267</span><span id="line-267"> curIndex++;</span>
<span class="source-line-no">268</span><span id="line-268"> sum += bb.remaining();</span>
<span class="source-line-no">269</span><span id="line-269"> // Make sure that its pos is zero, it's important because MBB will count from zero for all nio</span>
<span class="source-line-no">270</span><span id="line-270"> // ByteBuffers.</span>
<span class="source-line-no">271</span><span id="line-271"> return bb.slice();</span>
<span class="source-line-no">272</span><span id="line-272"> }</span>
<span class="source-line-no">273</span><span id="line-273"></span>
<span class="source-line-no">274</span><span id="line-274"> int getSum() {</span>
<span class="source-line-no">275</span><span id="line-275"> return sum;</span>
<span class="source-line-no">276</span><span id="line-276"> }</span>
<span class="source-line-no">277</span><span id="line-277"></span>
<span class="source-line-no">278</span><span id="line-278"> int getBufferCount() {</span>
<span class="source-line-no">279</span><span id="line-279"> return this.endBuffer - this.startBuffer + 1;</span>
<span class="source-line-no">280</span><span id="line-280"> }</span>
<span class="source-line-no">281</span><span id="line-281"> }</span>
<span class="source-line-no">282</span><span id="line-282">}</span>
</pre>
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