1 // Protocol Buffers - Google's data interchange format 2 // Copyright 2008 Google Inc. All rights reserved. 3 // https://developers.google.com/protocol-buffers/ 4 // 5 // Redistribution and use in source and binary forms, with or without 6 // modification, are permitted provided that the following conditions are 7 // met: 8 // 9 // * Redistributions of source code must retain the above copyright 10 // notice, this list of conditions and the following disclaimer. 11 // * Redistributions in binary form must reproduce the above 12 // copyright notice, this list of conditions and the following disclaimer 13 // in the documentation and/or other materials provided with the 14 // distribution. 15 // * Neither the name of Google Inc. nor the names of its 16 // contributors may be used to endorse or promote products derived from 17 // this software without specific prior written permission. 18 // 19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 31 package com.google.protobuf; 32 33 import static com.google.protobuf.Internal.EMPTY_BYTE_BUFFER; 34 35 import java.io.IOException; 36 import java.io.InputStream; 37 import java.nio.ByteBuffer; 38 import java.util.Iterator; 39 40 class IterableByteBufferInputStream extends InputStream { 41 /** The {@link Iterator} with type {@link ByteBuffer} of {@code input} */ 42 private Iterator<ByteBuffer> iterator; 43 /** The current ByteBuffer; */ 44 private ByteBuffer currentByteBuffer; 45 /** The number of ByteBuffers in the input data. */ 46 private int dataSize; 47 /** 48 * Current {@code ByteBuffer}'s index 49 * 50 * <p>If index equals dataSize, then all the data in the InputStream has been consumed 51 */ 52 private int currentIndex; 53 /** The current position for current ByteBuffer */ 54 private int currentByteBufferPos; 55 /** Whether current ByteBuffer has an array */ 56 private boolean hasArray; 57 /** 58 * If the current ByteBuffer is unsafe-direct based, currentArray is null; otherwise should be the 59 * array inside ByteBuffer. 60 */ 61 private byte[] currentArray; 62 /** Current ByteBuffer's array offset */ 63 private int currentArrayOffset; 64 /** 65 * If the current ByteBuffer is unsafe-direct based, currentAddress is the start address of this 66 * ByteBuffer; otherwise should be zero. 67 */ 68 private long currentAddress; 69 IterableByteBufferInputStream(Iterable<ByteBuffer> data)70 IterableByteBufferInputStream(Iterable<ByteBuffer> data) { 71 iterator = data.iterator(); 72 dataSize = 0; 73 for (ByteBuffer unused : data) { 74 dataSize++; 75 } 76 currentIndex = -1; 77 78 if (!getNextByteBuffer()) { 79 currentByteBuffer = EMPTY_BYTE_BUFFER; 80 currentIndex = 0; 81 currentByteBufferPos = 0; 82 currentAddress = 0; 83 } 84 } 85 getNextByteBuffer()86 private boolean getNextByteBuffer() { 87 currentIndex++; 88 if (!iterator.hasNext()) { 89 return false; 90 } 91 currentByteBuffer = iterator.next(); 92 currentByteBufferPos = currentByteBuffer.position(); 93 if (currentByteBuffer.hasArray()) { 94 hasArray = true; 95 currentArray = currentByteBuffer.array(); 96 currentArrayOffset = currentByteBuffer.arrayOffset(); 97 } else { 98 hasArray = false; 99 currentAddress = UnsafeUtil.addressOffset(currentByteBuffer); 100 currentArray = null; 101 } 102 return true; 103 } 104 updateCurrentByteBufferPos(int numberOfBytesRead)105 private void updateCurrentByteBufferPos(int numberOfBytesRead) { 106 currentByteBufferPos += numberOfBytesRead; 107 if (currentByteBufferPos == currentByteBuffer.limit()) { 108 getNextByteBuffer(); 109 } 110 } 111 112 @Override read()113 public int read() throws IOException { 114 if (currentIndex == dataSize) { 115 return -1; 116 } 117 if (hasArray) { 118 int result = currentArray[currentByteBufferPos + currentArrayOffset] & 0xFF; 119 updateCurrentByteBufferPos(1); 120 return result; 121 } else { 122 int result = UnsafeUtil.getByte(currentByteBufferPos + currentAddress) & 0xFF; 123 updateCurrentByteBufferPos(1); 124 return result; 125 } 126 } 127 128 @Override read(byte[] output, int offset, int length)129 public int read(byte[] output, int offset, int length) throws IOException { 130 if (currentIndex == dataSize) { 131 return -1; 132 } 133 int remaining = currentByteBuffer.limit() - currentByteBufferPos; 134 if (length > remaining) { 135 length = remaining; 136 } 137 if (hasArray) { 138 System.arraycopy( 139 currentArray, currentByteBufferPos + currentArrayOffset, output, offset, length); 140 updateCurrentByteBufferPos(length); 141 } else { 142 int prevPos = currentByteBuffer.position(); 143 currentByteBuffer.position(currentByteBufferPos); 144 currentByteBuffer.get(output, offset, length); 145 currentByteBuffer.position(prevPos); 146 updateCurrentByteBufferPos(length); 147 } 148 return length; 149 } 150 } 151