1 // Protocol Buffers - Google's data interchange format 2 // Copyright 2008 Google Inc. All rights reserved. 3 // http://code.google.com/p/protobuf/ 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.micro; 32 33 /** 34 * This class is used internally by the Protocol Buffer library and generated 35 * message implementations. It is public only because those generated messages 36 * do not reside in the {@code protobuf} package. Others should not use this 37 * class directly. 38 * 39 * This class contains constants and helper functions useful for dealing with 40 * the Protocol Buffer wire format. 41 * 42 * @author kenton@google.com Kenton Varda 43 */ 44 public final class WireFormatMicro { 45 // Do not allow instantiation. WireFormatMicro()46 private WireFormatMicro() {} 47 48 static final int WIRETYPE_VARINT = 0; 49 static final int WIRETYPE_FIXED64 = 1; 50 static final int WIRETYPE_LENGTH_DELIMITED = 2; 51 static final int WIRETYPE_START_GROUP = 3; 52 static final int WIRETYPE_END_GROUP = 4; 53 static final int WIRETYPE_FIXED32 = 5; 54 55 static final int TAG_TYPE_BITS = 3; 56 static final int TAG_TYPE_MASK = (1 << TAG_TYPE_BITS) - 1; 57 58 /** Given a tag value, determines the wire type (the lower 3 bits). */ getTagWireType(final int tag)59 static int getTagWireType(final int tag) { 60 return tag & TAG_TYPE_MASK; 61 } 62 63 /** Given a tag value, determines the field number (the upper 29 bits). */ getTagFieldNumber(final int tag)64 public static int getTagFieldNumber(final int tag) { 65 return tag >>> TAG_TYPE_BITS; 66 } 67 68 /** Makes a tag value given a field number and wire type. */ makeTag(final int fieldNumber, final int wireType)69 static int makeTag(final int fieldNumber, final int wireType) { 70 return (fieldNumber << TAG_TYPE_BITS) | wireType; 71 } 72 73 // Field numbers for feilds in MessageSet wire format. 74 static final int MESSAGE_SET_ITEM = 1; 75 static final int MESSAGE_SET_TYPE_ID = 2; 76 static final int MESSAGE_SET_MESSAGE = 3; 77 78 // Tag numbers. 79 static final int MESSAGE_SET_ITEM_TAG = 80 makeTag(MESSAGE_SET_ITEM, WIRETYPE_START_GROUP); 81 static final int MESSAGE_SET_ITEM_END_TAG = 82 makeTag(MESSAGE_SET_ITEM, WIRETYPE_END_GROUP); 83 static final int MESSAGE_SET_TYPE_ID_TAG = 84 makeTag(MESSAGE_SET_TYPE_ID, WIRETYPE_VARINT); 85 static final int MESSAGE_SET_MESSAGE_TAG = 86 makeTag(MESSAGE_SET_MESSAGE, WIRETYPE_LENGTH_DELIMITED); 87 } 88