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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// http://code.google.com/p/protobuf/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
package com.google.protobuf;
/**
* This class is used internally by the Protocol Buffer library and generated
* message implementations. It is public only because those generated messages
* do not reside in the {@code protobuf} package. Others should not use this
* class directly.
*
* This class contains constants and helper functions useful for dealing with
* the Protocol Buffer wire format.
*
* @author kenton@google.com Kenton Varda
*/
public final class WireFormat {
// Do not allow instantiation.
private WireFormat() {}
static final int WIRETYPE_VARINT = 0;
static final int WIRETYPE_FIXED64 = 1;
static final int WIRETYPE_LENGTH_DELIMITED = 2;
static final int WIRETYPE_START_GROUP = 3;
static final int WIRETYPE_END_GROUP = 4;
static final int WIRETYPE_FIXED32 = 5;
static final int TAG_TYPE_BITS = 3;
static final int TAG_TYPE_MASK = (1 << TAG_TYPE_BITS) - 1;
/** Given a tag value, determines the wire type (the lower 3 bits). */
static int getTagWireType(int tag) {
return tag & TAG_TYPE_MASK;
}
/** Given a tag value, determines the field number (the upper 29 bits). */
public static int getTagFieldNumber(int tag) {
return tag >>> TAG_TYPE_BITS;
}
/** Makes a tag value given a field number and wire type. */
static int makeTag(int fieldNumber, int wireType) {
return (fieldNumber << TAG_TYPE_BITS) | wireType;
}
static int getWireFormatForFieldType(Descriptors.FieldDescriptor.Type type) {
switch (type) {
case DOUBLE : return WIRETYPE_FIXED64;
case FLOAT : return WIRETYPE_FIXED32;
case INT64 : return WIRETYPE_VARINT;
case UINT64 : return WIRETYPE_VARINT;
case INT32 : return WIRETYPE_VARINT;
case FIXED64 : return WIRETYPE_FIXED64;
case FIXED32 : return WIRETYPE_FIXED32;
case BOOL : return WIRETYPE_VARINT;
case STRING : return WIRETYPE_LENGTH_DELIMITED;
case GROUP : return WIRETYPE_START_GROUP;
case MESSAGE : return WIRETYPE_LENGTH_DELIMITED;
case BYTES : return WIRETYPE_LENGTH_DELIMITED;
case UINT32 : return WIRETYPE_VARINT;
case ENUM : return WIRETYPE_VARINT;
case SFIXED32: return WIRETYPE_FIXED32;
case SFIXED64: return WIRETYPE_FIXED64;
case SINT32 : return WIRETYPE_VARINT;
case SINT64 : return WIRETYPE_VARINT;
}
throw new RuntimeException(
"There is no way to get here, but the compiler thinks otherwise.");
}
/** Given a field descriptor, returns the wire type. This differs from
* getWireFormatForFieldType for packed repeated fields. */
static int getWireFormatForField(Descriptors.FieldDescriptor descriptor) {
if (descriptor.getOptions().getPacked()) {
return WIRETYPE_LENGTH_DELIMITED;
} else {
return getWireFormatForFieldType(descriptor.getType());
}
}
// Field numbers for feilds in MessageSet wire format.
static final int MESSAGE_SET_ITEM = 1;
static final int MESSAGE_SET_TYPE_ID = 2;
static final int MESSAGE_SET_MESSAGE = 3;
// Tag numbers.
static final int MESSAGE_SET_ITEM_TAG =
makeTag(MESSAGE_SET_ITEM, WIRETYPE_START_GROUP);
static final int MESSAGE_SET_ITEM_END_TAG =
makeTag(MESSAGE_SET_ITEM, WIRETYPE_END_GROUP);
static final int MESSAGE_SET_TYPE_ID_TAG =
makeTag(MESSAGE_SET_TYPE_ID, WIRETYPE_VARINT);
static final int MESSAGE_SET_MESSAGE_TAG =
makeTag(MESSAGE_SET_MESSAGE, WIRETYPE_LENGTH_DELIMITED);
}
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