ProtobufWireFormat.java

/* Copyright (c) 2011 Danish Maritime Authority.
 *
 * 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 net.maritimecloud.internal.message.binary.protobuf;

/**
 * Copied from the Protobuf {@code WireFormat} class.
 * <p>
 * The primary reason for copying the class is that {@code getTagWireType()}
 * has package scope access, and we need access to the internal data representation.
 */
public class ProtobufWireFormat {

    public static final int WIRETYPE_VARINT           = 0;
    public static final int WIRETYPE_FIXED64          = 1;
    public static final int WIRETYPE_LENGTH_DELIMITED = 2;
    public static final int WIRETYPE_START_GROUP      = 3;
    public static final int WIRETYPE_END_GROUP        = 4;
    public 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(final int tag) {
        return tag & TAG_TYPE_MASK;
    }

    /** Given a tag value, determines the field number (the upper 29 bits). */
    public static int getTagFieldNumber(final int tag) {
        return tag >>> TAG_TYPE_BITS;
    }

}