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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() {}

  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;

  }

  /** Makes a tag value given a field number and wire type. */

  static int makeTag(final int fieldNumber, final int wireType) {

    return (fieldNumber << TAG_TYPE_BITS) | wireType;

  }

  /**

   * Lite equivalent to {@link Descriptors.FieldDescriptor.JavaType}.  This is

   * only here to support the lite runtime and should not be used by users.

   */

  public enum JavaType {

    INT(0),

    LONG(0L),

    FLOAT(0F),

    DOUBLE(0D),

    BOOLEAN(false),

    STRING(""),

    BYTE_STRING(ByteString.EMPTY),

    ENUM(null),

    MESSAGE(null);

    JavaType(final Object defaultDefault) {

      this.defaultDefault = defaultDefault;

    }

    /**

     * The default default value for fields of this type, if it's a primitive

     * type.

     */

    Object getDefaultDefault() {

      return defaultDefault;

    }

    private final Object defaultDefault;

  }

  /**

   * Lite equivalent to {@link Descriptors.FieldDescriptor.Type}.  This is

   * only here to support the lite runtime and should not be used by users.

   */

  public enum FieldType {

    DOUBLE  (JavaType.DOUBLE     , WIRETYPE_FIXED64         ),

    FLOAT   (JavaType.FLOAT      , WIRETYPE_FIXED32         ),

    INT64   (JavaType.LONG       , WIRETYPE_VARINT          ),

    UINT64  (JavaType.LONG       , WIRETYPE_VARINT          ),

    INT32   (JavaType.INT        , WIRETYPE_VARINT          ),

    FIXED64 (JavaType.LONG       , WIRETYPE_FIXED64         ),

    FIXED32 (JavaType.INT        , WIRETYPE_FIXED32         ),

    BOOL    (JavaType.BOOLEAN    , WIRETYPE_VARINT          ),

    STRING  (JavaType.STRING     , WIRETYPE_LENGTH_DELIMITED) {

      public boolean isPackable() { return false; }

    },

    GROUP   (JavaType.MESSAGE    , WIRETYPE_START_GROUP     ) {

      public boolean isPackable() { return false; }

    },

    MESSAGE (JavaType.MESSAGE    , WIRETYPE_LENGTH_DELIMITED) {

      public boolean isPackable() { return false; }

    },

    BYTES   (JavaType.BYTE_STRING, WIRETYPE_LENGTH_DELIMITED) {

      public boolean isPackable() { return false; }

    },

    UINT32  (JavaType.INT        , WIRETYPE_VARINT          ),

    ENUM    (JavaType.ENUM       , WIRETYPE_VARINT          ),

    SFIXED32(JavaType.INT        , WIRETYPE_FIXED32         ),

    SFIXED64(JavaType.LONG       , WIRETYPE_FIXED64         ),

    SINT32  (JavaType.INT        , WIRETYPE_VARINT          ),

    SINT64  (JavaType.LONG       , WIRETYPE_VARINT          );

    FieldType(final JavaType javaType, final int wireType) {

      this.javaType = javaType;

      this.wireType = wireType;

    }

    private final JavaType javaType;

    private final int wireType;

    public JavaType getJavaType() { return javaType; }

    public int getWireType() { return wireType; }

    public boolean isPackable() { return true; }

  }

  // 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);

}