WireFormat.java

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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// 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;
 
import java.io.IOException;
 
public final class WireFormat {
  // Do not allow instantiation.
  private WireFormat() {}
 
  static final int FIXED32_SIZE = 4;
  static final int FIXED64_SIZE = 8;
  static final int MAX_VARINT32_SIZE = 5;
  static final int MAX_VARINT64_SIZE = 10;
  static final int MAX_VARINT_SIZE = 10;
 
  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;
 
  public static int getTagWireType(final int tag) {
    return tag & TAG_TYPE_MASK;
  }
 
  public static int getTagFieldNumber(final int tag) {
    return tag >>> TAG_TYPE_BITS;
  }
 
  static int makeTag(final int fieldNumber, final int wireType) {
    return (fieldNumber << TAG_TYPE_BITS) | wireType;
  }
 
  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;
    }
 
    Object getDefaultDefault() {
      return defaultDefault;
    }
 
    private final Object defaultDefault;
  }
 
  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) {
      @Override
      public boolean isPackable() {
        return false;
      }
    },
    GROUP(JavaType.MESSAGE, WIRETYPE_START_GROUP) {
      @Override
      public boolean isPackable() {
        return false;
      }
    },
    MESSAGE(JavaType.MESSAGE, WIRETYPE_LENGTH_DELIMITED) {
      @Override
      public boolean isPackable() {
        return false;
      }
    },
    BYTES(JavaType.BYTE_STRING, WIRETYPE_LENGTH_DELIMITED) {
      @Override
      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 fields 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);
 
  enum Utf8Validation {
    LOOSE {
      @Override
      Object readString(CodedInputStream input) throws IOException {
        return input.readString();
      }
    },
    STRICT {
      @Override
      Object readString(CodedInputStream input) throws IOException {
        return input.readStringRequireUtf8();
      }
    },
    LAZY {
      @Override
      Object readString(CodedInputStream input) throws IOException {
        return input.readBytes();
      }
    };
 
    abstract Object readString(CodedInputStream input) throws IOException;
  }
 
  static Object readPrimitiveField(
      CodedInputStream input, FieldType type, Utf8Validation utf8Validation) throws IOException {
    switch (type) {
      case DOUBLE:
        return input.readDouble();
      case FLOAT:
        return input.readFloat();
      case INT64:
        return input.readInt64();
      case UINT64:
        return input.readUInt64();
      case INT32:
        return input.readInt32();
      case FIXED64:
        return input.readFixed64();
      case FIXED32:
        return input.readFixed32();
      case BOOL:
        return input.readBool();
      case BYTES:
        return input.readBytes();
      case UINT32:
        return input.readUInt32();
      case SFIXED32:
        return input.readSFixed32();
      case SFIXED64:
        return input.readSFixed64();
      case SINT32:
        return input.readSInt32();
      case SINT64:
        return input.readSInt64();
 
      case STRING:
        return utf8Validation.readString(input);
      case GROUP:
        throw new IllegalArgumentException("readPrimitiveField() cannot handle nested groups.");
      case MESSAGE:
        throw new IllegalArgumentException("readPrimitiveField() cannot handle embedded messages.");
      case ENUM:
        // We don't handle enums because we don't know what to do if the
        // value is not recognized.
        throw new IllegalArgumentException("readPrimitiveField() cannot handle enums.");
    }
 
    throw new RuntimeException("There is no way to get here, but the compiler thinks otherwise.");
  }
}