// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
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// modification, are permitted provided that the following conditions are
// met:
//
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// notice, this list of conditions and the following disclaimer.
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// distribution.
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package com.google.protobuf;

import java.io.IOException;

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 
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/**
 * 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.
 *
 * <p>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 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;

  
Given a tag value, determines the wire type (the lower 3 bits). /** Given a tag value, determines the wire type (the lower 3 bits). */
  public static int getTagWireType(final int tag) {
    return tag & TAG_TYPE_MASK;
  }

  
Given a tag value, determines the field number (the upper 29 bits). /** 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. /** 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 JavaType. This is only here to support the lite runtime and should not be used by users. /**
   * 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. /** 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 Type. This is only here to support the lite runtime and should not be used by users. /**
   * 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) {
      @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);

  
Validation level for handling incoming string field data which potentially contain non-UTF8
bytes.
/**
   * Validation level for handling incoming string field data which potentially contain non-UTF8
   * bytes.
   */
  enum Utf8Validation {
    
Eagerly parses to String; silently accepts invalid UTF8 bytes. /** Eagerly parses to String; silently accepts invalid UTF8 bytes. */
    LOOSE {
      @Override
      Object readString(CodedInputStream input) throws IOException {
        return input.readString();
      }
    },
    
Eagerly parses to String; throws an IOException on invalid bytes. /** Eagerly parses to String; throws an IOException on invalid bytes. */
    STRICT {
      @Override
      Object readString(CodedInputStream input) throws IOException {
        return input.readStringRequireUtf8();
      }
    },
    
Keep data as ByteString; validation/conversion to String is lazy. /** Keep data as ByteString; validation/conversion to String is lazy. */
    LAZY {
      @Override
      Object readString(CodedInputStream input) throws IOException {
        return input.readBytes();
      }
    };

    
Read a string field from the input with the proper UTF8 validation. /** Read a string field from the input with the proper UTF8 validation. */
    abstract Object readString(CodedInputStream input) throws IOException;
  }

  
Read a field of any primitive type for immutable messages from a CodedInputStream. Enums,
groups, and embedded messages are not handled by this method.
Params:
input – The stream from which to read.
type – Declared type of the field.
utf8Validation – Different string UTF8 validation level for handling string fields.
Returns:
An object representing the field's value, of the exact type which would be returned by MessageOrBuilder.getField(FieldDescriptor) for this field./**
   * Read a field of any primitive type for immutable messages from a CodedInputStream. Enums,
   * groups, and embedded messages are not handled by this method.
   *
   * @param input The stream from which to read.
   * @param type Declared type of the field.
   * @param utf8Validation Different string UTF8 validation level for handling string fields.
   * @return An object representing the field's value, of the exact type which would be returned by
   *     {@link Message#getField(Descriptors.FieldDescriptor)} for this field.
   */
  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.");
  }
}