Check in protobuf java code and generate lite jar.

third_party/protobuf/java/src/main/java/com/google/protobuf/UnknownFieldSet.java

Index: third_party/protobuf/java/src/main/java/com/google/protobuf/UnknownFieldSet.java
diff --git a/third_party/protobuf/java/src/main/java/com/google/protobuf/UnknownFieldSet.java b/third_party/protobuf/java/src/main/java/com/google/protobuf/UnknownFieldSet.java
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index 0000000000000000000000000000000000000000..26a15d0087285cb46c159d3aaf8454b032b74fd5
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@@ -0,0 +1,953 @@
+// 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;
+
+import com.google.protobuf.AbstractMessageLite.Builder.LimitedInputStream;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+/**
+ * {@code UnknownFieldSet} is used to keep track of fields which were seen when
+ * parsing a protocol message but whose field numbers or types are unrecognized.
+ * This most frequently occurs when new fields are added to a message type
+ * and then messages containing those feilds are read by old software that was
+ * compiled before the new types were added.
+ *
+ * <p>Every {@link Message} contains an {@code UnknownFieldSet} (and every
+ * {@link Message.Builder} contains an {@link Builder}).
+ *
+ * <p>Most users will never need to use this class.
+ *
+ * @author kenton@google.com Kenton Varda
+ */
+public final class UnknownFieldSet implements MessageLite {
+  private UnknownFieldSet() {}
+
+  /** Create a new {@link Builder}. */
+  public static Builder newBuilder() {
+    return Builder.create();
+  }
+
+  /**
+   * Create a new {@link Builder} and initialize it to be a copy
+   * of {@code copyFrom}.
+   */
+  public static Builder newBuilder(final UnknownFieldSet copyFrom) {
+    return newBuilder().mergeFrom(copyFrom);
+  }
+
+  /** Get an empty {@code UnknownFieldSet}. */
+  public static UnknownFieldSet getDefaultInstance() {
+    return defaultInstance;
+  }
+  public UnknownFieldSet getDefaultInstanceForType() {
+    return defaultInstance;
+  }
+  private static final UnknownFieldSet defaultInstance =
+    new UnknownFieldSet(Collections.<Integer, Field>emptyMap());
+
+  /**
+   * Construct an {@code UnknownFieldSet} around the given map.  The map is
+   * expected to be immutable.
+   */
+  private UnknownFieldSet(final Map<Integer, Field> fields) {
+    this.fields = fields;
+  }
+  private Map<Integer, Field> fields;
+
+  @Override
+  public boolean equals(final Object other) {
+    if (this == other) {
+      return true;
+    }
+    return (other instanceof UnknownFieldSet) &&
+           fields.equals(((UnknownFieldSet) other).fields);
+  }
+
+  @Override
+  public int hashCode() {
+    return fields.hashCode();
+  }
+
+  /** Get a map of fields in the set by number. */
+  public Map<Integer, Field> asMap() {
+    return fields;
+  }
+
+  /** Check if the given field number is present in the set. */
+  public boolean hasField(final int number) {
+    return fields.containsKey(number);
+  }
+
+  /**
+   * Get a field by number.  Returns an empty field if not present.  Never
+   * returns {@code null}.
+   */
+  public Field getField(final int number) {
+    final Field result = fields.get(number);
+    return (result == null) ? Field.getDefaultInstance() : result;
+  }
+
+  /** Serializes the set and writes it to {@code output}. */
+  public void writeTo(final CodedOutputStream output) throws IOException {
+    for (final Map.Entry<Integer, Field> entry : fields.entrySet()) {
+      entry.getValue().writeTo(entry.getKey(), output);
+    }
+  }
+
+  /**
+   * Converts the set to a string in protocol buffer text format. This is
+   * just a trivial wrapper around
+   * {@link TextFormat#printToString(UnknownFieldSet)}.
+   */
+  @Override
+  public String toString() {
+    return TextFormat.printToString(this);
+  }
+
+  /**
+   * Serializes the message to a {@code ByteString} and returns it. This is
+   * just a trivial wrapper around {@link #writeTo(CodedOutputStream)}.
+   */
+  public ByteString toByteString() {
+    try {
+      final ByteString.CodedBuilder out =
+        ByteString.newCodedBuilder(getSerializedSize());
+      writeTo(out.getCodedOutput());
+      return out.build();
+    } catch (final IOException e) {
+      throw new RuntimeException(
+        "Serializing to a ByteString threw an IOException (should " +
+        "never happen).", e);
+    }
+  }
+
+  /**
+   * Serializes the message to a {@code byte} array and returns it.  This is
+   * just a trivial wrapper around {@link #writeTo(CodedOutputStream)}.
+   */
+  public byte[] toByteArray() {
+    try {
+      final byte[] result = new byte[getSerializedSize()];
+      final CodedOutputStream output = CodedOutputStream.newInstance(result);
+      writeTo(output);
+      output.checkNoSpaceLeft();
+      return result;
+    } catch (final IOException e) {
+      throw new RuntimeException(
+        "Serializing to a byte array threw an IOException " +
+        "(should never happen).", e);
+    }
+  }
+
+  /**
+   * Serializes the message and writes it to {@code output}.  This is just a
+   * trivial wrapper around {@link #writeTo(CodedOutputStream)}.
+   */
+  public void writeTo(final OutputStream output) throws IOException {
+    final CodedOutputStream codedOutput = CodedOutputStream.newInstance(output);
+    writeTo(codedOutput);
+    codedOutput.flush();
+  }
+
+  public void writeDelimitedTo(OutputStream output) throws IOException {
+    final CodedOutputStream codedOutput = CodedOutputStream.newInstance(output);
+    codedOutput.writeRawVarint32(getSerializedSize());
+    writeTo(codedOutput);
+    codedOutput.flush();
+  }
+
+  /** Get the number of bytes required to encode this set. */
+  public int getSerializedSize() {
+    int result = 0;
+    for (final Map.Entry<Integer, Field> entry : fields.entrySet()) {
+      result += entry.getValue().getSerializedSize(entry.getKey());
+    }
+    return result;
+  }
+
+  /**
+   * Serializes the set and writes it to {@code output} using
+   * {@code MessageSet} wire format.
+   */
+  public void writeAsMessageSetTo(final CodedOutputStream output)
+      throws IOException {
+    for (final Map.Entry<Integer, Field> entry : fields.entrySet()) {
+      entry.getValue().writeAsMessageSetExtensionTo(
+        entry.getKey(), output);
+    }
+  }
+
+  /**
+   * Get the number of bytes required to encode this set using
+   * {@code MessageSet} wire format.
+   */
+  public int getSerializedSizeAsMessageSet() {
+    int result = 0;
+    for (final Map.Entry<Integer, Field> entry : fields.entrySet()) {
+      result += entry.getValue().getSerializedSizeAsMessageSetExtension(
+        entry.getKey());
+    }
+    return result;
+  }
+
+  public boolean isInitialized() {
+    // UnknownFieldSets do not have required fields, so they are always
+    // initialized.
+    return true;
+  }
+
+  /** Parse an {@code UnknownFieldSet} from the given input stream. */
+  public static UnknownFieldSet parseFrom(final CodedInputStream input)
+                                          throws IOException {
+    return newBuilder().mergeFrom(input).build();
+  }
+
+  /** Parse {@code data} as an {@code UnknownFieldSet} and return it. */
+  public static UnknownFieldSet parseFrom(final ByteString data)
+      throws InvalidProtocolBufferException {
+    return newBuilder().mergeFrom(data).build();
+  }
+
+  /** Parse {@code data} as an {@code UnknownFieldSet} and return it. */
+  public static UnknownFieldSet parseFrom(final byte[] data)
+      throws InvalidProtocolBufferException {
+    return newBuilder().mergeFrom(data).build();
+  }
+
+  /** Parse an {@code UnknownFieldSet} from {@code input} and return it. */
+  public static UnknownFieldSet parseFrom(final InputStream input)
+                                          throws IOException {
+    return newBuilder().mergeFrom(input).build();
+  }
+
+  public Builder newBuilderForType() {
+    return newBuilder();
+  }
+
+  public Builder toBuilder() {
+    return newBuilder().mergeFrom(this);
+  }
+
+  /**
+   * Builder for {@link UnknownFieldSet}s.
+   *
+   * <p>Note that this class maintains {@link Field.Builder}s for all fields
+   * in the set.  Thus, adding one element to an existing {@link Field} does not
+   * require making a copy.  This is important for efficient parsing of
+   * unknown repeated fields.  However, it implies that {@link Field}s cannot
+   * be constructed independently, nor can two {@link UnknownFieldSet}s share
+   * the same {@code Field} object.
+   *
+   * <p>Use {@link UnknownFieldSet#newBuilder()} to construct a {@code Builder}.
+   */
+  public static final class Builder implements MessageLite.Builder {
+    // This constructor should never be called directly (except from 'create').
+    private Builder() {}
+
+    private Map<Integer, Field> fields;
+
+    // Optimization:  We keep around a builder for the last field that was
+    //   modified so that we can efficiently add to it multiple times in a
+    //   row (important when parsing an unknown repeated field).
+    private int lastFieldNumber;
+    private Field.Builder lastField;
+
+    private static Builder create() {
+      Builder builder = new Builder();
+      builder.reinitialize();
+      return builder;
+    }
+
+    /**
+     * Get a field builder for the given field number which includes any
+     * values that already exist.
+     */
+    private Field.Builder getFieldBuilder(final int number) {
+      if (lastField != null) {
+        if (number == lastFieldNumber) {
+          return lastField;
+        }
+        // Note:  addField() will reset lastField and lastFieldNumber.
+        addField(lastFieldNumber, lastField.build());
+      }
+      if (number == 0) {
+        return null;
+      } else {
+        final Field existing = fields.get(number);
+        lastFieldNumber = number;
+        lastField = Field.newBuilder();
+        if (existing != null) {
+          lastField.mergeFrom(existing);
+        }
+        return lastField;
+      }
+    }
+
+    /**
+     * Build the {@link UnknownFieldSet} and return it.
+     *
+     * <p>Once {@code build()} has been called, the {@code Builder} will no
+     * longer be usable.  Calling any method after {@code build()} will result
+     * in undefined behavior and can cause a {@code NullPointerException} to be
+     * thrown.
+     */
+    public UnknownFieldSet build() {
+      getFieldBuilder(0);  // Force lastField to be built.
+      final UnknownFieldSet result;
+      if (fields.isEmpty()) {
+        result = getDefaultInstance();
+      } else {
+        result = new UnknownFieldSet(Collections.unmodifiableMap(fields));
+      }
+      fields = null;
+      return result;
+    }
+
+    public UnknownFieldSet buildPartial() {
+      // No required fields, so this is the same as build().
+      return build();
+    }
+
+    @Override
+    public Builder clone() {
+      getFieldBuilder(0);  // Force lastField to be built.
+      return UnknownFieldSet.newBuilder().mergeFrom(
+          new UnknownFieldSet(fields));
+    }
+
+    public UnknownFieldSet getDefaultInstanceForType() {
+      return UnknownFieldSet.getDefaultInstance();
+    }
+
+    private void reinitialize() {
+      fields = Collections.emptyMap();
+      lastFieldNumber = 0;
+      lastField = null;
+    }
+
+    /** Reset the builder to an empty set. */
+    public Builder clear() {
+      reinitialize();
+      return this;
+    }
+
+    /**
+     * Merge the fields from {@code other} into this set.  If a field number
+     * exists in both sets, {@code other}'s values for that field will be
+     * appended to the values in this set.
+     */
+    public Builder mergeFrom(final UnknownFieldSet other) {
+      if (other != getDefaultInstance()) {
+        for (final Map.Entry<Integer, Field> entry : other.fields.entrySet()) {
+          mergeField(entry.getKey(), entry.getValue());
+        }
+      }
+      return this;
+    }
+
+    /**
+     * Add a field to the {@code UnknownFieldSet}.  If a field with the same
+     * number already exists, the two are merged.
+     */
+    public Builder mergeField(final int number, final Field field) {
+      if (number == 0) {
+        throw new IllegalArgumentException("Zero is not a valid field number.");
+      }
+      if (hasField(number)) {
+        getFieldBuilder(number).mergeFrom(field);
+      } else {
+        // Optimization:  We could call getFieldBuilder(number).mergeFrom(field)
+        // in this case, but that would create a copy of the Field object.
+        // We'd rather reuse the one passed to us, so call addField() instead.
+        addField(number, field);
+      }
+      return this;
+    }
+
+    /**
+     * Convenience method for merging a new field containing a single varint
+     * value.  This is used in particular when an unknown enum value is
+     * encountered.
+     */
+    public Builder mergeVarintField(final int number, final int value) {
+      if (number == 0) {
+        throw new IllegalArgumentException("Zero is not a valid field number.");
+      }
+      getFieldBuilder(number).addVarint(value);
+      return this;
+    }
+
+    /** Check if the given field number is present in the set. */
+    public boolean hasField(final int number) {
+      if (number == 0) {
+        throw new IllegalArgumentException("Zero is not a valid field number.");
+      }
+      return number == lastFieldNumber || fields.containsKey(number);
+    }
+
+    /**
+     * Add a field to the {@code UnknownFieldSet}.  If a field with the same
+     * number already exists, it is removed.
+     */
+    public Builder addField(final int number, final Field field) {
+      if (number == 0) {
+        throw new IllegalArgumentException("Zero is not a valid field number.");
+      }
+      if (lastField != null && lastFieldNumber == number) {
+        // Discard this.
+        lastField = null;
+        lastFieldNumber = 0;
+      }
+      if (fields.isEmpty()) {
+        fields = new TreeMap<Integer,Field>();
+      }
+      fields.put(number, field);
+      return this;
+    }
+
+    /**
+     * Get all present {@code Field}s as an immutable {@code Map}.  If more
+     * fields are added, the changes may or may not be reflected in this map.
+     */
+    public Map<Integer, Field> asMap() {
+      getFieldBuilder(0);  // Force lastField to be built.
+      return Collections.unmodifiableMap(fields);
+    }
+
+    /**
+     * Parse an entire message from {@code input} and merge its fields into
+     * this set.
+     */
+    public Builder mergeFrom(final CodedInputStream input) throws IOException {
+      while (true) {
+        final int tag = input.readTag();
+        if (tag == 0 || !mergeFieldFrom(tag, input)) {
+          break;
+        }
+      }
+      return this;
+    }
+
+    /**
+     * Parse a single field from {@code input} and merge it into this set.
+     * @param tag The field's tag number, which was already parsed.
+     * @return {@code false} if the tag is an engroup tag.
+     */
+    public boolean mergeFieldFrom(final int tag, final CodedInputStream input)
+                                  throws IOException {
+      final int number = WireFormat.getTagFieldNumber(tag);
+      switch (WireFormat.getTagWireType(tag)) {
+        case WireFormat.WIRETYPE_VARINT:
+          getFieldBuilder(number).addVarint(input.readInt64());
+          return true;
+        case WireFormat.WIRETYPE_FIXED64:
+          getFieldBuilder(number).addFixed64(input.readFixed64());
+          return true;
+        case WireFormat.WIRETYPE_LENGTH_DELIMITED:
+          getFieldBuilder(number).addLengthDelimited(input.readBytes());
+          return true;
+        case WireFormat.WIRETYPE_START_GROUP:
+          final Builder subBuilder = newBuilder();
+          input.readGroup(number, subBuilder,
+                          ExtensionRegistry.getEmptyRegistry());
+          getFieldBuilder(number).addGroup(subBuilder.build());
+          return true;
+        case WireFormat.WIRETYPE_END_GROUP:
+          return false;
+        case WireFormat.WIRETYPE_FIXED32:
+          getFieldBuilder(number).addFixed32(input.readFixed32());
+          return true;
+        default:
+          throw InvalidProtocolBufferException.invalidWireType();
+      }
+    }
+
+    /**
+     * Parse {@code data} as an {@code UnknownFieldSet} and merge it with the
+     * set being built.  This is just a small wrapper around
+     * {@link #mergeFrom(CodedInputStream)}.
+     */
+    public Builder mergeFrom(final ByteString data)
+        throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = data.newCodedInput();
+        mergeFrom(input);
+        input.checkLastTagWas(0);
+        return this;
+      } catch (final InvalidProtocolBufferException e) {
+        throw e;
+      } catch (final IOException e) {
+        throw new RuntimeException(
+          "Reading from a ByteString threw an IOException (should " +
+          "never happen).", e);
+      }
+    }
+
+    /**
+     * Parse {@code data} as an {@code UnknownFieldSet} and merge it with the
+     * set being built.  This is just a small wrapper around
+     * {@link #mergeFrom(CodedInputStream)}.
+     */
+    public Builder mergeFrom(final byte[] data)
+        throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = CodedInputStream.newInstance(data);
+        mergeFrom(input);
+        input.checkLastTagWas(0);
+        return this;
+      } catch (final InvalidProtocolBufferException e) {
+        throw e;
+      } catch (final IOException e) {
+        throw new RuntimeException(
+          "Reading from a byte array threw an IOException (should " +
+          "never happen).", e);
+      }
+    }
+
+    /**
+     * Parse an {@code UnknownFieldSet} from {@code input} and merge it with the
+     * set being built.  This is just a small wrapper around
+     * {@link #mergeFrom(CodedInputStream)}.
+     */
+    public Builder mergeFrom(final InputStream input) throws IOException {
+      final CodedInputStream codedInput = CodedInputStream.newInstance(input);
+      mergeFrom(codedInput);
+      codedInput.checkLastTagWas(0);
+      return this;
+    }
+
+    public boolean mergeDelimitedFrom(InputStream input)
+        throws IOException {
+      final int firstByte = input.read();
+      if (firstByte == -1) {
+        return false;
+      }
+      final int size = CodedInputStream.readRawVarint32(firstByte, input);
+      final InputStream limitedInput = new LimitedInputStream(input, size);
+      mergeFrom(limitedInput);
+      return true;
+    }
+
+    public boolean mergeDelimitedFrom(
+        InputStream input,
+        ExtensionRegistryLite extensionRegistry) throws IOException {
+      // UnknownFieldSet has no extensions.
+      return mergeDelimitedFrom(input);
+    }
+
+    public Builder mergeFrom(
+        CodedInputStream input,
+        ExtensionRegistryLite extensionRegistry) throws IOException {
+      // UnknownFieldSet has no extensions.
+      return mergeFrom(input);
+    }
+
+    public Builder mergeFrom(
+        ByteString data,
+        ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException {
+      // UnknownFieldSet has no extensions.
+      return mergeFrom(data);
+    }
+
+    public Builder mergeFrom(byte[] data, int off, int len)
+        throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input =
+            CodedInputStream.newInstance(data, off, len);
+        mergeFrom(input);
+        input.checkLastTagWas(0);
+        return this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(
+          "Reading from a byte array threw an IOException (should " +
+          "never happen).", e);
+      }
+    }
+
+    public Builder mergeFrom(
+        byte[] data,
+        ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException {
+      // UnknownFieldSet has no extensions.
+      return mergeFrom(data);
+    }
+
+    public Builder mergeFrom(
+        byte[] data, int off, int len,
+        ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException {
+      // UnknownFieldSet has no extensions.
+      return mergeFrom(data, off, len);
+    }
+
+    public Builder mergeFrom(
+        InputStream input,
+        ExtensionRegistryLite extensionRegistry) throws IOException {
+      // UnknownFieldSet has no extensions.
+      return mergeFrom(input);
+    }
+
+    public boolean isInitialized() {
+      // UnknownFieldSets do not have required fields, so they are always
+      // initialized.
+      return true;
+    }
+  }
+
+  /**
+   * Represents a single field in an {@code UnknownFieldSet}.
+   *
+   * <p>A {@code Field} consists of five lists of values.  The lists correspond
+   * to the five "wire types" used in the protocol buffer binary format.
+   * The wire type of each field can be determined from the encoded form alone,
+   * without knowing the field's declared type.  So, we are able to parse
+   * unknown values at least this far and separate them.  Normally, only one
+   * of the five lists will contain any values, since it is impossible to
+   * define a valid message type that declares two different types for the
+   * same field number.  However, the code is designed to allow for the case
+   * where the same unknown field number is encountered using multiple different
+   * wire types.
+   *
+   * <p>{@code Field} is an immutable class.  To construct one, you must use a
+   * {@link Builder}.
+   *
+   * @see UnknownFieldSet
+   */
+  public static final class Field {
+    private Field() {}
+
+    /** Construct a new {@link Builder}. */
+    public static Builder newBuilder() {
+      return Builder.create();
+    }
+
+    /**
+     * Construct a new {@link Builder} and initialize it to a copy of
+     * {@code copyFrom}.
+     */
+    public static Builder newBuilder(final Field copyFrom) {
+      return newBuilder().mergeFrom(copyFrom);
+    }
+
+    /** Get an empty {@code Field}. */
+    public static Field getDefaultInstance() {
+      return fieldDefaultInstance;
+    }
+    private static final Field fieldDefaultInstance = newBuilder().build();
+
+    /** Get the list of varint values for this field. */
+    public List<Long> getVarintList()               { return varint;          }
+
+    /** Get the list of fixed32 values for this field. */
+    public List<Integer> getFixed32List()           { return fixed32;         }
+
+    /** Get the list of fixed64 values for this field. */
+    public List<Long> getFixed64List()              { return fixed64;         }
+
+    /** Get the list of length-delimited values for this field. */
+    public List<ByteString> getLengthDelimitedList() { return lengthDelimited; }
+
+    /**
+     * Get the list of embedded group values for this field.  These are
+     * represented using {@link UnknownFieldSet}s rather than {@link Message}s
+     * since the group's type is presumably unknown.
+     */
+    public List<UnknownFieldSet> getGroupList()      { return group;           }
+
+    @Override
+    public boolean equals(final Object other) {
+      if (this == other) {
+        return true;
+      }
+      if (!(other instanceof Field)) {
+        return false;
+      }
+      return Arrays.equals(getIdentityArray(),
+          ((Field) other).getIdentityArray());
+    }
+
+    @Override
+    public int hashCode() {
+      return Arrays.hashCode(getIdentityArray());
+    }
+
+    /**
+     * Returns the array of objects to be used to uniquely identify this
+     * {@link Field} instance.
+     */
+    private Object[] getIdentityArray() {
+      return new Object[] {
+          varint,
+          fixed32,
+          fixed64,
+          lengthDelimited,
+          group};
+    }
+
+    /**
+     * Serializes the field, including field number, and writes it to
+     * {@code output}.
+     */
+    public void writeTo(final int fieldNumber, final CodedOutputStream output)
+                        throws IOException {
+      for (final long value : varint) {
+        output.writeUInt64(fieldNumber, value);
+      }
+      for (final int value : fixed32) {
+        output.writeFixed32(fieldNumber, value);
+      }
+      for (final long value : fixed64) {
+        output.writeFixed64(fieldNumber, value);
+      }
+      for (final ByteString value : lengthDelimited) {
+        output.writeBytes(fieldNumber, value);
+      }
+      for (final UnknownFieldSet value : group) {
+        output.writeGroup(fieldNumber, value);
+      }
+    }
+
+    /**
+     * Get the number of bytes required to encode this field, including field
+     * number.
+     */
+    public int getSerializedSize(final int fieldNumber) {
+      int result = 0;
+      for (final long value : varint) {
+        result += CodedOutputStream.computeUInt64Size(fieldNumber, value);
+      }
+      for (final int value : fixed32) {
+        result += CodedOutputStream.computeFixed32Size(fieldNumber, value);
+      }
+      for (final long value : fixed64) {
+        result += CodedOutputStream.computeFixed64Size(fieldNumber, value);
+      }
+      for (final ByteString value : lengthDelimited) {
+        result += CodedOutputStream.computeBytesSize(fieldNumber, value);
+      }
+      for (final UnknownFieldSet value : group) {
+        result += CodedOutputStream.computeGroupSize(fieldNumber, value);
+      }
+      return result;
+    }
+
+    /**
+     * Serializes the field, including field number, and writes it to
+     * {@code output}, using {@code MessageSet} wire format.
+     */
+    public void writeAsMessageSetExtensionTo(
+        final int fieldNumber,
+        final CodedOutputStream output)
+        throws IOException {
+      for (final ByteString value : lengthDelimited) {
+        output.writeRawMessageSetExtension(fieldNumber, value);
+      }
+    }
+
+    /**
+     * Get the number of bytes required to encode this field, including field
+     * number, using {@code MessageSet} wire format.
+     */
+    public int getSerializedSizeAsMessageSetExtension(final int fieldNumber) {
+      int result = 0;
+      for (final ByteString value : lengthDelimited) {
+        result += CodedOutputStream.computeRawMessageSetExtensionSize(
+          fieldNumber, value);
+      }
+      return result;
+    }
+
+    private List<Long> varint;
+    private List<Integer> fixed32;
+    private List<Long> fixed64;
+    private List<ByteString> lengthDelimited;
+    private List<UnknownFieldSet> group;
+
+    /**
+     * Used to build a {@link Field} within an {@link UnknownFieldSet}.
+     *
+     * <p>Use {@link Field#newBuilder()} to construct a {@code Builder}.
+     */
+    public static final class Builder {
+      // This constructor should never be called directly (except from 'create').
+      private Builder() {}
+
+      private static Builder create() {
+        Builder builder = new Builder();
+        builder.result = new Field();
+        return builder;
+      }
+
+      private Field result;
+
+      /**
+       * Build the field.  After {@code build()} has been called, the
+       * {@code Builder} is no longer usable.  Calling any other method will
+       * result in undefined behavior and can cause a
+       * {@code NullPointerException} to be thrown.
+       */
+      public Field build() {
+        if (result.varint == null) {
+          result.varint = Collections.emptyList();
+        } else {
+          result.varint = Collections.unmodifiableList(result.varint);
+        }
+        if (result.fixed32 == null) {
+          result.fixed32 = Collections.emptyList();
+        } else {
+          result.fixed32 = Collections.unmodifiableList(result.fixed32);
+        }
+        if (result.fixed64 == null) {
+          result.fixed64 = Collections.emptyList();
+        } else {
+          result.fixed64 = Collections.unmodifiableList(result.fixed64);
+        }
+        if (result.lengthDelimited == null) {
+          result.lengthDelimited = Collections.emptyList();
+        } else {
+          result.lengthDelimited =
+            Collections.unmodifiableList(result.lengthDelimited);
+        }
+        if (result.group == null) {
+          result.group = Collections.emptyList();
+        } else {
+          result.group = Collections.unmodifiableList(result.group);
+        }
+
+        final Field returnMe = result;
+        result = null;
+        return returnMe;
+      }
+
+      /** Discard the field's contents. */
+      public Builder clear() {
+        result = new Field();
+        return this;
+      }
+
+      /**
+       * Merge the values in {@code other} into this field.  For each list
+       * of values, {@code other}'s values are append to the ones in this
+       * field.
+       */
+      public Builder mergeFrom(final Field other) {
+        if (!other.varint.isEmpty()) {
+          if (result.varint == null) {
+            result.varint = new ArrayList<Long>();
+          }
+          result.varint.addAll(other.varint);
+        }
+        if (!other.fixed32.isEmpty()) {
+          if (result.fixed32 == null) {
+            result.fixed32 = new ArrayList<Integer>();
+          }
+          result.fixed32.addAll(other.fixed32);
+        }
+        if (!other.fixed64.isEmpty()) {
+          if (result.fixed64 == null) {
+            result.fixed64 = new ArrayList<Long>();
+          }
+          result.fixed64.addAll(other.fixed64);
+        }
+        if (!other.lengthDelimited.isEmpty()) {
+          if (result.lengthDelimited == null) {
+            result.lengthDelimited = new ArrayList<ByteString>();
+          }
+          result.lengthDelimited.addAll(other.lengthDelimited);
+        }
+        if (!other.group.isEmpty()) {
+          if (result.group == null) {
+            result.group = new ArrayList<UnknownFieldSet>();
+          }
+          result.group.addAll(other.group);
+        }
+        return this;
+      }
+
+      /** Add a varint value. */
+      public Builder addVarint(final long value) {
+        if (result.varint == null) {
+          result.varint = new ArrayList<Long>();
+        }
+        result.varint.add(value);
+        return this;
+      }
+
+      /** Add a fixed32 value. */
+      public Builder addFixed32(final int value) {
+        if (result.fixed32 == null) {
+          result.fixed32 = new ArrayList<Integer>();
+        }
+        result.fixed32.add(value);
+        return this;
+      }
+
+      /** Add a fixed64 value. */
+      public Builder addFixed64(final long value) {
+        if (result.fixed64 == null) {
+          result.fixed64 = new ArrayList<Long>();
+        }
+        result.fixed64.add(value);
+        return this;
+      }
+
+      /** Add a length-delimited value. */
+      public Builder addLengthDelimited(final ByteString value) {
+        if (result.lengthDelimited == null) {
+          result.lengthDelimited = new ArrayList<ByteString>();
+        }
+        result.lengthDelimited.add(value);
+        return this;
+      }
+
+      /** Add an embedded group. */
+      public Builder addGroup(final UnknownFieldSet value) {
+        if (result.group == null) {
+          result.group = new ArrayList<UnknownFieldSet>();
+        }
+        result.group.add(value);
+        return this;
+      }
+    }
+  }
+}