com.google.protobuf.CodedInputStream# skipField ( ) 源码实例Demo

/**
 * Parses the entry.
 *
 * @param <K> the key type
 * @param <V> the value type
 * @param input the input
 * @param metadata the metadata
 * @param extensionRegistry the extension registry
 * @return the map. entry
 * @throws IOException Signals that an I/O exception has occurred.
 */
static <K, V> Map.Entry<K, V> parseEntry(CodedInputStream input, Metadata<K, V> metadata,
        ExtensionRegistryLite extensionRegistry) throws IOException {
    K key = metadata.defaultKey;
    V value = metadata.defaultValue;
    while (true) {
        int tag = input.readTag();
        if (tag == 0) {
            break;
        }
        if (tag == CodedConstant.makeTag(KEY_FIELD_NUMBER, metadata.keyType.getWireType())) {
            key = parseField(input, extensionRegistry, metadata.keyType, key);
        } else if (tag == CodedConstant.makeTag(VALUE_FIELD_NUMBER, metadata.valueType.getWireType())) {
            value = parseField(input, extensionRegistry, metadata.valueType, value);
        } else {
            if (!input.skipField(tag)) {
                break;
            }
        }
    }
    return new AbstractMap.SimpleImmutableEntry<K, V>(key, value);
}
 

/**
 * Parses an entry off of the input into the map. This helper avoids allocaton of a {@link MapEntryLite} by parsing
 * directly into the provided {@link MapFieldLite}.
 *
 * @param map the map
 * @param input the input
 * @param extensionRegistry the extension registry
 * @throws IOException Signals that an I/O exception has occurred.
 */
public void parseInto(MapFieldLite<K, V> map, CodedInputStream input, ExtensionRegistryLite extensionRegistry)
        throws IOException {
    int length = input.readRawVarint32();
    final int oldLimit = input.pushLimit(length);
    K key = metadata.defaultKey;
    V value = metadata.defaultValue;

    while (true) {
        int tag = input.readTag();
        if (tag == 0) {
            break;
        }
        if (tag == CodedConstant.makeTag(KEY_FIELD_NUMBER, metadata.keyType.getWireType())) {
            key = parseField(input, extensionRegistry, metadata.keyType, key);
        } else if (tag == CodedConstant.makeTag(VALUE_FIELD_NUMBER, metadata.valueType.getWireType())) {
            value = parseField(input, extensionRegistry, metadata.valueType, value);
        } else {
            if (!input.skipField(tag)) {
                break;
            }
        }
    }

    input.checkLastTagWas(0);
    input.popLimit(oldLimit);
    map.put(key, value);
}
 

public static ArrayList<ByteString> extractWireFormatTxOut(Transaction tx)
  throws ValidationException
{
  try
  {
    CodedInputStream code_in = CodedInputStream.newInstance(tx.getInnerData().toByteArray());

    ArrayList<ByteString> lst = new ArrayList<>();

    while(true)
    {
      int tag = code_in.readTag();
      if (tag == 0) break;
      
      // The least signficiate 3 bits are the proto field type
      // so shift to get out field number, which is 5 for TranasctionOutput
      if (tag >> 3 == 5)
      {
        ByteArrayOutputStream b_out = new ByteArrayOutputStream();
        CodedOutputStream c_out = CodedOutputStream.newInstance(b_out);
        code_in.skipField(tag, c_out);
        c_out.flush();

        ByteString bs = ByteString.copyFrom(b_out.toByteArray());

        // So funny story...when you get an inner message like this as opposed to just serializing
        // the object, protobuf puts a tag and size on the coded input stream.  So we need to figure
        // out how many bytes that is an trim it off.
        CodedInputStream read_again = CodedInputStream.newInstance(bs.toByteArray());
        // Expected tag
        int tag2 = read_again.readTag();
        // Size of element
        int size = read_again.readInt32();

        // All we really care is how many bytes those two take.  For shorter messages
        // it will be 2, but could be higher if protobuf needs more bytes to encode the size
        int offset = read_again.getTotalBytesRead();

        bs = bs.substring(offset);
        lst.add(bs);
      }
      else
      {
        code_in.skipField(tag);
      }

    }
    return lst;
  }
  catch(java.io.IOException e)
  {
    throw new ValidationException(e);
  }
}
 

@NonNull
@Override
public FileDataSource loadData(InputStream inputStream, String filePath) throws Exception {
    long propertiesOffset = 0L;
    Track track = new Track();
    CodedInputStream input = CodedInputStream.newInstance(inputStream);
    boolean done = false;
    while (!done) {
        long offset = input.getTotalBytesRead();
        int tag = input.readTag();
        int field = WireFormat.getTagFieldNumber(tag);
        switch (field) {
            case 0:
                done = true;
                break;
            default: {
                throw new com.google.protobuf.InvalidProtocolBufferException("Unsupported proto field: " + tag);
            }
            case FIELD_VERSION: {
                // skip version
                input.skipField(tag);
                break;
            }
            case FIELD_POINT: {
                int length = input.readRawVarint32();
                int oldLimit = input.pushLimit(length);
                readPoint(track, input);
                input.popLimit(oldLimit);
                input.checkLastTagWas(0);
                break;
            }
            case FIELD_NAME: {
                propertiesOffset = offset;
                track.name = input.readBytes().toStringUtf8();
                break;
            }
            case FIELD_COLOR: {
                track.style.color = input.readUInt32();
                break;
            }
            case FIELD_WIDTH: {
                track.style.width = input.readFloat();
                break;
            }
        }
    }
    inputStream.close();
    track.id = 31 * filePath.hashCode() + 1;
    FileDataSource dataSource = new FileDataSource();
    dataSource.name = track.name;
    dataSource.tracks.add(track);
    track.source = dataSource;
    dataSource.propertiesOffset = propertiesOffset;
    return dataSource;
}