Ability to convert parsed structure to Map<String, Object>

[mmindenhall]

Hi Igor,

I hope you'll accept this one into the core library. I think being able to convert the parsed data structure hierarchy to other formats (e.g., JSON, XML) is essential for many use cases. Most JSON libraries can convert from Map<String, Object> to JSON, and there are also libraries to convert from Map<String, Object> to XML. For example, I was able to easily do the following using the jackson library:

    final InputStream pngStream = getResourceAsInputStream("picture.png");
    try {
      final JBBPParser pngParser = JBBPParser.prepare(
              "long header;"
              + "// chunks\n"
              + "chunk [_]{"
              + "   int length; "
              + "   int type; "
              + "   byte[length] data; "
              + "   int crc;"
              + "}"
      );

      final JBBPFieldStruct result = pngParser.parse(pngStream);
      final Map<String, Object> resultMap = result.asMap();

      ObjectMapper mapper = new ObjectMapper();
      JsonNode jsonNode = mapper.valueToTree(resultMap);
      // do something with the JsonNode
    }
    finally {
      JBBPUtils.closeQuietly(pngStream);
    }
  }

Also note that these changes only add 3,859 bytes to the size of the library (151,686 vs 147,827).

Thanks!

[raydac]

I can't include such code into the library because it has specific purposes and cases, of course many products may be have such needs but in the case I guess should be developed something like JBBP-JSON or JBBP-XML libraries with specific codes and may be even adapted for specific JSON libraries (because there are a lot of such libraries), the main purpose of JBBP - parse binary data, it should not know about something behind that, take a look at how it can be implemented conversion of PNG to JSON in 100 lines