CBOR

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A Java implementation of Concise Binary Object Representation, a general-purpose binary data format defined in RFC 8949. According to that RFC, CBOR's data model "is an extended version of the JSON data model", supporting many more types of data than JSON. "CBOR was inspired by MessagePack", but "is not intended as a version of or replacement for MessagePack."

This implementation was written by Peter O. and is released to the Public Domain under the CC0 Declaration.

This implementation also doubles as a reader and writer of JSON, and can convert data from JSON to CBOR and back.

Finally, this implementation supports arbitrary-precision binary and decimal floating-point numbers and rational numbers with arbitrary-precision components.

How to Install

Starting with version 0.23.0, the Java implementation is available as an artifact in the Central Repository. To add this library to a Maven project, add the following to the dependencies section in your pom.xml file:

<dependency>
  <groupId>com.upokecenter</groupId>
  <artifactId>cbor</artifactId>
  <version>5.0.0-alpha2</version>
</dependency>

In other Java-based environments, the library can be referred to by its group ID (com.upokecenter), artifact ID (cbor), and version, as given earlier. A non-release version of this library is 5.0.0-alpha rather than the version number given earlier.

Documentation

This library defines one class, called CBORObject, that allows you to read and write CBOR objects to and from data streams and byte arrays, and to convert JSON text to CBOR objects and back.

See the Java API documentation.

Examples

Reading data from a file.

 // Java
 // Open the file stream
 try (FileInputStream stream = new FileInputStream("object.cbor")) {
    // Read the CBOR object from the stream
    var cbor = CBORObject.Read(stream);
    // At this point, the object is read, but the file stream might
    // not have ended yet.  Here, the code may choose to read another
    // CBOR object, check for the end of the stream, or just ignore the
    // rest of the file.  The following is an example of checking for the
    // end of the stream.
    if (stream.getChannel().position() != stream.getChannel().size()) {
      // The end of the stream wasn't reached yet.
    } else {
      // The end of the stream was reached.
    }
 }

Writing multiple objects to a file, including arbitrary objects:

// Java
// This example uses the "try-with-resources" statement from Java 7.
// This example writes different kinds of objects in CBOR
// format to the same file.
try (FileOutputStream stream = new FileOutputStream("object.cbor")) {
   CBORObject.Write(true, stream);
   CBORObject.Write(422.5, stream);
   CBORObject.Write("some string", stream);
   CBORObject.Write(CBORObject.Undefined, stream);
   CBORObject.NewArray().Add(42).WriteTo(stream);
}

NOTE: All code samples in this section are released to the Public Domain, as explained in https://creativecommons.org/publicdomain/zero/1.0/.

Source Code

Source code is available in the project page.

About

Written in 2013-2016 by Peter O.

Any copyright to this work is released to the Public Domain. In case this is not possible, this work is also licensed under the Unlicense: https://unlicense.org/

Signing Key

Release versions, in the Central Repository, of the Java version of this library are signed with the following signing key.

• ID: Peter Occil (Maven key) <poccil14@gmail.com>
• Fingerprint: 1A82D51407003717A4171AAC87522D618F2B2338

Release Notes

For release notes, see the CBOR .NET repository.

The commit history contains details on code changes in previous versions.

Acknowledgments

For acknowledgments, see the CBOR .NET repository.

I thank all users who sent issues to this repository.