Copper Multicodec

A Java implementation of Multicodec.

Features

• static codecs registry
  • no lookups for a codec when encoding
  • direct static access to codecs
  • confirugable set of codecs to support when decoding
• built-in Unsigned VarInt support
• no 3rd pary dependencies

Example

/* encode an input as P-521 public key */
byte[] encoded = KeyCodec.P521_PUBLIC_KEY.encode(input);

/* encode an input as an identity */
byte[] encoded = MultihashCodec.IDENTITY.encode(input);

/* get decoder instance initialized with all supported codecs */
var decoder = MulticodecDecoder.getInstance();

/* get custom decoder initialized with codecs tagged as key and hash */
var decoder = MulticodecDecoder.getInstance(Tag.Key, Tag.Hash);

/* get custom decoder initialized with custom codec set  */
var decoder = MulticodecDecoder.getInstance(codecs...);

/* decode */
byte[] decoded = decoder.decode(encoded);

/* or check if encoding is supported  */
Multicodec codec = decoder.getCodec(encoded).orElseThrow(() -> new IllegalArgumentException("Unsupported codec."));
byte[] decoded = codec.decode(encoded);

/* or directy when only one codec is supported */
byte[] decoded = KeyCodec.P521_PUBLIC_KEY.decode(encoded);

/* check if byte array is encoded with a codec */
if (KeyCodec.P521_PUBLIC_KEY.isEncoded(encoded)) {
  ...
}

/* create a custom codec */
var codec = Multicodec.of(name, tag, code);

/* get registry instance initialized with all supported codecs */
var registry = MulticodecRegistry.getInstance();

/* get custom registry initialized with codecs tagged as key and hash */
var registry = MulticodecRegistry.getInstance(Tag.Key, Tag.Hash);

/* get custom registry initialized with custom codec set  */
var registry = MulticodecRegistry.getInstance(codecs...);

/* get codec */
var codec = registry.getCodec(code).orElseThrow(() -> new IllegalArgumentException("Unsupported codec."));
byte[] encoded = codec.encode(input);

Installation

Maven

<dependency>
    <groupId>com.apicatalog</groupId>
    <artifactId>copper-multicodec</artifactId>
    <version>1.0.0</version>
</dependency>

Gradle

Android 12+ (API Level >=32)

implementation("com.apicatalog:copper-multicodec:1.0.0")

Do you need to support an older Android version? Contact me

Documentation

• 
• Supported Codecs

Contributing

All PR's welcome!

Building

Fork and clone the project repository.

> cd copper-multicodec
> mvn clean package

Resources

• Copper Multibase
• Multicodec
• unsigned-varint