Kotlin Unsigned utilities for JVM

This library mimics Dart's ByteData utility functions and add the following extension functions:

• ByteArray.getByte(byteOffset, value)
• ByteArray.setByte(byteOffset, value)
• ByteArray.getUByte(byteOffset, value)
• ByteArray.setUByte(byteOffset, value)
• ByteArray.getShort(byteOffset, value, endian)
• ByteArray.setShort(byteOffset, value, endian)
• ByteArray.getUShort(byteOffset, value, endian)
• ByteArray.setUShort(byteOffset, value, endian)
• ByteArray.getInt(byteOffset, value, endian)
• ByteArray.setInt(byteOffset, value, endian)
• ByteArray.getUInt(byteOffset, value, endian)
• ByteArray.setUInt(byteOffset, value, endian)
• ByteArray.getLong(byteOffset, value, endian)
• ByteArray.setLong(byteOffset, value, endian)
• ByteArray.getULong(byteOffset, value, endian)
• ByteArray.setULong(byteOffset, value, endian)

The endian value always defaults to Endian.big. Supports both Endian.Little and Endian.Big.

Using the library in your projects

The library is in Maven Central. The usage is very simple, just add this to your build.gradle:

repositories {
    mavenCentral()
}
dependencies {
    implementation("com.github.mvysny.kotlin-unsigned-jvm:kotlin-unsigned-jvm:0.1")
}

Motivation

Why yet another library when you can use DataInputStream.read*() and DataOutputStream.write*() functions? Two reasons:

• Data*Stream do not support unsigned Kotlin types directly;
• Data*Stream always use Endian.Big, it's not possible to configure them to write in Endian.Little.

What about Kotlin's built-in ByteArray.setUIntAt()?

• It's only for Kotlin/Native, it's not available in Kotlin/JVM
• The endianness is undocumented, which is a big issue. Could be big, little, or platform-specific.

Why not using Java built-in ByteBuffer as follows:

ByteBuffer buffer = ByteBuffer.wrap(new byte[10]);
buffer.order(ByteOrder.LITTLE_ENDIAN);
buffer.getLong().toULong();

Yeah.... that also works. Yet, I'd argue that working with ByteArray and indexes is simpler than with a ByteBuffer with a pointer.

Releasing

To release the library to Maven Central:

1. Edit build.gradle.kts and remove -SNAPSHOT in the version= stanza
2. Commit with the commit message of simply being the version being released, e.g. "1.2.13"
3. git tag the commit with the same tag name as the commit message above, e.g. 1.2.13
4. git push, git push --tags
5. Run ./gradlew clean build publish
6. Continue to the OSSRH Nexus and follow the release procedure.
7. Add the -SNAPSHOT back to the version= while increasing the version to something which will be released in the future, e.g. 1.2.14, then commit with the commit message "1.2.14-SNAPSHOT" and push.

License

See LICENSE