Minimal charset support for Kotlin Multiplatform

See CHANGELOG.md.

All Kotlin platforms are supported, except for Android Native.

kotlinx-charset aims to be straightforward for existing JDK consumers.
It replicates parts of the JDK's Charset API, albeit with more restrictions.

The core types you will work with are:

• XCharset - describes a character set
• XCharsetDecoder - decodes a byte sequence into characters
• XCharsetEncoder - encodes characters into a byte sequence
• XCharsetRegistrar - a registry and lookup service for obtaining XCharset instances

The core module provides the foundational components for implementing and registering new charsets.

// Create an empty charset registry
private val registrar = XCharsetRegistrar()

// Register a new charset
registrar.registerCharset(YourCharset())

// Retrieve and use a charset
val charset = registrar.getCharset("YourCharsetName")
val decoder = charset.newDecoder()
val encoder = charset.newEncoder()

The ebcdic module adds support for:

IBM037  IBM937   IBM1147
IBM273  IBM939   IBM1390
IBM278  IBM1047  IBM1399
IBM297  IBM1141
IBM930  IBM1143

You can register supported EBCDIC charsets to your XCharsetRegistrar via the provideCharsets function.

import com.lppedd.kotlinx.charset.ebcdic.provideCharsets as provideEbcdicCharsets

// Your shared charset registry
private val registrar = XCharsetRegistrar()

provideEbcdicCharsets(registrar)

The exported module allows JS consumers to decode bytes and encode strings, using top-level functions exported from ECMAScript modules.

You can depend on the @lppedd/kotlinx-charset npm package.
For example, consuming the library from TypeScript would look like:

import { decode, encode, getCharset } from "@lppedd/kotlinx-charset";

function funsExample(bytes: Uint8Array): Uint8Array {
  const str = decode("ibm037", bytes);
  return encode("ibm037", str);
}

// Alternatively, you can interact with a charset instance directly.
// This allows setting or removing (by passing null) the replacement character.
function instanceExample(bytes: Uint8Array): Uint8Array {
  const charset = getCharset("ibm037");

  const decoder = charset.newDecoder();
  const str = decoder.decode(bytes);

  const encoder = charset.newEncoder();
  return encoder.encode(str);
}

Both the decode and encode functions will throw an Error if the specified charset does not exist or if an error occurs during data processing.