A Kotlin Multiplatform (KMP) port of Java’s IO classes, bringing familiar IO operations to multiplatform projects—JVM, Android, iOS, macOS, Linux, Windows, Web, and beyond.

This library is organized into modular components for flexibility and clarity.

Note Direct file read/write APIs are not included. For file operations, use this library in combination with kotlinx-io or okio, which support stream conversions.

Core buffers plus the main stream/reader implementations and extensions.

• Buffer: Base container (like java.nio.Buffer)
• ByteBuffer, CharBuffer
• ByteBufferFactory, CharBufferFactory: Helper utilities to create buffers
• InputStream, OutputStream, Reader, BufferedReader
• ByteArrayInputStream, ByteArrayOutputStream, BufferedInputStream, BufferedOutputStream
• FilterInputStream, FilterOutputStream, FilterReader, PushbackReader
• StringReader, CharArrayReader
• Closeable, Readable, Flushable: Interfaces for IO components
• Core Extensions
  • "Hello".byteInputStream(), "Hello".reader()
  • byteArray.inputStream()
  • reader.buffered(), reader.readLines(), reader.readString(count)

Charset-aware reader adapter and InputStream extensions.

• InputStreamReader
• Charset Support CharsetsReadme.md
• Stream Extensions

  val byteArrayInputStream: ByteArrayInputStream = "...".byteInputStream(Charsets.UTF8) 
  val inputStreamReader: InputStreamReader = inputStream.reader(Charsets.UTF8) // return InputStreamReader
  val bufferReader: BufferedReader = inputStream.bufferedReader(Charsets.UTF8) // return BufferedReader

Multiplatform-safe version of java.net.URI.

• URI: Parse, resolve, normalize URIs
• URIFactory: Use this instead of URI.create()

Interop for working with kotlinx-io streams:

• Source.asInputStream(): InputStream
• RawSource.asInputStream(): InputStream
• InputStream.asSource(): RawSource

Interop for Okio-powered IO:

• Source.asInputStream(): InputStream
• InputStream.asSource(): Source

Support for standard and extended character sets:

• Standard: com.fleeksoft.charset:charset:<version>
• Extended: com.fleeksoft.charset:charset-ext:<version>

➡️ More info

Add dependencies in your build.gradle.kts:

commonMain.dependencies {
    implementation("com.fleeksoft.io:io-core:<version>")
    implementation("com.fleeksoft.io:io:<version>")

    // Optional integrations
    implementation("com.fleeksoft.io:kotlinx-io:<version>")
    implementation("com.fleeksoft.io:okio:<version>")
}

val str = "Hello, World!"
val byteArray = ByteArray(10)
val charArray = CharArray(10)

val byteArrayInputStream = str.byteInputStream()
val stringReader = str.reader()

val bufferedReader = stringReader.buffered()
val bufferedReader2 = byteArrayInputStream.bufferedReader()

val byteBuffer = ByteBufferFactory.wrap(byteArray)
val charBuffer = CharBufferFactory.wrap(charArray)

Contributions are welcome! Open an issue or submit a pull request to improve features, fix bugs, or enhance documentation.

Licensed under the Apache License 2.0. See LICENSE for full details.