littlebigIO is a lightweight Java library for Java 17 or newer that provides I/O streams and bit-conversion methods to deal with primitive data types in big-endian and little-endian byte order. Java's standard classes, such as DataInputStream, are mostly laid out for network transmission, which supports big-endian data only. In some scenarios, we have to use little-endian, so this small library was created to fill this gap. The project can be imported and opened in Eclipse.

The library's most important classes are:

• BinaryInputStream: An input stream to read primitive data types in a specified byte order from an underlying InputStream.
• BinaryOutputStream: An output stream to write primitive data types in a specified byte order to an underlying OutputStream.
• BitConverter: Consists of helper methods to convert between bytes and primitive data types, similar to .NET's BitConverter class.

Essentially, BinaryInputStream and BinaryOutputStream can be used like Java's DataInputStream and DataOutputStream, respectively.

All javadocs for this library can be found on my website.

This should help you get a basic idea of how to use the features of this library. Below is some example code showing how to read and write int array files. A byte order mark, or BOM for short, is written at the file's start, allowing us to detect the correct byte order while reading from the file.

	public int[] readIntArray(File f) throws IOException {
		try (BinaryInputStream in = new BinaryInputStream(new FileInputStream(f))) {
			// Read and verify BOM
			char bom = in.readChar();

			if (bom == 0xFFFE) {
				in.swapOrder();
			} else if (bom != 0xFEFF) {
				throw new BOMException("File does not start with UTF-16 BOM");
			}

			// Read int array
			int[] arr = new int[in.readInt()];

			for (int i = 0; i < arr.length; i++) {
				arr[i] = in.readInt();
			}

			return arr;
		}
	}

	public void writeIntArray(File f, int[] arr) throws IOException {
		try (BinaryOutputStream out = new BinaryOutputStream(new FileOutputStream(f))) {
			out.writeChar(0xFEFF);
			out.writeInt(arr.length);

			for (int i : arr) {
				out.writeInt(i);
			}
		}
	}