Bitfuck.java

import static java.lang.Integer.toHexString;
import static java.lang.Math.*;
import static java.lang.System.out;
import static java.util.Arrays.stream;

public class Bitfuck {

	public static void main(String[] args) {
		var counts = new int[] { 6, 30, 13 };
		var names = new String[] { "firstvalue", "secondvalue", "thirdvalue"};

		var u = new StringBuilder();
		var p = new StringBuilder();
		int bytePos = 0;
		int bitPos = 0;
		int displayPos = stream(names).mapToInt(String::length).max().orElse(0) + 1;
		for (int i = 0; i < counts.length; i++) {
			out.print(names[i]);
			out.print(" ".repeat(displayPos - names[i].length()));
			u.append("int ");

			int bitCount = counts[i];
			while (bitCount > 0) {
				int bitsUsed = min(bitCount, 8);
				if (bitsUsed > 8 - bitPos)
					bitsUsed -= bitPos;
				int shift = bitCount - bitsUsed;
				if (shift == 0)
					shift = -(8 - bitCount - bitPos);

				u.append(names[i]);
				u.append(" ");
				if (bitCount != counts[i])
					u.append("|");
				u.append("= ");
				if (bitsUsed != 8 && bitPos != 0)
					u.append("(");

				p.append("packed[");
				u.append("toUnsignedInt(packed[");
				p.append(bytePos);
				u.append(bytePos);
				p.append("] ");
				u.append("])");
				if (bitsUsed != 8 && bitPos != 0) {
					u.append(" & 0x");
					u.append(toHexString((2 << bitsUsed - 1) - 1 << max(8 - bitPos - bitsUsed, 0)));
					u.append(")");
				}
				if (bitPos != 0)
					p.append("|");
				p.append("= (byte) (");

				if (shift != 0)
					p.append("(");

				p.append(names[i]);
				p.append(" & 0x");
				p.append(toHexString((2 << bitsUsed - 1) - 1 << max(shift, 0)));
				if (shift != 0) {
					p.append(") ");
					u.append(" ");
					if (shift > 0) {
						p.append(">> ");
						u.append("<< ");
					} else {
						p.append("<< ");
						u.append(">> ");
					}
					p.append(abs(shift));
					u.append(abs(shift));
				}

				p.append(");\n");
				u.append(";\n");

				out.print("1".repeat(bitsUsed));
				displayPos += bitsUsed;

				if (bitPos + bitsUsed >= 8) {
					bytePos++;
					displayPos++;
					out.print(" ");
				}
				bitCount -= bitsUsed;
				bitPos = (bitPos + bitsUsed) % 8;
			}
			out.println();
		}

		out.println();
		out.println(p.toString());
		out.println(u.toString());
	}

}