ManualTestCRC16.java

/*
  TestCRC.java

  (c) 2013 Ed Swartz

  All rights reserved. This program and the accompanying materials
  are made available under the terms of the Eclipse Public License v1.0
  which accompanies this distribution, and is available at
  http://www.eclipse.org/legal/epl-v10.html
 */
package v9t9.machine.ti99.tests.dsr;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import v9t9.engine.dsr.realdisk.CRC16;
import v9t9.engine.dsr.realdisk.ICRCAlgorithm;
import ejs.base.utils.BinaryUtils;
import ejs.base.utils.HexUtils;

/**
 * @author ejs
 *
 */
public class ManualTestCRC16 {

	private Map<Integer, Integer> crcMatches = new HashMap<Integer, Integer>();
	
	public static void main(String[] args) {
		ManualTestCRC16 crc = new ManualTestCRC16();
		for (int i = 1; i < 0xffff; i+=2) {
//			crc.run(new CRC16(0x11021));
//			crc.run(new CRC16(0x8048));
//			crc.run(new CRC16(0x8005));
//			crc.run(new CRC16(0xa001));
//			crc.run(new CRC16(0xc002));
//			crc.run(new CRC16(0x8810));
			crc.run(new CRC16(i), new byte[] { 0, 0, 0, 1 }, 0xf1d3);
			crc.run(new CRC16(i), new byte[] { 0, 0, 2, 1 }, 0x97b1);
			crc.run(new CRC16(i), new byte[] { 0, 0, 7, 1 }, 0x6844);
			crc.run(new CRC16(i), new byte[] { 0, 0, 4, 1 }, 0x3d17);
		}
		
		for (Map.Entry<Integer, Integer> ent : crc.crcMatches.entrySet()) {
			if (ent.getValue() > 1)
				System.out.println("CRC " + HexUtils.toHex4(ent.getKey()) + " got " + ent.getValue() + " matches");
		}
	}

	/**
	 * 
	 */
	private void run(ICRCAlgorithm alg, byte[] middle, int exp) {
		byte[] bytes;
		for (int includeLead = 1; includeLead < 2; includeLead++) {
			for (int includeCRC = 0; includeCRC < 1; includeCRC++) {
				
				for (int invert = 0; invert < 1; invert++) {
					if (includeLead == 0) {
						if (includeCRC == 0) {
							bytes = Arrays.copyOf(middle, middle.length);
						} else {
							bytes = Arrays.copyOf(middle, middle.length + 2);
							bytes[middle.length+0] = (byte) (exp >> 8);
							bytes[middle.length+1] = (byte) (exp & 0xff);
						}
					} else {
						if (includeCRC == 0) {
							bytes = Arrays.copyOf(middle, middle.length + 1);
							System.arraycopy(bytes, 0, bytes, 1, middle.length);
							bytes[0] = (byte) 0xfe;
						} else {
							bytes = Arrays.copyOf(middle, middle.length + 3);
							System.arraycopy(bytes, 0, bytes, 1, middle.length);
							bytes[0] = (byte) 0xfe;
							bytes[middle.length+1] = (byte) (exp >> 8);
							bytes[middle.length+2] = (byte) (exp & 0xff);
						}
						
					}
					if (invert != 0) {
						for (int i = 0; i < bytes.length; i++)
							bytes[i] = (byte) ~bytes[i];
					}
					for (int reverse = 0; reverse < 1; reverse++) {
						runTest(includeLead+":"+includeCRC+":"+reverse+":"+invert, 
								alg, reverse!=0, 
								exp, bytes);
						runTest(includeLead+":"+includeCRC+":"+reverse+":"+invert, 
								alg, reverse!=0, 
								0, bytes);
					}
				}
			}
		}
		
	}

	/**
	 * @param string 
	 * @param alg
	 * @param i
	 * @param rev 
	 * @param bs
	 */
	private void runTest(String string, ICRCAlgorithm alg, boolean rev, int exp, byte[] bs) {
		alg.reset();
		int crc = 0;
		for (byte b : bs) {
			if (rev)
				b = BinaryUtils.swapBits(b);
			crc = alg.feed(b);
		}
		if ((short) crc == (short) exp ) {
			Integer count = crcMatches.get(alg.getPoly());
			if (count == null)
				count = 1;
			else
				count++;
			crcMatches.put(alg.getPoly(), count);
			
			System.out.println(string + ": CRC(" + alg.getClass().getSimpleName() + ":" +  
					Integer.toHexString(alg.getPoly()) + ")=" + HexUtils.toHex4(crc));
		}
	}

}