CrcValidator.java

/*
 * Copyright (c) 2012 Chris Ellison, Mike Deats, Liron Yahdav, Ryan Neal,
 * Brandon Sutherlin, Scott Griffin
 * 
 * This software is released under the MIT license
 * (http://www.opensource.org/licenses/mit-license.php)
 * 
 * Created on Apr 11, 2012
 */
package edu.cmu.sv.arinc838.validation;

import java.io.IOException;
import java.util.Arrays;

import edu.cmu.sv.arinc838.binary.BdfFile;
import edu.cmu.sv.arinc838.crc.Crc16Generator;
import edu.cmu.sv.arinc838.crc.Crc32Generator;
import edu.cmu.sv.arinc838.crc.Crc64Generator;
import edu.cmu.sv.arinc838.crc.CrcCalculator;
import edu.cmu.sv.arinc838.dao.SoftwareDefinitionFileDao;
import edu.cmu.sv.arinc838.util.Converter;

public class CrcValidator {

	public static class ChecksumValidationException extends RuntimeException {
		private static final long serialVersionUID = 4192961441341410894L;

		public ChecksumValidationException(String message) {
			super(message);
		}
	}

	public static int validateCrc16(int crcValue, byte[] data) {
		if (data == null) {
			throw new IllegalArgumentException("Data parameter cannot be null");
		}

		int crcActual = (int) new Crc16Generator().calculateCrc(data);
		if (crcActual != crcValue) {
			throw new ChecksumValidationException(
					"CRC16 check failed! Expected 0x"
							+ new String(Integer.toHexString(crcValue))
									.toUpperCase()
							+ " but calcuated 0x"
							+ new String(Integer.toHexString(crcActual))
									.toUpperCase());
		}

		return crcActual;
	}

	public static long validateCrc32(long crcValue, byte[] data) {
		if (data == null) {
			throw new IllegalArgumentException("Data parameter cannot be null");
		}

		long crcActual = new Crc32Generator().calculateCrc(data);
		if (crcActual != crcValue) {
			throw new ChecksumValidationException(
					"CRC32 check failed! Expected 0x"
							+ new String(Long.toHexString(crcValue))
									.toUpperCase()
							+ " but calcuated 0x"
							+ new String(Long.toHexString(crcActual))
									.toUpperCase());
		}

		return crcActual;
	}

	public static long validateCrc64(long crcValue, byte[] data) {
		if (data == null) {
			throw new IllegalArgumentException("Data parameter cannot be null");
		}

		long crcActual = new Crc64Generator().calculateCrc(data);
		if (crcActual != crcValue) {
			throw new ChecksumValidationException(
					"CRC64 check failed! Expected 0x"
							+ new String(Long.toHexString(crcValue))
									.toUpperCase()
							+ " but calcuated 0x"
							+ new String(Long.toHexString(crcActual))
									.toUpperCase());
		}

		return crcActual;
	}
	
	public static byte[] validateLspCrc(SoftwareDefinitionFileDao sdf, BdfFile bdf)
			throws IOException {
		if (sdf == null) {
			throw new IllegalArgumentException("SDF parameter cannot be null");
		}

		if (bdf == null) {
			throw new IllegalArgumentException("BDF parameter cannot be null");
		}

		byte[] crc = CrcCalculator.calculateLspCrc(sdf, bdf);
		byte[] sdfCrc = sdf.getLspIntegrityDefinition().getIntegrityValue();
		if (!Arrays.equals(crc, sdfCrc)) {
			String crcHex = Converter.bytesToHex(crc);
			String sdfCrcHex = Converter.bytesToHex(sdfCrc);
			throw new ChecksumValidationException(
					"LSP CRC did not validate! Expected 0x" + sdfCrcHex
							+ ", but got 0x" + crcHex);
		}

		return crc;
	}

	public static byte[] validateSdfCrc(SoftwareDefinitionFileDao sdf, BdfFile bdf)
			throws IOException {
		if (sdf == null) {
			throw new IllegalArgumentException("SDF parameter cannot be null");
		}

		if (bdf == null) {
			throw new IllegalArgumentException("BDF parameter cannot be null");
		}

		byte[] crc = CrcCalculator.calculateSdfCrc(sdf, bdf);
		byte[] sdfCrc = sdf.getSdfIntegrityDefinition().getIntegrityValue();
		if (!Arrays.equals(crc, sdfCrc)) {
			String crcHex = Converter.bytesToHex(crc);
			String sdfCrcHex = Converter.bytesToHex(sdfCrc);
			throw new ChecksumValidationException(
					"SDF CRC did not validate! Expected 0x" + sdfCrcHex
							+ ", but got 0x" + crcHex);
		}

		return crc;
	}
}