VINResultParser.java

/*
 * Copyright 2014 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.zxing.client.result;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.Result;

import java.util.regex.Pattern;

/**
 * Detects a result that is likely a vehicle identification number.
 * 
 * @author Sean Owen
 */
public final class VINResultParser extends ResultParser {

	private static final Pattern IOQ = Pattern.compile("[IOQ]");
	private static final Pattern AZ09 = Pattern.compile("[A-Z0-9]{17}");

	@Override
	public VINParsedResult parse(Result result) {
		if (result.getBarcodeFormat() != BarcodeFormat.CODE_39) {
			return null;
		}
		String rawText = result.getText();
		rawText = IOQ.matcher(rawText).replaceAll("").trim();
		if (!AZ09.matcher(rawText).matches()) {
			return null;
		}
		try {
			if (!checkChecksum(rawText)) {
				return null;
			}
			String wmi = rawText.substring(0, 3);
			return new VINParsedResult(rawText, wmi, rawText.substring(3, 9),
					rawText.substring(9, 17), countryCode(wmi),
					rawText.substring(3, 8), modelYear(rawText.charAt(9)),
					rawText.charAt(10), rawText.substring(11));
		} catch (IllegalArgumentException iae) {
			return null;
		}
	}

	private static boolean checkChecksum(CharSequence vin) {
		int sum = 0;
		for (int i = 0; i < vin.length(); i++) {
			sum += vinPositionWeight(i + 1) * vinCharValue(vin.charAt(i));
		}
		char checkChar = vin.charAt(8);
		char expectedCheckChar = checkChar(sum % 11);
		return checkChar == expectedCheckChar;
	}

	private static int vinCharValue(char c) {
		if (c >= 'A' && c <= 'I') {
			return (c - 'A') + 1;
		}
		if (c >= 'J' && c <= 'R') {
			return (c - 'J') + 1;
		}
		if (c >= 'S' && c <= 'Z') {
			return (c - 'S') + 2;
		}
		if (c >= '0' && c <= '9') {
			return c - '0';
		}
		throw new IllegalArgumentException();
	}

	private static int vinPositionWeight(int position) {
		if (position >= 1 && position <= 7) {
			return 9 - position;
		}
		if (position == 8) {
			return 10;
		}
		if (position == 9) {
			return 0;
		}
		if (position >= 10 && position <= 17) {
			return 19 - position;
		}
		throw new IllegalArgumentException();
	}

	private static char checkChar(int remainder) {
		if (remainder < 10) {
			return (char) ('0' + remainder);
		}
		if (remainder == 10) {
			return 'X';
		}
		throw new IllegalArgumentException();
	}

	private static int modelYear(char c) {
		if (c >= 'E' && c <= 'H') {
			return (c - 'E') + 1984;
		}
		if (c >= 'J' && c <= 'N') {
			return (c - 'J') + 1988;
		}
		if (c == 'P') {
			return 1993;
		}
		if (c >= 'R' && c <= 'T') {
			return (c - 'R') + 1994;
		}
		if (c >= 'V' && c <= 'Y') {
			return (c - 'V') + 1997;
		}
		if (c >= '1' && c <= '9') {
			return (c - '1') + 2001;
		}
		if (c >= 'A' && c <= 'D') {
			return (c - 'A') + 2010;
		}
		throw new IllegalArgumentException();
	}

	private static String countryCode(CharSequence wmi) {
		char c1 = wmi.charAt(0);
		char c2 = wmi.charAt(1);
		switch (c1) {
		case '1':
		case '4':
		case '5':
			return "US";
		case '2':
			return "CA";
		case '3':
			if (c2 >= 'A' && c2 <= 'W') {
				return "MX";
			}
			break;
		case '9':
			if ((c2 >= 'A' && c2 <= 'E') || (c2 >= '3' && c2 <= '9')) {
				return "BR";
			}
			break;
		case 'J':
			if (c2 >= 'A' && c2 <= 'T') {
				return "JP";
			}
			break;
		case 'K':
			if (c2 >= 'L' && c2 <= 'R') {
				return "KO";
			}
			break;
		case 'L':
			return "CN";
		case 'M':
			if (c2 >= 'A' && c2 <= 'E') {
				return "IN";
			}
			break;
		case 'S':
			if (c2 >= 'A' && c2 <= 'M') {
				return "UK";
			}
			if (c2 >= 'N' && c2 <= 'T') {
				return "DE";
			}
			break;
		case 'V':
			if (c2 >= 'F' && c2 <= 'R') {
				return "FR";
			}
			if (c2 >= 'S' && c2 <= 'W') {
				return "ES";
			}
			break;
		case 'W':
			return "DE";
		case 'X':
			if (c2 == '0' || (c2 >= '3' && c2 <= '9')) {
				return "RU";
			}
			break;
		case 'Z':
			if (c2 >= 'A' && c2 <= 'R') {
				return "IT";
			}
			break;
		}
		return null;
	}

}