Code3Of9.java

/*
 * Copyright 2014 Robin Stuart
 *
 * 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 uk.org.okapibarcode.backend;

/**
 * Implements Code 39 bar code symbology
 * According to ISO/IEC 16388:2007
 * <p>
 * Input data can be of any length and supports the characters 0-9, A-Z, dash
 * (-), full stop (.), space, asterisk (*), dollar ($), slash (/), plus (+)
 * and percent (%). The standard does not require a check digit but a
 * modulo-43 check digit can be added if required.
 *
 * @author <a href="mailto:rstuart114@gmail.com">Robin Stuart</a>
 */
public class Code3Of9 extends Symbol {

    public enum CheckDigit {
        NONE, MOD43
    }

    private static final String[] CODE_39 = {
        "1112212111", "2112111121", "1122111121", "2122111111", "1112211121",
        "2112211111", "1122211111", "1112112121", "2112112111", "1122112111",
        "2111121121", "1121121121", "2121121111", "1111221121", "2111221111",
        "1121221111", "1111122121", "2111122111", "1121122111", "1111222111",
        "2111111221", "1121111221", "2121111211", "1111211221", "2111211211",
        "1121211211", "1111112221", "2111112211", "1121112211", "1111212211",
        "2211111121", "1221111121", "2221111111", "1211211121", "2211211111",
        "1221211111", "1211112121", "2211112111", "1221112111", "1212121111",
        "1212111211", "1211121211", "1112121211"
    };

    private static final char[] LOOKUP = {
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
        'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R',
        'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '-', '.', ' ', '$', '/', '+',
        '%'
    };

    private CheckDigit checkOption = CheckDigit.NONE;

    /** Ratio of wide bar width to narrow bar width. */
    private double moduleWidthRatio = 2;

    /**
     * Sets the ratio of wide bar width to narrow bar width. Valid values are usually
     * between {@code 2} and {@code 3}. The default value is {@code 2}.
     *
     * @param moduleWidthRatio the ratio of wide bar width to narrow bar width
     */
    public void setModuleWidthRatio(double moduleWidthRatio) {
        this.moduleWidthRatio = moduleWidthRatio;
    }

    /**
     * Returns the ratio of wide bar width to narrow bar width.
     *
     * @return the ratio of wide bar width to narrow bar width
     */
    public double getModuleWidthRatio() {
        return moduleWidthRatio;
    }

    /**
     * Select addition of optional Modulo-43 check digit or encoding without
     * check digit.
     * @param checkMode Check digit option.
     */
    public void setCheckDigit(CheckDigit checkMode) {
        checkOption = checkMode;
    }

    @Override
    public boolean encode() {

        if (!(content.matches("[0-9A-Z\\. \\-$/+%]+"))) {
            error_msg = "Invalid characters in input";
            return false;
        }

        String p = "";
        String dest;
        int l = content.length();
        int charval;
        char thischar;
        int counter = 0;
        char check_digit = ' ';

        dest = "1211212111"; // Start
        for (int i = 0; i < l; i++) {
            thischar = content.charAt(i);
            charval = positionOf(thischar, LOOKUP);
            counter += charval;
            p += CODE_39[charval];
        }
        dest += p;

        if (checkOption == CheckDigit.MOD43) {
            //User has requested Mod-43 check digit

            counter = counter % 43;
            if(counter < 10) {
                check_digit = (char)(counter + '0');
            } else {
                if(counter < 36) {
                    check_digit = (char)((counter - 10) + 'A');
                } else {
                    switch(counter) {
                        case 36: check_digit = '-'; break;
                        case 37: check_digit = '.'; break;
                        case 38: check_digit = ' '; break;
                        case 39: check_digit = '$'; break;
                        case 40: check_digit = '/'; break;
                        case 41: check_digit = '+'; break;
                        default: check_digit = 37; break;
                    }
                }
            }

            charval = positionOf(check_digit, LOOKUP);
            p += CODE_39[charval];

            /* Display a space check digit as _, otherwise it looks like an error */
            if(check_digit == ' ') {
                check_digit = '_';
            }
        }

        dest += "121121211"; // Stop

        if (checkOption == CheckDigit.MOD43) {
            readable = "*" + content + check_digit + "*";
            encodeInfo += "Check Digit: " + check_digit + "\n";
        } else {
            readable = "*" + content + "*";
        }
        pattern = new String[] { dest };
        row_count = 1;
        row_height = new int[] { -1 };
        plotSymbol();
        return true;
    }

    /** {@inheritDoc} */
    @Override
    protected double getModuleWidth(int originalWidth) {
        if (originalWidth == 1) {
            return 1;
        } else {
            return moduleWidthRatio;
        }
    }

    /** {@inheritDoc} */
    @Override
    protected int[] getCodewords() {
        return getPatternAsCodewords(10);
    }
}