CodaBarWriter.java

/*
 * Copyright 2011 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.oned;

import java.util.Arrays;

/**
 * This class renders CodaBar as {@code boolean[]}.
 * 
 * @author dsbnatut@gmail.com (Kazuki Nishiura)
 */
public final class CodaBarWriter extends OneDimensionalCodeWriter {

	private static final char[] START_END_CHARS = { 'A', 'B', 'C', 'D' };
	private static final char[] ALT_START_END_CHARS = { 'T', 'N', '*', 'E' };
	private static final char[] CHARS_WHICH_ARE_TEN_LENGTH_EACH_AFTER_DECODED = {
			'/', ':', '+', '.' };

	@Override
	public boolean[] encode(String contents) {

		if (contents.length() < 2) {
			throw new IllegalArgumentException(
					"Codabar should start/end with start/stop symbols");
		}
		// Verify input and calculate decoded length.
		char firstChar = Character.toUpperCase(contents.charAt(0));
		char lastChar = Character
				.toUpperCase(contents.charAt(contents.length() - 1));
		boolean startsEndsNormal = CodaBarReader.arrayContains(START_END_CHARS,
				firstChar)
				&& CodaBarReader.arrayContains(START_END_CHARS, lastChar);
		boolean startsEndsAlt = CodaBarReader.arrayContains(
				ALT_START_END_CHARS, firstChar)
				&& CodaBarReader.arrayContains(ALT_START_END_CHARS, lastChar);
		if (!(startsEndsNormal || startsEndsAlt)) {
			throw new IllegalArgumentException("Codabar should start/end with "
					+ Arrays.toString(START_END_CHARS) + ", or start/end with "
					+ Arrays.toString(ALT_START_END_CHARS));
		}

		// The start character and the end character are decoded to 10 length
		// each.
		int resultLength = 20;
		for (int i = 1; i < contents.length() - 1; i++) {
			if (Character.isDigit(contents.charAt(i))
					|| contents.charAt(i) == '-' || contents.charAt(i) == '$') {
				resultLength += 9;
			} else if (CodaBarReader.arrayContains(
					CHARS_WHICH_ARE_TEN_LENGTH_EACH_AFTER_DECODED,
					contents.charAt(i))) {
				resultLength += 10;
			} else {
				throw new IllegalArgumentException("Cannot encode : '"
						+ contents.charAt(i) + '\'');
			}
		}
		// A blank is placed between each character.
		resultLength += contents.length() - 1;

		boolean[] result = new boolean[resultLength];
		int position = 0;
		for (int index = 0; index < contents.length(); index++) {
			char c = Character.toUpperCase(contents.charAt(index));
			if (index == 0 || index == contents.length() - 1) {
				// The start/end chars are not in the CodaBarReader.ALPHABET.
				switch (c) {
				case 'T':
					c = 'A';
					break;
				case 'N':
					c = 'B';
					break;
				case '*':
					c = 'C';
					break;
				case 'E':
					c = 'D';
					break;
				}
			}
			int code = 0;
			for (int i = 0; i < CodaBarReader.ALPHABET.length; i++) {
				// Found any, because I checked above.
				if (c == CodaBarReader.ALPHABET[i]) {
					code = CodaBarReader.CHARACTER_ENCODINGS[i];
					break;
				}
			}
			boolean color = true;
			int counter = 0;
			int bit = 0;
			while (bit < 7) { // A character consists of 7 digit.
				result[position] = color;
				position++;
				if (((code >> (6 - bit)) & 1) == 0 || counter == 1) {
					color = !color; // Flip the color.
					bit++;
					counter = 0;
				} else {
					counter++;
				}
			}
			if (index < contents.length() - 1) {
				result[position] = false;
				position++;
			}
		}
		return result;
	}
}