2 * Copyright 2008 Google Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 package com.google.zxing.oned;
19 import com.google.zxing.ReaderException;
20 import com.google.zxing.common.BitArray;
23 * <p>Implements decoding of the UPC-E format.</p>
25 * <p><a href="http://www.barcodeisland.com/upce.phtml">This</a> is a great reference for
26 * UPC-E information.</p>
28 * @author srowen@google.com (Sean Owen)
30 public final class UPCEReader extends AbstractUPCEANReader {
33 * The pattern that marks the middle, and end, of a UPC-E pattern.
34 * There is no "second half" to a UPC-E barcode.
36 private static final int[] MIDDLE_END_PATTERN = {1, 1, 1, 1, 1, 1};
39 * See {@link #L_AND_G_PATTERNS}; these values similarly represent patterns of
40 * even-odd parity encodings of digits that imply both the number system (0 or 1)
41 * used, and the check digit.
43 private static final int[][] NUMSYS_AND_CHECK_DIGIT_PATTERNS = {
44 {0x38, 0x34, 0x32, 0x31, 0x2C, 0x26, 0x23, 0x2A, 0x29, 0x25},
45 {0x07, 0x0B, 0x0D, 0x0E, 0x13, 0x19, 0x1C, 0x15, 0x16, 0x1A}
48 protected int decodeMiddle(BitArray row, int[] startRange, StringBuffer result) throws ReaderException {
50 int[] counters = new int[4];
51 int end = row.getSize();
52 int rowOffset = startRange[1];
54 int lgPatternFound = 0;
56 for (int x = 0; x < 6 && rowOffset < end; x++) {
57 int bestMatch = decodeDigit(row, counters, rowOffset, L_AND_G_PATTERNS);
58 result.append((char) ('0' + bestMatch % 10));
59 for (int i = 0; i < counters.length; i++) {
60 rowOffset += counters[i];
62 if (bestMatch >= 10) {
63 lgPatternFound |= 1 << (5 - x);
67 determineNumSysAndCheckDigit(result, lgPatternFound);
72 protected int[] decodeEnd(BitArray row, int endStart) throws ReaderException {
73 return findGuardPattern(row, endStart, true, MIDDLE_END_PATTERN);
76 protected boolean checkChecksum(String s) throws ReaderException {
77 return super.checkChecksum(convertUPCEtoUPCA(s));
80 private static void determineNumSysAndCheckDigit(StringBuffer resultString, int lgPatternFound)
81 throws ReaderException {
83 for (int numSys = 0; numSys <= 1; numSys++) {
84 for (int d = 0; d < 10; d++) {
85 if (lgPatternFound == NUMSYS_AND_CHECK_DIGIT_PATTERNS[numSys][d]) {
86 resultString.insert(0, (char) ('0' + numSys));
87 resultString.append((char) ('0' + d));
92 throw new ReaderException("Unable to determine number system and check digit");
96 * Expands a UPC-E value back into its full, equivalent UPC-A code value.
98 * @param upce UPC-E code as string of digits
99 * @return equivalent UPC-A code as string of digits
101 private static String convertUPCEtoUPCA(String upce) {
102 char[] upceChars = new char[6];
103 upce.getChars(1, 7, upceChars, 0);
104 StringBuffer result = new StringBuffer(12);
105 result.append(upce.charAt(0));
106 char lastChar = upceChars[5];
111 result.append(upceChars, 0, 2);
112 result.append(lastChar);
113 result.append("0000");
114 result.append(upceChars, 2, 3);
117 result.append(upceChars, 0, 3);
118 result.append("00000");
119 result.append(upceChars, 3, 2);
122 result.append(upceChars, 0, 4);
123 result.append("00000");
124 result.append(upceChars[4]);
127 result.append(upceChars, 0, 5);
128 result.append("0000");
129 result.append(lastChar);
132 result.append(upce.charAt(7));
133 return result.toString();