/*
- * Copyright 2008 Google Inc.
+ * Copyright 2008 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
package com.google.zxing.oned;
import com.google.zxing.BarcodeFormat;
-import com.google.zxing.ReaderException;
+import com.google.zxing.ChecksumException;
+import com.google.zxing.FormatException;
+import com.google.zxing.NotFoundException;
import com.google.zxing.Result;
import com.google.zxing.ResultPoint;
import com.google.zxing.common.BitArray;
-import com.google.zxing.common.GenericResultPoint;
import java.util.Hashtable;
/**
- * <p>Decodes Code 39 barcodes. This does not supported "Full ASCII Code 39" yet.</p>
+ * <p>Decodes Code 39 barcodes. This does not support "Full ASCII Code 39" yet.</p>
*
- * @author srowen@google.com (Sean Owen)
+ * @author Sean Owen
+ * @see Code93Reader
*/
-public final class Code39Reader extends AbstractOneDReader {
+public final class Code39Reader extends OneDReader {
- private static final String ALPHABET_STRING = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. *$/+%";
+ static final String ALPHABET_STRING = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. *$/+%";
private static final char[] ALPHABET = ALPHABET_STRING.toCharArray();
/**
* The 9 least-significant bits of each int correspond to the pattern of wide and narrow,
* with 1s representing "wide" and 0s representing narrow.
*/
- private static final int[] CHARACTER_ENCODINGS = {
+ static final int[] CHARACTER_ENCODINGS = {
0x034, 0x121, 0x061, 0x160, 0x031, 0x130, 0x070, 0x025, 0x124, 0x064, // 0-9
0x109, 0x049, 0x148, 0x019, 0x118, 0x058, 0x00D, 0x10C, 0x04C, 0x01C, // A-J
0x103, 0x043, 0x142, 0x013, 0x112, 0x052, 0x007, 0x106, 0x046, 0x016, // K-T
* It will not decoded "extended Code 39" sequences.
*
* @param usingCheckDigit if true, treat the last data character as a check digit, not
- * data, and verify that the checksum passes
+ * data, and verify that the checksum passes.
*/
public Code39Reader(boolean usingCheckDigit) {
this.usingCheckDigit = usingCheckDigit;
* the full ASCII character set.
*
* @param usingCheckDigit if true, treat the last data character as a check digit, not
- * data, and verify that the checksum passes
- * @param extendedMode if true, willa tetmpt to decode extended Code 39 sequences in the
- * text
+ * data, and verify that the checksum passes.
+ * @param extendedMode if true, will attempt to decode extended Code 39 sequences in the
+ * text.
*/
public Code39Reader(boolean usingCheckDigit, boolean extendedMode) {
this.usingCheckDigit = usingCheckDigit;
this.extendedMode = extendedMode;
}
- public Result decodeRow(int rowNumber, BitArray row, Hashtable hints) throws ReaderException {
+ public Result decodeRow(int rowNumber, BitArray row, Hashtable hints)
+ throws NotFoundException, ChecksumException, FormatException {
int[] start = findAsteriskPattern(row);
-
int nextStart = start[1];
-
int end = row.getSize();
// Read off white space
nextStart++;
}
- StringBuffer result = new StringBuffer();
+ StringBuffer result = new StringBuffer(20);
int[] counters = new int[9];
char decodedChar;
int lastStart;
do {
recordPattern(row, nextStart, counters);
int pattern = toNarrowWidePattern(counters);
+ if (pattern < 0) {
+ throw NotFoundException.getNotFoundInstance();
+ }
decodedChar = patternToChar(pattern);
result.append(decodedChar);
lastStart = nextStart;
} while (decodedChar != '*');
result.deleteCharAt(result.length() - 1); // remove asterisk
+ // Look for whitespace after pattern:
+ int lastPatternSize = 0;
+ for (int i = 0; i < counters.length; i++) {
+ lastPatternSize += counters[i];
+ }
+ int whiteSpaceAfterEnd = nextStart - lastStart - lastPatternSize;
+ // If 50% of last pattern size, following last pattern, is not whitespace, fail
+ // (but if it's whitespace to the very end of the image, that's OK)
+ if (nextStart != end && whiteSpaceAfterEnd / 2 < lastPatternSize) {
+ throw NotFoundException.getNotFoundInstance();
+ }
+
if (usingCheckDigit) {
int max = result.length() - 1;
int total = 0;
for (int i = 0; i < max; i++) {
total += ALPHABET_STRING.indexOf(result.charAt(i));
}
- if (total % 43 != ALPHABET_STRING.indexOf(result.charAt(max))) {
- throw new ReaderException("Checksum failed");
+ if (result.charAt(max) != ALPHABET[total % 43]) {
+ throw ChecksumException.getChecksumInstance();
}
result.deleteCharAt(max);
}
- String resultString = result.toString();
+ if (result.length() == 0) {
+ // Almost surely a false positive
+ throw NotFoundException.getNotFoundInstance();
+ }
+
+ String resultString;
if (extendedMode) {
- resultString = decodeExtended(resultString);
+ resultString = decodeExtended(result);
+ } else {
+ resultString = result.toString();
}
+
float left = (float) (start[1] + start[0]) / 2.0f;
float right = (float) (nextStart + lastStart) / 2.0f;
return new Result(
resultString,
null,
new ResultPoint[]{
- new GenericResultPoint(left, (float) rowNumber),
- new GenericResultPoint(right, (float) rowNumber)},
+ new ResultPoint(left, (float) rowNumber),
+ new ResultPoint(right, (float) rowNumber)},
BarcodeFormat.CODE_39);
}
- private static int[] findAsteriskPattern(BitArray row) throws ReaderException {
+ private static int[] findAsteriskPattern(BitArray row) throws NotFoundException {
int width = row.getSize();
int rowOffset = 0;
while (rowOffset < width) {
for (int i = rowOffset; i < width; i++) {
boolean pixel = row.get(i);
- if ((!pixel && isWhite) || (pixel && !isWhite)) {
+ if (pixel ^ isWhite) {
counters[counterPosition]++;
} else {
if (counterPosition == patternLength - 1) {
- try {
- if (toNarrowWidePattern(counters) == ASTERISK_ENCODING) {
+ if (toNarrowWidePattern(counters) == ASTERISK_ENCODING) {
+ // Look for whitespace before start pattern, >= 50% of width of start pattern
+ if (row.isRange(Math.max(0, patternStart - (i - patternStart) / 2), patternStart, false)) {
return new int[]{patternStart, i};
}
- } catch (ReaderException re) {
- // no match, continue
}
patternStart += counters[0] + counters[1];
for (int y = 2; y < patternLength; y++) {
isWhite = !isWhite;
}
}
- throw new ReaderException("Can't find pattern");
+ throw NotFoundException.getNotFoundInstance();
}
- private static int toNarrowWidePattern(int[] counters) throws ReaderException {
+ // For efficiency, returns -1 on failure. Not throwing here saved as many as 700 exceptions
+ // per image when using some of our blackbox images.
+ private static int toNarrowWidePattern(int[] counters) {
int numCounters = counters.length;
int maxNarrowCounter = 0;
int wideCounters;
}
maxNarrowCounter = minCounter;
wideCounters = 0;
+ int totalWideCountersWidth = 0;
int pattern = 0;
for (int i = 0; i < numCounters; i++) {
+ int counter = counters[i];
if (counters[i] > maxNarrowCounter) {
pattern |= 1 << (numCounters - 1 - i);
wideCounters++;
+ totalWideCountersWidth += counter;
}
}
if (wideCounters == 3) {
+ // Found 3 wide counters, but are they close enough in width?
+ // We can perform a cheap, conservative check to see if any individual
+ // counter is more than 1.5 times the average:
+ for (int i = 0; i < numCounters && wideCounters > 0; i++) {
+ int counter = counters[i];
+ if (counters[i] > maxNarrowCounter) {
+ wideCounters--;
+ // totalWideCountersWidth = 3 * average, so this checks if counter >= 3/2 * average
+ if ((counter << 1) >= totalWideCountersWidth) {
+ return -1;
+ }
+ }
+ }
return pattern;
}
} while (wideCounters > 3);
- throw new ReaderException("Can't find 3 wide bars/spaces out of 9");
+ return -1;
}
- private static char patternToChar(int pattern) throws ReaderException {
+ private static char patternToChar(int pattern) throws NotFoundException {
for (int i = 0; i < CHARACTER_ENCODINGS.length; i++) {
if (CHARACTER_ENCODINGS[i] == pattern) {
return ALPHABET[i];
}
}
- throw new ReaderException("Pattern did not match character encoding");
+ throw NotFoundException.getNotFoundInstance();
}
- private static String decodeExtended(String encoded) throws ReaderException {
+ private static String decodeExtended(StringBuffer encoded) throws FormatException {
int length = encoded.length();
StringBuffer decoded = new StringBuffer(length);
for (int i = 0; i < length; i++) {
if (next >= 'A' && next <= 'Z') {
decodedChar = (char) (next + 32);
} else {
- throw new ReaderException("Invalid extended code 39 sequence: " + c + next);
+ throw FormatException.getFormatInstance();
}
break;
case '$':
if (next >= 'A' && next <= 'Z') {
decodedChar = (char) (next - 64);
} else {
- throw new ReaderException("Invalid extended code 39 sequence: " + c + next);
+ throw FormatException.getFormatInstance();
}
break;
case '%':
} else if (next >= 'F' && next <= 'W') {
decodedChar = (char) (next - 11);
} else {
- throw new ReaderException("Invalid extended code 39 sequence: " + c + next);
+ throw FormatException.getFormatInstance();
}
break;
case '/':
} else if (next == 'Z') {
decodedChar = ':';
} else {
- throw new ReaderException("Invalid extended sequence: " + c + next);
+ throw FormatException.getFormatInstance();
}
break;
}
return decoded.toString();
}
-}
\ No newline at end of file
+}
projects / zxing.git / blobdiff