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 128 barcodes.</p>
*
- * @author srowen@google.com (Sean Owen)
+ * @author Sean Owen
*/
-public final class Code128Reader extends AbstractOneDReader {
+public final class Code128Reader extends OneDReader {
- private static final int[][] CODE_PATTERNS = {
+ static final int[][] CODE_PATTERNS = {
{2, 1, 2, 2, 2, 2}, // 0
{2, 2, 2, 1, 2, 2},
{2, 2, 2, 2, 2, 1},
private static final int CODE_START_C = 105;
private static final int CODE_STOP = 106;
- private static int[] findStartPattern(BitArray row) throws ReaderException {
+ private static int[] findStartPattern(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) {
int bestVariance = MAX_AVG_VARIANCE;
int bestMatch = -1;
for (int startCode = CODE_START_A; startCode <= CODE_START_C; startCode++) {
- int variance = patternMatchVariance(counters, CODE_PATTERNS[startCode], MAX_INDIVIDUAL_VARIANCE);
+ int variance = patternMatchVariance(counters, CODE_PATTERNS[startCode],
+ MAX_INDIVIDUAL_VARIANCE);
if (variance < bestVariance) {
bestVariance = variance;
bestMatch = startCode;
}
}
if (bestMatch >= 0) {
- return new int[]{patternStart, i, bestMatch};
+ // 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, bestMatch};
+ }
}
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 decodeCode(BitArray row, int[] counters, int rowOffset) throws ReaderException {
+ private static int decodeCode(BitArray row, int[] counters, int rowOffset) throws NotFoundException {
recordPattern(row, rowOffset, counters);
int bestVariance = MAX_AVG_VARIANCE; // worst variance we'll accept
int bestMatch = -1;
bestMatch = d;
}
}
- // TODO We're overlooking the fact that the STOP pattern has 7 values, not 6
+ // TODO We're overlooking the fact that the STOP pattern has 7 values, not 6.
if (bestMatch >= 0) {
return bestMatch;
} else {
- throw new ReaderException("Could not match any code pattern");
+ throw NotFoundException.getNotFoundInstance();
}
}
- public Result decodeRow(int rowNumber, BitArray row, Hashtable hints) throws ReaderException {
+ public Result decodeRow(int rowNumber, BitArray row, Hashtable hints)
+ throws NotFoundException, FormatException, ChecksumException {
int[] startPatternInfo = findStartPattern(row);
int startCode = startPatternInfo[2];
codeSet = CODE_CODE_C;
break;
default:
- throw new ReaderException("Illegal start code");
+ throw FormatException.getFormatInstance();
}
boolean done = false;
boolean isNextShifted = false;
- StringBuffer result = new StringBuffer();
+ StringBuffer result = new StringBuffer(20);
int lastStart = startPatternInfo[0];
int nextStart = startPatternInfo[1];
int[] counters = new int[6];
while (!done) {
- lastCharacterWasPrintable = true;
-
boolean unshift = isNextShifted;
isNextShifted = false;
+ // Save off last code
lastCode = code;
+
+ // Decode another code from image
code = decodeCode(row, counters, nextStart);
+
+ // Remember whether the last code was printable or not (excluding CODE_STOP)
+ if (code != CODE_STOP) {
+ lastCharacterWasPrintable = true;
+ }
+
+ // Add to checksum computation (if not CODE_STOP of course)
if (code != CODE_STOP) {
multiplier++;
checksumTotal += multiplier * code;
}
+ // Advance to where the next code will to start
lastStart = nextStart;
for (int i = 0; i < counters.length; i++) {
nextStart += counters[i];
case CODE_START_A:
case CODE_START_B:
case CODE_START_C:
- throw new ReaderException("Unexpected start code");
+ throw FormatException.getFormatInstance();
}
switch (codeSet) {
} else if (code < 96) {
result.append((char) (code - 64));
} else {
- lastCharacterWasPrintable = false;
+ // Don't let CODE_STOP, which always appears, affect whether whether we think the last
+ // code was printable or not.
+ if (code != CODE_STOP) {
+ lastCharacterWasPrintable = false;
+ }
switch (code) {
case CODE_FNC_1:
case CODE_FNC_2:
if (code < 96) {
result.append((char) (' ' + code));
} else {
- lastCharacterWasPrintable = false;
+ if (code != CODE_STOP) {
+ lastCharacterWasPrintable = false;
+ }
switch (code) {
case CODE_FNC_1:
case CODE_FNC_2:
}
result.append(code);
} else {
- lastCharacterWasPrintable = false;
+ if (code != CODE_STOP) {
+ lastCharacterWasPrintable = false;
+ }
switch (code) {
case CODE_FNC_1:
// do nothing?
break;
}
+ // Unshift back to another code set if we were shifted
if (unshift) {
switch (codeSet) {
case CODE_CODE_A:
}
+ // Check for ample whitespace following pattern, but, to do this we first need to remember that
+ // we fudged decoding CODE_STOP since it actually has 7 bars, not 6. There is a black bar left
+ // to read off. Would be slightly better to properly read. Here we just skip it:
+ int width = row.getSize();
+ while (nextStart < width && row.get(nextStart)) {
+ nextStart++;
+ }
+ if (!row.isRange(nextStart, Math.min(width, nextStart + (nextStart - lastStart) / 2),
+ false)) {
+ throw NotFoundException.getNotFoundInstance();
+ }
+
// Pull out from sum the value of the penultimate check code
checksumTotal -= multiplier * lastCode;
+ // lastCode is the checksum then:
if (checksumTotal % 103 != lastCode) {
- throw new ReaderException("Checksum failed");
+ throw ChecksumException.getChecksumInstance();
}
// Need to pull out the check digits from string
int resultLength = result.length();
+ // Only bother if the result had at least one character, and if the checksum digit happened to
+ // be a printable character. If it was just interpreted as a control code, nothing to remove.
if (resultLength > 0 && lastCharacterWasPrintable) {
if (codeSet == CODE_CODE_C) {
result.delete(resultLength - 2, resultLength);
if (resultString.length() == 0) {
// Almost surely a false positive
- throw new ReaderException("Empty barcode found; assuming a false positive");
+ throw FormatException.getFormatInstance();
}
float left = (float) (startPatternInfo[1] + startPatternInfo[0]) / 2.0f;
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_128);
}
projects / zxing.git / blobdiff