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Core barcode encoding/decoding library
/*
* 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.
* 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 com.google.zxing.BarcodeFormat;
import com.google.zxing.ChecksumException;
import com.google.zxing.DecodeHintType;
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 java.util.ArrayList;
import java.util.List;
import java.util.Map;
/**
* Decodes Code 128 barcodes.
*
* @author Sean Owen
*/
public final class Code128Reader extends OneDReader {
static final int[][] CODE_PATTERNS = {
{2, 1, 2, 2, 2, 2}, // 0
{2, 2, 2, 1, 2, 2},
{2, 2, 2, 2, 2, 1},
{1, 2, 1, 2, 2, 3},
{1, 2, 1, 3, 2, 2},
{1, 3, 1, 2, 2, 2}, // 5
{1, 2, 2, 2, 1, 3},
{1, 2, 2, 3, 1, 2},
{1, 3, 2, 2, 1, 2},
{2, 2, 1, 2, 1, 3},
{2, 2, 1, 3, 1, 2}, // 10
{2, 3, 1, 2, 1, 2},
{1, 1, 2, 2, 3, 2},
{1, 2, 2, 1, 3, 2},
{1, 2, 2, 2, 3, 1},
{1, 1, 3, 2, 2, 2}, // 15
{1, 2, 3, 1, 2, 2},
{1, 2, 3, 2, 2, 1},
{2, 2, 3, 2, 1, 1},
{2, 2, 1, 1, 3, 2},
{2, 2, 1, 2, 3, 1}, // 20
{2, 1, 3, 2, 1, 2},
{2, 2, 3, 1, 1, 2},
{3, 1, 2, 1, 3, 1},
{3, 1, 1, 2, 2, 2},
{3, 2, 1, 1, 2, 2}, // 25
{3, 2, 1, 2, 2, 1},
{3, 1, 2, 2, 1, 2},
{3, 2, 2, 1, 1, 2},
{3, 2, 2, 2, 1, 1},
{2, 1, 2, 1, 2, 3}, // 30
{2, 1, 2, 3, 2, 1},
{2, 3, 2, 1, 2, 1},
{1, 1, 1, 3, 2, 3},
{1, 3, 1, 1, 2, 3},
{1, 3, 1, 3, 2, 1}, // 35
{1, 1, 2, 3, 1, 3},
{1, 3, 2, 1, 1, 3},
{1, 3, 2, 3, 1, 1},
{2, 1, 1, 3, 1, 3},
{2, 3, 1, 1, 1, 3}, // 40
{2, 3, 1, 3, 1, 1},
{1, 1, 2, 1, 3, 3},
{1, 1, 2, 3, 3, 1},
{1, 3, 2, 1, 3, 1},
{1, 1, 3, 1, 2, 3}, // 45
{1, 1, 3, 3, 2, 1},
{1, 3, 3, 1, 2, 1},
{3, 1, 3, 1, 2, 1},
{2, 1, 1, 3, 3, 1},
{2, 3, 1, 1, 3, 1}, // 50
{2, 1, 3, 1, 1, 3},
{2, 1, 3, 3, 1, 1},
{2, 1, 3, 1, 3, 1},
{3, 1, 1, 1, 2, 3},
{3, 1, 1, 3, 2, 1}, // 55
{3, 3, 1, 1, 2, 1},
{3, 1, 2, 1, 1, 3},
{3, 1, 2, 3, 1, 1},
{3, 3, 2, 1, 1, 1},
{3, 1, 4, 1, 1, 1}, // 60
{2, 2, 1, 4, 1, 1},
{4, 3, 1, 1, 1, 1},
{1, 1, 1, 2, 2, 4},
{1, 1, 1, 4, 2, 2},
{1, 2, 1, 1, 2, 4}, // 65
{1, 2, 1, 4, 2, 1},
{1, 4, 1, 1, 2, 2},
{1, 4, 1, 2, 2, 1},
{1, 1, 2, 2, 1, 4},
{1, 1, 2, 4, 1, 2}, // 70
{1, 2, 2, 1, 1, 4},
{1, 2, 2, 4, 1, 1},
{1, 4, 2, 1, 1, 2},
{1, 4, 2, 2, 1, 1},
{2, 4, 1, 2, 1, 1}, // 75
{2, 2, 1, 1, 1, 4},
{4, 1, 3, 1, 1, 1},
{2, 4, 1, 1, 1, 2},
{1, 3, 4, 1, 1, 1},
{1, 1, 1, 2, 4, 2}, // 80
{1, 2, 1, 1, 4, 2},
{1, 2, 1, 2, 4, 1},
{1, 1, 4, 2, 1, 2},
{1, 2, 4, 1, 1, 2},
{1, 2, 4, 2, 1, 1}, // 85
{4, 1, 1, 2, 1, 2},
{4, 2, 1, 1, 1, 2},
{4, 2, 1, 2, 1, 1},
{2, 1, 2, 1, 4, 1},
{2, 1, 4, 1, 2, 1}, // 90
{4, 1, 2, 1, 2, 1},
{1, 1, 1, 1, 4, 3},
{1, 1, 1, 3, 4, 1},
{1, 3, 1, 1, 4, 1},
{1, 1, 4, 1, 1, 3}, // 95
{1, 1, 4, 3, 1, 1},
{4, 1, 1, 1, 1, 3},
{4, 1, 1, 3, 1, 1},
{1, 1, 3, 1, 4, 1},
{1, 1, 4, 1, 3, 1}, // 100
{3, 1, 1, 1, 4, 1},
{4, 1, 1, 1, 3, 1},
{2, 1, 1, 4, 1, 2},
{2, 1, 1, 2, 1, 4},
{2, 1, 1, 2, 3, 2}, // 105
{2, 3, 3, 1, 1, 1, 2}
};
private static final float MAX_AVG_VARIANCE = 0.25f;
private static final float MAX_INDIVIDUAL_VARIANCE = 0.7f;
private static final int CODE_SHIFT = 98;
private static final int CODE_CODE_C = 99;
private static final int CODE_CODE_B = 100;
private static final int CODE_CODE_A = 101;
private static final int CODE_FNC_1 = 102;
private static final int CODE_FNC_2 = 97;
private static final int CODE_FNC_3 = 96;
private static final int CODE_FNC_4_A = 101;
private static final int CODE_FNC_4_B = 100;
private static final int CODE_START_A = 103;
private static final int CODE_START_B = 104;
private static final int CODE_START_C = 105;
private static final int CODE_STOP = 106;
private static int[] findStartPattern(BitArray row) throws NotFoundException {
int width = row.getSize();
int rowOffset = row.getNextSet(0);
int counterPosition = 0;
int[] counters = new int[6];
int patternStart = rowOffset;
boolean isWhite = false;
int patternLength = counters.length;
for (int i = rowOffset; i < width; i++) {
if (row.get(i) != isWhite) {
counters[counterPosition]++;
} else {
if (counterPosition == patternLength - 1) {
float bestVariance = MAX_AVG_VARIANCE;
int bestMatch = -1;
for (int startCode = CODE_START_A; startCode <= CODE_START_C; startCode++) {
float variance = patternMatchVariance(counters, CODE_PATTERNS[startCode],
MAX_INDIVIDUAL_VARIANCE);
if (variance < bestVariance) {
bestVariance = variance;
bestMatch = startCode;
}
}
// Look for whitespace before start pattern, >= 50% of width of start pattern
if (bestMatch >= 0 &&
row.isRange(Math.max(0, patternStart - (i - patternStart) / 2), patternStart, false)) {
return new int[]{patternStart, i, bestMatch};
}
patternStart += counters[0] + counters[1];
System.arraycopy(counters, 2, counters, 0, counterPosition - 1);
counters[counterPosition - 1] = 0;
counters[counterPosition] = 0;
counterPosition--;
} else {
counterPosition++;
}
counters[counterPosition] = 1;
isWhite = !isWhite;
}
}
throw NotFoundException.getNotFoundInstance();
}
private static int decodeCode(BitArray row, int[] counters, int rowOffset)
throws NotFoundException {
recordPattern(row, rowOffset, counters);
float bestVariance = MAX_AVG_VARIANCE; // worst variance we'll accept
int bestMatch = -1;
for (int d = 0; d < CODE_PATTERNS.length; d++) {
int[] pattern = CODE_PATTERNS[d];
float variance = patternMatchVariance(counters, pattern, MAX_INDIVIDUAL_VARIANCE);
if (variance < bestVariance) {
bestVariance = variance;
bestMatch = d;
}
}
// TODO We're overlooking the fact that the STOP pattern has 7 values, not 6.
if (bestMatch >= 0) {
return bestMatch;
} else {
throw NotFoundException.getNotFoundInstance();
}
}
@Override
public Result decodeRow(int rowNumber, BitArray row, Map hints)
throws NotFoundException, FormatException, ChecksumException {
boolean convertFNC1 = hints != null && hints.containsKey(DecodeHintType.ASSUME_GS1);
int[] startPatternInfo = findStartPattern(row);
int startCode = startPatternInfo[2];
List rawCodes = new ArrayList<>(20);
rawCodes.add((byte) startCode);
int codeSet;
switch (startCode) {
case CODE_START_A:
codeSet = CODE_CODE_A;
break;
case CODE_START_B:
codeSet = CODE_CODE_B;
break;
case CODE_START_C:
codeSet = CODE_CODE_C;
break;
default:
throw FormatException.getFormatInstance();
}
boolean done = false;
boolean isNextShifted = false;
StringBuilder result = new StringBuilder(20);
int lastStart = startPatternInfo[0];
int nextStart = startPatternInfo[1];
int[] counters = new int[6];
int lastCode = 0;
int code = 0;
int checksumTotal = startCode;
int multiplier = 0;
boolean lastCharacterWasPrintable = true;
boolean upperMode = false;
boolean shiftUpperMode = false;
while (!done) {
boolean unshift = isNextShifted;
isNextShifted = false;
// Save off last code
lastCode = code;
// Decode another code from image
code = decodeCode(row, counters, nextStart);
rawCodes.add((byte) code);
// 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 counter : counters) {
nextStart += counter;
}
// Take care of illegal start codes
switch (code) {
case CODE_START_A:
case CODE_START_B:
case CODE_START_C:
throw FormatException.getFormatInstance();
}
switch (codeSet) {
case CODE_CODE_A:
if (code < 64) {
if (shiftUpperMode == upperMode) {
result.append((char) (' ' + code));
} else {
result.append((char) (' ' + code + 128));
}
shiftUpperMode = false;
} else if (code < 96) {
if (shiftUpperMode == upperMode) {
result.append((char) (code - 64));
} else {
result.append((char) (code + 64));
}
shiftUpperMode = false;
} else {
// 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:
if (convertFNC1) {
if (result.length() == 0) {
// GS1 specification 5.4.3.7. and 5.4.6.4. If the first char after the start code
// is FNC1 then this is GS1-128. We add the symbology identifier.
result.append("]C1");
} else {
// GS1 specification 5.4.7.5. Every subsequent FNC1 is returned as ASCII 29 (GS)
result.append((char) 29);
}
}
break;
case CODE_FNC_2:
case CODE_FNC_3:
// do nothing?
break;
case CODE_FNC_4_A:
if (!upperMode && shiftUpperMode) {
upperMode = true;
shiftUpperMode = false;
} else if (upperMode && shiftUpperMode) {
upperMode = false;
shiftUpperMode = false;
} else {
shiftUpperMode = true;
}
break;
case CODE_SHIFT:
isNextShifted = true;
codeSet = CODE_CODE_B;
break;
case CODE_CODE_B:
codeSet = CODE_CODE_B;
break;
case CODE_CODE_C:
codeSet = CODE_CODE_C;
break;
case CODE_STOP:
done = true;
break;
}
}
break;
case CODE_CODE_B:
if (code < 96) {
if (shiftUpperMode == upperMode) {
result.append((char) (' ' + code));
} else {
result.append((char) (' ' + code + 128));
}
shiftUpperMode = false;
} else {
if (code != CODE_STOP) {
lastCharacterWasPrintable = false;
}
switch (code) {
case CODE_FNC_1:
if (convertFNC1) {
if (result.length() == 0) {
// GS1 specification 5.4.3.7. and 5.4.6.4. If the first char after the start code
// is FNC1 then this is GS1-128. We add the symbology identifier.
result.append("]C1");
} else {
// GS1 specification 5.4.7.5. Every subsequent FNC1 is returned as ASCII 29 (GS)
result.append((char) 29);
}
}
break;
case CODE_FNC_2:
case CODE_FNC_3:
// do nothing?
break;
case CODE_FNC_4_B:
if (!upperMode && shiftUpperMode) {
upperMode = true;
shiftUpperMode = false;
} else if (upperMode && shiftUpperMode) {
upperMode = false;
shiftUpperMode = false;
} else {
shiftUpperMode = true;
}
break;
case CODE_SHIFT:
isNextShifted = true;
codeSet = CODE_CODE_A;
break;
case CODE_CODE_A:
codeSet = CODE_CODE_A;
break;
case CODE_CODE_C:
codeSet = CODE_CODE_C;
break;
case CODE_STOP:
done = true;
break;
}
}
break;
case CODE_CODE_C:
if (code < 100) {
if (code < 10) {
result.append('0');
}
result.append(code);
} else {
if (code != CODE_STOP) {
lastCharacterWasPrintable = false;
}
switch (code) {
case CODE_FNC_1:
if (convertFNC1) {
if (result.length() == 0) {
// GS1 specification 5.4.3.7. and 5.4.6.4. If the first char after the start code
// is FNC1 then this is GS1-128. We add the symbology identifier.
result.append("]C1");
} else {
// GS1 specification 5.4.7.5. Every subsequent FNC1 is returned as ASCII 29 (GS)
result.append((char) 29);
}
}
break;
case CODE_CODE_A:
codeSet = CODE_CODE_A;
break;
case CODE_CODE_B:
codeSet = CODE_CODE_B;
break;
case CODE_STOP:
done = true;
break;
}
}
break;
}
// Unshift back to another code set if we were shifted
if (unshift) {
codeSet = codeSet == CODE_CODE_A ? CODE_CODE_B : CODE_CODE_A;
}
}
int lastPatternSize = nextStart - lastStart;
// 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:
nextStart = row.getNextUnset(nextStart);
if (!row.isRange(nextStart,
Math.min(row.getSize(), 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 ChecksumException.getChecksumInstance();
}
// Need to pull out the check digits from string
int resultLength = result.length();
if (resultLength == 0) {
// false positive
throw NotFoundException.getNotFoundInstance();
}
// 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);
} else {
result.delete(resultLength - 1, resultLength);
}
}
float left = (startPatternInfo[1] + startPatternInfo[0]) / 2.0f;
float right = lastStart + lastPatternSize / 2.0f;
int rawCodesSize = rawCodes.size();
byte[] rawBytes = new byte[rawCodesSize];
for (int i = 0; i < rawCodesSize; i++) {
rawBytes[i] = rawCodes.get(i);
}
return new Result(
result.toString(),
rawBytes,
new ResultPoint[]{
new ResultPoint(left, rowNumber),
new ResultPoint(right, rowNumber)},
BarcodeFormat.CODE_128);
}
}