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Core barcode encoding/decoding library
/*
* Copyright 2010 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.EncodeHintType;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Map;
/**
* This object renders a CODE128 code as a {@link BitMatrix}.
*
* @author [email protected] (Erik Barbara)
*/
public final class Code128Writer extends OneDimensionalCodeWriter {
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_CODE_A = 101;
private static final int CODE_CODE_B = 100;
private static final int CODE_CODE_C = 99;
private static final int CODE_STOP = 106;
// Dummy characters used to specify control characters in input
private static final char ESCAPE_FNC_1 = '\u00f1';
private static final char ESCAPE_FNC_2 = '\u00f2';
private static final char ESCAPE_FNC_3 = '\u00f3';
private static final char ESCAPE_FNC_4 = '\u00f4';
private static final int CODE_FNC_1 = 102; // Code A, Code B, Code C
private static final int CODE_FNC_2 = 97; // Code A, Code B
private static final int CODE_FNC_3 = 96; // Code A, Code B
private static final int CODE_FNC_4_A = 101; // Code A
private static final int CODE_FNC_4_B = 100; // Code B
// Results of minimal lookahead for code C
private enum CType {
UNCODABLE,
ONE_DIGIT,
TWO_DIGITS,
FNC_1
}
@Override
public BitMatrix encode(String contents,
BarcodeFormat format,
int width,
int height,
Map hints) throws WriterException {
if (format != BarcodeFormat.CODE_128) {
throw new IllegalArgumentException("Can only encode CODE_128, but got " + format);
}
return super.encode(contents, format, width, height, hints);
}
@Override
public boolean[] encode(String contents) {
int length = contents.length();
// Check length
if (length < 1 || length > 80) {
throw new IllegalArgumentException(
"Contents length should be between 1 and 80 characters, but got " + length);
}
// Check content
for (int i = 0; i < length; i++) {
char c = contents.charAt(i);
switch (c) {
case ESCAPE_FNC_1:
case ESCAPE_FNC_2:
case ESCAPE_FNC_3:
case ESCAPE_FNC_4:
break;
default:
if (c > 127) {
// support for FNC4 isn't implemented, no full Latin-1 character set available at the moment
throw new IllegalArgumentException("Bad character in input: " + c);
}
}
}
Collection patterns = new ArrayList<>(); // temporary storage for patterns
int checkSum = 0;
int checkWeight = 1;
int codeSet = 0; // selected code (CODE_CODE_B or CODE_CODE_C)
int position = 0; // position in contents
while (position < length) {
//Select code to use
int newCodeSet = chooseCode(contents, position, codeSet);
//Get the pattern index
int patternIndex;
if (newCodeSet == codeSet) {
// Encode the current character
// First handle escapes
switch (contents.charAt(position)) {
case ESCAPE_FNC_1:
patternIndex = CODE_FNC_1;
break;
case ESCAPE_FNC_2:
patternIndex = CODE_FNC_2;
break;
case ESCAPE_FNC_3:
patternIndex = CODE_FNC_3;
break;
case ESCAPE_FNC_4:
if (codeSet == CODE_CODE_A) {
patternIndex = CODE_FNC_4_A;
} else {
patternIndex = CODE_FNC_4_B;
}
break;
default:
// Then handle normal characters otherwise
switch (codeSet) {
case CODE_CODE_A:
patternIndex = contents.charAt(position) - ' ';
if (patternIndex < 0) {
// everything below a space character comes behind the underscore in the code patterns table
patternIndex += '`';
}
break;
case CODE_CODE_B:
patternIndex = contents.charAt(position) - ' ';
break;
default:
// CODE_CODE_C
patternIndex = Integer.parseInt(contents.substring(position, position + 2));
position++; // Also incremented below
break;
}
}
position++;
} else {
// Should we change the current code?
// Do we have a code set?
if (codeSet == 0) {
// No, we don't have a code set
switch (newCodeSet) {
case CODE_CODE_A:
patternIndex = CODE_START_A;
break;
case CODE_CODE_B:
patternIndex = CODE_START_B;
break;
default:
patternIndex = CODE_START_C;
break;
}
} else {
// Yes, we have a code set
patternIndex = newCodeSet;
}
codeSet = newCodeSet;
}
// Get the pattern
patterns.add(Code128Reader.CODE_PATTERNS[patternIndex]);
// Compute checksum
checkSum += patternIndex * checkWeight;
if (position != 0) {
checkWeight++;
}
}
// Compute and append checksum
checkSum %= 103;
patterns.add(Code128Reader.CODE_PATTERNS[checkSum]);
// Append stop code
patterns.add(Code128Reader.CODE_PATTERNS[CODE_STOP]);
// Compute code width
int codeWidth = 0;
for (int[] pattern : patterns) {
for (int width : pattern) {
codeWidth += width;
}
}
// Compute result
boolean[] result = new boolean[codeWidth];
int pos = 0;
for (int[] pattern : patterns) {
pos += appendPattern(result, pos, pattern, true);
}
return result;
}
private static CType findCType(CharSequence value, int start) {
int last = value.length();
if (start >= last) {
return CType.UNCODABLE;
}
char c = value.charAt(start);
if (c == ESCAPE_FNC_1) {
return CType.FNC_1;
}
if (c < '0' || c > '9') {
return CType.UNCODABLE;
}
if (start + 1 >= last) {
return CType.ONE_DIGIT;
}
c = value.charAt(start + 1);
if (c < '0' || c > '9') {
return CType.ONE_DIGIT;
}
return CType.TWO_DIGITS;
}
private static int chooseCode(CharSequence value, int start, int oldCode) {
CType lookahead = findCType(value, start);
if (lookahead == CType.ONE_DIGIT) {
if (oldCode == CODE_CODE_A) {
return CODE_CODE_A;
}
return CODE_CODE_B;
}
if (lookahead == CType.UNCODABLE) {
if (start < value.length()) {
char c = value.charAt(start);
if (c < ' ' || (oldCode == CODE_CODE_A && (c < '`' || (c >= ESCAPE_FNC_1 && c <= ESCAPE_FNC_4)))) {
// can continue in code A, encodes ASCII 0 to 95 or FNC1 to FNC4
return CODE_CODE_A;
}
}
return CODE_CODE_B; // no choice
}
if (oldCode == CODE_CODE_A && lookahead == CType.FNC_1) {
return CODE_CODE_A;
}
if (oldCode == CODE_CODE_C) { // can continue in code C
return CODE_CODE_C;
}
if (oldCode == CODE_CODE_B) {
if (lookahead == CType.FNC_1) {
return CODE_CODE_B; // can continue in code B
}
// Seen two consecutive digits, see what follows
lookahead = findCType(value, start + 2);
if (lookahead == CType.UNCODABLE || lookahead == CType.ONE_DIGIT) {
return CODE_CODE_B; // not worth switching now
}
if (lookahead == CType.FNC_1) { // two digits, then FNC_1...
lookahead = findCType(value, start + 3);
if (lookahead == CType.TWO_DIGITS) { // then two more digits, switch
return CODE_CODE_C;
} else {
return CODE_CODE_B; // otherwise not worth switching
}
}
// At this point, there are at least 4 consecutive digits.
// Look ahead to choose whether to switch now or on the next round.
int index = start + 4;
while ((lookahead = findCType(value, index)) == CType.TWO_DIGITS) {
index += 2;
}
if (lookahead == CType.ONE_DIGIT) { // odd number of digits, switch later
return CODE_CODE_B;
}
return CODE_CODE_C; // even number of digits, switch now
}
// Here oldCode == 0, which means we are choosing the initial code
if (lookahead == CType.FNC_1) { // ignore FNC_1
lookahead = findCType(value, start + 1);
}
if (lookahead == CType.TWO_DIGITS) { // at least two digits, start in code C
return CODE_CODE_C;
}
return CODE_CODE_B;
}
}
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