5 * Copyright 2010 ZXing authors All rights reserved.
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
20 #include "UPCEANReader.h"
21 #include <zxing/oned/OneDResultPoint.h>
22 #include <zxing/ReaderException.h>
28 * Start/end guard pattern.
30 static const int START_END_PATTERN[3] = {1, 1, 1};
33 * Pattern marking the middle of a UPC/EAN pattern, separating the two halves.
35 static const int MIDDLE_PATTERN_LEN = 5;
36 static const int MIDDLE_PATTERN[MIDDLE_PATTERN_LEN] = {1, 1, 1, 1, 1};
39 * "Odd", or "L" patterns used to encode UPC/EAN digits.
41 const int L_PATTERNS_LEN = 10;
42 const int L_PATTERNS_SUB_LEN = 4;
43 const int L_PATTERNS[10][4] = {
57 * As above but also including the "even", or "G" patterns used to encode UPC/EAN digits.
59 const int L_AND_G_PATTERNS_LEN = 20;
60 const int L_AND_G_PATTERNS_SUB_LEN = 4;
61 const int L_AND_G_PATTERNS[L_AND_G_PATTERNS_LEN][L_AND_G_PATTERNS_SUB_LEN] = {
72 {1, 1, 2, 3}, // 10 reversed 0
73 {1, 2, 2, 2}, // 11 reversed 1
74 {2, 2, 1, 2}, // 12 reversed 2
75 {1, 1, 4, 1}, // 13 reversed 3
76 {2, 3, 1, 1}, // 14 reversed 4
77 {1, 3, 2, 1}, // 15 reversed 5
78 {4, 1, 1, 1}, // 16 reversed 6
79 {2, 1, 3, 1}, // 17 reversed 7
80 {3, 1, 2, 1}, // 18 reversed 8
81 {2, 1, 1, 3} // 19 reversed 9
85 const int UPCEANReader::getMIDDLE_PATTERN_LEN() {
86 return MIDDLE_PATTERN_LEN;
89 const int* UPCEANReader::getMIDDLE_PATTERN() {
90 return MIDDLE_PATTERN;
93 UPCEANReader::UPCEANReader() {
97 Ref<Result> UPCEANReader::decodeRow(int rowNumber, Ref<BitArray> row) {
100 start = findStartGuardPattern(row);
101 Ref<Result> result = decodeRow(rowNumber, row, start);
104 } catch (ReaderException const& re) {
106 return Ref<Result>();
110 Ref<Result> UPCEANReader::decodeRow(int rowNumber, Ref<BitArray> row, int startGuardRange[]) {
111 int* endRange = NULL;
113 std::string tmpResultString;
114 std::string& tmpResultStringRef = tmpResultString;
115 int endStart = decodeMiddle(row, startGuardRange, 2 /*reference findGuardPattern*/ ,
117 endRange = decodeEnd(row, endStart);
119 // Make sure there is a quiet zone at least as big as the end pattern after the barcode.
120 // The spec might want more whitespace, but in practice this is the maximum we can count on.
121 size_t end = endRange[1];
122 size_t quietEnd = end + (end - endRange[0]);
123 if (quietEnd >= row->getSize() || !row->isRange(end, quietEnd, false)) {
124 throw ReaderException("Quiet zone asserrt fail.");
127 if (!checkChecksum(tmpResultString)) {
128 throw ReaderException("Checksum fail.");
131 Ref<String> resultString(new String(tmpResultString));
133 float left = (float) (startGuardRange[1] + startGuardRange[0]) / 2.0f;
134 float right = (float) (endRange[1] + endRange[0]) / 2.0f;
136 std::vector< Ref<ResultPoint> > resultPoints(2);
137 Ref<OneDResultPoint> resultPoint1(new OneDResultPoint(left, (float) rowNumber));
138 Ref<OneDResultPoint> resultPoint2(new OneDResultPoint(right, (float) rowNumber));
139 resultPoints[0] = resultPoint1;
140 resultPoints[1] = resultPoint2;
142 ArrayRef<unsigned char> resultBytes(1);
144 Ref<Result> res(new Result(resultString, resultBytes, resultPoints, getBarcodeFormat()));
147 } catch (ReaderException const& re) {
153 int* UPCEANReader::findStartGuardPattern(Ref<BitArray> row) {
154 bool foundStart = false;
155 int* startRange = NULL;
158 while (!foundStart) {
159 delete [] startRange;
161 startRange = findGuardPattern(row, nextStart, false, START_END_PATTERN,
162 sizeof(START_END_PATTERN) / sizeof(int));
163 int start = startRange[0];
164 nextStart = startRange[1];
165 // Make sure there is a quiet zone at least as big as the start pattern before the barcode.
166 // If this check would run off the left edge of the image, do not accept this barcode,
167 // as it is very likely to be a false positive.
168 int quietStart = start - (nextStart - start);
169 if (quietStart >= 0) {
170 foundStart = row->isRange(quietStart, start, false);
174 } catch (ReaderException const& re) {
175 delete [] startRange;
180 // TODO(flyashi): Return a pair<int, int> for return value to avoid using the heap.
181 int* UPCEANReader::findGuardPattern(Ref<BitArray> row, int rowOffset, bool whiteFirst,
182 const int pattern[], int patternLen) {
183 int patternLength = patternLen;
184 int counters[patternLength];
185 int countersCount = sizeof(counters) / sizeof(int);
186 for (int i = 0; i < countersCount; i++) {
189 int width = row->getSize();
190 bool isWhite = false;
191 while (rowOffset < width) {
192 isWhite = !row->get(rowOffset);
193 if (whiteFirst == isWhite) {
199 int counterPosition = 0;
200 int patternStart = rowOffset;
201 for (int x = rowOffset; x < width; x++) {
202 bool pixel = row->get(x);
203 if (pixel ^ isWhite) {
204 counters[counterPosition]++;
206 if (counterPosition == patternLength - 1) {
207 if (patternMatchVariance(counters, countersCount, pattern,
208 MAX_INDIVIDUAL_VARIANCE) < MAX_AVG_VARIANCE) {
209 int* resultValue = new int[2];
210 resultValue[0] = patternStart;
214 patternStart += counters[0] + counters[1];
215 for (int y = 2; y < patternLength; y++) {
216 counters[y - 2] = counters[y];
218 counters[patternLength - 2] = 0;
219 counters[patternLength - 1] = 0;
224 counters[counterPosition] = 1;
228 throw ReaderException("findGuardPattern");
231 int* UPCEANReader::decodeEnd(Ref<BitArray> row, int endStart) {
232 return findGuardPattern(row, endStart, false, START_END_PATTERN,
233 sizeof(START_END_PATTERN) / sizeof(int));
236 // int UPCEANReader::decodeDigit(Ref<BitArray> row, int counters[], int countersLen, int rowOffset, int** patterns/*[][]*/, int paterns1Len, int paterns2Len)
237 int UPCEANReader::decodeDigit(Ref<BitArray> row, int counters[], int countersLen, int rowOffset,
238 UPC_EAN_PATTERNS patternType) {
239 recordPattern(row, rowOffset, counters, countersLen);
240 unsigned int bestVariance = MAX_AVG_VARIANCE; // worst variance we'll accept
244 switch (patternType) {
245 case UPC_EAN_PATTERNS_L_PATTERNS:
246 max = L_PATTERNS_LEN;
247 for (int i = 0; i < max; i++) {
248 int pattern[countersLen];
249 for(int j = 0; j< countersLen; j++){
250 pattern[j] = L_PATTERNS[i][j];
253 unsigned int variance = patternMatchVariance(counters, countersLen, pattern,
254 MAX_INDIVIDUAL_VARIANCE);
255 if (variance < bestVariance) {
256 bestVariance = variance;
261 case UPC_EAN_PATTERNS_L_AND_G_PATTERNS:
262 max = L_AND_G_PATTERNS_LEN;
263 for (int i = 0; i < max; i++) {
264 int pattern[countersLen];
265 for(int j = 0; j< countersLen; j++){
266 pattern[j] = L_AND_G_PATTERNS[i][j];
269 unsigned int variance = patternMatchVariance(counters, countersLen, pattern,
270 MAX_INDIVIDUAL_VARIANCE);
271 if (variance < bestVariance) {
272 bestVariance = variance;
280 if (bestMatch >= 0) {
283 throw ReaderException("UPCEANReader::decodeDigit: No best mach");
289 * @return {@link #checkStandardUPCEANChecksum(String)}
291 bool UPCEANReader::checkChecksum(std::string s) {
292 return checkStandardUPCEANChecksum(s);
296 * Computes the UPC/EAN checksum on a string of digits, and reports
297 * whether the checksum is correct or not.
299 * @param s string of digits to check
300 * @return true iff string of digits passes the UPC/EAN checksum algorithm
301 * @throws ReaderException if the string does not contain only digits
303 bool UPCEANReader::checkStandardUPCEANChecksum(std::string s) {
304 int length = s.length();
310 for (int i = length - 2; i >= 0; i -= 2) {
311 int digit = (int) s[i] - (int) '0';
312 if (digit < 0 || digit > 9) {
313 throw ReaderException("checkStandardUPCEANChecksum");
318 for (int i = length - 1; i >= 0; i -= 2) {
319 int digit = (int) s[i] - (int) '0';
320 if (digit < 0 || digit > 9) {
321 throw ReaderException("checkStandardUPCEANChecksum");
325 return sum % 10 == 0;
328 UPCEANReader::~UPCEANReader() {