cpp/core/src/zxing/oned/UPCEANReader.cpp

   1 /*
   2  *  UPCEANReader.cpp
   3  *  ZXing
   4  *
   5  *  Created by Lukasz Warchol on 10-01-21.
   6  *  Copyright 2010 ZXing authors All rights reserved.
   7  *
   8  * Licensed under the Apache License, Version 2.0 (the "License");
   9  * you may not use this file except in compliance with the License.
  10  * You may obtain a copy of the License at
  11  *
  12  *      http://www.apache.org/licenses/LICENSE-2.0
  13  *
  14  * Unless required by applicable law or agreed to in writing, software
  15  * distributed under the License is distributed on an "AS IS" BASIS,
  16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  17  * See the License for the specific language governing permissions and
  18  * limitations under the License.
  19  */
  20
  21 #include "UPCEANReader.h"
  22 #include <zxing/oned/OneDResultPoint.h>
  23 #include <zxing/ReaderException.h>
  24 namespace zxing {
  25         namespace oned {
  26
  27                 /**
  28                  * Start/end guard pattern.
  29                  */
  30                 static const int START_END_PATTERN[3] = {1, 1, 1};
  31
  32                 /**
  33                  * Pattern marking the middle of a UPC/EAN pattern, separating the two halves.
  34                  */
  35                 static const int MIDDLE_PATTERN_LEN = 5;
  36                 static const int MIDDLE_PATTERN[MIDDLE_PATTERN_LEN] = {1, 1, 1, 1, 1};
  37
  38                 /**
  39                  * "Odd", or "L" patterns used to encode UPC/EAN digits.
  40                  */
  41                 const int L_PATTERNS_LEN = 10;
  42                 const int L_PATTERNS_SUB_LEN = 4;
  43                 const int L_PATTERNS[10][4] = {
  44                         {3, 2, 1, 1}, // 0
  45                         {2, 2, 2, 1}, // 1
  46                         {2, 1, 2, 2}, // 2
  47                         {1, 4, 1, 1}, // 3
  48                         {1, 1, 3, 2}, // 4
  49                         {1, 2, 3, 1}, // 5
  50                         {1, 1, 1, 4}, // 6
  51                         {1, 3, 1, 2}, // 7
  52                         {1, 2, 1, 3}, // 8
  53                         {3, 1, 1, 2}  // 9
  54                 };
  55
  56                 /**
  57                  * As above but also including the "even", or "G" patterns used to encode UPC/EAN digits.
  58                  */
  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] = {
  62                         {3, 2, 1, 1}, // 0
  63                         {2, 2, 2, 1}, // 1
  64                         {2, 1, 2, 2}, // 2
  65                         {1, 4, 1, 1}, // 3
  66                         {1, 1, 3, 2}, // 4
  67                         {1, 2, 3, 1}, // 5
  68                         {1, 1, 1, 4}, // 6
  69                         {1, 3, 1, 2}, // 7
  70                         {1, 2, 1, 3}, // 8
  71                         {3, 1, 1, 2}, // 9
  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
  82                 };
  83
  84
  85                 const int UPCEANReader::getMIDDLE_PATTERN_LEN(){
  86                         return MIDDLE_PATTERN_LEN;
  87                 }
  88                 const int* UPCEANReader::getMIDDLE_PATTERN(){
  89                         return MIDDLE_PATTERN;
  90                 }
  91
  92                 UPCEANReader::UPCEANReader(){
  93                 }
  94
  95
  96                 Ref<Result> UPCEANReader::decodeRow(int rowNumber, Ref<BitArray> row){
  97                         return decodeRow(rowNumber, row, findStartGuardPattern(row));
  98                 }
  99                 Ref<Result> UPCEANReader::decodeRow(int rowNumber, Ref<BitArray> row, int startGuardRange[]){
 100
 101                         std::string tmpResultString;
 102                         std::string& tmpResultStringRef = tmpResultString;
 103                         int endStart;
 104                         try {
 105                                 endStart = decodeMiddle(row, startGuardRange, 2 /*reference findGuardPattern*/ , tmpResultStringRef);
 106                         } catch (ReaderException re) {
 107                                 if (startGuardRange!=NULL) {
 108                                         delete [] startGuardRange;
 109                                         startGuardRange = NULL;
 110                                 }
 111                                 throw re;
 112                         }
 113
 114                         int* endRange = decodeEnd(row, endStart);
 115
 116                         // Make sure there is a quiet zone at least as big as the end pattern after the barcode. The
 117                         // spec might want more whitespace, but in practice this is the maximum we can count on.
 118                         size_t end = endRange[1];
 119                         size_t quietEnd = end + (end - endRange[0]);
 120                         if (quietEnd >= row->getSize() || !row->isRange(end, quietEnd, false)) {
 121                                 throw ReaderException("Quiet zone asserrt fail.");
 122                         }
 123
 124                         if (!checkChecksum(tmpResultString)) {
 125                                 if (startGuardRange!=NULL) {
 126                                         delete [] startGuardRange;
 127                                         startGuardRange = NULL;
 128                                 }
 129                                 if (endRange!=NULL) {
 130                                         delete [] endRange;
 131                                         endRange = NULL;
 132                                 }
 133                                 throw ReaderException("Checksum fail.");
 134                         }
 135
 136                         Ref<String> resultString(new String(tmpResultString));
 137
 138                         float left = (float) (startGuardRange[1] + startGuardRange[0]) / 2.0f;
 139                         float right = (float) (endRange[1] + endRange[0]) / 2.0f;
 140
 141                         std::vector< Ref<ResultPoint> > resultPoints(2);
 142                         Ref<OneDResultPoint> resultPoint1(new OneDResultPoint(left, (float) rowNumber));
 143                         Ref<OneDResultPoint> resultPoint2(new OneDResultPoint(right, (float) rowNumber));
 144                         resultPoints[0] = resultPoint1;
 145                         resultPoints[1] = resultPoint2;
 146
 147                         ArrayRef<unsigned char> resultBytes(1);
 148
 149                         if (startGuardRange!=NULL) {
 150                                 delete [] startGuardRange;
 151                                 startGuardRange = NULL;
 152                         }
 153                         if (endRange!=NULL) {
 154                                 delete [] endRange;
 155                                 endRange = NULL;
 156                         }
 157
 158                         Ref<Result> res(new Result(resultString, resultBytes, resultPoints, getBarcodeFormat()));
 159                         return res;
 160                 }
 161
 162                 int* UPCEANReader::findStartGuardPattern(Ref<BitArray> row){
 163                         bool foundStart = false;
 164
 165                         int* startRange = NULL;
 166                         int nextStart = 0;
 167                         while (!foundStart) {
 168                                 startRange = findGuardPattern(row, nextStart, false, START_END_PATTERN, sizeof(START_END_PATTERN)/sizeof(int));
 169                                 int start = startRange[0];
 170                                 nextStart = startRange[1];
 171                                 // Make sure there is a quiet zone at least as big as the start pattern before the barcode.
 172                                 // If this check would run off the left edge of the image, do not accept this barcode,
 173                                 // as it is very likely to be a false positive.
 174                                 int quietStart = start - (nextStart - start);
 175                                 if (quietStart >= 0) {
 176                                         foundStart = row->isRange(quietStart, start, false);
 177                                 }
 178                                 if (!foundStart) {
 179                                         delete [] startRange;
 180                                 }
 181                         }
 182                         return startRange;
 183                 }
 184
 185                 int* UPCEANReader::findGuardPattern(Ref<BitArray> row, int rowOffset, bool whiteFirst, const int pattern[], int patternLen){
 186                         int patternLength = patternLen;
 187
 188                         int counters[patternLength];
 189                         int countersCount = sizeof(counters)/sizeof(int);
 190                         for (int i=0; i<countersCount ; i++) {
 191                                 counters[i]=0;
 192                         }
 193                         int width = row->getSize();
 194                         bool isWhite = false;
 195                         while (rowOffset < width) {
 196                                 isWhite = !row->get(rowOffset);
 197                                 if (whiteFirst == isWhite) {
 198                                         break;
 199                                 }
 200                                 rowOffset++;
 201                         }
 202
 203                         int counterPosition = 0;
 204                         int patternStart = rowOffset;
 205                         for (int x = rowOffset; x < width; x++) {
 206                                 bool pixel = row->get(x);
 207                                 if (pixel ^ isWhite) {
 208                                         counters[counterPosition]++;
 209                                 } else {
 210                                         if (counterPosition == patternLength - 1) {
 211                                                 if (patternMatchVariance(counters, countersCount, pattern, MAX_INDIVIDUAL_VARIANCE) < MAX_AVG_VARIANCE) {
 212                                                         int* resultValue = new int[2];
 213                                                         resultValue[0] = patternStart;
 214                                                         resultValue[1] = x;
 215                                                         return resultValue;
 216                                                 }
 217                                                 patternStart += counters[0] + counters[1];
 218                                                 for (int y = 2; y < patternLength; y++) {
 219                                                         counters[y - 2] = counters[y];
 220                                                 }
 221                                                 counters[patternLength - 2] = 0;
 222                                                 counters[patternLength - 1] = 0;
 223                                                 counterPosition--;
 224                                         } else {
 225                                                 counterPosition++;
 226                                         }
 227                                         counters[counterPosition] = 1;
 228                                         isWhite = !isWhite;
 229                                 }
 230                         }
 231                         throw ReaderException("findGuardPattern");
 232                 }
 233
 234                 int* UPCEANReader::decodeEnd(Ref<BitArray> row, int endStart){
 235                         return findGuardPattern(row, endStart, false, START_END_PATTERN, sizeof(START_END_PATTERN)/sizeof(int));
 236                 }
 237
 238 //              int UPCEANReader::decodeDigit(Ref<BitArray> row, int counters[], int countersLen, int rowOffset, int** patterns/*[][]*/, int paterns1Len, int paterns2Len)
 239                 int UPCEANReader::decodeDigit(Ref<BitArray> row, int counters[], int countersLen, int rowOffset, UPC_EAN_PATTERNS patternType){
 240                         recordPattern(row, rowOffset, counters, countersLen);
 241                         unsigned int bestVariance = MAX_AVG_VARIANCE; // worst variance we'll accept
 242                         int bestMatch = -1;
 243
 244                         int max = 0;
 245                         switch (patternType) {
 246                                 case UPC_EAN_PATTERNS_L_PATTERNS:
 247                                         max = L_PATTERNS_LEN;
 248                                         for (int i = 0; i < max; i++) {
 249                                                 int pattern[countersLen];
 250                                                 for(int j = 0; j< countersLen; j++){
 251                                                         pattern[j] = L_PATTERNS[i][j];
 252                                                 }
 253
 254                                                 unsigned int variance = patternMatchVariance(counters, countersLen, pattern, MAX_INDIVIDUAL_VARIANCE);
 255                                                 if (variance < bestVariance) {
 256                                                         bestVariance = variance;
 257                                                         bestMatch = i;
 258                                                 }
 259                                         }
 260                                         break;
 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];
 267                                                 }
 268
 269                                                 unsigned int variance = patternMatchVariance(counters, countersLen, pattern, MAX_INDIVIDUAL_VARIANCE);
 270                                                 if (variance < bestVariance) {
 271                                                         bestVariance = variance;
 272                                                         bestMatch = i;
 273                                                 }
 274                                         }
 275                                         break;
 276                                 default:
 277                                         break;
 278                         }
 279                         if (bestMatch >= 0) {
 280                                 return bestMatch;
 281                         } else {
 282                                 throw ReaderException("UPCEANReader::decodeDigit: No best mach");
 283                         }
 284                 }
 285
 286
 287                 /**
 288                  * @return {@link #checkStandardUPCEANChecksum(String)}
 289                  */
 290                 bool UPCEANReader::checkChecksum(std::string s){
 291                         return checkStandardUPCEANChecksum(s);
 292                 }
 293
 294                 /**
 295                  * Computes the UPC/EAN checksum on a string of digits, and reports
 296                  * whether the checksum is correct or not.
 297                  *
 298                  * @param s string of digits to check
 299                  * @return true iff string of digits passes the UPC/EAN checksum algorithm
 300                  * @throws ReaderException if the string does not contain only digits
 301                  */
 302                 bool UPCEANReader::checkStandardUPCEANChecksum(std::string s){
 303                         int length = s.length();
 304                         if (length == 0) {
 305                                 return false;
 306                         }
 307
 308                         int sum = 0;
 309                         for (int i = length - 2; i >= 0; i -= 2) {
 310                                 int digit = (int) s[i] - (int) '0';
 311                                 if (digit < 0 || digit > 9) {
 312                                         throw ReaderException("checkStandardUPCEANChecksum");
 313                                 }
 314                                 sum += digit;
 315                         }
 316                         sum *= 3;
 317                         for (int i = length - 1; i >= 0; i -= 2) {
 318                                 int digit = (int) s[i] - (int) '0';
 319                                 if (digit < 0 || digit > 9) {
 320                                         throw ReaderException("checkStandardUPCEANChecksum");
 321                                 }
 322                                 sum += digit;
 323                         }
 324                         return sum % 10 == 0;
 325                 }
 326                 UPCEANReader::~UPCEANReader(){
 327                 }
 328         }
 329 }