cpp/core/src/zxing/oned/UPCEReader.cpp

   1 /*
   2  *  UPCEReader.cpp
   3  *  ZXing
   4  *
   5  *  Copyright 2010 ZXing authors All rights reserved.
   6  *
   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
  10  *
  11  *      http://www.apache.org/licenses/LICENSE-2.0
  12  *
  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.
  18  */
  19
  20 #include "UPCEReader.h"
  21 #include <zxing/ReaderException.h>
  22
  23 namespace zxing {
  24         namespace oned {
  25
  26                 /**
  27                  * The pattern that marks the middle, and end, of a UPC-E pattern.
  28                  * There is no "second half" to a UPC-E barcode.
  29                  */
  30                 static const int MIDDLE_END_PATTERN[6] = {1, 1, 1, 1, 1, 1};
  31
  32                 /**
  33                  * See {@link #L_AND_G_PATTERNS}; these values similarly represent patterns of
  34                  * even-odd parity encodings of digits that imply both the number system (0 or 1)
  35                  * used, and the check digit.
  36                  */
  37                 static const int NUMSYS_AND_CHECK_DIGIT_PATTERNS[2][10] = {
  38                         {0x38, 0x34, 0x32, 0x31, 0x2C, 0x26, 0x23, 0x2A, 0x29, 0x25},
  39                         {0x07, 0x0B, 0x0D, 0x0E, 0x13, 0x19, 0x1C, 0x15, 0x16, 0x1A}
  40                 };
  41
  42                 UPCEReader::UPCEReader() {
  43                 }
  44
  45                 int UPCEReader::decodeMiddle(Ref<BitArray> row, int startRange[], int startRangeLen,
  46                     std::string& resultString) {
  47                         const int countersLen = 4;
  48                         int counters[countersLen] = { 0, 0, 0, 0 };
  49
  50                         int end = row->getSize();
  51                         int rowOffset = startRange[1];
  52                         int lgPatternFound = 0;
  53
  54                         for (int x = 0; x < 6 && rowOffset < end; x++) {
  55                                 int bestMatch = decodeDigit(row, counters, countersLen, rowOffset,
  56                                     UPC_EAN_PATTERNS_L_AND_G_PATTERNS);
  57                                 if (bestMatch < 0) {
  58           return -1;
  59         }
  60                                 resultString.append(1, (char) ('0' + bestMatch % 10));
  61                                 for (int i = 0; i < countersLen; i++) {
  62                                         rowOffset += counters[i];
  63                                 }
  64                                 if (bestMatch >= 10) {
  65                                         lgPatternFound |= 1 << (5 - x);
  66                                 }
  67                         }
  68
  69                         if (!determineNumSysAndCheckDigit(resultString, lgPatternFound)) {
  70         return -1;
  71       }
  72                         return rowOffset;
  73                 }
  74
  75                 int* UPCEReader::decodeEnd(Ref<BitArray> row, int endStart) {
  76                         return findGuardPattern(row, endStart, true, MIDDLE_END_PATTERN,
  77                             sizeof(MIDDLE_END_PATTERN) / sizeof(int));
  78                 }
  79
  80                 bool UPCEReader::checkChecksum(std::string s){
  81                         return UPCEANReader::checkChecksum(convertUPCEtoUPCA(s));
  82                 }
  83
  84
  85                 bool UPCEReader::determineNumSysAndCheckDigit(std::string& resultString, int lgPatternFound) {
  86                         for (int numSys = 0; numSys <= 1; numSys++) {
  87                                 for (int d = 0; d < 10; d++) {
  88                                         if (lgPatternFound == NUMSYS_AND_CHECK_DIGIT_PATTERNS[numSys][d]) {
  89                                                 resultString.insert(0, 1, (char) ('0' + numSys));
  90                                                 resultString.append(1, (char) ('0' + d));
  91                                                 return true;
  92                                         }
  93                                 }
  94                         }
  95                         return false;
  96                 }
  97
  98                 /**
  99                  * Expands a UPC-E value back into its full, equivalent UPC-A code value.
 100                  *
 101                  * @param upce UPC-E code as string of digits
 102                  * @return equivalent UPC-A code as string of digits
 103                  */
 104                 std::string UPCEReader::convertUPCEtoUPCA(std::string upce) {
 105                         std::string result;
 106                         result.append(1, upce[0]);
 107                         char lastChar = upce[6];
 108                         switch (lastChar) {
 109                                 case '0':
 110                                 case '1':
 111                                 case '2':
 112                                         result.append(upce.substr(1,2));
 113                                         result.append(1, lastChar);
 114                                         result.append("0000");
 115                                         result.append(upce.substr(3,3));
 116                                         break;
 117                                 case '3':
 118                                         result.append(upce.substr(1,3));
 119                                         result.append("00000");
 120                                         result.append(upce.substr(4,2));
 121                                         break;
 122                                 case '4':
 123                                         result.append(upce.substr(1,4));
 124                                         result.append("00000");
 125                                         result.append(1, upce[5]);
 126                                         break;
 127                                 default:
 128                                         result.append(upce.substr(1,5));
 129                                         result.append("0000");
 130                                         result.append(1, lastChar);
 131                                         break;
 132                         }
 133                         result.append(1, upce[7]);
 134                         return result;
 135                 }
 136
 137
 138                 BarcodeFormat UPCEReader::getBarcodeFormat() {
 139                         return BarcodeFormat_UPC_E;
 140                 }
 141         }
 142 }