UPCEReader.cpp Example File

 // -*- mode:c++; tab-width:2; indent-tabs-mode:nil; c-basic-offset:2 -*-
 /*
  *  Copyright 2010 ZXing authors All rights reserved.
  *
  * 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.
  */

 #include <zxing/ZXing.h>
 #include <zxing/oned/UPCEReader.h>
 #include <zxing/ReaderException.h>

 using std::string;
 using std::vector;
 using zxing::Ref;
 using zxing::String;
 using zxing::oned::UPCEReader;

 // VC++
 using zxing::BitArray;

 #define VECTOR_INIT(v) v, v + sizeof(v)/sizeof(v[0])

 namespace {
   /**
    * The pattern that marks the middle, and end, of a UPC-E pattern.
    * There is no "second half" to a UPC-E barcode.
    */
   const int MIDDLE_END_PATTERN_[6] = {1, 1, 1, 1, 1, 1};
   const vector<int> MIDDLE_END_PATTERN (VECTOR_INIT(MIDDLE_END_PATTERN_));

   /**
    * See {@link #L_AND_G_PATTERNS}; these values similarly represent patterns of
    * even-odd parity encodings of digits that imply both the number system (0 or 1)
    * used, and the check digit.
    */
   const int NUMSYS_AND_CHECK_DIGIT_PATTERNS[2][10] = {
     {0x38, 0x34, 0x32, 0x31, 0x2C, 0x26, 0x23, 0x2A, 0x29, 0x25},
     {0x07, 0x0B, 0x0D, 0x0E, 0x13, 0x19, 0x1C, 0x15, 0x16, 0x1A}
   };
 }

 UPCEReader::UPCEReader() {
 }

 int UPCEReader::decodeMiddle(Ref<BitArray> row, Range const& startRange, string& result) {
   vector<int>& counters (decodeMiddleCounters);
   counters.clear();
   counters.resize(4);
   int end = row->getSize();
   int rowOffset = startRange[1];

   int lgPatternFound = 0;

   for (int x = 0; x < 6 && rowOffset < end; x++) {
     int bestMatch = decodeDigit(row, counters, rowOffset, L_AND_G_PATTERNS);
     result.append(1, (byte) ('0' + bestMatch % 10));
     for (int i = 0, e = counters.size(); i < e; i++) {
       rowOffset += counters[i];
     }
     if (bestMatch >= 10) {
       lgPatternFound |= 1 << (5 - x);
     }
   }

   determineNumSysAndCheckDigit(result, lgPatternFound);

   return rowOffset;
 }

 UPCEReader::Range UPCEReader::decodeEnd(Ref<BitArray> row, int endStart) {
   return findGuardPattern(row, endStart, true, MIDDLE_END_PATTERN);
 }

 bool UPCEReader::checkChecksum(Ref<String> const& s){
   return UPCEANReader::checkChecksum(convertUPCEtoUPCA(s));
 }

 bool UPCEReader::determineNumSysAndCheckDigit(std::string& resultString, int lgPatternFound) {
   for (int numSys = 0; numSys <= 1; numSys++) {
     for (int d = 0; d < 10; d++) {
       if (lgPatternFound == NUMSYS_AND_CHECK_DIGIT_PATTERNS[numSys][d]) {
           resultString.insert((size_t)0, (size_t)1, (byte) ('0' + numSys));
         resultString.append(1, (byte) ('0' + d));
         return true;
       }
     }
   }
   return false;
 }

 /**
  * Expands a UPC-E value back into its full, equivalent UPC-A code value.
  *
  * @param upce UPC-E code as string of digits
  * @return equivalent UPC-A code as string of digits
  */
 Ref<String> UPCEReader::convertUPCEtoUPCA(Ref<String> const& upce_) {
   string const& upce(upce_->getText());
   string result;
   result.append(1, upce[0]);
   char lastChar = upce[6];
   switch (lastChar) {
   case '0':
   case '1':
   case '2':
     result.append(upce.substr(1,2));
     result.append(1, lastChar);
     result.append("0000");
     result.append(upce.substr(3,3));
     break;
   case '3':
     result.append(upce.substr(1,3));
     result.append("00000");
     result.append(upce.substr(4,2));
     break;
   case '4':
     result.append(upce.substr(1,4));
     result.append("00000");
     result.append(1, upce[5]);
     break;
   default:
     result.append(upce.substr(1,5));
     result.append("0000");
     result.append(1, lastChar);
     break;
   }
   result.append(1, upce[7]);
   return Ref<String>(new String(result));
 }

 zxing::BarcodeFormat UPCEReader::getBarcodeFormat() {
   return BarcodeFormat::UPC_E;
 }