MultiFormatUPCEANReader.cpp Example File

 // -*- mode:c++; tab-width:2; indent-tabs-mode:nil; c-basic-offset:2 -*-
 /*
  *  MultiFormatUPCEANReader.cpp
  *  ZXing
  *
  *  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/MultiFormatUPCEANReader.h>
 #include <zxing/oned/EAN13Reader.h>
 #include <zxing/oned/EAN8Reader.h>
 #include <zxing/oned/UPCEReader.h>
 #include <zxing/oned/UPCAReader.h>
 #include <zxing/oned/OneDResultPoint.h>
 #include <zxing/common/Array.h>
 #include <zxing/ReaderException.h>
 #include <zxing/NotFoundException.h>
 #include <math.h>

 using zxing::NotFoundException;
 using zxing::Ref;
 using zxing::Result;
 using zxing::oned::MultiFormatUPCEANReader;

 // VC++
 using zxing::DecodeHints;
 using zxing::BitArray;

 MultiFormatUPCEANReader::MultiFormatUPCEANReader(DecodeHints hints) : readers() {
   if (hints.containsFormat(BarcodeFormat::EAN_13)) {
     readers.push_back(Ref<UPCEANReader>(new EAN13Reader()));
   } else if (hints.containsFormat(BarcodeFormat::UPC_A)) {
     readers.push_back(Ref<UPCEANReader>(new UPCAReader()));
   }
   if (hints.containsFormat(BarcodeFormat::EAN_8)) {
     readers.push_back(Ref<UPCEANReader>(new EAN8Reader()));
   }
   if (hints.containsFormat(BarcodeFormat::UPC_E)) {
     readers.push_back(Ref<UPCEANReader>(new UPCEReader()));
   }
   if (readers.size() == 0) {
     readers.push_back(Ref<UPCEANReader>(new EAN13Reader()));
     // UPC-A is covered by EAN-13
     readers.push_back(Ref<UPCEANReader>(new EAN8Reader()));
     readers.push_back(Ref<UPCEANReader>(new UPCEReader()));
   }
 }

 #include <typeinfo>

 Ref<Result> MultiFormatUPCEANReader::decodeRow(int rowNumber, Ref<BitArray> row, zxing::DecodeHints /*hints*/) {
   // Compute this location once and reuse it on multiple implementations
   UPCEANReader::Range startGuardPattern = UPCEANReader::findStartGuardPattern(row);
   for (int i = 0, e = readers.size(); i < e; i++) {
     Ref<UPCEANReader> reader = readers[i];
     Ref<Result> result;
     try {
       result = reader->decodeRow(rowNumber, row, startGuardPattern);
     } catch (ReaderException const& ignored) {
       (void)ignored;
       continue;
     }

     //added this because reader->decodeRow returns null if row is null
     //TODO: investigate why the execution reaches here with empty row.
     if(result.empty())
         continue;

     // Special case: a 12-digit code encoded in UPC-A is identical
     // to a "0" followed by those 12 digits encoded as EAN-13. Each
     // will recognize such a code, UPC-A as a 12-digit string and
     // EAN-13 as a 13-digit string starting with "0".  Individually
     // these are correct and their readers will both read such a
     // code and correctly call it EAN-13, or UPC-A, respectively.
     //
     // In this case, if we've been looking for both types, we'd like
     // to call it a UPC-A code. But for efficiency we only run the
     // EAN-13 decoder to also read UPC-A. So we special case it
     // here, and convert an EAN-13 result to a UPC-A result if
     // appropriate.
     bool ean13MayBeUPCA =
       result->getBarcodeFormat() == BarcodeFormat::EAN_13 &&
       result->getText()->charAt(0) == '0';

     // Note: doesn't match Java which uses hints

     bool canReturnUPCA = true;

     if (ean13MayBeUPCA && canReturnUPCA) {
       // Transfer the metdata across
       Ref<Result> resultUPCA (new Result(result->getText()->substring(1),
                                          result->getRawBytes(),
                                          result->getResultPoints(),
                                          BarcodeFormat::UPC_A));
       // needs java metadata stuff
       return resultUPCA;
     }
     return result;
   }

   throw NotFoundException();
 }