DataMatrixDataBlock.cpp Example File

 /*
  *  DataBlock.cpp
  *  zxing
  *
  *  Created by Luiz Silva on 09/02/2010.
  *  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/datamatrix/decoder/DataBlock.h>
 #include <zxing/common/IllegalArgumentException.h>

 namespace zxing {
 namespace datamatrix {

 using namespace std;

 DataBlock::DataBlock(int numDataCodewords, ArrayRef<byte> codewords) :
     numDataCodewords_(numDataCodewords), codewords_(codewords) {
 }

 int DataBlock::getNumDataCodewords() {
   return numDataCodewords_;
 }

 ArrayRef<byte> DataBlock::getCodewords() {
   return codewords_;
 }

 std::vector<Ref<DataBlock> > DataBlock::getDataBlocks(ArrayRef<byte> rawCodewords, Version *version) {
   // Figure out the number and size of data blocks used by this version and
   // error correction level
   ECBlocks* ecBlocks = version->getECBlocks();

   // First count the total number of data blocks
   int totalBlocks = 0;
   vector<ECB*> ecBlockArray = ecBlocks->getECBlocks();
   for (size_t i = 0; i < ecBlockArray.size(); i++) {
     totalBlocks += ecBlockArray[i]->getCount();
   }

   // Now establish DataBlocks of the appropriate size and number of data codewords
   std::vector<Ref<DataBlock> > result(totalBlocks);
   int numResultBlocks = 0;
   for (size_t j = 0; j < ecBlockArray.size(); j++) {
     ECB *ecBlock = ecBlockArray[j];
     for (int i = 0; i < ecBlock->getCount(); i++) {
       int numDataCodewords = ecBlock->getDataCodewords();
       int numBlockCodewords = ecBlocks->getECCodewords() + numDataCodewords;
       ArrayRef<byte> buffer(numBlockCodewords);
       Ref<DataBlock> blockRef(new DataBlock(numDataCodewords, buffer));
       result[numResultBlocks++] = blockRef;
     }
   }

   // All blocks have the same amount of data, except that the last n
   // (where n may be 0) have 1 more byte. Figure out where these start.
   int shorterBlocksTotalCodewords = result[0]->codewords_->size();
   int longerBlocksStartAt = result.size() - 1;
   while (longerBlocksStartAt >= 0) {
     int numCodewords = result[longerBlocksStartAt]->codewords_->size();
     if (numCodewords == shorterBlocksTotalCodewords) {
       break;
     }
     if (numCodewords != shorterBlocksTotalCodewords + 1) {
       throw IllegalArgumentException("Data block sizes differ by more than 1");
     }
     longerBlocksStartAt--;
   }
   longerBlocksStartAt++;

   int shorterBlocksNumDataCodewords = shorterBlocksTotalCodewords - ecBlocks->getECCodewords();
   // The last elements of result may be 1 element longer;
   // first fill out as many elements as all of them have
   int rawCodewordsOffset = 0;
   for (int i = 0; i < shorterBlocksNumDataCodewords; i++) {
     for (int j = 0; j < numResultBlocks; j++) {
       result[j]->codewords_[i] = rawCodewords[rawCodewordsOffset++];
     }
   }
   // Fill out the last data block in the longer ones
   for (int j = longerBlocksStartAt; j < numResultBlocks; j++) {
     result[j]->codewords_[shorterBlocksNumDataCodewords] = rawCodewords[rawCodewordsOffset++];
   }
   // Now add in error correction blocks
   int max = result[0]->codewords_->size();
   for (int i = shorterBlocksNumDataCodewords; i < max; i++) {
     for (int j = 0; j < numResultBlocks; j++) {
       int iOffset = j < longerBlocksStartAt ? i : i + 1;
       result[j]->codewords_[iOffset] = rawCodewords[rawCodewordsOffset++];
     }
   }

   if (rawCodewordsOffset != rawCodewords->size()) {
     throw IllegalArgumentException("rawCodewordsOffset != rawCodewords.length");
   }

   return result;
 }

 }
 }