static DataBlock[] getDataBlocks(byte[] rawCodewords,
                                   Version version,
                                   ErrorCorrectionLevel ecLevel) {

    if (rawCodewords.length != version.getTotalCodewords()) {
      throw new IllegalArgumentException();
    }

    // Figure out the number and size of data blocks used by this version and
    // error correction level
    Version.ECBlocks ecBlocks = version.getECBlocksForLevel(ecLevel);

    // First count the total number of data blocks
    int totalBlocks = 0;
    Version.ECB[] ecBlockArray = ecBlocks.getECBlocks();
    for (Version.ECB ecBlock : ecBlockArray) {
      totalBlocks += ecBlock.getCount();
    }

    // Now establish DataBlocks of the appropriate size and number of data codewords
    DataBlock[] result = new DataBlock[totalBlocks];
    int numResultBlocks = 0;
    for (Version.ECB ecBlock : ecBlockArray) {
      for (int i = 0; i < ecBlock.getCount(); i++) {
        int numDataCodewords = ecBlock.getDataCodewords();
        int numBlockCodewords = ecBlocks.getECCodewordsPerBlock() + numDataCodewords;
        result[numResultBlocks++] = new DataBlock(numDataCodewords, new byte[numBlockCodewords]);
      }
    }

    // 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.length;
    int longerBlocksStartAt = result.length - 1;
    while (longerBlocksStartAt >= 0) {
      int numCodewords = result[longerBlocksStartAt].codewords.length;
      if (numCodewords == shorterBlocksTotalCodewords) {
        break;
      }
      longerBlocksStartAt--;
    }
    longerBlocksStartAt++;

    int shorterBlocksNumDataCodewords = shorterBlocksTotalCodewords - ecBlocks.getECCodewordsPerBlock();
    // 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.length;
    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++];
      }
    }
    return result;
  }
static DataBlock [ ] getDataBlocks ( byte [ ] rawCodewords , Version version , ErrorCorrectionLevel ecLevel ) { if ( rawCodewords . length != version . getTotalCodewords ( ) ) { throw new IllegalArgumentException ( ) ; } Version . ECBlocks ecBlocks = version . getECBlocksForLevel ( ecLevel ) ; int totalBlocks = 0 ; Version . ECB [ ] ecBlockArray = ecBlocks . getECBlocks ( ) ; for ( Version . ECB ecBlock : ecBlockArray ) { totalBlocks += ecBlock . getCount ( ) ; } DataBlock [ ] result = new DataBlock [ totalBlocks ] ; int numResultBlocks = 0 ; for ( Version . ECB ecBlock : ecBlockArray ) { for ( int i = 0 ; i < ecBlock . getCount ( ) ; i ++ ) { int numDataCodewords = ecBlock . getDataCodewords ( ) ; int numBlockCodewords = ecBlocks . getECCodewordsPerBlock ( ) + numDataCodewords ; result [ numResultBlocks ++ ] = new DataBlock ( numDataCodewords , new byte [ numBlockCodewords ] ) ; } } int shorterBlocksTotalCodewords = result [ 0 ] . codewords . length ; int longerBlocksStartAt = result . length - 1 ; while ( longerBlocksStartAt >= 0 ) { int numCodewords = result [ longerBlocksStartAt ] . codewords . length ; if ( numCodewords == shorterBlocksTotalCodewords ) { break ; } longerBlocksStartAt -- ; } longerBlocksStartAt ++ ; int shorterBlocksNumDataCodewords = shorterBlocksTotalCodewords - ecBlocks . getECCodewordsPerBlock ( ) ; int rawCodewordsOffset = 0 ; for ( int i = 0 ; i < shorterBlocksNumDataCodewords ; i ++ ) { for ( int j = 0 ; j < numResultBlocks ; j ++ ) { result [ j ] . codewords [ i ] = rawCodewords [ rawCodewordsOffset ++ ] ; } } for ( int j = longerBlocksStartAt ; j < numResultBlocks ; j ++ ) { result [ j ] . codewords [ shorterBlocksNumDataCodewords ] = rawCodewords [ rawCodewordsOffset ++ ] ; } int max = result [ 0 ] . codewords . length ; 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 ++ ] ; } } return result ; }
<p>When QR Codes use multiple data blocks, they are actually interleaved.
That is, the first byte of data block 1 to n is written, then the second bytes, and so on. This
method will separate the data into original blocks.</p>

@param rawCodewords bytes as read directly from the QR Code
@param version version of the QR Code
@param ecLevel error-correction level of the QR Code
@return DataBlocks containing original bytes, "de-interleaved" from representation in the
QR Code