encodeECC200 static method

String encodeECC200(String codewords, SymbolInfo symbolInfo)

Creates the ECC200 error correction for an encoded message.

@param codewords the codewords @param symbolInfo information about the symbol to be encoded @return the codewords with interleaved error correction.

Implementation

static String encodeECC200(String codewords, SymbolInfo symbolInfo) {
  if (codewords.length != symbolInfo.dataCapacity) {
    throw ArgumentError(
      'The number of codewords does not match the selected symbol',
    );
  }
  final sb = StringBuilder();
  sb.write(codewords);
  final blockCount = symbolInfo.interleavedBlockCount;
  if (blockCount == 1) {
    final ecc = _createECCBlock(codewords, symbolInfo.errorCodewords);
    sb.write(ecc);
  } else {
    sb.setLength(symbolInfo.dataCapacity + symbolInfo.errorCodewords);
    // this is using for temp StringBuffer's init length
    //List<int> dataSizes = List.generate(blockCount, (index) => symbolInfo.getDataLengthForInterleavedBlock(index + 1));
    final errorSizes = List.generate(
      blockCount,
      (index) => symbolInfo.getErrorLengthForInterleavedBlock(index + 1),
    );

    for (int block = 0; block < blockCount; block++) {
      final temp = StringBuffer();
      for (int d = block; d < symbolInfo.dataCapacity; d += blockCount) {
        temp.write(codewords[d]);
      }
      final ecc = _createECCBlock(temp.toString(), errorSizes[block]);
      int pos = 0;
      for (int e = block;
          e < errorSizes[block] * blockCount;
          e += blockCount) {
        sb.setCharAt(symbolInfo.dataCapacity + e, ecc[pos++]);
      }
    }
  }
  return sb.toString();
}