Method isValidFieldLayout

Source/Structs/StructDef.cpp:58–115

}

bool StructDef::isValidFieldLayout(u32 length, QVector<FieldDef*> fields)
{
  const size_t segbitsize = sizeof(uint64_t) * 8;
  const size_t structSegments = static_cast<size_t>(ceil(static_cast<float>(length) / segbitsize));
  uint64_t* structBytes = new uint64_t[structSegments];
  for (size_t i = 0; i < structSegments; i++)
  {
    structBytes[i] = 0;
  }

  for (FieldDef* field : fields)
  {
    size_t fieldOffset = field->getOffset();
    size_t fieldLength = static_cast<size_t>(field->getFieldSize());
    if (fieldOffset + fieldLength > length)
    {
      return false;
    }

    size_t firstSegment = static_cast<size_t>(floor(static_cast<float>(fieldOffset) / segbitsize));
    size_t lastSegment =
        static_cast<size_t>(floor(static_cast<float>(fieldOffset + fieldLength) / segbitsize));

    size_t lengthChecked = 0;
    for (size_t i = firstSegment; i <= lastSegment; i++)
    {
      uint64_t entryByteMask = 0ULL;
      if (i == firstSegment)
      {
        size_t maskLength = std::min(fieldLength, (segbitsize - fieldOffset % segbitsize));
        if (maskLength == 0x40)
          entryByteMask--;
        else
          entryByteMask = ((1ULL << (maskLength)) - 1) << fieldOffset;
        lengthChecked += maskLength;
      }
      else if (i == lastSegment)
      {
        entryByteMask = ((1ULL << (fieldLength - lengthChecked)) - 1);
        lengthChecked += (fieldLength - lengthChecked);
      }
      else
      {
        entryByteMask--;
        lengthChecked += segbitsize;
      }

      if (structBytes[i] & entryByteMask)
      {
        return false;
      }

      structBytes[i] ^= entryByteMask;
    }
  }

  return true;
}