Method decodePattern

czxing/src/main/cpp/zxing/src/oned/ODDataBarReader.cpp:153–212

};

Result DataBarReader::decodePattern(int rowNumber, PatternView& next,
									std::unique_ptr<RowReader::DecodingState>& state) const
{
#if 0 // non-stacked version
	next = next.subView(-1, FULL_PAIR_SIZE + 1); // +1 reflects the guard pattern on the right, see IsRightPair());
	// yes: the first view we test is at index 1 (black bar at 0 would be the guard pattern)
	while (next.shift(2)) {
		if (IsLeftPair(next)) {
			if (auto leftPair = ReadPair(next, false); leftPair && next.shift(FULL_PAIR_SIZE) && IsRightPair(next)) {
				if (auto rightPair = ReadPair(next, true); rightPair && ChecksumIsValid(leftPair, rightPair)) {
					return {ConstructText(leftPair, rightPair), rowNumber, leftPair.xStart, rightPair.xStop,
							BarcodeFormat::DataBar};
				}
			}
		}
	}
#else
	if (!state)
		state.reset(new State);
	auto* prevState = static_cast<State*>(state.get());

	next = next.subView(0, FULL_PAIR_SIZE + 1); // +1 reflects the guard pattern on the right, see IsRightPair()
	// yes: the first view we test is at index 1 (black bar at 0 would be the guard pattern)
	while (next.shift(1)) {
		if (IsLeftPair(next)) {
			if (auto leftPair = ReadPair(next, false)) {
				leftPair.y = rowNumber;
				prevState->leftPairs.insert(leftPair);
				next.shift(FULL_PAIR_SIZE - 1);
			}
		}

		if (next.shift(1) && IsRightPair(next)) {
			if (auto rightPair = ReadPair(next, true)) {
				rightPair.y = rowNumber;
				prevState->rightPairs.insert(rightPair);
				next.shift(FULL_PAIR_SIZE + 2);
			}
		}
	}

	for (const auto& leftPair : prevState->leftPairs)
		for (const auto& rightPair : prevState->rightPairs)
			if (ChecksumIsValid(leftPair, rightPair)) {
				// Symbology identifier ISO/IEC 24724:2011 Section 9 and GS1 General Specifications 5.1.3 Figure 5.1.3-2
				Result res{DecoderResult(Content(ByteArray(ConstructText(leftPair, rightPair)), {'e', '0'}))
							   .setLineCount(EstimateLineCount(leftPair, rightPair)),
						   EstimatePosition(leftPair, rightPair), BarcodeFormat::DataBar};

				prevState->leftPairs.erase(leftPair);
				prevState->rightPairs.erase(rightPair);
				return res;
			}
#endif

	// guarantee progress (see loop in ODReader.cpp)
	next = {};