text: #pragma once
  /*
  * Copyright 2016 Nu-book Inc.
  * Copyright 2016 ZXing authors
  *
  * 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 "BitArray.h"
  #include "DecodeStatus.h"
  
  #include <cstddef>
  #include <memory>
  
  namespace ZXing {
  
  class Result;
  
  namespace OneD {
  
  /**
  * Encapsulates functionality and implementation that is common to all families
  * of one-dimensional barcodes.
  *
  * @author dswitkin@google.com (Daniel Switkin)
  * @author Sean Owen
  */
  class RowReader
  {
  public:
  
  	struct DecodingState
  	{
  		virtual ~DecodingState() {}
  	};
  
  	Result decodeSingleRow(int rowNumber, const BitArray& row) const;
  
  	virtual ~RowReader() {}
  
  	/**
  	* <p>Attempts to decode a one-dimensional barcode format given a single row of
  	* an image.</p>
  	*
  	* @param rowNumber row number from top of the row
  	* @param row the black/white pixel data of the row
  	* @param hints decode hints
  	* @return {@link Result} containing encoded string and start/end of barcode
  	* @throws NotFoundException if no potential barcode is found
  	* @throws ChecksumException if a potential barcode is found but does not pass its checksum
  	* @throws FormatException if a potential barcode is found but format is invalid
  	*/
  	virtual Result decodeRow(int rowNumber, const BitArray& row, std::unique_ptr<DecodingState>& state) const = 0;
  
  	/**
  	* Scans the given bit range for a pattern identified by evaluating the function object match for each
  	* successive run of counters.size() bars. If the pattern is found, it returns the bit range with the
  	* pattern. Otherwise an empty range is returned.
  	*
  	* @param begin/end bit range to scan for pattern
  	* @param counters array into which to record counts
  	* @param match predicate that gets evaluated to identify the pattern
  	* @throws NotFoundException if counters cannot be filled entirely from row before running out
  	*  of pixels
  	*/
  	template <typename Iterator, typename Container, typename Predicate>
  	static Range<Iterator> FindPattern(Iterator begin, Iterator end, Container& counters, Predicate match) {
  		if (begin == end)
  			return {end, end};
  
  		Iterator li = begin, i = begin;
  		auto currentCounter = counters.begin();
  		while ((i = BitArray::getNextSetTo(i, end, !*i)) != end) {
  			*currentCounter = i - li;
  			if (++currentCounter == counters.end()) {
  				if (match(begin, i, counters)) {
  					return {begin, i};
  				}
  				std::advance(begin, counters[0] + counters[1]);
  				std::copy(counters.begin() + 2, counters.end(), counters.begin());
  				std::advance(currentCounter, -2);
  			}
  			li = i;
  		}
  		// if we ran into the end, still set the currentCounter. see RecordPattern.
  		*currentCounter = i - li;
  
  		return {end, end};
  	}
  
  	/**
  	* Records the size of successive runs of white and black pixels in a row, starting at a given point.
  	* The values are recorded in the given array, and the number of runs recorded is equal to the size
  	* of the array. If the row starts on a white pixel at the given start point, then the first count
  	* recorded is the run of white pixels starting from that point; likewise it is the count of a run
  	* of black pixels if the row begin on a black pixels at that point.
  	*
  	* @param row row to count from
  	* @param start offset into row to start at
  	* @param counters array into which to record counts
  	* @throws NotFoundException if counters cannot be filled entirely from row before running out
  	*  of pixels
  	*/
  	template <typename Iterator, typename Container>
  	static Range<Iterator> RecordPattern(Iterator begin, Iterator end, Container& counters) {
  		// mark the last counter-slot as empty
  		counters.back() = 0;
  
  		auto range = FindPattern(begin, end, counters, [](Iterator, Iterator, Container&) { return true; });
  
  		// If we reached the end iterator but touched the last counter-slot, we accept the result.
  		if (range.end == end && counters.back() != 0)
  			return {begin, end};
  		else
  			return range;
  	}
  
  	template <typename Iterator, typename Container>
  	static Range<Iterator> RecordPatternInReverse(Iterator begin, Iterator end, Container& counters) {
  		std::reverse_iterator<Iterator> rbegin(end), rend(begin);
  		auto range = RecordPattern(rbegin, rend, counters);
  		std::reverse(counters.begin(), counters.end());
  		return {range.end.base(), range.begin.base()};
  	}
  
  	/**
  	* Determines how closely a set of observed counts of runs of black/white values matches a given
  	* target pattern. This is reported as the ratio of the total variance from the expected pattern
  	* proportions across all pattern elements, to the length of the pattern.
  	*
  	* @param counters observed counters
  	* @param pattern expected pattern
  	* @param maxIndividualVariance The most any counter can differ before we give up
  	* @return ratio of total variance between counters and pattern compared to total pattern size
  	*/
  	template <typename Container>
  	static float PatternMatchVariance(const Container& counters, const Container& pattern, float maxIndividualVariance) {
  		assert(counters.size() <= pattern.size()); //TODO: this should test for equality, see ODCode128Reader.cpp:93
  		return PatternMatchVariance(counters.data(), pattern.data(), counters.size(), maxIndividualVariance);
  	}
  
  	/**
  	* Attempts to decode a sequence of black/white lines into single
  	* digit.
  	*
  	* @param counters the counts of runs of observed black/white/black/... values
  	* @param patterns the list of patterns to compare the contens of counters to
  	* @param requireUnambiguousMatch the 'best match' must be better than all other matches
  	* @return The decoded digit index, -1 if no pattern matched
  	*/
  	template <typename Patterns, typename Counters>
  	static int DecodeDigit(const Counters& counters, const Patterns& patterns, float maxAvgVariance,
  						   float maxIndividualVariance, bool requireUnambiguousMatch = true)
  	{
  		float bestVariance = maxAvgVariance; // worst variance we'll accept
  		constexpr int INVALID_MATCH = -1;
  		int bestMatch = INVALID_MATCH;
  		for (size_t i = 0; i < patterns.size(); i++) {
  			float variance = PatternMatchVariance(counters, patterns[i], maxIndividualVariance);
  			if (variance < bestVariance) {
  				bestVariance = variance;
  				bestMatch = static_cast<int>(i);
  			} else if (requireUnambiguousMatch && variance == bestVariance) {
  				// if we find a second 'best match' with the same variance, we can not reliably report to have a suitable match
  				bestMatch = INVALID_MATCH;
  			}
  		}
  		return bestMatch;
  	}
  
  public:
  	static float PatternMatchVariance(const int *counters, const int* pattern, size_t length, float maxIndividualVariance);
  };
  
  } // OneD
  } // ZXing
  