87 lines
2.3 KiB
C++
87 lines
2.3 KiB
C++
/*
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* Copyright 2016 Nu-book Inc.
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* Copyright 2016 ZXing authors
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*/
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// SPDX-License-Identifier: Apache-2.0
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#include "ODITFReader.h"
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#include "ReaderOptions.h"
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#include "GTIN.h"
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#include "Barcode.h"
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#include "ZXAlgorithms.h"
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namespace ZXing::OneD {
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Barcode ITFReader::decodePattern(int rowNumber, PatternView& next, std::unique_ptr<DecodingState>&) const
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{
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const int minCharCount = 6;
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const int minQuietZone = 6; // spec requires 10
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next = FindLeftGuard(next, 4 + minCharCount/2 + 3, FixedPattern<4, 4>{1, 1, 1, 1}, minQuietZone);
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if (!next.isValid())
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return {};
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// get threshold of first character pair
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auto threshold = NarrowWideThreshold(next.subView(4, 10));
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if (!threshold.isValid())
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return {};
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// check that each bar/space in the start pattern is < threshold
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for (int i = 0; i < 4; ++i)
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if (next[i] > threshold[i])
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return {};
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constexpr int weights[] = {1, 2, 4, 7, 0};
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int xStart = next.pixelsInFront();
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next = next.subView(4, 10);
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std::string txt;
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txt.reserve(20);
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while (next.isValid()) {
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threshold = NarrowWideThreshold(next);
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if (!threshold.isValid())
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break;
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BarAndSpace<int> digits, numWide;
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for (int i = 0; i < 10; ++i) {
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if (next[i] > threshold[i] * 2)
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break;
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numWide[i] += next[i] > threshold[i];
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digits[i] += weights[i/2] * (next[i] > threshold[i]);
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}
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if (numWide.bar != 2 || numWide.space != 2)
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break;
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for (int i = 0; i < 2; ++i)
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txt.push_back(ToDigit(digits[i] == 11 ? 0 : digits[i]));
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next.skipSymbol();
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}
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next = next.subView(0, 3);
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if (Size(txt) < minCharCount || !next.isValid())
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return {};
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// Check quiet zone size
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if (!(next.isAtLastBar() || next[3] > minQuietZone * (threshold.bar + threshold.space) / 3))
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return {};
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// Check stop pattern
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if (next[0] < threshold[0] || next[1] > threshold[1] || next[2] > threshold[2])
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return {};
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Error error = _opts.validateITFCheckSum() && !GTIN::IsCheckDigitValid(txt) ? ChecksumError() : Error();
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// Symbology identifier ISO/IEC 16390:2007 Annex C Table C.1
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// See also GS1 General Specifications 5.1.2 Figure 5.1.2-2
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SymbologyIdentifier symbologyIdentifier = {'I', GTIN::IsCheckDigitValid(txt) ? '1' : '0'};
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int xStop = next.pixelsTillEnd();
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return Barcode(txt, rowNumber, xStart, xStop, BarcodeFormat::ITF, symbologyIdentifier, error);
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}
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} // namespace ZXing::OneD
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