--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/zxing-cpp/core/src/ReedSolomonEncoder.cpp	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,54 @@
+/*
+* Copyright 2016 Huy Cuong Nguyen
+* Copyright 2016 ZXing authors
+*/
+// SPDX-License-Identifier: Apache-2.0
+
+#include "ReedSolomonEncoder.h"
+
+#include "GenericGF.h"
+
+#include <algorithm>
+#include <iterator>
+#include <stdexcept>
+
+namespace ZXing {
+
+ReedSolomonEncoder::ReedSolomonEncoder(const GenericGF& field)
+: _field(&field)
+{
+	_cachedGenerators.push_back(GenericGFPoly(field, { 1 }));
+}
+
+const GenericGFPoly&
+ReedSolomonEncoder::buildGenerator(int degree)
+{
+	int cachedGenSize = Size(_cachedGenerators);
+	if (degree >= cachedGenSize) {
+		GenericGFPoly lastGenerator = _cachedGenerators.back();
+		for (int d = cachedGenSize; d <= degree; d++) {
+			lastGenerator.multiply(GenericGFPoly(*_field, { 1, _field->exp(d - 1 + _field->generatorBase()) }));
+			_cachedGenerators.push_back(lastGenerator);
+		}
+	}
+
+	return *std::next(_cachedGenerators.begin(), degree);
+}
+
+void
+ReedSolomonEncoder::encode(std::vector<int>& message, const int numECCodeWords)
+{
+	if (numECCodeWords == 0 || numECCodeWords >= Size(message))
+		throw std::invalid_argument("Invalid number of error correction code words");
+
+	GenericGFPoly info = GenericGFPoly(*_field, std::vector<int>(message.begin(), message.end() - numECCodeWords));
+	info.multiplyByMonomial(1, numECCodeWords);
+	GenericGFPoly _;
+	info.divide(buildGenerator(numECCodeWords), _);
+	auto& coefficients = info.coefficients();
+	int numZeroCoefficients = numECCodeWords - Size(coefficients);
+	std::fill_n(message.end() - numECCodeWords, numZeroCoefficients, 0);
+	std::copy(coefficients.begin(), coefficients.end(), message.end() - numECCodeWords + numZeroCoefficients);
+}
+
+} // ZXing