--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/zxing-cpp/core/src/GTIN.h	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,52 @@
+/*
+* Copyright 2016 Nu-book Inc.
+* Copyright 2016 ZXing authors
+* Copyright 2020 Axel Waggershauser
+*/
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include "Barcode.h"
+#include "BarcodeFormat.h"
+#include "ZXAlgorithms.h"
+
+#include <string>
+
+namespace ZXing::GTIN {
+
+template <typename T>
+T ComputeCheckDigit(const std::basic_string<T>& digits, bool skipTail = false)
+{
+	int sum = 0, N = Size(digits) - skipTail;
+	for (int i = N - 1; i >= 0; i -= 2)
+		sum += digits[i] - '0';
+	sum *= 3;
+	for (int i = N - 2; i >= 0; i -= 2)
+		sum += digits[i] - '0';
+	return ToDigit<T>((10 - (sum % 10)) % 10);
+}
+
+template <typename T>
+bool IsCheckDigitValid(const std::basic_string<T>& s)
+{
+	return ComputeCheckDigit(s, true) == s.back();
+}
+
+/**
+ * Evaluate the prefix of the GTIN to estimate the country of origin. See
+ * <a href="https://www.gs1.org/standards/id-keys/company-prefix">
+ * https://www.gs1.org/standards/id-keys/company-prefix</a> and
+ * <a href="https://en.wikipedia.org/wiki/List_of_GS1_country_codes">
+ * https://en.wikipedia.org/wiki/List_of_GS1_country_codes</a>.
+ *
+ * `format` required for EAN-8 (UPC-E assumed if not given)
+ */
+std::string LookupCountryIdentifier(const std::string& GTIN, const BarcodeFormat format = BarcodeFormat::None);
+
+std::string EanAddOn(const Barcode& barcode);
+
+std::string IssueNr(const std::string& ean2AddOn);
+std::string Price(const std::string& ean5AddOn);
+
+} // namespace ZXing::GTIN