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diff --git a/intl/icu/source/common/lsr.h b/intl/icu/source/common/lsr.h
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+++ b/intl/icu/source/common/lsr.h
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+// © 2019 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+
+// lsr.h
+// created: 2019may08 Markus W. Scherer
+
+#ifndef __LSR_H__
+#define __LSR_H__
+
+#include "unicode/utypes.h"
+#include "unicode/uobject.h"
+#include "cstring.h"
+
+U_NAMESPACE_BEGIN
+
+struct LSR final : public UMemory {
+    static constexpr int32_t REGION_INDEX_LIMIT = 1001 + 26 * 26;
+
+    static constexpr int32_t EXPLICIT_LSR = 7;
+    static constexpr int32_t EXPLICIT_LANGUAGE = 4;
+    static constexpr int32_t EXPLICIT_SCRIPT = 2;
+    static constexpr int32_t EXPLICIT_REGION = 1;
+    static constexpr int32_t IMPLICIT_LSR = 0;
+    static constexpr int32_t DONT_CARE_FLAGS = 0;
+
+    const char *language;
+    const char *script;
+    const char *region;
+    char *owned = nullptr;
+    /** Index for region, 0 if ill-formed. @see indexForRegion */
+    int32_t regionIndex = 0;
+    int32_t flags = 0;
+    /** Only set for LSRs that will be used in a hash table. */
+    int32_t hashCode = 0;
+
+    LSR() : language("und"), script(""), region("") {}
+
+    /** Constructor which aliases all subtag pointers. */
+    LSR(const char *lang, const char *scr, const char *r, int32_t f) :
+            language(lang),  script(scr), region(r),
+            regionIndex(indexForRegion(region)), flags(f) {}
+    /**
+     * Constructor which prepends the prefix to the language and script,
+     * copies those into owned memory, and aliases the region.
+     */
+    LSR(char prefix, const char *lang, const char *scr, const char *r, int32_t f,
+        UErrorCode &errorCode);
+    LSR(LSR &&other) noexcept;
+    LSR(const LSR &other) = delete;
+    inline ~LSR() {
+        // Pure inline code for almost all instances.
+        if (owned != nullptr) {
+            deleteOwned();
+        }
+    }
+
+    LSR &operator=(LSR &&other) noexcept;
+    LSR &operator=(const LSR &other) = delete;
+
+    /**
+     * Returns a positive index (>0) for a well-formed region code.
+     * Do not rely on a particular region->index mapping; it may change.
+     * Returns 0 for ill-formed strings.
+     */
+    static int32_t indexForRegion(const char *region);
+
+    UBool isEquivalentTo(const LSR &other) const;
+    bool operator==(const LSR &other) const;
+
+    inline bool operator!=(const LSR &other) const {
+        return !operator==(other);
+    }
+
+    LSR &setHashCode();
+
+private:
+    void deleteOwned();
+};
+
+U_NAMESPACE_END
+
+#endif  // __LSR_H__