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diff --git a/intl/icu/source/i18n/collationweights.h b/intl/icu/source/i18n/collationweights.h
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+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*  
+*******************************************************************************
+*
+*   Copyright (C) 1999-2014, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+*
+*******************************************************************************
+*   file name:  collationweights.h
+*   encoding:   UTF-8
+*   tab size:   8 (not used)
+*   indentation:4
+*
+*   created on: 2001mar08 as ucol_wgt.h
+*   created by: Markus W. Scherer
+*/
+
+#ifndef __COLLATIONWEIGHTS_H__
+#define __COLLATIONWEIGHTS_H__
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_COLLATION
+
+#include "unicode/uobject.h"
+
+U_NAMESPACE_BEGIN
+
+/**
+ * Allocates n collation element weights between two exclusive limits.
+ * Used only internally by the collation tailoring builder.
+ */
+class U_I18N_API CollationWeights : public UMemory {
+public:
+    CollationWeights();
+
+    static inline int32_t lengthOfWeight(uint32_t weight) {
+        if((weight&0xffffff)==0) {
+            return 1;
+        } else if((weight&0xffff)==0) {
+            return 2;
+        } else if((weight&0xff)==0) {
+            return 3;
+        } else {
+            return 4;
+        }
+    }
+
+    void initForPrimary(UBool compressible);
+    void initForSecondary();
+    void initForTertiary();
+
+    /**
+     * Determine heuristically
+     * what ranges to use for a given number of weights between (excluding)
+     * two limits.
+     *
+     * @param lowerLimit A collation element weight; the ranges will be filled to cover
+     *                   weights greater than this one.
+     * @param upperLimit A collation element weight; the ranges will be filled to cover
+     *                   weights less than this one.
+     * @param n          The number of collation element weights w necessary such that
+     *                   lowerLimit<w<upperLimit in lexical order.
+     * @return true if it is possible to fit n elements between the limits
+     */
+    UBool allocWeights(uint32_t lowerLimit, uint32_t upperLimit, int32_t n);
+
+    /**
+     * Given a set of ranges calculated by allocWeights(),
+     * iterate through the weights.
+     * The ranges are modified to keep the current iteration state.
+     *
+     * @return The next weight in the ranges, or 0xffffffff if there is none left.
+     */
+    uint32_t nextWeight();
+
+    /** @internal */
+    struct WeightRange {
+        uint32_t start, end;
+        int32_t length, count;
+    };
+
+private:
+    /** @return number of usable byte values for byte idx */
+    inline int32_t countBytes(int32_t idx) const {
+        return (int32_t)(maxBytes[idx] - minBytes[idx] + 1);
+    }
+
+    uint32_t incWeight(uint32_t weight, int32_t length) const;
+    uint32_t incWeightByOffset(uint32_t weight, int32_t length, int32_t offset) const;
+    void lengthenRange(WeightRange &range) const;
+    /**
+     * Takes two CE weights and calculates the
+     * possible ranges of weights between the two limits, excluding them.
+     * For weights with up to 4 bytes there are up to 2*4-1=7 ranges.
+     */
+    UBool getWeightRanges(uint32_t lowerLimit, uint32_t upperLimit);
+    UBool allocWeightsInShortRanges(int32_t n, int32_t minLength);
+    UBool allocWeightsInMinLengthRanges(int32_t n, int32_t minLength);
+
+    int32_t middleLength;
+    uint32_t minBytes[5];  // for byte 1, 2, 3, 4
+    uint32_t maxBytes[5];
+    WeightRange ranges[7];
+    int32_t rangeIndex;
+    int32_t rangeCount;
+};
+
+U_NAMESPACE_END
+
+#endif  // !UCONFIG_NO_COLLATION
+#endif  // __COLLATIONWEIGHTS_H__