/src/icu/source/i18n/measunit_impl.h

Source (jump to first uncovered line)
// © 2020 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html

#ifndef __MEASUNIT_IMPL_H__
#define __MEASUNIT_IMPL_H__

#include "unicode/utypes.h"

#if !UCONFIG_NO_FORMATTING

#include "unicode/measunit.h"
#include "cmemory.h"
#include "charstr.h"

U_NAMESPACE_BEGIN

namespace number {
namespace impl {
class LongNameHandler;
}
} // namespace number

static const char16_t kDefaultCurrency[] = u"XXX";
static const char kDefaultCurrency8[] = "XXX";

/**
 * Looks up the "unitQuantity" (aka "type" or "category") of a base unit
 * identifier. The category is returned via `result`, which must initially be
 * empty.
 *
 * This only supports base units: other units must be resolved to base units
 * before passing to this function, otherwise U_UNSUPPORTED_ERROR status will be
 * returned.
 *
 * Categories are found in `unitQuantities` in the `units` resource (see
 * `units.txt`).
 */
CharString U_I18N_API getUnitQuantity(StringPiece baseUnitIdentifier, UErrorCode &status);

/**
 * A struct representing a single unit (optional SI or binary prefix, and dimensionality).
 */
struct U_I18N_API SingleUnitImpl : public UMemory {
    /**
     * Gets a single unit from the MeasureUnit. If there are multiple single units, sets an error
     * code and returns the base dimensionless unit. Parses if necessary.
     */
    static SingleUnitImpl forMeasureUnit(const MeasureUnit& measureUnit, UErrorCode& status);

    /** Transform this SingleUnitImpl into a MeasureUnit, simplifying if possible. */
    MeasureUnit build(UErrorCode& status) const;

    /**
     * Returns the "simple unit ID", without SI or dimensionality prefix: this
     * instance may represent a square-kilometer, but only "meter" will be
     * returned.
     *
     * The returned pointer points at memory that exists for the duration of the
     * program's running.
     */
    const char *getSimpleUnitID() const;

    /**
     * Generates and append a neutral identifier string for a single unit which means we do not include
     * the dimension signal.
     */
    void appendNeutralIdentifier(CharString &result, UErrorCode &status) const;

    /**
     * Returns the index of this unit's "quantity" in unitQuantities (in
     * measunit_extra.cpp). The value of this index determines sort order for
     * normalization of unit identifiers.
     */
    int32_t getUnitCategoryIndex() const;

    /**
     * Compare this SingleUnitImpl to another SingleUnitImpl for the sake of
     * sorting and coalescing.
     *
     * Sort order of units is specified by UTS #35
     * (https://unicode.org/reports/tr35/tr35-info.html#Unit_Identifier_Normalization).
     *
     * Takes the sign of dimensionality into account, but not the absolute
     * value: per-meter is not considered the same as meter, but meter is
     * considered the same as square-meter.
     *
     * The dimensionless unit generally does not get compared, but if it did, it
     * would sort before other units by virtue of index being < 0 and
     * dimensionality not being negative.
     */
    int32_t compareTo(const SingleUnitImpl& other) const {
        if (dimensionality < 0 && other.dimensionality > 0) {
            // Positive dimensions first
            return 1;
        }
        if (dimensionality > 0 && other.dimensionality < 0) {
            return -1;
        }
        // Sort by official quantity order
        int32_t thisQuantity = this->getUnitCategoryIndex();
        int32_t otherQuantity = other.getUnitCategoryIndex();
        if (thisQuantity < otherQuantity) {
            return -1;
        }
        if (thisQuantity > otherQuantity) {
            return 1;
        }
        // If quantity order didn't help, then we go by index.
        if (index < other.index) {
            return -1;
        }
        if (index > other.index) {
            return 1;
        }
        // TODO: revisit if the spec dictates prefix sort order - it doesn't
        // currently. For now we're sorting binary prefixes before SI prefixes,
        // as per enum values order.
        if (unitPrefix < other.unitPrefix) {
            return -1;
        }
        if (unitPrefix > other.unitPrefix) {
            return 1;
        }
        return 0;
    }

    /**
     * Return whether this SingleUnitImpl is compatible with another for the purpose of coalescing.
     *
     * Units with the same base unit and SI or binary prefix should match, except that they must also
     * have the same dimensionality sign, such that we don't merge numerator and denominator.
     */
    bool isCompatibleWith(const SingleUnitImpl& other) const {
        return (compareTo(other) == 0);
    }

    /**
     * Returns true if this unit is the "dimensionless base unit", as produced
     * by the MeasureUnit() default constructor. (This does not include the
     * likes of concentrations or angles.)
     */
    bool isDimensionless() const {
        return index == -1;
    }

    /**
     * Simple unit index, unique for every simple unit, -1 for the dimensionless
     * unit. This is an index into a string list in measunit_extra.cpp, as
     * loaded by SimpleUnitIdentifiersSink.
     *
     * The default value is -1, meaning the dimensionless unit:
     * isDimensionless() will return true, until index is changed.
     */
    int32_t index = -1;

    /**
     * SI or binary prefix.
     *
     * This is ignored for the dimensionless unit.
     */
    UMeasurePrefix unitPrefix = UMEASURE_PREFIX_ONE;

    /**
     * Dimensionality.
     *
     * This is meaningless for the dimensionless unit.
     */
    int32_t dimensionality = 1;
};

// Forward declaration
struct MeasureUnitImplWithIndex;

// Export explicit template instantiations of MaybeStackArray, MemoryPool and
// MaybeStackVector. This is required when building DLLs for Windows. (See
// datefmt.h, collationiterator.h, erarules.h and others for similar examples.)
#if U_PF_WINDOWS <= U_PLATFORM && U_PLATFORM <= U_PF_CYGWIN
template class U_I18N_API MaybeStackArray<SingleUnitImpl *, 8>;
template class U_I18N_API MemoryPool<SingleUnitImpl, 8>;
template class U_I18N_API MaybeStackVector<SingleUnitImpl, 8>;
#endif

/**
 * Internal representation of measurement units. Capable of representing all complexities of units,
 * including mixed and compound units.
 */
class U_I18N_API MeasureUnitImpl : public UMemory {
  public:
    MeasureUnitImpl() = default;
    MeasureUnitImpl(MeasureUnitImpl &&other) = default;
    // No copy constructor, use MeasureUnitImpl::copy() to make it explicit.
    MeasureUnitImpl(const MeasureUnitImpl &other, UErrorCode &status) = delete;
    MeasureUnitImpl(const SingleUnitImpl &singleUnit, UErrorCode &status);

    MeasureUnitImpl &operator=(MeasureUnitImpl &&other) noexcept = default;

    /** Extract the MeasureUnitImpl from a MeasureUnit. */
    static inline const MeasureUnitImpl *get(const MeasureUnit &measureUnit) {
        return measureUnit.fImpl;
    }

    /**
     * Parse a unit identifier into a MeasureUnitImpl.
     *
     * @param identifier The unit identifier string.
     * @param status Set if the identifier string is not valid.
     * @return A newly parsed value object. Behaviour of this unit is
     * unspecified if an error is returned via status.
     */
    static MeasureUnitImpl forIdentifier(StringPiece identifier, UErrorCode& status);

    /**
     * Extract the MeasureUnitImpl from a MeasureUnit, or parse if it is not present.
     * 
     * @param measureUnit The source MeasureUnit.
     * @param memory A place to write the new MeasureUnitImpl if parsing is required.
     * @param status Set if an error occurs.
     * @return A reference to either measureUnit.fImpl or memory.
     */
    static const MeasureUnitImpl& forMeasureUnit(
        const MeasureUnit& measureUnit, MeasureUnitImpl& memory, UErrorCode& status);

    /**
     * Extract the MeasureUnitImpl from a MeasureUnit, or parse if it is not present.
     *
     * @param measureUnit The source MeasureUnit.
     * @param status Set if an error occurs.
     * @return A value object, either newly parsed or copied from measureUnit.
     */
    static MeasureUnitImpl forMeasureUnitMaybeCopy(
        const MeasureUnit& measureUnit, UErrorCode& status);

    /**
     * Used for currency units.
     */
    static inline MeasureUnitImpl forCurrencyCode(StringPiece currencyCode) {
        MeasureUnitImpl result;
        UErrorCode localStatus = U_ZERO_ERROR;
        result.identifier.append(currencyCode, localStatus);
        // localStatus is not expected to fail since currencyCode should be 3 chars long
        return result;
    }

    /** Transform this MeasureUnitImpl into a MeasureUnit, simplifying if possible. */
    MeasureUnit build(UErrorCode& status) &&;

    /**
     * Create a copy of this MeasureUnitImpl. Don't use copy constructor to make this explicit.
     */
    MeasureUnitImpl copy(UErrorCode& status) const;

    /**
     * Extracts the list of all the individual units inside the `MeasureUnitImpl` with their indices.
     *      For example:    
     *          -   if the `MeasureUnitImpl` is `foot-per-hour`
     *                  it will return a list of 1 {(0, `foot-per-hour`)} 
     *          -   if the `MeasureUnitImpl` is `foot-and-inch` 
     *                  it will return a list of 2 {(0, `foot`), (1, `inch`)}
     */
    MaybeStackVector<MeasureUnitImplWithIndex>
    extractIndividualUnitsWithIndices(UErrorCode &status) const;

    /** Mutates this MeasureUnitImpl to take the reciprocal. */
    void takeReciprocal(UErrorCode& status);

    /**
     * Mutates this MeasureUnitImpl to append a single unit.
     *
     * @return true if a new item was added. If unit is the dimensionless unit,
     * it is never added: the return value will always be false.
     */
    bool appendSingleUnit(const SingleUnitImpl& singleUnit, UErrorCode& status);

    /** The complexity, either SINGLE, COMPOUND, or MIXED. */
    UMeasureUnitComplexity complexity = UMEASURE_UNIT_SINGLE;

    /**
     * The list of single units. These may be summed or multiplied, based on the
     * value of the complexity field.
     *
     * The "dimensionless" unit (SingleUnitImpl default constructor) must not be
     * added to this list.
     */
    MaybeStackVector<SingleUnitImpl> singleUnits;

    /**
     * The full unit identifier.  Owned by the MeasureUnitImpl.  Empty if not computed.
     */
    CharString identifier;

  private:
    /**
     * Normalizes a MeasureUnitImpl and generate the identifier string in place.
     */
    void serialize(UErrorCode &status);

    // For calling serialize
    // TODO(icu-units#147): revisit serialization
    friend class number::impl::LongNameHandler;
};

struct U_I18N_API MeasureUnitImplWithIndex : public UMemory {
    const int32_t index;
    MeasureUnitImpl unitImpl;
    // Makes a copy of unitImpl.
    MeasureUnitImplWithIndex(int32_t index, const MeasureUnitImpl &unitImpl, UErrorCode &status)
        : index(index), unitImpl(unitImpl.copy(status)) {
    }
    MeasureUnitImplWithIndex(int32_t index, const SingleUnitImpl &singleUnitImpl, UErrorCode &status)
        : index(index), unitImpl(MeasureUnitImpl(singleUnitImpl, status)) {
    }
};

// Export explicit template instantiations of MaybeStackArray, MemoryPool and
// MaybeStackVector. This is required when building DLLs for Windows. (See
// datefmt.h, collationiterator.h, erarules.h and others for similar examples.)
#if U_PF_WINDOWS <= U_PLATFORM && U_PLATFORM <= U_PF_CYGWIN
template class U_I18N_API MaybeStackArray<MeasureUnitImplWithIndex *, 8>;
template class U_I18N_API MemoryPool<MeasureUnitImplWithIndex, 8>;
template class U_I18N_API MaybeStackVector<MeasureUnitImplWithIndex, 8>;

// Export an explicit template instantiation of the LocalPointer that is used as a
// data member of MeasureUnitImpl.
// (When building DLLs for Windows this is required.)
#if defined(_MSC_VER)
// Ignore warning 4661 as LocalPointerBase does not use operator== or operator!=
#pragma warning(push)
#pragma warning(disable : 4661)
#endif
template class U_I18N_API LocalPointerBase<MeasureUnitImpl>;
template class U_I18N_API LocalPointer<MeasureUnitImpl>;
#if defined(_MSC_VER)
#pragma warning(pop)
#endif
#endif

U_NAMESPACE_END

#endif /* #if !UCONFIG_NO_FORMATTING */
#endif //__MEASUNIT_IMPL_H__

Coverage Report

Created: 2025-06-24 06:43

Line	Count	Source (jump to first uncovered line)
1		// © 2020 and later: Unicode, Inc. and others.
2		// License & terms of use: http://www.unicode.org/copyright.html
3
4		#ifndef __MEASUNIT_IMPL_H__
5		#define __MEASUNIT_IMPL_H__
6
7		#include "unicode/utypes.h"
8
9		#if !UCONFIG_NO_FORMATTING
10
11		#include "unicode/measunit.h"
12		#include "cmemory.h"
13		#include "charstr.h"
14
15		U_NAMESPACE_BEGIN
16
17		namespace number {
18		namespace impl {
19		class LongNameHandler;
20		}
21		} // namespace number
22
23		static const char16_t kDefaultCurrency[] = u"XXX";
24		static const char kDefaultCurrency8[] = "XXX";
25
26		/**
27		* Looks up the "unitQuantity" (aka "type" or "category") of a base unit
28		* identifier. The category is returned via `result`, which must initially be
29		* empty.
30		*
31		* This only supports base units: other units must be resolved to base units
32		* before passing to this function, otherwise U_UNSUPPORTED_ERROR status will be
33		* returned.
34		*
35		* Categories are found in `unitQuantities` in the `units` resource (see
36		* `units.txt`).
37		*/
38		CharString U_I18N_API getUnitQuantity(StringPiece baseUnitIdentifier, UErrorCode &status);
39
40		/**
41		* A struct representing a single unit (optional SI or binary prefix, and dimensionality).
42		*/
43		struct U_I18N_API SingleUnitImpl : public UMemory {
44		/**
45		* Gets a single unit from the MeasureUnit. If there are multiple single units, sets an error
46		* code and returns the base dimensionless unit. Parses if necessary.
47		*/
48		static SingleUnitImpl forMeasureUnit(const MeasureUnit& measureUnit, UErrorCode& status);
49
50		/** Transform this SingleUnitImpl into a MeasureUnit, simplifying if possible. */
51		MeasureUnit build(UErrorCode& status) const;
52
53		/**
54		* Returns the "simple unit ID", without SI or dimensionality prefix: this
55		* instance may represent a square-kilometer, but only "meter" will be
56		* returned.
57		*
58		* The returned pointer points at memory that exists for the duration of the
59		* program's running.
60		*/
61		const char *getSimpleUnitID() const;
62
63		/**
64		* Generates and append a neutral identifier string for a single unit which means we do not include
65		* the dimension signal.
66		*/
67		void appendNeutralIdentifier(CharString &result, UErrorCode &status) const;
68
69		/**
70		* Returns the index of this unit's "quantity" in unitQuantities (in
71		* measunit_extra.cpp). The value of this index determines sort order for
72		* normalization of unit identifiers.
73		*/
74		int32_t getUnitCategoryIndex() const;
75
76		/**
77		* Compare this SingleUnitImpl to another SingleUnitImpl for the sake of
78		* sorting and coalescing.
79		*
80		* Sort order of units is specified by UTS #35
81		* (https://unicode.org/reports/tr35/tr35-info.html#Unit_Identifier_Normalization).
82		*
83		* Takes the sign of dimensionality into account, but not the absolute
84		* value: per-meter is not considered the same as meter, but meter is
85		* considered the same as square-meter.
86		*
87		* The dimensionless unit generally does not get compared, but if it did, it
88		* would sort before other units by virtue of index being < 0 and
89		* dimensionality not being negative.
90		*/
91	0	int32_t compareTo(const SingleUnitImpl& other) const {
92	0	if (dimensionality < 0 && other.dimensionality > 0) {
93		// Positive dimensions first
94	0	return 1;
95	0	}
96	0	if (dimensionality > 0 && other.dimensionality < 0) {
97	0	return -1;
98	0	}
99		// Sort by official quantity order
100	0	int32_t thisQuantity = this->getUnitCategoryIndex();
101	0	int32_t otherQuantity = other.getUnitCategoryIndex();
102	0	if (thisQuantity < otherQuantity) {
103	0	return -1;
104	0	}
105	0	if (thisQuantity > otherQuantity) {
106	0	return 1;
107	0	}
108		// If quantity order didn't help, then we go by index.
109	0	if (index < other.index) {
110	0	return -1;
111	0	}
112	0	if (index > other.index) {
113	0	return 1;
114	0	}
115		// TODO: revisit if the spec dictates prefix sort order - it doesn't
116		// currently. For now we're sorting binary prefixes before SI prefixes,
117		// as per enum values order.
118	0	if (unitPrefix < other.unitPrefix) {
119	0	return -1;
120	0	}
121	0	if (unitPrefix > other.unitPrefix) {
122	0	return 1;
123	0	}
124	0	return 0;
125	0	}
126
127		/**
128		* Return whether this SingleUnitImpl is compatible with another for the purpose of coalescing.
129		*
130		* Units with the same base unit and SI or binary prefix should match, except that they must also
131		* have the same dimensionality sign, such that we don't merge numerator and denominator.
132		*/
133	0	bool isCompatibleWith(const SingleUnitImpl& other) const {
134	0	return (compareTo(other) == 0);
135	0	}
136
137		/**
138		* Returns true if this unit is the "dimensionless base unit", as produced
139		* by the MeasureUnit() default constructor. (This does not include the
140		* likes of concentrations or angles.)
141		*/
142	0	bool isDimensionless() const {
143	0	return index == -1;
144	0	}
145
146		/**
147		* Simple unit index, unique for every simple unit, -1 for the dimensionless
148		* unit. This is an index into a string list in measunit_extra.cpp, as
149		* loaded by SimpleUnitIdentifiersSink.
150		*
151		* The default value is -1, meaning the dimensionless unit:
152		* isDimensionless() will return true, until index is changed.
153		*/
154		int32_t index = -1;
155
156		/**
157		* SI or binary prefix.
158		*
159		* This is ignored for the dimensionless unit.
160		*/
161		UMeasurePrefix unitPrefix = UMEASURE_PREFIX_ONE;
162
163		/**
164		* Dimensionality.
165		*
166		* This is meaningless for the dimensionless unit.
167		*/
168		int32_t dimensionality = 1;
169		};
170
171		// Forward declaration
172		struct MeasureUnitImplWithIndex;
173
174		// Export explicit template instantiations of MaybeStackArray, MemoryPool and
175		// MaybeStackVector. This is required when building DLLs for Windows. (See
176		// datefmt.h, collationiterator.h, erarules.h and others for similar examples.)
177		#if U_PF_WINDOWS <= U_PLATFORM && U_PLATFORM <= U_PF_CYGWIN
178		template class U_I18N_API MaybeStackArray<SingleUnitImpl *, 8>;
179		template class U_I18N_API MemoryPool<SingleUnitImpl, 8>;
180		template class U_I18N_API MaybeStackVector<SingleUnitImpl, 8>;
181		#endif
182
183		/**
184		* Internal representation of measurement units. Capable of representing all complexities of units,
185		* including mixed and compound units.
186		*/
187		class U_I18N_API MeasureUnitImpl : public UMemory {
188		public:
189	0	MeasureUnitImpl() = default;
190	0	MeasureUnitImpl(MeasureUnitImpl &&other) = default;
191		// No copy constructor, use MeasureUnitImpl::copy() to make it explicit.
192		MeasureUnitImpl(const MeasureUnitImpl &other, UErrorCode &status) = delete;
193		MeasureUnitImpl(const SingleUnitImpl &singleUnit, UErrorCode &status);
194
195	0	MeasureUnitImpl &operator=(MeasureUnitImpl &&other) noexcept = default;
196
197		/** Extract the MeasureUnitImpl from a MeasureUnit. */
198	0	static inline const MeasureUnitImpl *get(const MeasureUnit &measureUnit) {
199	0	return measureUnit.fImpl;
200	0	}
201
202		/**
203		* Parse a unit identifier into a MeasureUnitImpl.
204		*
205		* @param identifier The unit identifier string.
206		* @param status Set if the identifier string is not valid.
207		* @return A newly parsed value object. Behaviour of this unit is
208		* unspecified if an error is returned via status.
209		*/
210		static MeasureUnitImpl forIdentifier(StringPiece identifier, UErrorCode& status);
211
212		/**
213		* Extract the MeasureUnitImpl from a MeasureUnit, or parse if it is not present.
214		*
215		* @param measureUnit The source MeasureUnit.
216		* @param memory A place to write the new MeasureUnitImpl if parsing is required.
217		* @param status Set if an error occurs.
218		* @return A reference to either measureUnit.fImpl or memory.
219		*/
220		static const MeasureUnitImpl& forMeasureUnit(
221		const MeasureUnit& measureUnit, MeasureUnitImpl& memory, UErrorCode& status);
222
223		/**
224		* Extract the MeasureUnitImpl from a MeasureUnit, or parse if it is not present.
225		*
226		* @param measureUnit The source MeasureUnit.
227		* @param status Set if an error occurs.
228		* @return A value object, either newly parsed or copied from measureUnit.
229		*/
230		static MeasureUnitImpl forMeasureUnitMaybeCopy(
231		const MeasureUnit& measureUnit, UErrorCode& status);
232
233		/**
234		* Used for currency units.
235		*/
236	0	static inline MeasureUnitImpl forCurrencyCode(StringPiece currencyCode) {
237	0	MeasureUnitImpl result;
238	0	UErrorCode localStatus = U_ZERO_ERROR;
239	0	result.identifier.append(currencyCode, localStatus);
240		// localStatus is not expected to fail since currencyCode should be 3 chars long
241	0	return result;
242	0	}
243
244		/** Transform this MeasureUnitImpl into a MeasureUnit, simplifying if possible. */
245		MeasureUnit build(UErrorCode& status) &&;
246
247		/**
248		* Create a copy of this MeasureUnitImpl. Don't use copy constructor to make this explicit.
249		*/
250		MeasureUnitImpl copy(UErrorCode& status) const;
251
252		/**
253		* Extracts the list of all the individual units inside the `MeasureUnitImpl` with their indices.
254		* For example:
255		* - if the `MeasureUnitImpl` is `foot-per-hour`
256		* it will return a list of 1 {(0, `foot-per-hour`)}
257		* - if the `MeasureUnitImpl` is `foot-and-inch`
258		* it will return a list of 2 {(0, `foot`), (1, `inch`)}
259		*/
260		MaybeStackVector<MeasureUnitImplWithIndex>
261		extractIndividualUnitsWithIndices(UErrorCode &status) const;
262
263		/** Mutates this MeasureUnitImpl to take the reciprocal. */
264		void takeReciprocal(UErrorCode& status);
265
266		/**
267		* Mutates this MeasureUnitImpl to append a single unit.
268		*
269		* @return true if a new item was added. If unit is the dimensionless unit,
270		* it is never added: the return value will always be false.
271		*/
272		bool appendSingleUnit(const SingleUnitImpl& singleUnit, UErrorCode& status);
273
274		/** The complexity, either SINGLE, COMPOUND, or MIXED. */
275		UMeasureUnitComplexity complexity = UMEASURE_UNIT_SINGLE;
276
277		/**
278		* The list of single units. These may be summed or multiplied, based on the
279		* value of the complexity field.
280		*
281		* The "dimensionless" unit (SingleUnitImpl default constructor) must not be
282		* added to this list.
283		*/
284		MaybeStackVector<SingleUnitImpl> singleUnits;
285
286		/**
287		* The full unit identifier. Owned by the MeasureUnitImpl. Empty if not computed.
288		*/
289		CharString identifier;
290
291		private:
292		/**
293		* Normalizes a MeasureUnitImpl and generate the identifier string in place.
294		*/
295		void serialize(UErrorCode &status);
296
297		// For calling serialize
298		// TODO(icu-units#147): revisit serialization
299		friend class number::impl::LongNameHandler;
300		};
301
302		struct U_I18N_API MeasureUnitImplWithIndex : public UMemory {
303		const int32_t index;
304		MeasureUnitImpl unitImpl;
305		// Makes a copy of unitImpl.
306		MeasureUnitImplWithIndex(int32_t index, const MeasureUnitImpl &unitImpl, UErrorCode &status)
307	0	: index(index), unitImpl(unitImpl.copy(status)) {
308	0	}
309		MeasureUnitImplWithIndex(int32_t index, const SingleUnitImpl &singleUnitImpl, UErrorCode &status)
310	0	: index(index), unitImpl(MeasureUnitImpl(singleUnitImpl, status)) {
311	0	}
312		};
313
314		// Export explicit template instantiations of MaybeStackArray, MemoryPool and
315		// MaybeStackVector. This is required when building DLLs for Windows. (See
316		// datefmt.h, collationiterator.h, erarules.h and others for similar examples.)
317		#if U_PF_WINDOWS <= U_PLATFORM && U_PLATFORM <= U_PF_CYGWIN
318		template class U_I18N_API MaybeStackArray<MeasureUnitImplWithIndex *, 8>;
319		template class U_I18N_API MemoryPool<MeasureUnitImplWithIndex, 8>;
320		template class U_I18N_API MaybeStackVector<MeasureUnitImplWithIndex, 8>;
321
322		// Export an explicit template instantiation of the LocalPointer that is used as a
323		// data member of MeasureUnitImpl.
324		// (When building DLLs for Windows this is required.)
325		#if defined(_MSC_VER)
326		// Ignore warning 4661 as LocalPointerBase does not use operator== or operator!=
327		#pragma warning(push)
328		#pragma warning(disable : 4661)
329		#endif
330		template class U_I18N_API LocalPointerBase<MeasureUnitImpl>;
331		template class U_I18N_API LocalPointer<MeasureUnitImpl>;
332		#if defined(_MSC_VER)
333		#pragma warning(pop)
334		#endif
335		#endif
336
337		U_NAMESPACE_END
338
339		#endif /* #if !UCONFIG_NO_FORMATTING */
340		#endif //__MEASUNIT_IMPL_H__