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// © 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
static const char16_t kDefaultCurrency[] = u"XXX";
static const char kDefaultCurrency8[] = "XXX";
/**
* A struct representing a single unit (optional SI prefix and dimensionality).
*/
struct 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;
/**
* Compare this SingleUnitImpl to another SingleUnitImpl for the sake of
* sorting and coalescing.
*
* 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;
}
if (index < other.index) {
return -1;
}
if (index > other.index) {
return 1;
}
if (siPrefix < other.siPrefix) {
return -1;
}
if (siPrefix > other.siPrefix) {
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 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.
*
* The default value is -1, meaning the dimensionless unit:
* isDimensionless() will return true, until index is changed.
*/
int32_t index = -1;
/**
* SI prefix.
*
* This is ignored for the dimensionless unit.
*/
UMeasureSIPrefix siPrefix = UMEASURE_SI_PREFIX_ONE;
/**
* Dimensionality.
*
* This is meaningless for the dimensionless unit.
*/
int32_t dimensionality = 1;
};
/**
* Internal representation of measurement units. Capable of representing all complexities of units,
* including mixed and compound units.
*/
struct MeasureUnitImpl : public UMemory {
/** 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.
*/
inline MeasureUnitImpl copy(UErrorCode& status) const {
MeasureUnitImpl result;
result.complexity = complexity;
result.units.appendAll(units, status);
result.identifier.append(identifier, status);
return result;
}
/** 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 append(const SingleUnitImpl& singleUnit, UErrorCode& status);
/** The complexity, either SINGLE, COMPOUND, or MIXED. */
UMeasureUnitComplexity complexity = UMEASURE_UNIT_SINGLE;
/**
* The list of simple 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> units;
/**
* The full unit identifier. Owned by the MeasureUnitImpl. Empty if not computed.
*/
CharString identifier;
};
U_NAMESPACE_END
#endif /* #if !UCONFIG_NO_FORMATTING */
#endif //__MEASUNIT_IMPL_H__
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