icu4c/source/i18n/number_microprops.h

// © 2017 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html

#include "unicode/utypes.h"

#if !UCONFIG_NO_FORMATTING
#ifndef __NUMBER_MICROPROPS_H__
#define __NUMBER_MICROPROPS_H__

// TODO: minimize includes
#include "unicode/numberformatter.h"
#include "number_types.h"
#include "number_decimalquantity.h"
#include "number_scientific.h"
#include "number_patternstring.h"
#include "number_modifiers.h"
#include "number_multiplier.h"
#include "number_roundingutils.h"
#include "decNumber.h"
#include "charstr.h"

U_NAMESPACE_BEGIN namespace number {
namespace impl {

// TODO(units): generated by MicroPropsGenerator, but inherits from it too. Do
// we want to better document why? There's an explanation for processQuantity:
//  * As MicroProps is the "base instance", this implementation of
//  * MicroPropsGenerator::processQuantity() just ensures that the output
//  * `micros` is correctly initialized.
struct MicroProps : public MicroPropsGenerator {

    // NOTE: All of these fields are properly initialized in NumberFormatterImpl.
    RoundingImpl rounder;
    Grouper grouping;
    Padder padding;
    IntegerWidth integerWidth;
    UNumberSignDisplay sign;
    UNumberDecimalSeparatorDisplay decimal;
    bool useCurrency;
    char nsName[9];

    // Note: This struct has no direct ownership of the following pointers.
    const DecimalFormatSymbols* symbols;
    const Modifier* modOuter;
    const Modifier* modMiddle = nullptr;
    const Modifier* modInner;

    // The following "helper" fields may optionally be used during the MicroPropsGenerator.
    // They live here to retain memory.
    struct {
        ScientificModifier scientificModifier;
        EmptyModifier emptyWeakModifier{false};
        EmptyModifier emptyStrongModifier{true};
        MultiplierFormatHandler multiplier;
    } helpers;

    // The MeasureUnit with which the output measurement is represented.
    MeasureUnit outputUnit;

    MicroProps() = default;

    MicroProps(const MicroProps& other) = default;

    MicroProps& operator=(const MicroProps& other) = default;

    /**
     * As MicroProps is the "base instance", this implementation of
     * MicroPropsGenerator::processQuantity() just ensures that the output
     * `micros` is correctly initialized.
     *
     * For the "safe" invocation of this function, micros must not be *this,
     * such that a copy of the base instance is made. For the "unsafe" path,
     * this function can be used only once, because the base MicroProps instance
     * will be modified and thus not be available for re-use.
     *
     * @param quantity The quantity for consideration and optional mutation.
     * @param micros The MicroProps instance to populate. If this parameter is
     * not already `*this`, it will be overwritten with a copy of `*this`.
     */
    void processQuantity(DecimalQuantity &quantity, MicroProps &micros,
                         UErrorCode &status) const U_OVERRIDE {
        (void) quantity;
        (void) status;
        if (this == &micros) {
            // Unsafe path: no need to perform a copy.
            U_ASSERT(!exhausted);
            micros.exhausted = true;
            U_ASSERT(exhausted);
        } else {
            // Safe path: copy self into the output micros.
            U_ASSERT(!exhausted);
            micros = *this;
        }
    }

  private:
    // Internal fields:
    bool exhausted = false;
};

} // namespace impl
} // namespace number
U_NAMESPACE_END

#endif // __NUMBER_MICROPROPS_H__

#endif /* #if !UCONFIG_NO_FORMATTING */