The Tor Browser: intl/icu/source/i18n/tmunit.cpp@fc2d59ddac77

     1 /*

     2  *******************************************************************************

     3  * Copyright (C) 2008-2012, Google, International Business Machines Corporation and

     4  * others. All Rights Reserved.

     5  *******************************************************************************

     6  */

     8 #include "utypeinfo.h"  // for 'typeid' to work

    10 #include "unicode/tmunit.h"

    12 #if !UCONFIG_NO_FORMATTING

    14 U_NAMESPACE_BEGIN

    16 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(TimeUnit)

    19 /*

    20  * There are only 7 time units.

    21  * So, TimeUnit could be made as singleton

    22  * (similar to uniset_props.cpp, or unorm.cpp,

    23  * in which a static TimeUnit* array is created, and

    24  * the creatInstance() returns a const TimeUnit*).

    25  * But the constraint is TimeUnit is a data member of Measure.

    26  * But Measure (which is an existing API) does not expect it's "unit" member

    27  * as singleton. Meaure takes ownership of the "unit" member.

    28  * In its constructor, it does not take a const "unit" pointer.

    29  * Also, Measure can clone and destruct the "unit" pointer.

    30  * In order to preserve the old behavior and let Measure handle singleton "unit",

    31  * 1. a flag need to be added in Measure;

    32  * 2. a new constructor which takes const "unit" as parameter need to be added,

    33  *    and this new constructor will set the flag on.

    34  * 3. clone and destructor need to check upon this flag to distinguish on how

    35  *    to handle the "unit".

    36  *

    37  * Since TimeUnit is such a light weight object, comparing with the heavy weight

    38  * format operation, we decided to avoid the above complication.

    39  *

    40  * So, both TimeUnit and CurrencyUnit (the 2 subclasses of MeasureUnit) are

    41  * immutable and non-singleton.

    42  *

    43  * Currently, TimeUnitAmount and CurrencyAmount are immutable.

    44  * If an application needs to create a long list of TimeUnitAmount on the same

    45  * time unit but different number, for example,

    46  * 1 hour, 2 hour, 3 hour, ................. 10,000 hour,

    47  * there might be performance hit because 10,000 TimeUnit object,

    48  * although all are the same time unit, will be created in heap and deleted.

    49  *

    50  * To address this performance issue, if there is any in the future,

    51  * we should and need to change TimeUnitAmount and CurrencyAmount to be

    52  * immutable by allowing a setter on the number.

    53  * Or we need to add 2 parallel mutable classes in order to

    54  * preserve the existing API.

    55  * Or we can use freezable.

    56  */

    57 TimeUnit* U_EXPORT2

    58 TimeUnit::createInstance(TimeUnit::UTimeUnitFields timeUnitField,

    59                          UErrorCode& status) {

    60     if (U_FAILURE(status)) {

    61         return NULL;

    62     }

    63     if (timeUnitField < 0 || timeUnitField >= UTIMEUNIT_FIELD_COUNT) {

    64         status = U_ILLEGAL_ARGUMENT_ERROR;

    65         return NULL;

    66     }

    67     return new TimeUnit(timeUnitField);

    68 }

    71 TimeUnit::TimeUnit(TimeUnit::UTimeUnitFields timeUnitField) {

    72     fTimeUnitField = timeUnitField;

    73 }

    76 TimeUnit::TimeUnit(const TimeUnit& other)

    77 :   MeasureUnit(other) {

    78     *this = other;

    79 }

    82 UObject*

    83 TimeUnit::clone() const {

    84     return new TimeUnit(*this);

    85 }

    88 TimeUnit&

    89 TimeUnit::operator=(const TimeUnit& other) {

    90     if (this == &other) {

    91         return *this;

    92     }

    93     fTimeUnitField = other.fTimeUnitField;

    94     return *this;

    95 }

    98 UBool

    99 TimeUnit::operator==(const UObject& other) const {

   100     return (typeid(*this) == typeid(other)

   101             && fTimeUnitField == ((TimeUnit*)&other)->fTimeUnitField);

   102 }

   105 TimeUnit::UTimeUnitFields

   106 TimeUnit::getTimeUnitField() const {

   107     return fTimeUnitField;

   108 }

   111 TimeUnit::~TimeUnit() {

   112 }

   115 U_NAMESPACE_END

   117 #endif

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