icuSources/i18n/tmunit.cpp

   1 // © 2016 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 /*
   4  *******************************************************************************
   5  * Copyright (C) 2008-2014, Google, International Business Machines Corporation and
   6  * others. All Rights Reserved.
   7  *******************************************************************************
   8  */
   9
  10 #include "unicode/tmunit.h"
  11 #include "uassert.h"
  12
  13 #if !UCONFIG_NO_FORMATTING
  14
  15 U_NAMESPACE_BEGIN
  16
  17 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(TimeUnit)
  18
  19
  20 /*
  21  * There are only 7 time units.
  22  * So, TimeUnit could be made as singleton
  23  * (similar to uniset_props.cpp, or unorm.cpp,
  24  * in which a static TimeUnit* array is created, and
  25  * the creatInstance() returns a const TimeUnit*).
  26  * But the constraint is TimeUnit is a data member of Measure.
  27  * But Measure (which is an existing API) does not expect it's "unit" member
  28  * as singleton. Meaure takes ownership of the "unit" member.
  29  * In its constructor, it does not take a const "unit" pointer.
  30  * Also, Measure can clone and destruct the "unit" pointer.
  31  * In order to preserve the old behavior and let Measure handle singleton "unit",
  32  * 1. a flag need to be added in Measure;
  33  * 2. a new constructor which takes const "unit" as parameter need to be added,
  34  *    and this new constructor will set the flag on.
  35  * 3. clone and destructor need to check upon this flag to distinguish on how
  36  *    to handle the "unit".
  37  *
  38  * Since TimeUnit is such a light weight object, comparing with the heavy weight
  39  * format operation, we decided to avoid the above complication.
  40  *
  41  * So, both TimeUnit and CurrencyUnit (the 2 subclasses of MeasureUnit) are
  42  * immutable and non-singleton.
  43  *
  44  * Currently, TimeUnitAmount and CurrencyAmount are immutable.
  45  * If an application needs to create a long list of TimeUnitAmount on the same
  46  * time unit but different number, for example,
  47  * 1 hour, 2 hour, 3 hour, ................. 10,000 hour,
  48  * there might be performance hit because 10,000 TimeUnit object,
  49  * although all are the same time unit, will be created in heap and deleted.
  50  *
  51  * To address this performance issue, if there is any in the future,
  52  * we should and need to change TimeUnitAmount and CurrencyAmount to be
  53  * immutable by allowing a setter on the number.
  54  * Or we need to add 2 parallel mutable classes in order to
  55  * preserve the existing API.
  56  * Or we can use freezable.
  57  */
  58 TimeUnit* U_EXPORT2
  59 TimeUnit::createInstance(TimeUnit::UTimeUnitFields timeUnitField,
  60                          UErrorCode& status) {
  61     if (U_FAILURE(status)) {
  62         return NULL;
  63     }
  64     if (timeUnitField < 0 || timeUnitField >= UTIMEUNIT_FIELD_COUNT) {
  65         status = U_ILLEGAL_ARGUMENT_ERROR;
  66         return NULL;
  67     }
  68     return new TimeUnit(timeUnitField);
  69 }
  70
  71
  72 TimeUnit::TimeUnit(TimeUnit::UTimeUnitFields timeUnitField) {
  73     fTimeUnitField = timeUnitField;
  74     switch (fTimeUnitField) {
  75     case UTIMEUNIT_YEAR:
  76         initTime("year");
  77         break;
  78     case UTIMEUNIT_MONTH:
  79         initTime("month");
  80         break;
  81     case UTIMEUNIT_DAY:
  82         initTime("day");
  83         break;
  84     case UTIMEUNIT_WEEK:
  85         initTime("week");
  86         break;
  87     case UTIMEUNIT_HOUR:
  88         initTime("hour");
  89         break;
  90     case UTIMEUNIT_MINUTE:
  91         initTime("minute");
  92         break;
  93     case UTIMEUNIT_SECOND:
  94         initTime("second");
  95         break;
  96     default:
  97         UPRV_UNREACHABLE;
  98     }
  99 }
 100
 101 TimeUnit::TimeUnit(const TimeUnit& other)
 102 :   MeasureUnit(other), fTimeUnitField(other.fTimeUnitField) {
 103 }
 104
 105 UObject*
 106 TimeUnit::clone() const {
 107     return new TimeUnit(*this);
 108 }
 109
 110 TimeUnit&
 111 TimeUnit::operator=(const TimeUnit& other) {
 112     if (this == &other) {
 113         return *this;
 114     }
 115     MeasureUnit::operator=(other);
 116     fTimeUnitField = other.fTimeUnitField;
 117     return *this;
 118 }
 119
 120 TimeUnit::UTimeUnitFields
 121 TimeUnit::getTimeUnitField() const {
 122     return fTimeUnitField;
 123 }
 124
 125 TimeUnit::~TimeUnit() {
 126 }
 127
 128
 129 U_NAMESPACE_END
 130
 131 #endif