icuSources/i18n/digitinterval.h

   1 // © 2016 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 /*
   4 *******************************************************************************
   5 * Copyright (C) 2015, International Business Machines
   6 * Corporation and others.  All Rights Reserved.
   7 *******************************************************************************
   8 * digitinterval.h
   9 *
  10 * created on: 2015jan6
  11 * created by: Travis Keep
  12 */
  13
  14 #ifndef __DIGITINTERVAL_H__
  15 #define __DIGITINTERVAL_H__
  16
  17 #include "unicode/uobject.h"
  18 #include "unicode/utypes.h"
  19
  20 U_NAMESPACE_BEGIN
  21
  22 /**
  23  * An interval of digits.
  24  * DigitIntervals are for fixed point formatting. A DigitInterval specifies
  25  * zero or more integer digits and zero or more fractional digits. This class
  26  * specifies particular digits in a number by their power of 10. For example,
  27  * the digit position just to the left of the decimal is 0, and the digit
  28  * position just left of that is 1. The digit position just to the right of
  29  * the decimal is -1. The digit position just to the right of that is -2.
  30  */
  31 class U_I18N_API DigitInterval : public UMemory {
  32 public:
  33
  34     /**
  35      * Spans all integer and fraction digits
  36      */
  37     DigitInterval()
  38             : fLargestExclusive(INT32_MAX), fSmallestInclusive(INT32_MIN) { }
  39
  40
  41     /**
  42      * Makes this instance span all digits.
  43      */
  44     void clear() {
  45         fLargestExclusive = INT32_MAX;
  46         fSmallestInclusive = INT32_MIN;
  47     }
  48
  49     /**
  50      * Returns TRUE if this interval contains this digit position.
  51      */
  52     UBool contains(int32_t digitPosition) const;
  53
  54     /**
  55      * Returns true if this object is the same as rhs.
  56      */
  57     UBool equals(const DigitInterval &rhs) const {
  58         return ((fLargestExclusive == rhs.fLargestExclusive) &&
  59                 (fSmallestInclusive == rhs.fSmallestInclusive));
  60     }
  61
  62     /**
  63      * Expand this interval so that it contains all of rhs.
  64      */
  65     void expandToContain(const DigitInterval &rhs);
  66
  67     /**
  68      * Shrink this interval so that it contains no more than rhs.
  69      */
  70     void shrinkToFitWithin(const DigitInterval &rhs);
  71
  72     /**
  73      * Expand this interval as necessary to contain digit with given exponent
  74      * After this method returns, this interval is guaranteed to contain
  75      * digitExponent.
  76      */
  77     void expandToContainDigit(int32_t digitExponent);
  78
  79     /**
  80      * Changes the number of digits to the left of the decimal point that
  81      * this interval spans. If count is negative, it means span all digits
  82      * to the left of the decimal point.
  83      */
  84     void setIntDigitCount(int32_t count);
  85
  86     /**
  87      * Changes the number of digits to the right of the decimal point that
  88      * this interval spans. If count is negative, it means span all digits
  89      * to the right of the decimal point.
  90      */
  91     void setFracDigitCount(int32_t count);
  92
  93     /**
  94      * Sets the least significant inclusive value to smallest. If smallest >= 0
  95      * then least significant inclusive value becomes 0.
  96      */
  97     void setLeastSignificantInclusive(int32_t smallest) {
  98         fSmallestInclusive = smallest < 0 ? smallest : 0;
  99     }
 100
 101     /**
 102      * Sets the most significant exclusive value to largest.
 103      * If largest <= 0 then most significant exclusive value becomes 0.
 104      */
 105     void setMostSignificantExclusive(int32_t largest) {
 106         fLargestExclusive = largest > 0 ? largest : 0;
 107     }
 108
 109     /**
 110      * If returns 8, the most significant digit in interval is the 10^7 digit.
 111      * Returns INT32_MAX if this interval spans all digits to left of
 112      * decimal point.
 113      */
 114     int32_t getMostSignificantExclusive() const {
 115         return fLargestExclusive;
 116     }
 117
 118     /**
 119      * Returns number of digits to the left of the decimal that this
 120      * interval includes. This is a synonym for getMostSignificantExclusive().
 121      */
 122     int32_t getIntDigitCount() const {
 123         return fLargestExclusive;
 124     }
 125
 126     /**
 127      * Returns number of digits to the right of the decimal that this
 128      * interval includes.
 129      */
 130     int32_t getFracDigitCount() const {
 131         return fSmallestInclusive == INT32_MIN ? INT32_MAX : -fSmallestInclusive;
 132     }
 133
 134     /**
 135      * Returns the total number of digits that this interval spans.
 136      * Caution: If this interval spans all digits to the left or right of
 137      * decimal point instead of some fixed number, then what length()
 138      * returns is undefined.
 139      */
 140     int32_t length() const {
 141         return fLargestExclusive - fSmallestInclusive;
 142      }
 143
 144     /**
 145      * If returns -3, the least significant digit in interval is the 10^-3
 146      * digit. Returns INT32_MIN if this interval spans all digits to right of
 147      * decimal point.
 148      */
 149     int32_t getLeastSignificantInclusive() const {
 150         return fSmallestInclusive;
 151     }
 152 private:
 153     int32_t fLargestExclusive;
 154     int32_t fSmallestInclusive;
 155 };
 156
 157 U_NAMESPACE_END
 158
 159 #endif  // __DIGITINTERVAL_H__