blob: bc025e2ee33716413f4c14dc8586e5b10195f5e3 [file] [log] [blame]
* Copyright (C) 1997-2001, International Business Machines
* Corporation and others. All Rights Reserved.
* Modification History:
* Date Name Description
* 02/25/97 aliu Converted from java.
* 03/21/97 clhuang Updated per C++ implementation.
* 04/15/97 aliu Changed MAX_COUNT to DBL_DIG. Changed Digit to char.
* 09/09/97 aliu Adapted for exponential notation support.
* 08/02/98 stephen Added nearest/even rounding
* 06/29/99 stephen Made LONG_DIGITS a macro to satisfy SUN compiler
* 07/09/99 stephen Removed kMaxCount (unused, for HP compiler)
#ifndef DIGITLST_H
#define DIGITLST_H
#include "unicode/utypes.h"
#include <float.h>
// Decimal digits in a 32-bit int
//#define LONG_DIGITS 19
typedef enum EDigitListValues {
// "+." + fDigits + "e" + fDecimalAt
} EDigitListValues;
* Digit List. Private to DecimalFormat. Handles the transcoding
* between numeric values and strings of characters. Only handles
* non-negative numbers. The division of labor between DigitList and
* DecimalFormat is that DigitList handles the radix 10 representation
* issues; DecimalFormat handles the locale-specific issues such as
* positive/negative, grouping, decimal point, currency, and so on.
* <P>
* A DigitList is really a representation of a floating point value.
* It may be an integer value; we assume that a double has sufficient
* precision to represent all digits of a long.
* <P>
* The DigitList representation consists of a string of characters,
* which are the digits radix 10, from '0' to '9'. It also has a radix
* 10 exponent associated with it. The value represented by a DigitList
* object can be computed by mulitplying the fraction f, where 0 <= f < 1,
* derived by placing all the digits of the list to the right of the
* decimal point, by 10^exponent.
class U_COMMON_API DigitList { // Declare external to make compiler happy
DigitList(const DigitList&); // copy constructor
DigitList& operator=(const DigitList&); // assignment operator
* Return true if another object is semantically equal to this one.
UBool operator==(const DigitList& other) const;
* Return true if another object is semantically unequal to this one.
UBool operator!=(const DigitList& other) const { return !operator==(other); }
* Clears out the digits.
* Use before appending them.
* Typically, you set a series of digits with append, then at the point
* you hit the decimal point, you set myDigitList.fDecimalAt = myDigitList.fCount;
* then go on appending digits.
void clear(void);
* Appends digits to the list. Ignores all digits beyond the first DBL_DIG,
* since they are not significant for either longs or doubles.
inline void append(char digit);
* Utility routine to get the value of the digit list
* Returns 0.0 if zero length.
double getDouble(void);
* Utility routine to get the value of the digit list
* Make sure that fitsIntoLong() is called before calling this function.
* Returns 0 if zero length.
int32_t getLong(void);
* Return true if the number represented by this object can fit into
* a long.
UBool fitsIntoLong(UBool ignoreNegativeZero);
* Utility routine to set the value of the digit list from a double
* Input must be non-negative, and must not be Inf, -Inf, or NaN.
* The maximum fraction digits helps us round properly.
void set(double source, int32_t maximumDigits, UBool fixedPoint = TRUE);
* Utility routine to set the value of the digit list from a long.
* If a non-zero maximumDigits is specified, no more than that number of
* significant digits will be produced.
void set(int32_t source, int32_t maximumDigits = 0);
* Return true if this is a representation of zero.
UBool isZero(void) const;
* Return true if this is a representation of LONG_MIN. You must use
* this method to determine if this is so; you cannot check directly,
* because a special format is used to handle this.
UBool isLONG_MIN(void) const;
* These data members are intentionally public and can be set directly.
* The value represented is given by placing the decimal point before
* fDigits[fDecimalAt]. If fDecimalAt is < 0, then leading zeros between
* the decimal point and the first nonzero digit are implied. If fDecimalAt
* is > fCount, then trailing zeros between the fDigits[fCount-1] and the
* decimal point are implied.
* <P>
* Equivalently, the represented value is given by f * 10^fDecimalAt. Here
* f is a value 0.1 <= f < 1 arrived at by placing the digits in fDigits to
* the right of the decimal.
* <P>
* DigitList is normalized, so if it is non-zero, fDigits[0] is non-zero. We
* don't allow denormalized numbers because our exponent is effectively of
* unlimited magnitude. The fCount value contains the number of significant
* digits present in fDigits[].
* <P>
* Zero is represented by any DigitList with fCount == 0 or with each fDigits[i]
* for all i <= fCount == '0'.
int32_t fDecimalAt;
int32_t fCount;
UBool fIsPositive;
char *fDigits;
/* One character before fDigits for the decimal*/
char fDecimalDigits[MAX_DEC_DIGITS + 1];
* Round the representation to the given number of digits.
* @param maximumDigits The maximum number of digits to be shown.
* Upon return, count will be less than or equal to maximumDigits.
void round(int32_t maximumDigits);
* Initializes the buffer that records the mimimum long value.
/*static void initializeLONG_MIN_REP(void);*/
UBool shouldRoundUp(int32_t maximumDigits);
// -------------------------------------
// Appends the digit to the digit list if it's not out of scope.
// Ignores the digit, otherwise.
inline void
DigitList::append(char digit)
// Ignore digits which exceed the precision we can represent
if (fCount < MAX_DIGITS)
fDigits[fCount++] = digit;
#endif // _DIGITLST