skia / external / github.com / unicode-org / icu / refs/tags/icu-release-3-6-d02 / . / source / i18n / digitlst.h

/* | |

****************************************************************************** | |

* | |

* Copyright (C) 1997-2004, International Business Machines | |

* Corporation and others. All Rights Reserved. | |

* | |

****************************************************************************** | |

* | |

* File DIGITLST.H | |

* | |

* 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 "unicode/uobject.h" | |

#include <float.h> | |

// Decimal digits in a 64-bit int | |

//#define LONG_DIGITS 19 | |

#define INT64_DIGITS 19 | |

typedef enum EDigitListValues { | |

MAX_DBL_DIGITS = DBL_DIG, | |

MAX_I64_DIGITS = INT64_DIGITS, | |

MAX_DIGITS = MAX_I64_DIGITS, | |

MAX_EXPONENT = DBL_DIG, | |

DIGIT_PADDING = 3, | |

// "+." + fDigits + "e" + fDecimalAt | |

MAX_DEC_DIGITS = MAX_DIGITS + DIGIT_PADDING + MAX_EXPONENT | |

} EDigitListValues; | |

U_NAMESPACE_BEGIN | |

/** | |

* Digit List utility class. 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_I18N_API DigitList : public UMemory { // Declare external to make compiler happy | |

public: | |

DigitList(); | |

~DigitList(); | |

/* copy constructor | |

* @param DigitList The object to be copied. | |

* @return the newly created object. | |

*/ | |

DigitList(const DigitList&); // copy constructor | |

/* assignment operator | |

* @param DigitList The object to be copied. | |

* @return the newly created object. | |

*/ | |

DigitList& operator=(const DigitList&); // assignment operator | |

/** | |

* Return true if another object is semantically equal to this one. | |

* @param other The DigitList to be compared for equality | |

* @return true if another object is semantically equal to this one. | |

* return false otherwise. | |

*/ | |

UBool operator==(const DigitList& other) const; | |

/** | |

* Return true if another object is semantically unequal to this one. | |

* @param other The DigitList to be compared for inequality | |

* @return true if another object is semantically unequal to this one. | |

* return false otherwise. | |

*/ | |

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. | |

* @param digit The digit to be appended. | |

*/ | |

inline void append(char digit); | |

/** | |

* Utility routine to get the value of the digit list | |

* Returns 0.0 if zero length. | |

* @return the value of the digit list. | |

*/ | |

double getDouble(void) /*const*/; | |

/** | |

* 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. | |

* @return the value of the digit list, return 0 if it is zero length | |

*/ | |

int32_t getLong(void) /*const*/; | |

/** | |

* Utility routine to get the value of the digit list | |

* Make sure that fitsIntoInt64() is called before calling this function. | |

* Returns 0 if zero length. | |

* @return the value of the digit list, return 0 if it is zero length | |

*/ | |

int64_t getInt64(void) /*const*/; | |

/** | |

* Return true if the number represented by this object can fit into | |

* a long. | |

* @param ignoreNegativeZero True if negative zero is ignored. | |

* @return true if the number represented by this object can fit into | |

* a long, return false otherwise. | |

*/ | |

UBool fitsIntoLong(UBool ignoreNegativeZero) /*const*/; | |

/** | |

* Return true if the number represented by this object can fit into | |

* an int64_t. | |

* @param ignoreNegativeZero True if negative zero is ignored. | |

* @return true if the number represented by this object can fit into | |

* a long, return false otherwise. | |

*/ | |

UBool fitsIntoInt64(UBool ignoreNegativeZero) /*const*/; | |

/** | |

* 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. | |

* @param source The value to be set | |

* @param maximunDigits The maximum number of digits to be shown | |

* @param fixedPoint True if the point is fixed | |

*/ | |

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. | |

* @param source The value to be set | |

* @param maximunDigits The maximum number of digits to be shown | |

*/ | |

void set(int32_t source, int32_t maximumDigits = 0); | |

/** | |

* Utility routine to set the value of the digit list from an int64. | |

* If a non-zero maximumDigits is specified, no more than that number of | |

* significant digits will be produced. | |

* @param source The value to be set | |

* @param maximunDigits The maximum number of digits to be shown | |

*/ | |

void set(int64_t source, int32_t maximumDigits = 0); | |

/** | |

* Return true if this is a representation of zero. | |

* @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. | |

*/ | |

// This code is unused. | |

//UBool isLONG_MIN(void) const; | |

public: | |

/** | |

* These data members are intentionally public and can be set directly. | |

*<P> | |

* 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; | |

private: | |

/* 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); | |

UBool shouldRoundUp(int32_t maximumDigits) const; | |

}; | |

// ------------------------------------- | |

// 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; | |

} | |

U_NAMESPACE_END | |

#endif // _DIGITLST | |

//eof |