457 lines
15 KiB
C++
457 lines
15 KiB
C++
/*
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******************************************************************************
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*
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* Copyright (C) 1997-2013, International Business Machines
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* Corporation and others. All Rights Reserved.
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*
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******************************************************************************
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*
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* File DIGITLST.H
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*
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* Modification History:
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*
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* Date Name Description
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* 02/25/97 aliu Converted from java.
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* 03/21/97 clhuang Updated per C++ implementation.
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* 04/15/97 aliu Changed MAX_COUNT to DBL_DIG. Changed Digit to char.
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* 09/09/97 aliu Adapted for exponential notation support.
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* 08/02/98 stephen Added nearest/even rounding
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* 06/29/99 stephen Made LONG_DIGITS a macro to satisfy SUN compiler
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* 07/09/99 stephen Removed kMaxCount (unused, for HP compiler)
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******************************************************************************
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*/
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#ifndef DIGITLST_H
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#define DIGITLST_H
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#include "unicode/uobject.h"
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#if !UCONFIG_NO_FORMATTING
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#include "unicode/decimfmt.h"
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#include <float.h>
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#include "decContext.h"
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#include "decNumber.h"
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#include "cmemory.h"
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// Decimal digits in a 64-bit int
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#define INT64_DIGITS 19
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typedef enum EDigitListValues {
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MAX_DBL_DIGITS = DBL_DIG,
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MAX_I64_DIGITS = INT64_DIGITS,
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MAX_DIGITS = MAX_I64_DIGITS,
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MAX_EXPONENT = DBL_DIG,
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DIGIT_PADDING = 3,
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DEFAULT_DIGITS = 40, // Initial storage size, will grow as needed.
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// "+." + fDigits + "e" + fDecimalAt
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MAX_DEC_DIGITS = MAX_DIGITS + DIGIT_PADDING + MAX_EXPONENT
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} EDigitListValues;
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U_NAMESPACE_BEGIN
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class CharString;
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// Export an explicit template instantiation of the MaybeStackHeaderAndArray that
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// is used as a data member of DigitList.
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//
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// MSVC requires this, even though it should not be necessary.
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// No direct access to the MaybeStackHeaderAndArray leaks out of the i18n library.
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//
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// Macintosh produces duplicate definition linker errors with the explicit template
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// instantiation.
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//
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#if !U_PLATFORM_IS_DARWIN_BASED
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template class U_I18N_API MaybeStackHeaderAndArray<decNumber, char, DEFAULT_DIGITS>;
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#endif
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enum EStackMode { kOnStack };
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enum EFastpathBits { kFastpathOk = 1, kNoDecimal = 2 };
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/**
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* Digit List is actually a Decimal Floating Point number.
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* The original implementation has been replaced by a thin wrapper onto a
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* decimal number from the decNumber library.
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*
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* The original DigitList API has been retained, to minimize the impact of
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* the change on the rest of the ICU formatting code.
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*
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* The change to decNumber enables support for big decimal numbers, and
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* allows rounding computations to be done directly in decimal, avoiding
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* extra, and inaccurate, conversions to and from doubles.
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*
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* Original DigitList comments:
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*
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* Digit List utility class. Private to DecimalFormat. Handles the transcoding
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* between numeric values and strings of characters. Only handles
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* non-negative numbers. The division of labor between DigitList and
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* DecimalFormat is that DigitList handles the radix 10 representation
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* issues; DecimalFormat handles the locale-specific issues such as
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* positive/negative, grouping, decimal point, currency, and so on.
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* <P>
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* A DigitList is really a representation of a floating point value.
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* It may be an integer value; we assume that a double has sufficient
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* precision to represent all digits of a long.
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* <P>
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* The DigitList representation consists of a string of characters,
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* which are the digits radix 10, from '0' to '9'. It also has a radix
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* 10 exponent associated with it. The value represented by a DigitList
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* object can be computed by mulitplying the fraction f, where 0 <= f < 1,
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* derived by placing all the digits of the list to the right of the
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* decimal point, by 10^exponent.
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*
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* --------
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*
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* DigitList vs. decimalNumber:
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*
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* DigitList stores digits with the most significant first.
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* decNumber stores digits with the least significant first.
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*
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* DigitList, decimal point is before the most significant.
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* decNumber, decimal point is after the least signficant digit.
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*
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* digitList: 0.ddddd * 10 ^ exp
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* decNumber: ddddd. * 10 ^ exp
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*
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* digitList exponent = decNumber exponent + digit count
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*
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* digitList, digits are platform invariant chars, '0' - '9'
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* decNumber, digits are binary, one per byte, 0 - 9.
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*
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* (decNumber library is configurable in how digits are stored, ICU has configured
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* it this way for convenience in replacing the old DigitList implementation.)
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*/
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class U_I18N_API DigitList : public UMemory { // Declare external to make compiler happy
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public:
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DigitList();
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~DigitList();
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/* copy constructor
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* @param DigitList The object to be copied.
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* @return the newly created object.
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*/
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DigitList(const DigitList&); // copy constructor
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/* assignment operator
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* @param DigitList The object to be copied.
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* @return the newly created object.
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*/
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DigitList& operator=(const DigitList&); // assignment operator
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/**
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* Return true if another object is semantically equal to this one.
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* @param other The DigitList to be compared for equality
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* @return true if another object is semantically equal to this one.
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* return false otherwise.
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*/
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UBool operator==(const DigitList& other) const;
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int32_t compare(const DigitList& other);
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inline UBool operator!=(const DigitList& other) const { return !operator==(other); }
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/**
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* Clears out the digits.
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* Use before appending them.
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* Typically, you set a series of digits with append, then at the point
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* you hit the decimal point, you set myDigitList.fDecimalAt = myDigitList.fCount;
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* then go on appending digits.
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*/
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void clear(void);
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/**
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* Remove, by rounding, any fractional part of the decimal number,
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* leaving an integer value.
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*/
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void toIntegralValue();
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/**
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* Appends digits to the list.
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* CAUTION: this function is not recommended for new code.
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* In the original DigitList implementation, decimal numbers were
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* parsed by appending them to a digit list as they were encountered.
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* With the revamped DigitList based on decNumber, append is very
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* inefficient, and the interaction with the exponent value is confusing.
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* Best avoided.
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* TODO: remove this function once all use has been replaced.
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* TODO: describe alternative to append()
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* @param digit The digit to be appended.
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*/
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void append(char digit);
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/**
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* Utility routine to get the value of the digit list
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* Returns 0.0 if zero length.
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* @return the value of the digit list.
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*/
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double getDouble(void) const;
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/**
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* Utility routine to get the value of the digit list
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* Make sure that fitsIntoLong() is called before calling this function.
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* Returns 0 if zero length.
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* @return the value of the digit list, return 0 if it is zero length
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*/
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int32_t getLong(void) /*const*/;
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/**
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* Utility routine to get the value of the digit list
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* Make sure that fitsIntoInt64() is called before calling this function.
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* Returns 0 if zero length.
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* @return the value of the digit list, return 0 if it is zero length
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*/
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int64_t getInt64(void) /*const*/;
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/**
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* Utility routine to get the value of the digit list as a decimal string.
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*/
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void getDecimal(CharString &str, UErrorCode &status);
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/**
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* Return true if the number represented by this object can fit into
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* a long.
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* @param ignoreNegativeZero True if negative zero is ignored.
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* @return true if the number represented by this object can fit into
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* a long, return false otherwise.
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*/
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UBool fitsIntoLong(UBool ignoreNegativeZero) /*const*/;
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/**
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* Return true if the number represented by this object can fit into
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* an int64_t.
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* @param ignoreNegativeZero True if negative zero is ignored.
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* @return true if the number represented by this object can fit into
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* a long, return false otherwise.
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*/
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UBool fitsIntoInt64(UBool ignoreNegativeZero) /*const*/;
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/**
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* Utility routine to set the value of the digit list from a double.
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* @param source The value to be set
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*/
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void set(double source);
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/**
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* Utility routine to set the value of the digit list from a long.
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* If a non-zero maximumDigits is specified, no more than that number of
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* significant digits will be produced.
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* @param source The value to be set
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*/
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void set(int32_t source);
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/**
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* Utility routine to set the value of the digit list from an int64.
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* If a non-zero maximumDigits is specified, no more than that number of
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* significant digits will be produced.
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* @param source The value to be set
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*/
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void set(int64_t source);
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/**
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* Utility routine to set the value of the digit list from an int64.
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* Does not set the decnumber unless requested later
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* If a non-zero maximumDigits is specified, no more than that number of
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* significant digits will be produced.
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* @param source The value to be set
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*/
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void setInteger(int64_t source);
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/**
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* Utility routine to set the value of the digit list from a decimal number
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* string.
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* @param source The value to be set. The string must be nul-terminated.
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* @param fastpathBits special flags for fast parsing
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*/
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void set(const StringPiece &source, UErrorCode &status, uint32_t fastpathBits = 0);
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/**
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* Multiply this = this * arg
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* This digitlist will be expanded if necessary to accomodate the result.
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* @param arg the number to multiply by.
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*/
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void mult(const DigitList &arg, UErrorCode &status);
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/**
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* Divide this = this / arg
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*/
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void div(const DigitList &arg, UErrorCode &status);
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// The following functions replace direct access to the original DigitList implmentation
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// data structures.
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void setRoundingMode(DecimalFormat::ERoundingMode m);
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/** Test a number for zero.
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* @return TRUE if the number is zero
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*/
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UBool isZero(void) const;
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/** Test for a Nan
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* @return TRUE if the number is a NaN
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*/
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UBool isNaN(void) const {return decNumberIsNaN(fDecNumber);}
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UBool isInfinite() const {return decNumberIsInfinite(fDecNumber);}
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/** Reduce, or normalize. Removes trailing zeroes, adjusts exponent appropriately. */
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void reduce();
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/** Remove trailing fraction zeros, adjust exponent accordingly. */
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void trim();
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/** Set to zero */
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void setToZero() {uprv_decNumberZero(fDecNumber);}
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/** get the number of digits in the decimal number */
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int32_t digits() const {return fDecNumber->digits;}
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/**
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* Round the number to the given number of digits.
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* @param maximumDigits The maximum number of digits to be shown.
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* Upon return, count will be less than or equal to maximumDigits.
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*/
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void round(int32_t maximumDigits);
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void roundFixedPoint(int32_t maximumFractionDigits);
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/** Ensure capacity for digits. Grow the storage if it is currently less than
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* the requested size. Capacity is not reduced if it is already greater
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* than requested.
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*/
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void ensureCapacity(int32_t requestedSize, UErrorCode &status);
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UBool isPositive(void) const { return decNumberIsNegative(fDecNumber) == 0;}
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void setPositive(UBool s);
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void setDecimalAt(int32_t d);
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int32_t getDecimalAt();
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void setCount(int32_t c);
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int32_t getCount() const;
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/**
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* Set the digit in platform (invariant) format, from '0'..'9'
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* @param i index of digit
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* @param v digit value, from '0' to '9' in platform invariant format
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*/
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void setDigit(int32_t i, char v);
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/**
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* Get the digit in platform (invariant) format, from '0'..'9' inclusive
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* @param i index of digit
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* @return invariant format of the digit
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*/
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char getDigit(int32_t i);
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/**
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* Get the digit's value, as an integer from 0..9 inclusive.
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* Note that internally this value is a decNumberUnit, but ICU configures it to be a uint8_t.
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* @param i index of digit
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* @return value of that digit
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*/
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uint8_t getDigitValue(int32_t i);
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private:
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/*
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* These data members are intentionally public and can be set directly.
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*<P>
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* The value represented is given by placing the decimal point before
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* fDigits[fDecimalAt]. If fDecimalAt is < 0, then leading zeros between
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* the decimal point and the first nonzero digit are implied. If fDecimalAt
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* is > fCount, then trailing zeros between the fDigits[fCount-1] and the
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* decimal point are implied.
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* <P>
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* Equivalently, the represented value is given by f * 10^fDecimalAt. Here
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* f is a value 0.1 <= f < 1 arrived at by placing the digits in fDigits to
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* the right of the decimal.
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* <P>
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* DigitList is normalized, so if it is non-zero, fDigits[0] is non-zero. We
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* don't allow denormalized numbers because our exponent is effectively of
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* unlimited magnitude. The fCount value contains the number of significant
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* digits present in fDigits[].
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* <P>
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* Zero is represented by any DigitList with fCount == 0 or with each fDigits[i]
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* for all i <= fCount == '0'.
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*
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* int32_t fDecimalAt;
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* int32_t fCount;
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* UBool fIsPositive;
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* char *fDigits;
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* DecimalFormat::ERoundingMode fRoundingMode;
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*/
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public:
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decContext fContext; // public access to status flags.
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private:
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decNumber *fDecNumber;
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MaybeStackHeaderAndArray<decNumber, char, DEFAULT_DIGITS> fStorage;
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/* Cached double value corresponding to this decimal number.
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* This is an optimization for the formatting implementation, which may
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* ask for the double value multiple times.
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*/
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union DoubleOrInt64 {
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double fDouble;
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int64_t fInt64;
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} fUnion;
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enum EHave {
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kNone=0,
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kDouble,
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kInt64
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} fHave;
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UBool shouldRoundUp(int32_t maximumDigits) const;
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public:
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#if U_OVERRIDE_CXX_ALLOCATION
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using UMemory::operator new;
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using UMemory::operator delete;
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#else
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static inline void * U_EXPORT2 operator new(size_t size) U_NO_THROW { return ::operator new(size); };
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static inline void U_EXPORT2 operator delete(void *ptr ) U_NO_THROW { ::operator delete(ptr); };
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#endif
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/**
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* Placement new for stack usage
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* @internal
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*/
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static inline void * U_EXPORT2 operator new(size_t /*size*/, void * onStack, EStackMode /*mode*/) U_NO_THROW { return onStack; }
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/**
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* Placement delete for stack usage
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* @internal
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*/
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static inline void U_EXPORT2 operator delete(void * /*ptr*/, void * /*onStack*/, EStackMode /*mode*/) U_NO_THROW {}
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private:
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inline void internalSetDouble(double d) {
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fHave = kDouble;
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fUnion.fDouble=d;
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}
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inline void internalSetInt64(int64_t d) {
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fHave = kInt64;
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fUnion.fInt64=d;
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}
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inline void internalClear() {
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fHave = kNone;
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}
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};
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U_NAMESPACE_END
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#endif // #if !UCONFIG_NO_FORMATTING
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#endif // _DIGITLST
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//eof
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