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// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
part of intl;
/**
* Provides the ability to format a number in a locale-specific way. The
* format is specified as a pattern using a subset of the ICU formatting
* patterns.
*
* 0 - A single digit
* # - A single digit, omitted if the value is zero
* . - Decimal separator
* - - Minus sign
* , - Grouping separator
* E - Separates mantissa and expontent
* + - Before an exponent, indicates it should be prefixed with a plus sign.
* % - In prefix or suffix, multiply by 100 and show as percentage
* \u2030 - In prefix or suffix, multiply by 1000 and show as per mille
* \u00A4 - Currency sign, replaced by currency name
* ' - Used to quote special characters
* ; - Used to separate the positive and negative patterns if both are present
*
* For example,
* var f = new NumberFormat("###.0#", "en_US");
* print(f.format(12.345));
* ==> 12.34
* If the locale is not specified, it will default to the current locale. If
* the format is not specified it will print in a basic format with at least
* one integer digit and three fraction digits.
*
* There are also standard patterns available via the special constructors. e.g.
* var symbols = new NumberFormat.percentFormat("ar");
* There are four such constructors: decimalFormat, percentFormat,
* scientificFormat and currencyForamt. However, at the moment,
* scientificFormat prints only as equivalent to "#E0" and does not take
* into account significant digits. currencyFormat will always use the name
* of the currency rather than the symbol.
*/
class NumberFormat {
/** Variables to determine how number printing behaves. */
// TODO(alanknight): If these remain as variables and are set based on the
// pattern, can we make them final?
String _negativePrefix = '-';
String _positivePrefix = '';
String _negativeSuffix = '';
String _positiveSuffix = '';
/**
* How many numbers in a group when using punctuation to group digits in
* large numbers. e.g. in en_US: "1,000,000" has a grouping size of 3 digits
* between commas.
*/
int _groupingSize = 3;
bool _decimalSeparatorAlwaysShown = false;
bool _useSignForPositiveExponent = false;
bool _useExponentialNotation = false;
int _maximumIntegerDigits = 40;
int _minimumIntegerDigits = 1;
int _maximumFractionDigits = 3;
int _minimumFractionDigits = 0;
int _minimumExponentDigits = 0;
int _multiplier = 1;
/**
* Stores the pattern used to create this format. This isn't used, but
* is helpful in debugging.
*/
String _pattern;
/**
* Set the maximum digits printed to the left of the decimal point.
* Normally this is computed from the pattern, but it's exposed here for
* testing purposes and for rare cases where you want to force it explicitly.
*/
void setMaximumIntegerDigits(int max) {
_maximumIntegerDigits = max;
}
/**
* Set the minimum number of digits printed to the left of the decimal point.
* Normally this is computed from the pattern, but it's exposed here for
* testing purposes and for rare cases where you want to force it explicitly.
*/
void setMinimumIntegerDigits(int min) {
_minimumIntegerDigits = min;
}
/**
* Set the maximum number of digits printed to the right of the decimal point.
* Normally this is computed from the pattern, but it's exposed here for
* testing purposes and for rare cases where you want to force it explicitly.
*/
void setMaximumFractionDigits(int max) {
_maximumFractionDigits = max;
}
/**
* Set the minimum digits printed to the left of the decimal point.
* Normally this is computed from the pattern, but it's exposed here for
* testing purposes and for rare cases where you want to force it explicitly.
*/
void setMinimumFractionDigits(int max) {
_minimumFractionDigits = max;
}
/** The locale in which we print numbers. */
final String _locale;
/** Caches the symbols used for our locale. */
NumberSymbols _symbols;
/**
* Transient internal state in which to build up the result of the format
* operation. We can have this be just an instance variable because Dart is
* single-threaded and unless we do an asynchronous operation in the process
* of formatting then there will only ever be one number being formatted
* at a time. In languages with threads we'd need to pass this on the stack.
*/
StringBuffer _buffer;
/**
* Create a number format that prints using [newPattern] as it applies in
* [locale].
*/
factory NumberFormat([String newPattern, String locale]) {
return new NumberFormat._forPattern(locale, (x) => newPattern);
}
/** Create a number format that prints as DECIMAL_PATTERN. */
NumberFormat.decimalPattern([String locale]) :
this._forPattern(locale, (x) => x.DECIMAL_PATTERN);
/** Create a number format that prints as PERCENT_PATTERN. */
NumberFormat.percentPattern([String locale]) :
this._forPattern(locale, (x) => x.PERCENT_PATTERN);
/** Create a number format that prints as SCIENTIFIC_PATTERN. */
NumberFormat.scientificPattern([String locale]) :
this._forPattern(locale, (x) => x.SCIENTIFIC_PATTERN);
/** Create a number format that prints as CURRENCY_PATTERN. */
NumberFormat.currencyPattern([String locale]) :
this._forPattern(locale, (x) => x.CURRENCY_PATTERN);
/**
* Create a number format that prints in a pattern we get from
* the [getPattern] function using the locale [locale].
*/
NumberFormat._forPattern(String locale, Function getPattern) :
_locale = Intl.verifiedLocale(locale, localeExists) {
_symbols = numberFormatSymbols[_locale];
_setPattern(getPattern(_symbols));
}
/**
* Return the locale code in which we operate, e.g. 'en_US' or 'pt'.
*/
String get locale => _locale;
/**
* Return true if the locale exists, or if it is null. The null case
* is interpreted to mean that we use the default locale.
*/
static bool localeExists(localeName) {
if (localeName == null) return false;
return numberFormatSymbols.containsKey(localeName);
}
/**
* Return the symbols which are used in our locale. Cache them to avoid
* repeated lookup.
*/
NumberSymbols get symbols {
return _symbols;
}
/**
* Format [number] according to our pattern and return the formatted string.
*/
String format(num number) {
// TODO(alanknight): Do we have to do anything for printing numbers bidi?
// Or are they always printed left to right?
if (number.isNaN) return symbols.NAN;
if (number.isInfinite) return "${_signPrefix(number)}${symbols.INFINITY}";
_newBuffer();
_add(_signPrefix(number));
_formatNumber(number.abs() * _multiplier);
_add(_signSuffix(number));
var result = _buffer.toString();
_buffer = null;
return result;
}
/**
* Format the main part of the number in the form dictated by the pattern.
*/
void _formatNumber(num number) {
if (_useExponentialNotation) {
_formatExponential(number);
} else {
_formatFixed(number);
}
}
/** Format the number in exponential notation. */
void _formatExponential(num number) {
if (number == 0.0) {
_formatFixed(number);
_formatExponent(0);
return;
}
var exponent = (log(number) / log(10)).floor();
var mantissa = number / pow(10.0, exponent);
var minIntDigits = _minimumIntegerDigits;
if (_maximumIntegerDigits > 1 &&
_maximumIntegerDigits > _minimumIntegerDigits) {
// A repeating range is defined; adjust to it as follows.
// If repeat == 3, we have 6,5,4=>3; 3,2,1=>0; 0,-1,-2=>-3;
// -3,-4,-5=>-6, etc. This takes into account that the
// exponent we have here is off by one from what we expect;
// it is for the format 0.MMMMMx10^n.
while ((exponent % _maximumIntegerDigits) != 0) {
mantissa *= 10;
exponent--;
}
minIntDigits = 1;
} else {
// No repeating range is defined, use minimum integer digits.
if (_minimumIntegerDigits < 1) {
exponent++;
mantissa /= 10;
} else {
exponent -= _minimumIntegerDigits - 1;
mantissa *= pow(10, _minimumIntegerDigits - 1);
}
}
_formatFixed(mantissa);
_formatExponent(exponent);
}
/**
* Format the exponent portion, e.g. in "1.3e-5" the "e-5".
*/
void _formatExponent(num exponent) {
_add(symbols.EXP_SYMBOL);
if (exponent < 0) {
exponent = -exponent;
_add(symbols.MINUS_SIGN);
} else if (_useSignForPositiveExponent) {
_add(symbols.PLUS_SIGN);
}
_pad(_minimumExponentDigits, exponent.toString());
}
/** Used to test if we have exceeded Javascript integer limits. */
final _maxInt = pow(2, 52);
/**
* Format the basic number portion, inluding the fractional digits.
*/
void _formatFixed(num number) {
// Very fussy math to get integer and fractional parts.
var power = pow(10, _maximumFractionDigits);
var shiftedNumber = (number * power);
// We must not roundToDouble() an int or it will lose precision. We must not
// round() a large double or it will take its loss of precision and
// preserve it in an int, which we will then print to the right
// of the decimal place. Therefore, only roundToDouble if we are already
// a double.
if (shiftedNumber is double) {
shiftedNumber = shiftedNumber.roundToDouble();
}
var intValue, fracValue;
if (shiftedNumber.isInfinite) {
intValue = number.toInt();
fracValue = 0;
} else {
intValue = shiftedNumber.round() ~/ power;
fracValue = (shiftedNumber - intValue * power).floor();
}
var fractionPresent = _minimumFractionDigits > 0 || fracValue > 0;
// If the int part is larger than 2^52 and we're on Javascript (so it's
// really a float) it will lose precision, so pad out the rest of it
// with zeros. Check for Javascript by seeing if an integer is double.
var paddingDigits = new StringBuffer();
if (1 is double && intValue > _maxInt) {
var howManyDigitsTooBig = (log(intValue) / LN10).ceil() - 16;
var divisor = pow(10, howManyDigitsTooBig).round();
for (var each in new List(howManyDigitsTooBig.toInt())) {
paddingDigits.write(symbols.ZERO_DIGIT);
}
intValue = (intValue / divisor).truncate();
}
var integerDigits = "${intValue}${paddingDigits}".codeUnits;
var digitLength = integerDigits.length;
if (_hasPrintableIntegerPart(intValue)) {
_pad(_minimumIntegerDigits - digitLength);
for (var i = 0; i < digitLength; i++) {
_addDigit(integerDigits[i]);
_group(digitLength, i);
}
} else if (!fractionPresent) {
// If neither fraction nor integer part exists, just print zero.
_addZero();
}
_decimalSeparator(fractionPresent);
_formatFractionPart((fracValue + power).toString());
}
/**
* Format the part after the decimal place in a fixed point number.
*/
void _formatFractionPart(String fractionPart) {
var fractionCodes = fractionPart.codeUnits;
var fractionLength = fractionPart.length;
while(fractionCodes[fractionLength - 1] == _zero &&
fractionLength > _minimumFractionDigits + 1) {
fractionLength--;
}
for (var i = 1; i < fractionLength; i++) {
_addDigit(fractionCodes[i]);
}
}
/** Print the decimal separator if appropriate. */
void _decimalSeparator(bool fractionPresent) {
if (_decimalSeparatorAlwaysShown || fractionPresent) {
_add(symbols.DECIMAL_SEP);
}
}
/**
* Return true if we have a main integer part which is printable, either
* because we have digits left of the decimal point, or because there are
* a minimum number of printable digits greater than 1.
*/
bool _hasPrintableIntegerPart(int intValue) {
return intValue > 0 || _minimumIntegerDigits > 0;
}
/**
* Create a new empty buffer. See comment on [_buffer] variable for why
* we have it as an instance variable rather than passing it on the stack.
*/
void _newBuffer() { _buffer = new StringBuffer(); }
/** A group of methods that provide support for writing digits and other
* required characters into [_buffer] easily.
*/
void _add(String x) { _buffer.write(x);}
void _addCharCode(int x) { _buffer.writeCharCode(x); }
void _addZero() { _buffer.write(symbols.ZERO_DIGIT); }
void _addDigit(int x) { _buffer.writeCharCode(_localeZero + x - _zero); }
/** Print padding up to [numberOfDigits] above what's included in [basic]. */
void _pad(int numberOfDigits, [String basic = '']) {
for (var i = 0; i < numberOfDigits - basic.length; i++) {
_add(symbols.ZERO_DIGIT);
}
for (var x in basic.codeUnits) {
_addDigit(x);
}
}
/**
* We are printing the digits of the number from left to right. We may need
* to print a thousands separator or other grouping character as appropriate
* to the locale. So we find how many places we are from the end of the number
* by subtracting our current [position] from the [totalLength] and print
* the separator character every [_groupingSize] digits.
*/
void _group(int totalLength, int position) {
var distanceFromEnd = totalLength - position;
if (distanceFromEnd <= 1 || _groupingSize <= 0) return;
if (distanceFromEnd % _groupingSize == 1) {
_add(symbols.GROUP_SEP);
}
}
/** Returns the code point for the character '0'. */
final _zero = '0'.codeUnits.first;
/** Returns the code point for the locale's zero digit. */
// Note that there is a slight risk of a locale's zero digit not fitting
// into a single code unit, but it seems very unlikely, and if it did,
// there's a pretty good chance that our assumptions about being able to do
// arithmetic on it would also be invalid.
get _localeZero => symbols.ZERO_DIGIT.codeUnits.first;
/**
* Returns the prefix for [x] based on whether it's positive or negative.
* In en_US this would be '' and '-' respectively.
*/
String _signPrefix(num x) {
return x.isNegative ? _negativePrefix : _positivePrefix;
}
/**
* Returns the suffix for [x] based on wether it's positive or negative.
* In en_US there are no suffixes for positive or negative.
*/
String _signSuffix(num x) {
return x.isNegative ? _negativeSuffix : _positiveSuffix;
}
void _setPattern(String newPattern) {
if (newPattern == null) return;
// Make spaces non-breaking
_pattern = newPattern.replaceAll(' ', '\u00a0');
var parser = new _NumberFormatParser(this, newPattern);
parser.parse();
}
String toString() => "NumberFormat($_locale, $_pattern)";
}
/**
* Private class that parses the numeric formatting pattern and sets the
* variables in [format] to appropriate values. Instances of this are
* transient and store parsing state in instance variables, so can only be used
* to parse a single pattern.
*/
class _NumberFormatParser {
/**
* The special characters in the pattern language. All others are treated
* as literals.
*/
static const _PATTERN_SEPARATOR = ';';
static const _QUOTE = "'";
static const _PATTERN_DIGIT = '#';
static const _PATTERN_ZERO_DIGIT = '0';
static const _PATTERN_GROUPING_SEPARATOR = ',';
static const _PATTERN_DECIMAL_SEPARATOR = '.';
static const _PATTERN_CURRENCY_SIGN = '\u00A4';
static const _PATTERN_PER_MILLE = '\u2030';
static const _PATTERN_PERCENT = '%';
static const _PATTERN_EXPONENT = 'E';
static const _PATTERN_PLUS = '+';
/** The format whose state we are setting. */
final NumberFormat format;
/** The pattern we are parsing. */
final _StringIterator pattern;
/**
* Create a new [_NumberFormatParser] for a particular [NumberFormat] and
* [input] pattern.
*/
_NumberFormatParser(this.format, input) : pattern = _iterator(input) {
pattern.moveNext();
}
/** The [NumberSymbols] for the locale in which our [format] prints. */
NumberSymbols get symbols => format.symbols;
/** Parse the input pattern and set the values. */
void parse() {
format._positivePrefix = _parseAffix();
var trunk = _parseTrunk();
format._positiveSuffix = _parseAffix();
// If we have separate positive and negative patterns, now parse the
// the negative version.
if (pattern.current == _NumberFormatParser._PATTERN_SEPARATOR) {
pattern.moveNext();
format._negativePrefix = _parseAffix();
// Skip over the negative trunk, verifying that it's identical to the
// positive trunk.
for (var each in _iterable(trunk)) {
if (pattern.current != each && pattern.current != null) {
throw new FormatException(
"Positive and negative trunks must be the same");
}
pattern.moveNext();
}
format._negativeSuffix = _parseAffix();
} else {
// If no negative affix is specified, they share the same positive affix.
format._negativePrefix = format._positivePrefix + format._negativePrefix;
format._negativeSuffix = format._negativeSuffix + format._positiveSuffix;
}
}
/** Variable used in parsing prefixes and suffixes to keep track of
* whether or not we are in a quoted region. */
bool inQuote = false;
/**
* Parse a prefix or suffix and return the prefix/suffix string. Note that
* this also may modify the state of [format].
*/
String _parseAffix() {
var affix = new StringBuffer();
inQuote = false;
var loop = true;
while (loop) {
loop = parseCharacterAffix(affix) && pattern.moveNext();
}
return affix.toString();
}
/**
* Parse an individual character as part of a prefix or suffix. Return true
* if we should continue to look for more affix characters, and false if
* we have reached the end.
*/
bool parseCharacterAffix(StringBuffer affix) {
var ch = pattern.current;
if (ch == null) return false;
if (ch == _QUOTE) {
var nextChar = pattern.peek;
if (nextChar == _QUOTE) {
pattern.moveNext();
affix.write(_QUOTE); // 'don''t'
} else {
inQuote = !inQuote;
}
return true;
}
if (inQuote) {
affix.write(ch);
} else {
switch (ch) {
case _PATTERN_DIGIT:
case _PATTERN_ZERO_DIGIT:
case _PATTERN_GROUPING_SEPARATOR:
case _PATTERN_DECIMAL_SEPARATOR:
case _PATTERN_SEPARATOR:
return false;
case _PATTERN_CURRENCY_SIGN:
// TODO(alanknight): Handle the local/global/portable currency signs
affix.write(symbols.DEF_CURRENCY_CODE);
break;
case _PATTERN_PERCENT:
if (format._multiplier != 1) {
throw new FormatException('Too many percent/permill');
}
format._multiplier = 100;
affix.write(symbols.PERCENT);
break;
case _PATTERN_PER_MILLE:
if (format._multiplier != 1) {
throw new FormatException('Too many percent/permill');
}
format._multiplier = 1000;
affix.write(symbols.PERMILL);
break;
default:
affix.write(ch);
}
}
return true;
}
/** Variables used in [_parseTrunk] and [parseTrunkCharacter]. */
var decimalPos;
var digitLeftCount;
var zeroDigitCount;
var digitRightCount;
var groupingCount;
var trunk;
/**
* Parse the "trunk" portion of the pattern, the piece that doesn't include
* positive or negative prefixes or suffixes.
*/
String _parseTrunk() {
decimalPos = -1;
digitLeftCount = 0;
zeroDigitCount = 0;
digitRightCount = 0;
groupingCount = -1;
var loop = true;
trunk = new StringBuffer();
while (pattern.current != null && loop) {
loop = parseTrunkCharacter();
}
if (zeroDigitCount == 0 && digitLeftCount > 0 && decimalPos >= 0) {
// Handle '###.###' and '###.' and '.###'
var n = decimalPos;
if (n == 0) { // Handle '.###'
n++;
}
digitRightCount = digitLeftCount - n;
digitLeftCount = n - 1;
zeroDigitCount = 1;
}
// Do syntax checking on the digits.
if (decimalPos < 0 && digitRightCount > 0 ||
decimalPos >= 0 && (decimalPos < digitLeftCount ||
decimalPos > digitLeftCount + zeroDigitCount) ||
groupingCount == 0) {
throw new FormatException('Malformed pattern "${pattern.input}"');
}
var totalDigits = digitLeftCount + zeroDigitCount + digitRightCount;
format._maximumFractionDigits =
decimalPos >= 0 ? totalDigits - decimalPos : 0;
if (decimalPos >= 0) {
format._minimumFractionDigits =
digitLeftCount + zeroDigitCount - decimalPos;
if (format._minimumFractionDigits < 0) {
format._minimumFractionDigits = 0;
}
}
// The effectiveDecimalPos is the position the decimal is at or would be at
// if there is no decimal. Note that if decimalPos<0, then digitTotalCount
// == digitLeftCount + zeroDigitCount.
var effectiveDecimalPos = decimalPos >= 0 ? decimalPos : totalDigits;
format._minimumIntegerDigits = effectiveDecimalPos - digitLeftCount;
if (format._useExponentialNotation) {
format._maximumIntegerDigits =
digitLeftCount + format._minimumIntegerDigits;
// In exponential display, we need to at least show something.
if (format._maximumFractionDigits == 0 &&
format._minimumIntegerDigits == 0) {
format._minimumIntegerDigits = 1;
}
}
format._groupingSize = max(0, groupingCount);
format._decimalSeparatorAlwaysShown = decimalPos == 0 ||
decimalPos == totalDigits;
return trunk.toString();
}
/**
* Parse an individual character of the trunk. Return true if we should
* continue to look for additional trunk characters or false if we have
* reached the end.
*/
bool parseTrunkCharacter() {
var ch = pattern.current;
switch (ch) {
case _PATTERN_DIGIT:
if (zeroDigitCount > 0) {
digitRightCount++;
} else {
digitLeftCount++;
}
if (groupingCount >= 0 && decimalPos < 0) {
groupingCount++;
}
break;
case _PATTERN_ZERO_DIGIT:
if (digitRightCount > 0) {
throw new FormatException('Unexpected "0" in pattern "'
+ pattern.input + '"');
}
zeroDigitCount++;
if (groupingCount >= 0 && decimalPos < 0) {
groupingCount++;
}
break;
case _PATTERN_GROUPING_SEPARATOR:
groupingCount = 0;
break;
case _PATTERN_DECIMAL_SEPARATOR:
if (decimalPos >= 0) {
throw new FormatException(
'Multiple decimal separators in pattern "$pattern"');
}
decimalPos = digitLeftCount + zeroDigitCount + digitRightCount;
break;
case _PATTERN_EXPONENT:
trunk.write(ch);
if (format._useExponentialNotation) {
throw new FormatException(
'Multiple exponential symbols in pattern "$pattern"');
}
format._useExponentialNotation = true;
format._minimumExponentDigits = 0;
// exponent pattern can have a optional '+'.
pattern.moveNext();
var nextChar = pattern.current;
if (nextChar == _PATTERN_PLUS) {
trunk.write(pattern.current);
pattern.moveNext();
format._useSignForPositiveExponent = true;
}
// Use lookahead to parse out the exponential part
// of the pattern, then jump into phase 2.
while (pattern.current == _PATTERN_ZERO_DIGIT) {
trunk.write(pattern.current);
pattern.moveNext();
format._minimumExponentDigits++;
}
if ((digitLeftCount + zeroDigitCount) < 1 ||
format._minimumExponentDigits < 1) {
throw new FormatException(
'Malformed exponential pattern "$pattern"');
}
return false;
default:
return false;
}
trunk.write(ch);
pattern.moveNext();
return true;
}
}
/**
* Returns an [Iterable] on the string as a list of substrings.
*/
Iterable _iterable(String s) => new _StringIterable(s);
/**
* Return an iterator on the string as a list of substrings.
*/
Iterator _iterator(String s) => new _StringIterator(s);
// TODO(nweiz): remove this when issue 3780 is fixed.
/**
* Provides an Iterable that wraps [_iterator] so it can be used in a `for`
* loop.
*/
class _StringIterable extends Iterable<String> {
final Iterator<String> iterator;
_StringIterable(String s)
: iterator = _iterator(s);
}
/**
* Provides an iterator over a string as a list of substrings, and also
* gives us a lookahead of one via the [peek] method.
*/
class _StringIterator implements Iterator<String> {
String input;
var index = -1;
inBounds(i) => i >= 0 && i < input.length;
_StringIterator(this.input);
String get current => inBounds(index) ? input[index] : null;
bool moveNext() => inBounds(++index);
String get peek => inBounds(index + 1) ? input[index + 1] : null;
Iterator<String> get iterator => this;
}