PatternStringParser.java
// © 2017 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
package com.ibm.icu.impl.number;
import com.ibm.icu.impl.number.Padder.PadPosition;
/** Implements a recursive descent parser for decimal format patterns. */
public class PatternStringParser {
public static final int IGNORE_ROUNDING_NEVER = 0;
public static final int IGNORE_ROUNDING_IF_CURRENCY = 1;
public static final int IGNORE_ROUNDING_ALWAYS = 2;
/**
* Runs the recursive descent parser on the given pattern string, returning a data structure
* with raw information about the pattern string.
*
* <p>To obtain a more useful form of the data, consider using {@link #parseToProperties}
* instead.
*
* @param patternString The LDML decimal format pattern (Excel-style pattern) to parse.
* @return The results of the parse.
*/
public static ParsedPatternInfo parseToPatternInfo(String patternString) {
ParserState state = new ParserState(patternString);
ParsedPatternInfo result = new ParsedPatternInfo(patternString);
consumePattern(state, result);
return result;
}
/**
* Parses a pattern string into a new property bag.
*
* @param pattern The pattern string, like "#,##0.00"
* @param ignoreRounding Whether to leave out rounding information (minFrac, maxFrac, and
* rounding increment) when parsing the pattern. This may be desirable if a custom rounding
* mode, such as CurrencyUsage, is to be used instead. One of {@link
* PatternStringParser#IGNORE_ROUNDING_ALWAYS}, {@link
* PatternStringParser#IGNORE_ROUNDING_IF_CURRENCY}, or {@link
* PatternStringParser#IGNORE_ROUNDING_NEVER}.
* @return A property bag object.
* @throws IllegalArgumentException If there is a syntax error in the pattern string.
*/
public static DecimalFormatProperties parseToProperties(String pattern, int ignoreRounding) {
DecimalFormatProperties properties = new DecimalFormatProperties();
parseToExistingPropertiesImpl(pattern, properties, ignoreRounding);
return properties;
}
public static DecimalFormatProperties parseToProperties(String pattern) {
return parseToProperties(pattern, PatternStringParser.IGNORE_ROUNDING_NEVER);
}
/**
* Parses a pattern string into an existing property bag. All properties that can be encoded
* into a pattern string will be overwritten with either their default value or with the value
* coming from the pattern string. Properties that cannot be encoded into a pattern string, such
* as rounding mode, are not modified.
*
* @param pattern The pattern string, like "#,##0.00"
* @param properties The property bag object to overwrite.
* @param ignoreRounding See {@link #parseToProperties(String pattern, int ignoreRounding)}.
* @throws IllegalArgumentException If there was a syntax error in the pattern string.
*/
public static void parseToExistingProperties(
String pattern, DecimalFormatProperties properties, int ignoreRounding) {
parseToExistingPropertiesImpl(pattern, properties, ignoreRounding);
}
public static void parseToExistingProperties(
String pattern, DecimalFormatProperties properties) {
parseToExistingProperties(pattern, properties, PatternStringParser.IGNORE_ROUNDING_NEVER);
}
/** Contains raw information about the parsed decimal format pattern string. */
public static class ParsedPatternInfo implements AffixPatternProvider {
public String pattern;
public ParsedSubpatternInfo positive;
public ParsedSubpatternInfo negative;
private ParsedPatternInfo(String pattern) {
this.pattern = pattern;
}
@Override
public char charAt(int flags, int index) {
long endpoints = getEndpoints(flags);
int left = (int) (endpoints & 0xffffffff);
int right = (int) (endpoints >>> 32);
if (index < 0 || index >= right - left) {
throw new IndexOutOfBoundsException();
}
return pattern.charAt(left + index);
}
@Override
public int length(int flags) {
return getLengthFromEndpoints(getEndpoints(flags));
}
public static int getLengthFromEndpoints(long endpoints) {
int left = (int) (endpoints & 0xffffffff);
int right = (int) (endpoints >>> 32);
return right - left;
}
@Override
public String getString(int flags) {
long endpoints = getEndpoints(flags);
int left = (int) (endpoints & 0xffffffff);
int right = (int) (endpoints >>> 32);
if (left == right) {
return "";
}
return pattern.substring(left, right);
}
private long getEndpoints(int flags) {
boolean prefix = (flags & Flags.PREFIX) != 0;
boolean isNegative = (flags & Flags.NEGATIVE_SUBPATTERN) != 0;
boolean padding = (flags & Flags.PADDING) != 0;
if (isNegative && padding) {
return negative.paddingEndpoints;
} else if (padding) {
return positive.paddingEndpoints;
} else if (prefix && isNegative) {
return negative.prefixEndpoints;
} else if (prefix) {
return positive.prefixEndpoints;
} else if (isNegative) {
return negative.suffixEndpoints;
} else {
return positive.suffixEndpoints;
}
}
@Override
public boolean positiveHasPlusSign() {
return positive.hasPlusSign;
}
@Override
public boolean hasNegativeSubpattern() {
return negative != null;
}
@Override
public boolean negativeHasMinusSign() {
return negative.hasMinusSign;
}
@Override
public boolean hasCurrencySign() {
return positive.hasCurrencySign || (negative != null && negative.hasCurrencySign);
}
@Override
public boolean containsSymbolType(int type) {
return AffixUtils.containsType(pattern, type);
}
@Override
public boolean hasBody() {
return positive.integerTotal > 0;
}
@Override
public boolean currencyAsDecimal() {
return positive.hasCurrencyDecimal;
}
}
public static class ParsedSubpatternInfo {
public long groupingSizes = 0x0000ffffffff0000L;
public int integerLeadingHashSigns = 0;
public int integerTrailingHashSigns = 0;
public int integerNumerals = 0;
public int integerAtSigns = 0;
public int integerTotal = 0; // for convenience
public int fractionNumerals = 0;
public int fractionHashSigns = 0;
public int fractionTotal = 0; // for convenience
public boolean hasDecimal = false;
public int widthExceptAffixes = 0;
public PadPosition paddingLocation = null;
public DecimalQuantity_DualStorageBCD rounding = null;
public boolean exponentHasPlusSign = false;
public int exponentZeros = 0;
public boolean hasPercentSign = false;
public boolean hasPerMilleSign = false;
public boolean hasCurrencySign = false;
public boolean hasCurrencyDecimal = false;
public boolean hasMinusSign = false;
public boolean hasPlusSign = false;
public long prefixEndpoints = 0;
public long suffixEndpoints = 0;
public long paddingEndpoints = 0;
}
/////////////////////////////////////////////////////
/// BEGIN RECURSIVE DESCENT PARSER IMPLEMENTATION ///
/////////////////////////////////////////////////////
/** An internal class used for tracking the cursor during parsing of a pattern string. */
private static class ParserState {
final String pattern;
int offset;
ParserState(String pattern) {
this.pattern = pattern;
this.offset = 0;
}
/** Returns the next code point, or -1 if string is too short. */
int peek() {
if (offset == pattern.length()) {
return -1;
} else {
return pattern.codePointAt(offset);
}
}
/** Returns the code point after the next code point, or -1 if string is too short. */
int peek2() {
if (offset == pattern.length()) {
return -1;
}
int cp1 = pattern.codePointAt(offset);
int offset2 = offset + Character.charCount(cp1);
if (offset2 == pattern.length()) {
return -1;
}
return pattern.codePointAt(offset2);
}
/** Returns the next code point and then steps forward. */
int next() {
int codePoint = peek();
offset += Character.charCount(codePoint);
return codePoint;
}
IllegalArgumentException toParseException(String message) {
StringBuilder sb = new StringBuilder();
sb.append("Malformed pattern for ICU DecimalFormat: \"");
sb.append(pattern);
sb.append("\": ");
sb.append(message);
sb.append(" at position ");
sb.append(offset);
return new IllegalArgumentException(sb.toString());
}
}
private static void consumePattern(ParserState state, ParsedPatternInfo result) {
// pattern := subpattern (';' subpattern)?
result.positive = new ParsedSubpatternInfo();
consumeSubpattern(state, result.positive);
if (state.peek() == ';') {
state.next(); // consume the ';'
// Don't consume the negative subpattern if it is empty (trailing ';')
if (state.peek() != -1) {
result.negative = new ParsedSubpatternInfo();
consumeSubpattern(state, result.negative);
}
}
if (state.peek() != -1) {
throw state.toParseException("Found unquoted special character");
}
}
private static void consumeSubpattern(ParserState state, ParsedSubpatternInfo result) {
// subpattern := literals? number exponent? literals?
consumePadding(state, result, PadPosition.BEFORE_PREFIX);
result.prefixEndpoints = consumeAffix(state, result);
consumePadding(state, result, PadPosition.AFTER_PREFIX);
consumeFormat(state, result);
consumeExponent(state, result);
consumePadding(state, result, PadPosition.BEFORE_SUFFIX);
result.suffixEndpoints = consumeAffix(state, result);
consumePadding(state, result, PadPosition.AFTER_SUFFIX);
}
private static void consumePadding(
ParserState state, ParsedSubpatternInfo result, PadPosition paddingLocation) {
if (state.peek() != '*') {
return;
}
if (result.paddingLocation != null) {
throw state.toParseException("Cannot have multiple pad specifiers");
}
result.paddingLocation = paddingLocation;
state.next(); // consume the '*'
result.paddingEndpoints |= state.offset;
consumeLiteral(state);
result.paddingEndpoints |= ((long) state.offset) << 32;
}
private static long consumeAffix(ParserState state, ParsedSubpatternInfo result) {
// literals := { literal }
long endpoints = state.offset;
outer:
while (true) {
switch (state.peek()) {
case '#':
case '@':
case ';':
case '*':
case '.':
case ',':
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case -1:
// Characters that cannot appear unquoted in a literal
break outer;
case '%':
result.hasPercentSign = true;
break;
case '‰':
result.hasPerMilleSign = true;
break;
case '¤':
result.hasCurrencySign = true;
break;
case '-':
result.hasMinusSign = true;
break;
case '+':
result.hasPlusSign = true;
break;
}
consumeLiteral(state);
}
endpoints |= ((long) state.offset) << 32;
return endpoints;
}
private static void consumeLiteral(ParserState state) {
if (state.peek() == -1) {
throw state.toParseException("Expected unquoted literal but found EOL");
} else if (state.peek() == '\'') {
state.next(); // consume the starting quote
while (state.peek() != '\'') {
if (state.peek() == -1) {
throw state.toParseException("Expected quoted literal but found EOL");
} else {
state.next(); // consume a quoted character
}
}
state.next(); // consume the ending quote
} else {
// consume a non-quoted literal character
state.next();
}
}
private static void consumeFormat(ParserState state, ParsedSubpatternInfo result) {
consumeIntegerFormat(state, result);
if (state.peek() == '.') {
state.next(); // consume the decimal point
result.hasDecimal = true;
result.widthExceptAffixes += 1;
consumeFractionFormat(state, result);
} else if (state.peek() == '¤') {
// Check if currency is a decimal separator
switch (state.peek2()) {
case '#':
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
break;
default:
// Currency symbol followed by a non-numeric character;
// treat as a normal affix.
return;
}
// Currency symbol is followed by a numeric character;
// treat as a decimal separator.
result.hasCurrencySign = true;
result.hasCurrencyDecimal = true;
result.hasDecimal = true;
result.widthExceptAffixes += 1;
state.next(); // consume the symbol
consumeFractionFormat(state, result);
}
}
private static void consumeIntegerFormat(ParserState state, ParsedSubpatternInfo result) {
outer:
while (true) {
switch (state.peek()) {
case ',':
result.widthExceptAffixes += 1;
result.groupingSizes <<= 16;
break;
case '#':
if (result.integerNumerals > 0) {
throw state.toParseException("# cannot follow 0 before decimal point");
}
result.widthExceptAffixes += 1;
result.groupingSizes += 1;
if (result.integerAtSigns > 0) {
result.integerTrailingHashSigns += 1;
} else {
result.integerLeadingHashSigns += 1;
}
result.integerTotal += 1;
break;
case '@':
if (result.integerNumerals > 0) {
throw state.toParseException("Cannot mix 0 and @");
}
if (result.integerTrailingHashSigns > 0) {
throw state.toParseException("Cannot nest # inside of a run of @");
}
result.widthExceptAffixes += 1;
result.groupingSizes += 1;
result.integerAtSigns += 1;
result.integerTotal += 1;
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
if (result.integerAtSigns > 0) {
throw state.toParseException("Cannot mix @ and 0");
}
result.widthExceptAffixes += 1;
result.groupingSizes += 1;
result.integerNumerals += 1;
result.integerTotal += 1;
if (state.peek() != '0' && result.rounding == null) {
result.rounding = new DecimalQuantity_DualStorageBCD();
}
if (result.rounding != null) {
result.rounding.appendDigit((byte) (state.peek() - '0'), 0, true);
}
break;
default:
break outer;
}
state.next(); // consume the symbol
}
// Disallow patterns with a trailing ',' or with two ',' next to each other
short grouping1 = (short) (result.groupingSizes & 0xffff);
short grouping2 = (short) ((result.groupingSizes >>> 16) & 0xffff);
short grouping3 = (short) ((result.groupingSizes >>> 32) & 0xffff);
if (grouping1 == 0 && grouping2 != -1) {
throw state.toParseException("Trailing grouping separator is invalid");
}
if (grouping2 == 0 && grouping3 != -1) {
throw state.toParseException("Grouping width of zero is invalid");
}
}
private static void consumeFractionFormat(ParserState state, ParsedSubpatternInfo result) {
int zeroCounter = 0;
while (true) {
switch (state.peek()) {
case '#':
result.widthExceptAffixes += 1;
result.fractionHashSigns += 1;
result.fractionTotal += 1;
zeroCounter++;
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
if (result.fractionHashSigns > 0) {
throw state.toParseException("0 cannot follow # after decimal point");
}
result.widthExceptAffixes += 1;
result.fractionNumerals += 1;
result.fractionTotal += 1;
if (state.peek() == '0') {
zeroCounter++;
} else {
if (result.rounding == null) {
result.rounding = new DecimalQuantity_DualStorageBCD();
}
result.rounding.appendDigit(
(byte) (state.peek() - '0'), zeroCounter, false);
zeroCounter = 0;
}
break;
default:
return;
}
state.next(); // consume the symbol
}
}
private static void consumeExponent(ParserState state, ParsedSubpatternInfo result) {
if (state.peek() != 'E') {
return;
}
if ((result.groupingSizes & 0xffff0000L) != 0xffff0000L) {
throw state.toParseException("Cannot have grouping separator in scientific notation");
}
state.next(); // consume the E
result.widthExceptAffixes++;
if (state.peek() == '+') {
state.next(); // consume the +
result.exponentHasPlusSign = true;
result.widthExceptAffixes++;
}
while (state.peek() == '0') {
state.next(); // consume the 0
result.exponentZeros += 1;
result.widthExceptAffixes++;
}
}
///////////////////////////////////////////////////
/// END RECURSIVE DESCENT PARSER IMPLEMENTATION ///
///////////////////////////////////////////////////
private static void parseToExistingPropertiesImpl(
String pattern, DecimalFormatProperties properties, int ignoreRounding) {
if (pattern == null || pattern.length() == 0) {
// Backwards compatibility requires that we reset to the default values.
// TODO: Only overwrite the properties that "saveToProperties" normally touches?
properties.clear();
return;
}
// TODO: Use thread locals here?
ParsedPatternInfo patternInfo = parseToPatternInfo(pattern);
patternInfoToProperties(properties, patternInfo, ignoreRounding);
}
/** Finalizes the temporary data stored in the ParsedPatternInfo to the Properties. */
private static void patternInfoToProperties(
DecimalFormatProperties properties,
ParsedPatternInfo patternInfo,
int _ignoreRounding) {
// Translate from PatternParseResult to Properties.
// Note that most data from "negative" is ignored per the specification of DecimalFormat.
ParsedSubpatternInfo positive = patternInfo.positive;
boolean ignoreRounding;
if (_ignoreRounding == PatternStringParser.IGNORE_ROUNDING_NEVER) {
ignoreRounding = false;
} else if (_ignoreRounding == PatternStringParser.IGNORE_ROUNDING_IF_CURRENCY) {
ignoreRounding = positive.hasCurrencySign;
} else {
assert _ignoreRounding == PatternStringParser.IGNORE_ROUNDING_ALWAYS;
ignoreRounding = true;
}
// Grouping settings
short grouping1 = (short) (positive.groupingSizes & 0xffff);
short grouping2 = (short) ((positive.groupingSizes >>> 16) & 0xffff);
short grouping3 = (short) ((positive.groupingSizes >>> 32) & 0xffff);
if (grouping2 != -1) {
properties.setGroupingSize(grouping1);
properties.setGroupingUsed(true);
} else {
properties.setGroupingSize(-1);
properties.setGroupingUsed(false);
}
if (grouping3 != -1) {
properties.setSecondaryGroupingSize(grouping2);
} else {
properties.setSecondaryGroupingSize(-1);
}
// For backwards compatibility, require that the pattern emit at least one min digit.
int minInt, minFrac;
if (positive.integerTotal == 0 && positive.fractionTotal > 0) {
// patterns like ".##"
minInt = 0;
minFrac = Math.max(1, positive.fractionNumerals);
} else if (positive.integerNumerals == 0 && positive.fractionNumerals == 0) {
// patterns like "#.##"
minInt = 1;
minFrac = 0;
} else {
minInt = positive.integerNumerals;
minFrac = positive.fractionNumerals;
}
// Rounding settings
// Don't set basic rounding when there is a currency sign; defer to CurrencyUsage
if (positive.integerAtSigns > 0) {
properties.setMinimumFractionDigits(-1);
properties.setMaximumFractionDigits(-1);
properties.setRoundingIncrement(null);
properties.setMinimumSignificantDigits(positive.integerAtSigns);
properties.setMaximumSignificantDigits(
positive.integerAtSigns + positive.integerTrailingHashSigns);
} else if (positive.rounding != null) {
if (!ignoreRounding) {
properties.setMinimumFractionDigits(minFrac);
properties.setMaximumFractionDigits(positive.fractionTotal);
properties.setRoundingIncrement(
positive.rounding.toBigDecimal().setScale(positive.fractionNumerals));
} else {
properties.setMinimumFractionDigits(-1);
properties.setMaximumFractionDigits(-1);
properties.setRoundingIncrement(null);
}
properties.setMinimumSignificantDigits(-1);
properties.setMaximumSignificantDigits(-1);
} else {
if (!ignoreRounding) {
properties.setMinimumFractionDigits(minFrac);
properties.setMaximumFractionDigits(positive.fractionTotal);
properties.setRoundingIncrement(null);
} else {
properties.setMinimumFractionDigits(-1);
properties.setMaximumFractionDigits(-1);
properties.setRoundingIncrement(null);
}
properties.setMinimumSignificantDigits(-1);
properties.setMaximumSignificantDigits(-1);
}
// If the pattern ends with a '.' then force the decimal point.
if (positive.hasDecimal && positive.fractionTotal == 0) {
properties.setDecimalSeparatorAlwaysShown(true);
} else {
properties.setDecimalSeparatorAlwaysShown(false);
}
// Persist the currency as decimal separator
properties.setCurrencyAsDecimal(positive.hasCurrencyDecimal);
// Scientific notation settings
if (positive.exponentZeros > 0) {
properties.setExponentSignAlwaysShown(positive.exponentHasPlusSign);
properties.setMinimumExponentDigits(positive.exponentZeros);
if (positive.integerAtSigns == 0) {
// patterns without '@' can define max integer digits, used for engineering notation
properties.setMinimumIntegerDigits(positive.integerNumerals);
properties.setMaximumIntegerDigits(positive.integerTotal);
} else {
// patterns with '@' cannot define max integer digits
properties.setMinimumIntegerDigits(1);
properties.setMaximumIntegerDigits(-1);
}
} else {
properties.setExponentSignAlwaysShown(false);
properties.setMinimumExponentDigits(-1);
properties.setMinimumIntegerDigits(minInt);
properties.setMaximumIntegerDigits(-1);
}
// Compute the affix patterns (required for both padding and affixes)
String posPrefix = patternInfo.getString(AffixPatternProvider.Flags.PREFIX);
String posSuffix = patternInfo.getString(0);
// Padding settings
if (positive.paddingLocation != null) {
// The width of the positive prefix and suffix templates are included in the padding
int paddingWidth =
positive.widthExceptAffixes
+ AffixUtils.estimateLength(posPrefix)
+ AffixUtils.estimateLength(posSuffix);
properties.setFormatWidth(paddingWidth);
String rawPaddingString = patternInfo.getString(AffixPatternProvider.Flags.PADDING);
if (rawPaddingString.length() == 1) {
properties.setPadString(rawPaddingString);
} else if (rawPaddingString.length() == 2) {
if (rawPaddingString.charAt(0) == '\'') {
properties.setPadString("'");
} else {
properties.setPadString(rawPaddingString);
}
} else {
properties.setPadString(
rawPaddingString.substring(1, rawPaddingString.length() - 1));
}
assert positive.paddingLocation != null;
properties.setPadPosition(positive.paddingLocation);
} else {
properties.setFormatWidth(-1);
properties.setPadString(null);
properties.setPadPosition(null);
}
// Set the affixes
// Always call the setter, even if the prefixes are empty, especially in the case of the
// negative prefix pattern, to prevent default values from overriding the pattern.
properties.setPositivePrefixPattern(posPrefix);
properties.setPositiveSuffixPattern(posSuffix);
if (patternInfo.negative != null) {
properties.setNegativePrefixPattern(
patternInfo.getString(
AffixPatternProvider.Flags.NEGATIVE_SUBPATTERN
| AffixPatternProvider.Flags.PREFIX));
properties.setNegativeSuffixPattern(
patternInfo.getString(AffixPatternProvider.Flags.NEGATIVE_SUBPATTERN));
} else {
properties.setNegativePrefixPattern(null);
properties.setNegativeSuffixPattern(null);
}
// Set the magnitude multiplier
if (positive.hasPercentSign) {
properties.setMagnitudeMultiplier(2);
} else if (positive.hasPerMilleSign) {
properties.setMagnitudeMultiplier(3);
} else {
properties.setMagnitudeMultiplier(0);
}
}
}