org.jruby.util.ConvertDouble Maven / Gradle / Ivy
/***** BEGIN LICENSE BLOCK *****
* Version: CPL 1.0/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Common Public
* License Version 1.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.eclipse.org/legal/cpl-v10.html
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* Copyright (C) 2010 Thomas E Enebo ([email protected])
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
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package org.jruby.util;
public class ConvertDouble {
/**
* Converts supplied ByteList into a double. strict-mode will not like
* extra text non-numeric text or multiple sequention underscores.
*/
public static final double byteListToDouble(ByteList bytes, boolean strict) {
return new DoubleConverter().parse(bytes, strict, false);
}
/**
* Converts supplied ByteList into a double. This is almost exactly the
* same as byteListToDouble, but leading underscores are no longer skipped
* in 1.9 (e.g. __1 == 0.0 in 1.9 while 1.8 parses it as 1.0).
*/
public static final double byteListToDouble19(ByteList bytes, boolean strict) {
return new DoubleConverter().parse(bytes, strict, true);
}
public static class DoubleConverter {
private byte[] bytes;
private int index;
private int endIndex;
private boolean isStrict;
private boolean is19;
private char[] chars; // result string we use to parse.
private int charsIndex;
public DoubleConverter() {}
public void init(ByteList list, boolean isStrict, boolean is19) {
bytes = list.getUnsafeBytes();
index = list.begin();
endIndex = index + list.length();
this.isStrict = isStrict;
this.is19 = is19;
chars = new char[list.length()+1]; // +1 for implicit '0' for terminating 'E'
charsIndex = 0;
}
private byte next() {
return bytes[index++];
}
/**
* Shift back to previous character in the incoming bytes
* @return false to indicate we are not in an EOS condition
*/
private boolean previous() {
index--;
return false;
}
private boolean isDigit(byte b) {
return b >= '0' && b <= '9';
}
private boolean isEOS() {
return index >= endIndex;
}
private boolean isExponent(byte b) {
return b == 'e' || b == 'E';
}
private boolean isWhitespace(byte b) {
return b == ' ' || (b <= 13 && b >= 9 && b != 11);
}
private void addToResult(byte b) {
chars[charsIndex++] = (char) b;
}
private boolean eatUnderscores() {
while (!isEOS()) {
byte value = next();
if (value != '_') {
previous();
return isEOS();
} else if (isStrict) {
strictError();
}
}
return true;
}
private double completeCalculation() {
// ENEBO: Not sure about the '-' check here.
if (charsIndex == 0 || (charsIndex == 1 && chars[0] == '-')) {
if (isStrict) strictError(); // Strict requires at least one digit.
return 0.0;
} else if (isExponent((byte) chars[charsIndex - 1])) { // Covers 12.0efrog
if (isStrict) strictError();
addToResult((byte) '0');
} else if (isStrict && !isEOS()) {
strictError(); // We know it is not whitespace at this point
}
return SafeDoubleParser.parseDouble(new String(chars));
}
private void strictError() {
throw new NumberFormatException("does not meet strict criteria");
}
public double parse(ByteList list, boolean strict, boolean is19) {
init(list, strict, is19);
if (skipWhitespace()) return completeCalculation();
if (parseOptionalSign()) return completeCalculation();
parseDigits();
return completeCalculation();
}
/**
* Consume initial whitespace and underscores so that next character
* examined is not whitespace. 1.9 and strict do not allow leading
* underscores. Returns whether next position is at the end of the
* string or not.
*
* Trivia: " _ _ _ _ 1".to_f == 1.0 in Ruby 1.8
*/
private boolean skipWhitespace() {
while (!isEOS()) {
byte value = next();
if (isWhitespace(value)) continue;
if (value != '_' || isStrict || is19) return previous();
}
return true;
}
private boolean parseOptionalSign() {
byte sign = next();
if (sign == '-') {
addToResult(sign);
} else if (sign != '+') {
previous(); // backup...not a sign-char
}
return isEOS();
}
private boolean parseDigits() {
if (!isEOS()) {
byte value = next();
if (isDigit(value)) {
addToResult(value);
} else if (value == '.') {
addToResult(value);
return parseDecimalDigits();
} else {
return isEOS();
}
} else if (isStrict) {
strictError();
}
while (!isEOS()) {
byte value = next();
if (isDigit(value)) {
addToResult(value);
} else if (value == '.') {
addToResult(value);
return parseDecimalDigits();
} else if (value == '_') {
verifyNumberAfterUnderscore();
} else if (isExponent(value)) {
addToResult(value);
return parseExponent();
} else if (isWhitespace(value)) {
return skipWhitespace();
} else {
if (isStrict) strictError();
return isEOS();
}
}
return true;
}
private boolean parseDecimalDigits() {
if (isEOS()) {
if (isStrict) strictError();
return true;
}
byte value = next();
if (isDigit(value)) {
addToResult(value);
} else if (value == '_') {
if (isStrict) strictError();
while (!isEOS()) { // Wonky, but 12._2e2 is 1200.0 and 12.__e2 is 12.0
value = next();
if (isDigit(value)) {
addToResult(value);
break;
} else if (value != '_') {
return true;
}
}
} else {
if (isStrict) strictError();
return true; // Found garbage must be at end of string.
}
while (!isEOS()) {
value = next();
if (isDigit(value)) {
addToResult(value);
} else if (isExponent(value)) {
addToResult(value);
return parseExponent();
} else if (value == '_') {
verifyNumberAfterUnderscore();
} else if (isWhitespace(value)) {
return skipWhitespace();
} else {
if (isStrict) strictError();
return true;
}
}
return true;
}
private boolean parseExponent() {
if (eatUnderscores()) return isEOS();
byte value = next();
if (value == '-' || value == '+') {
addToResult(value);
} else {
previous();
}
while (!isEOS()) {
value = next();
if (isDigit(value)) {
addToResult(value);
} else if (isWhitespace(value)) {
return skipWhitespace();
} else if (value == '_') {
verifyNumberAfterUnderscore();
} else {
if (isStrict) strictError();
return true;
}
}
return true; // Exponent end of double...let's finish.
}
private void verifyNumberAfterUnderscore() {
if (isStrict) {
if (isEOS()) strictError();
byte value = next();
if (!isDigit(value)) {
previous();
strictError();
} else {
addToResult(value);
}
}
}
}
}