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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 (tom.enebo@gmail.com) 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 of those above. If you wish to allow use of your version of this file only under the terms of either the GPL or the LGPL, and not to allow others to use your version of this file under the terms of the CPL, indicate your decision by deleting the provisions above and replace them with the notice and other provisions required by the GPL or the LGPL. If you do not delete the provisions above, a recipient may use your version of this file under the terms of any one of the CPL, the GPL or the LGPL. END LICENSE BLOCK ***
 
 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 bytesboolean strict) {
         return new DoubleConverter().parse(bytesstrictfalse);
     }

    
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 bytesboolean strict) {
         return new DoubleConverter().parse(bytesstricttrue);
     }
 
     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 listboolean isStrictboolean is19) {
              = list.getUnsafeBytes();
              = list.begin();
              =  + list.length();
             this. = isStrict;
             this. = is19;
              = new char[list.length()+1]; // +1 for implicit '0' for terminating 'E'
              = 0;
         }
 
         private byte next() {
             return [++];
         }

        
Shift back to previous character in the incoming bytes

Returns:
false to indicate we are not in an EOS condition
 
         private boolean previous() {
             --;
             
             return false;
         }
 
         private boolean isDigit(byte b) {
             return b >= '0' && b <= '9';
         }
 
         private boolean isEOS() {
             return  >= ;
         }
 
         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) {
            [++] = (charb;
        }
        private boolean eatUnderscores() {
            while (!isEOS()) {
                byte value = next();
                if (value != '_') {
                    previous();
                    return isEOS();
                } else if () {
                    strictError();
                }
            }
            return true;
        }
        private double completeCalculation() {
            // ENEBO: Not sure about the '-' check here.
            if ( == 0 || ( == 1 && [0] == '-')) {
                if (strictError(); // Strict requires at least one digit.
                return 0.0;
            } else if (isExponent((byte[ - 1])) { // Covers 12.0efrog
                if (strictError();
                addToResult((byte'0');
            } else if ( && !isEOS()) {
                strictError(); // We know it is not whitespace at this point
            }
            return SafeDoubleParser.parseDouble(new String());
        }
        
        private void strictError() {
            throw new NumberFormatException("does not meet strict criteria");
        }
        public double parse(ByteList listboolean strictboolean is19) {
            init(liststrictis19);
            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 != '_' ||  || 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 () {
                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 (strictError();
                    
                    return isEOS();
                }
 
            }
            return true;
        }
        private boolean parseDecimalDigits() {
            if (isEOS()) {
                if (strictError();
                
                return true;
            }
            
            byte value = next();
            if (isDigit(value)) {
                addToResult(value);
            } else if (value == '_') {
                if (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 (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 (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 (strictError();
                    return true;
                }
            } 
            return true// Exponent end of double...let's finish.
        }
        private void verifyNumberAfterUnderscore() {
            if () {
                if (isEOS()) strictError();
                byte value = next();
                
                if (!isDigit(value)) {
                    previous();
                    strictError();
                } else {
                    addToResult(value);
                }
            }
        }
    }
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