package org.apache.commons.lang;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2002 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
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 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

import java.math.BigInteger;
import java.math.BigDecimal;
/**
 * Java Number クラスに対する付加機能を提供します。
 * {@primary Provides extra functionality for Java Number classes.}
 *
 * @author <a href="mailto:bayard@generationjava.com">Henri Yandell</a>
 * @author <a href="mailto:rand_mcneely@yahoo.com">Rand McNeely</a>
 * @author <a href="mailto:scolebourne@joda.org">Stephen Colebourne</a>
 * @author <a href="mailto:steve.downey@netfolio.com">Steve Downey</a>
 * @translator 日置 聡
 * @status firstdraft
 * @update 2003/08/13
 * @version $Id: NumberUtils.java,v 1.1.1.1 2004/02/13 10:02:04 hioki Exp $
 */
public final class NumberUtils {

    /**
     * NumberUtils のインスタンスは一般的なプログラムからは生成すべきではありません。
     * 代わりに <code>NumberUtils.stringToInt("6");</code> というように使用すべきです。
     * このコンストラクタは、処理に JavaBean インスタンスを必要とするツールのために public になっています。
     * {@primary NumberUtils instances should NOT be constructed in standard programming.
     * Instead, the class should be used as <code>NumberUtils.stringToInt("6");</code>.
     * This constructor is public to permit tools that require a JavaBean instance
     * to operate.}
     */
    public NumberUtils() {
    }

    //--------------------------------------------------------------------
    
    /**
     * String を int に変換します。変換に失敗した場合には 0 を返します。
     * {@primary Convert a String to an int, returning zero if the conversion fails}
     * 
     * @param str  変換する文字列
     * {@primary the string to convert}
     * @return 文字列が示す int の値、変換に失敗した場合には 0
     * {@primary the int represented by the string, or zero if conversion fails}
     */
    public static int stringToInt(String str) {
        return stringToInt(str, 0);
    }

    /**
     * String を int に変換します。変換に失敗した場合にはデフォルトの値を返します。
     * {@primary Convert a String to an int, returning a default value if the 
     * conversion fails.}
     * 
     * @param str  変換する文字列
     * {@primary the string to convert}
     * @param defaultValue  デフォルトの値
     * {@primary the default value}
     * @return 文字列が示す int の値、変換に失敗した場合にはデフォルトの値
     * {@primary the int represented by the string, or the default if conversion fails}
     */
    public static int stringToInt(String str, int defaultValue) {
        try {
            return Integer.parseInt(str);
        } catch (NumberFormatException nfe) {
            return defaultValue;
        }
    }

    //--------------------------------------------------------------------
    
    // must handle Long, Float, Integer, Float, Short,
    //                  BigDecimal, BigInteger and Byte
    // useful methods:
    // Byte.decode(String)
    // Byte.valueOf(String,int radix)
    // Byte.valueOf(String)
    // Double.valueOf(String)
    // Float.valueOf(String)
    // new Float(String)
    // Integer.valueOf(String,int radix)
    // Integer.valueOf(String)
    // Integer.decode(String)
    // Integer.getInteger(String)
    // Integer.getInteger(String,int val)
    // Integer.getInteger(String,Integer val)
    // new Integer(String)
    // new Double(String)
    // new Byte(String)
    // new Long(String)
    // Long.getLong(String)
    // Long.getLong(String,int)
    // Long.getLong(String,Integer)
    // Long.valueOf(String,int)
    // Long.valueOf(String)
    // new Short(String)
    // Short.decode(String)
    // Short.valueOf(String,int)
    // Short.valueOf(String)
    // new BigDecimal(String)
    // new BigInteger(String)
    // new BigInteger(String,int radix)
    // Possible inputs:
    // 45 45.5 45E7 4.5E7 Hex Oct Binary xxxF xxxD xxxf xxxd
    // plus minus everything. Prolly more. A lot are not separable.

    /**
     * <p>
     * 文字列の値を java.lang.Number に変換します。
     * まず最初に文字列の末尾の修飾(<code>'f','F','d','D','l','L'</code>)を調べます。
     * これが見つかった場合、指定された型に該当する型を保持する値が小さいものから順に試行し生成します。
     * {@primary Turns a string value into a java.lang.Number.
     * First, the value is examined for a type qualifier on the end 
     * (<code>'f','F','d','D','l','L'</code>).  If it is found, it starts 
     * trying to create succissively larger types from the type specified
     * until one is found that can hold the value.}
     * </p>
     * <p>
     * 型を定義する記述が見つからなかった場合には、小数点がなかった場合には
     * Integer から BigInteger まで、あった場合には Float から BigDecimal までを順に
     * 試行し生成します。
     * {@primary If a type specifier is not found, it will check for a decimal point
     * and then try successively larger types from Integer to BigInteger 
     * and from Float to BigDecimal.}
     * </p>
     * <p>
     * 文字列が "0x" または "-0x" で始まる場合には16進数とみなされます。
     * 0 で始まる値は8進数とはみなされません。
     * {@primary If the string starts with "0x" or "-0x", it will be interpreted as a 
     * hexadecimal integer.  Values with leading 0's will not be interpreted 
     * as octal.}
     * </p>
     * 
     * @param val 数値を含んだ文字列
     * {@primary String containing a number}
     * @return 文字列から生成された Number
     * {@primary Number created from the string}
     * @throws NumberFormatException 変換が行えなかった場合
     * {@primary if the value cannot be converted}
     */
    public static Number createNumber(String val) throws NumberFormatException {
        if (val == null) {
            return null;
        }
        if (val.length() == 0) {
            throw new NumberFormatException("\"\" is not a valid number.");
        }
        if (val.startsWith("--")) {
            // this is protection for poorness in java.lang.BigDecimal.
            // it accepts this as a legal value, but it does not appear 
            // to be in specification of class. OS X Java parses it to 
            // a wrong value.
            return null;
        }
        if (val.startsWith("0x") || val.startsWith("-0x")) {
            return createInteger(val);
        }   
        char lastChar = val.charAt(val.length() - 1);
        String mant;
        String dec;
        String exp;
        int decPos = val.indexOf('.');
        int expPos = val.indexOf('e') + val.indexOf('E') + 1;

        if (decPos > -1) {

            if (expPos > -1) {
                if (expPos < decPos) {
                    throw new NumberFormatException(val + " is not a valid number.");
                }
                dec = val.substring(decPos + 1, expPos);
            } else {
                dec = val.substring(decPos + 1);
            }
            mant = val.substring(0, decPos);
        } else {
            if (expPos > -1) {
                mant = val.substring(0, expPos);
            } else {
                mant = val;
            }
            dec = null;
        }
        if (!Character.isDigit(lastChar)) {
            if (expPos > -1 && expPos < val.length() - 1) {
                exp = val.substring(expPos + 1, val.length() - 1);
            } else {
                exp = null;
            }
            //Requesting a specific type..
            String numeric = val.substring(0, val.length() - 1);
            boolean allZeros = isAllZeros(mant) && isAllZeros(exp);
            switch (lastChar) {
                case 'l' :
                case 'L' :
                    if (dec == null
                        && exp == null
                        && isDigits(numeric.substring(1))
                        && (numeric.charAt(0) == '-' || Character.isDigit(numeric.charAt(0)))) {
                        try {
                            return createLong(numeric);
                        } catch (NumberFormatException nfe) {
                            //Too big for a long
                        }
                        return createBigInteger(numeric);

                    }
                    throw new NumberFormatException(val + " is not a valid number.");
                case 'f' :
                case 'F' :
                    try {
                        Float f = NumberUtils.createFloat(numeric);
                        if (!(f.isInfinite() || (f.floatValue() == 0.0F && !allZeros))) {
                            //If it's too big for a float or the float value = 0 and the string
                            //has non-zeros in it, then float doens't have the presision we want
                            return f;
                        }

                    } catch (NumberFormatException nfe) {
                    }
                    //Fall through
                case 'd' :
                case 'D' :
                    try {
                        Double d = NumberUtils.createDouble(numeric);
                        if (!(d.isInfinite() || (d.floatValue() == 0.0D && !allZeros))) {
                            return d;
                        }
                    } catch (NumberFormatException nfe) {
                    }
                    try {
                        return createBigDecimal(numeric);
                    } catch (NumberFormatException e) {
                    }
                    //Fall through
                default :
                    throw new NumberFormatException(val + " is not a valid number.");

            }
        } else {
            //User doesn't have a preference on the return type, so let's start
            //small and go from there...
            if (expPos > -1 && expPos < val.length() - 1) {
                exp = val.substring(expPos + 1, val.length());
            } else {
                exp = null;
            }
            if (dec == null && exp == null) {
                //Must be an int,long,bigint
                try {
                    return createInteger(val);
                } catch (NumberFormatException nfe) {
                }
                try {
                    return createLong(val);
                } catch (NumberFormatException nfe) {
                }
                return createBigInteger(val);

            } else {
                //Must be a float,double,BigDec
                boolean allZeros = isAllZeros(mant) && isAllZeros(exp);
                try {
                    Float f = createFloat(val);
                    if (!(f.isInfinite() || (f.floatValue() == 0.0F && !allZeros))) {
                        return f;
                    }
                } catch (NumberFormatException nfe) {
                }
                try {
                    Double d = createDouble(val);
                    if (!(d.isInfinite() || (d.doubleValue() == 0.0D && !allZeros))) {
                        return d;
                    }
                } catch (NumberFormatException nfe) {
                }

                return createBigDecimal(val);

            }

        }
    }

    /**
     * createNumber のためのユーティリティメソッド。s が null だった場合に true を返します。
     * {@primary Utility method for createNumber.  Returns true if s is null}
     * 
     * @param s 評価対象となる String
     * {@primary the String to check}
     * @return null または全て0だった場合
     * {@primary if it is all zeros or null}
     */
    private static boolean isAllZeros(String s) {
        if (s == null) {
            return true;
        }
        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) != '0') {
                return false;
            }
        }
        return s.length() > 0;
    }

    //--------------------------------------------------------------------
    
    /**
     * String を Float に変換します。
     * {@primary Convert a String to a Float}
     * 
     * @param val  変換の対象となる String
     * {@primary a String to convert}
     * @return 変換された Float
     * {@primary converted Float}
     * @throws NumberFormatException 変換が行えなかった場合
     * {@primary if the value cannot be converted}
     */
    public static Float createFloat(String val) {
        return Float.valueOf(val);
    }

    /**
     * String を Double に変換します。
     * {@primary Convert a String to a Double}
     * 
     * @param val  変換の対象となる String
     * {@primary a String to convert}
     * @return 変換された Double
     * {@primary converted Double}
     * @throws NumberFormatException 変換が行えなかった場合
     * {@primary if the value cannot be converted}
     */
    public static Double createDouble(String val) {
        return Double.valueOf(val);
    }

    /**
     * 16進数、8進数の記号をハンドリングして String を Integer に変換します。
     * {@primary Convert a String to a Integer, handling hex and
     * octal notations.}
     * 
     * @param val  変換の対象となる String
     * {@primary a String to convert}
     * @return 変換された Integer
     * {@primary converted Integer}
     * @throws NumberFormatException 変換が行えなかった場合
     * {@primary if the value cannot be converted}
     */
    public static Integer createInteger(String val) {
        // decode() handles 0xAABD and 0777 (hex and octal) as well.
        return Integer.decode(val);
    }

    /**
     * String を Long に変換します。
     * {@primary Convert a String to a Long}
     * 
     * @param val  変換の対象となる String
     * {@primary a String to convert}
     * @return 変換された Long
     * {@primary converted Long}
     * @throws NumberFormatException 変換が行えなかった場合
     * {@primary if the value cannot be converted}
     */
    public static Long createLong(String val) {
        return Long.valueOf(val);
    }

    /**
     * String を BigInteger に変換します。
     * {@primary Convert a String to a BigInteger}
     * 
     * @param val  変換の対象となる String
     * {@primary a String to convert}
     * @return 変換された BigInteger
     * {@primary converted BigInteger}
     * @throws NumberFormatException 変換が行えなかった場合
     * {@primary if the value cannot be converted}
     */
    public static BigInteger createBigInteger(String val) {
        BigInteger bi = new BigInteger(val);
        return bi;
    }

    /**
     * String を BigDecimal に変換します。
     * {@primary Convert a String to a BigDecimal}
     * 
     * @param val  変換の対象となる String
     * {@primary a String to convert}
     * @return 変換された BigDecimal
     * {@primary converted BigDecimal}
     * @throws NumberFormatException 変換が行えなかった場合
     * {@primary if the value cannot be converted}
     */
    public static BigDecimal createBigDecimal(String val) {
        BigDecimal bd = new BigDecimal(val);
        return bd;
    }

    //--------------------------------------------------------------------
    
    /**
     * 3つの中で一番小さい long の値を取得します。
     * {@primary Gets the minimum of three long values.}
     * 
     * @param a  値1
     * {@primary value 1}
     * @param b  値2
     * {@primary value 2}
     * @param c  値3
     * {@primary value 3}
     * @return  一番小さな値
     * {@primary the largest of the values}
     */
    public static long minimum(long a, long b, long c) {
        if (b < a) {
            a = b;
        }
        if (c < a) {
            a = c;
        }
        return a;
    }

    /**
     * 3つの中で一番小さい int の値を取得します。
     * {@primary Gets the minimum of three int values.}
     * 
     * @param a  値1
     * {@primary value 1}
     * @param b  値2
     * {@primary value 2}
     * @param c  値3
     * {@primary value 3}
     * @return  一番小さな値
     * {@primary the largest of the values}
     */
    public static int minimum(int a, int b, int c) {
        if (b < a) {
            a = b;
        }
        if (c < a) {
            a = c;
        }
        return a;
    }

    /**
     * 3つの中で一番大きな long の値を取得します。
     * {@primary Gets the maximum of three long values.} 
     * 
     * @param a  値1
     * {@primary value 1}
     * @param b  値2
     * {@primary value 2}
     * @param c  値3
     * {@primary value 3}
     * @return  一番大きな値
     * {@primary the largest of the values}
     */
    public static long maximum(long a, long b, long c) {
        if (b > a) {
            a = b;
        }
        if (c > a) {
            a = c;
        }
        return a;
    }

    /**
     * 3つの中で一番大きな int の値を取得します。
     * {@primary Gets the maximum of three int values.} 
     * 
     * @param a  値1
     * {@primary value 1}
     * @param b  値2
     * {@primary value 2}
     * @param c  値3
     * {@primary value 3}
     * @return  一番大きな値
     * {@primary the largest of the values}
     */
    public static int maximum(int a, int b, int c) {
        if (b > a) {
            a = b;
        }
        if (c > a) {
            a = c;
        }
        return a;
    }

    //--------------------------------------------------------------------
    
    /**
     * 2つの double の大きさを比べます。
     * {@primary Compares two doubles for order.}
     * <p>
     * このメソッドは標準的なJavaの比較演算よりも包括的です。
     * 最初の値が2つ目の値よりも小さい場合 -1 を返します。
     * 最初の値が2つ目の値よりも大きい場合 +1 を返します。
     * 両方の値が等しい場合 0 を返します。
     * {@primary This method is more comprhensive than the standard Java greater than,
     * less than and equals operators.
     * It returns -1 if the first value is less than the second.
     * It returns +1 if the first value is greater than the second.
     * It returns 0 if the values are equal.}
     * <p>
     * 評価される順番は大きい順に以下のようになります:
     * <ul>
     * <li>NaN
     * <li>正の無限大
     * <li>double の最大値
     * <li>正の数値
     * <li>+0.0
     * <li>-0.0
     * <li>負の数値
     * <li>double の最小値(-Double.MAX_VALUE)
     * <li>負の無限大
     * </ul>
     * NaN と NaN の比較は 0 を返します。
     * {@primary The ordering is as follows, largest to smallest:
     * <ul>
     * <li>NaN
     * <li>Positive infinity
     * <li>Maximum double
     * <li>Normal positve numbers
     * <li>+0.0
     * <li>-0.0
     * <li>Normal negative numbers
     * <li>Minimum double (-Double.MAX_VALUE)
     * <li>Negative infinity
     * </ul>
     * Comparing NaN with NaN will return 0.}
     * 
     * @param lhs  最初の double
     * {@primary the first double}
     * @param rhs  次の double
     * {@primary the second double}
     * @return lhsの方が小さい場合 -1、lhsの方が大きい場合 +1、等しい場合 0
     * {@primary -1 if lhs is less, +1 if greater, 0 if equal to rhs}
     */
    public static int compare(double lhs, double rhs) {
        if (lhs < rhs) {
            return -1;
        }
        if (lhs > rhs) {
            return +1;
        }
        // Need to compare bits to handle 0.0 == -0.0 being true
        // compare should put -0.0 < +0.0
        // Two NaNs are also == for compare purposes
        // where NaN == NaN is false
        long lhsBits = Double.doubleToLongBits(lhs);
        long rhsBits = Double.doubleToLongBits(rhs);
        if (lhsBits == rhsBits) {
            return 0;
        }
        // Something exotic! A comparison to NaN or 0.0 vs -0.0
        // Fortunately NaN's long is > than everything else
        // Also negzeros bits < poszero
        // NAN: 9221120237041090560
        // MAX: 9218868437227405311
        // NEGZERO: -9223372036854775808
        if (lhsBits < rhsBits) {
            return -1;
        } else {
            return +1;
        }
    }
    
    /**
     * 2つの float の大きさを比べます。
     * {@primary Compares two floats for order.}
     * <p>
     * このメソッドは標準的なJavaの比較演算よりも包括的です。
     * 最初の値が2つ目の値よりも小さい場合 -1 を返します。
     * 最初の値が2つ目の値よりも大きい場合 +1 を返します。
     * 両方の値が等しい場合 0 を返します。
     * {@primary This method is more comprhensive than the standard Java greater than,
     * less than and equals operators.
     * It returns -1 if the first value is less than the second.
     * It returns +1 if the first value is greater than the second.
     * It returns 0 if the values are equal.}
     * <p>
     * 評価される順番は大きい順に以下のようになります:
     * <ul>
     * <li>NaN
     * <li>正の無限大
     * <li>float の最大値
     * <li>正の数値
     * <li>+0.0
     * <li>-0.0
     * <li>負の数値
     * <li>float の最小値(-Float.MAX_VALUE)
     * <li>負の無限大
     * </ul>
     * NaN と NaN の比較は 0 を返します。
     * {@primary The ordering is as follows, largest to smallest:
     * <ul>
     * <li>NaN
     * <li>Positive infinity
     * <li>Maximum float
     * <li>Normal positve numbers
     * <li>+0.0
     * <li>-0.0
     * <li>Normal negative numbers
     * <li>Minimum float (-Float.MAX_VALUE)
     * <li>Negative infinity
     * </ul>
     * Comparing NaN with NaN will return 0.}
     * 
     * @param lhs  最初の float
     * {@primary the first float}
     * @param rhs  次の float
     * {@primary the second float}
     * @return lhsの方が小さい場合 -1、lhsの方が大きい場合 +1、等しい場合 0
     * {@primary -1 if lhs is less, +1 if greater, 0 if equal to rhs}
     */
    public static int compare(float lhs, float rhs) {
        if (lhs < rhs) {
            return -1;
        }
        if (lhs > rhs) {
            return +1;
        }
        //Need to compare bits to handle 0.0 == -0.0 being true
        // compare should put -0.0 < +0.0
        // Two NaNs are also == for compare purposes
        // where NaN == NaN is false
        int lhsBits = Float.floatToIntBits(lhs);
        int rhsBits = Float.floatToIntBits(rhs);
        if (lhsBits == rhsBits) {
            return 0;
        }
        //Something exotic! A comparison to NaN or 0.0 vs -0.0
        //Fortunately NaN's int is > than everything else
        //Also negzeros bits < poszero
        //NAN: 2143289344
        //MAX: 2139095039
        //NEGZERO: -2147483648
        if (lhsBits < rhsBits) {
            return -1;
        } else {
            return +1;
        }
    }
    
    //--------------------------------------------------------------------
    
    /**
     * String が数字の文字だけで構成されているかをチェックします。
     * null 、空の文字列が指定された場合には false を返します。
     * {@primary Checks whether the String contains only digit characters.
     * Null and blank string will return false.}
     *
     * @param str  評価対象となる文字列
     * {@primary the string to check}
     * @return 数字の文字だけで構成されているかどうか
     * {@primary boolean contains only unicode numeric}
     */
    public static boolean isDigits(String str) {
        if ((str == null) || (str.length() == 0)) {
            return false;
        }
        for (int i = 0; i < str.length(); i++) {
            if (!Character.isDigit(str.charAt(i))) {
                return false;
            }
        }
        return true;
    }

    /**
     * <p>
     * String が有効な Java の数値を示しているかをチェックします。
     * 有効な数値には "0x" の修飾のある16進数、数値を表す際に使用される記号、
     * 型を定義する符号(例 123L)が含まれます。
     * {@primary Checks whether the String a valid Java number.
     * Valid numbers include hexadecimal marked with the "0x" qualifier,
     * scientific notation and numbers marked with a type qualifier (e.g. 123L).}
     * </p>
     * <p>
     * null 、空の文字列が指定された場合には false を返します。
     * {@primary Null and blank string will return false.}
     * </p>
     * 
     * @param str  評価対象となる文字列
     * {@primary the string to check}
     * @return 文字列が正しい数値のフォーマットだった場合 true
     * {@primary true if the string is a correctly formatted number}
     */
    public static boolean isNumber(String str) {
        if ((str == null) || (str.length() == 0)) {
            return false;
        }
        char[] chars = str.toCharArray();
        int sz = chars.length;
        boolean hasExp = false;
        boolean hasDecPoint = false;
        boolean allowSigns = false;
        boolean foundDigit = false;
        //Deal with any possible sign up front
        int start = (chars[0] == '-') ? 1 : 0;
        if (sz > start + 1) {
            if (chars[start] == '0' && chars[start + 1] == 'x') {
                int i = start + 2;
                if (i == sz) {
                    return false; // str == "0x"
                }
                //Checking hex (it can't be anything else)
                for (; i < chars.length; i++) {
                    if ((chars[i] < '0' || chars[i] > '9')
                        && (chars[i] < 'a' || chars[i] > 'f')
                        && (chars[i] < 'A' || chars[i] > 'F')) {
                        return false;
                    }
                }
                return true;
            }
        }
        sz--; //Don't want to loop to the last char, check it afterwords
              //for type qualifiers
        int i = start;
        //Loop to the next to last char or to the last char if we need another digit to
        //make a valid number (e.g. chars[0..5] = "1234E")
        while (i < sz || (i < sz + 1 && allowSigns && !foundDigit)) {
            if (chars[i] >= '0' && chars[i] <= '9') {
                foundDigit = true;
                allowSigns = false;

            } else if (chars[i] == '.') {
                if (hasDecPoint || hasExp) {
                    //Two decimal points or dec in exponent   
                    return false;
                }
                hasDecPoint = true;
            } else if (chars[i] == 'e' || chars[i] == 'E') {
                //We've already taken care of hex.
                if (hasExp) {
                    //Two E's
                    return false;
                }
                if (!foundDigit) {
                    return false;
                }
                hasExp = true;
                allowSigns = true;
            } else if (chars[i] == '+' || chars[i] == '-') {
                if (!allowSigns) {
                    return false;
                }
                allowSigns = false;
                foundDigit = false; //We need a digit after the E
            } else {
                return false;
            }
            i++;
        }
        if (i < chars.length) {
            if (chars[i] >= '0' && chars[i] <= '9') {
                //No type qualifier, OK
                return true;
            }
            if (chars[i] == 'e' || chars[i] == 'E') {
                //Can't have an E at the last byte
                return false;
            }
            if (!allowSigns
                && (chars[i] == 'd'
                    || chars[i] == 'D'
                    || chars[i] == 'f'
                    || chars[i] == 'F')) {
                return foundDigit;
            }
            if (chars[i] == 'l'
                || chars[i] == 'L') {
                //Not allowing L with an exponoent
                return foundDigit && !hasExp;
            }
        }
        //allowSigns is true iff the val ends in 'E'
        //Found digit it to make sure weird stuff like '.' and '1E-' doesn't pass
        return !allowSigns && foundDigit;
    }
}