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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

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 *

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package java.util;

import java.io.BufferedWriter;

import java.io.Closeable;

import java.io.IOException;

import java.io.File;

import java.io.FileOutputStream;

import java.io.FileNotFoundException;

import java.io.Flushable;

import java.io.OutputStream;

import java.io.OutputStreamWriter;

import java.io.PrintStream;

import java.io.UnsupportedEncodingException;

import java.math.BigDecimal;

import java.math.BigInteger;

import java.math.MathContext;

import java.math.RoundingMode;

import java.nio.charset.Charset;

import java.nio.charset.IllegalCharsetNameException;

import java.nio.charset.UnsupportedCharsetException;

import java.text.DateFormatSymbols;

import java.text.DecimalFormat;

import java.text.DecimalFormatSymbols;

import java.text.NumberFormat;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import sun.misc.DoubleConsts;

import sun.misc.FormattedFloatingDecimal;

/**

 * An interpreter for printf-style format strings.  This class provides support

 * for layout justification and alignment, common formats for numeric, string,

 * and date/time data, and locale-specific output.  Common Java types such as

 * {@code byte}, {@link java.math.BigDecimal BigDecimal}, and {@link Calendar}

 * are supported.  Limited formatting customization for arbitrary user types is

 * provided through the {@link Formattable} interface.

 *

 * <p> Formatters are not necessarily safe for multithreaded access.  Thread

 * safety is optional and is the responsibility of users of methods in this

 * class.

 *

 * <p> Formatted printing for the Java language is heavily inspired by C's

 * {@code printf}.  Although the format strings are similar to C, some

 * customizations have been made to accommodate the Java language and exploit

 * some of its features.  Also, Java formatting is more strict than C's; for

 * example, if a conversion is incompatible with a flag, an exception will be

 * thrown.  In C inapplicable flags are silently ignored.  The format strings

 * are thus intended to be recognizable to C programmers but not necessarily

 * completely compatible with those in C.

 *

 * <p> Examples of expected usage:

 *

 * <blockquote><pre>

 *   StringBuilder sb = new StringBuilder();

 *   // Send all output to the Appendable object sb

 *   Formatter formatter = new Formatter(sb, Locale.US);

 *

 *   // Explicit argument indices may be used to re-order output.

 *   formatter.format("%4$2s %3$2s %2$2s %1$2s", "a", "b", "c", "d")

 *   // -> " d  c  b  a"

 *

 *   // Optional locale as the first argument can be used to get

 *   // locale-specific formatting of numbers.  The precision and width can be

 *   // given to round and align the value.

 *   formatter.format(Locale.FRANCE, "e = %+10.4f", Math.E);

 *   // -> "e =    +2,7183"

 *

 *   // The '(' numeric flag may be used to format negative numbers with

 *   // parentheses rather than a minus sign.  Group separators are

 *   // automatically inserted.

 *   formatter.format("Amount gained or lost since last statement: $ %(,.2f",

 *                    balanceDelta);

 *   // -> "Amount gained or lost since last statement: $ (6,217.58)"

 * </pre></blockquote>

 *

 * <p> Convenience methods for common formatting requests exist as illustrated

 * by the following invocations:

 *

 * <blockquote><pre>

 *   // Writes a formatted string to System.out.

 *   System.out.format("Local time: %tT", Calendar.getInstance());

 *   // -> "Local time: 13:34:18"

 *

 *   // Writes formatted output to System.err.

 *   System.err.printf("Unable to open file '%1$s': %2$s",

 *                     fileName, exception.getMessage());

 *   // -> "Unable to open file 'food': No such file or directory"

 * </pre></blockquote>

 *

 * <p> Like C's {@code sprintf(3)}, Strings may be formatted using the static

 * method {@link String#format(String,Object...) String.format}:

 *

 * <blockquote><pre>

 *   // Format a string containing a date.

 *   import java.util.Calendar;

 *   import java.util.GregorianCalendar;

 *   import static java.util.Calendar.*;

 *

 *   Calendar c = new GregorianCalendar(1995, MAY, 23);

 *   String s = String.format("Duke's Birthday: %1$tm %1$te,%1$tY", c);

 *   // -> s == "Duke's Birthday: May 23, 1995"

 * </pre></blockquote>

 *

 * <h3><a name="org">Organization</a></h3>

 *

 * <p> This specification is divided into two sections.  The first section, <a

 * href="#summary">Summary</a>, covers the basic formatting concepts.  This

 * section is intended for users who want to get started quickly and are

 * familiar with formatted printing in other programming languages.  The second

 * section, <a href="#detail">Details</a>, covers the specific implementation

 * details.  It is intended for users who want more precise specification of

 * formatting behavior.

 *

 * <h3><a name="summary">Summary</a></h3>

 *

 * <p> This section is intended to provide a brief overview of formatting

 * concepts.  For precise behavioral details, refer to the <a

 * href="#detail">Details</a> section.

 *

 * <h4><a name="syntax">Format String Syntax</a></h4>

 *

 * <p> Every method which produces formatted output requires a <i>format

 * string</i> and an <i>argument list</i>.  The format string is a {@link

 * String} which may contain fixed text and one or more embedded <i>format

 * specifiers</i>.  Consider the following example:

 *

 * <blockquote><pre>

 *   Calendar c = ...;

 *   String s = String.format("Duke's Birthday: %1$tm %1$te,%1$tY", c);

 * </pre></blockquote>

 *

 * This format string is the first argument to the {@code format} method.  It

 * contains three format specifiers "{@code %1$tm}", "{@code %1$te}", and

 * "{@code %1$tY}" which indicate how the arguments should be processed and

 * where they should be inserted in the text.  The remaining portions of the

 * format string are fixed text including {@code "Dukes Birthday: "} and any

 * other spaces or punctuation.

 *

 * The argument list consists of all arguments passed to the method after the

 * format string.  In the above example, the argument list is of size one and

 * consists of the {@link java.util.Calendar Calendar} object {@code c}.

 *

 * <ul>

 *

 * <li> The format specifiers for general, character, and numeric types have

 * the following syntax:

 *

 * <blockquote><pre>

 *   %[argument_index$][flags][width][.precision]conversion

 * </pre></blockquote>

 *

 * <p> The optional <i>argument_index</i> is a decimal integer indicating the

 * position of the argument in the argument list.  The first argument is

 * referenced by "{@code 1$}", the second by "{@code 2$}", etc.

 *

 * <p> The optional <i>flags</i> is a set of characters that modify the output

 * format.  The set of valid flags depends on the conversion.

 *

 * <p> The optional <i>width</i> is a non-negative decimal integer indicating

 * the minimum number of characters to be written to the output.

 *

 * <p> The optional <i>precision</i> is a non-negative decimal integer usually

 * used to restrict the number of characters.  The specific behavior depends on

 * the conversion.

 *

 * <p> The required <i>conversion</i> is a character indicating how the

 * argument should be formatted.  The set of valid conversions for a given

 * argument depends on the argument's data type.

 *

 * <li> The format specifiers for types which are used to represents dates and

 * times have the following syntax:

 *

 * <blockquote><pre>

 *   %[argument_index$][flags][width]conversion

 * </pre></blockquote>

 *

 * <p> The optional <i>argument_index</i>, <i>flags</i> and <i>width</i> are

 * defined as above.

 *

 * <p> The required <i>conversion</i> is a two character sequence.  The first

 * character is {@code 't'} or {@code 'T'}.  The second character indicates

 * the format to be used.  These characters are similar to but not completely

 * identical to those defined by GNU {@code date} and POSIX

 * {@code strftime(3c)}.

 *

 * <li> The format specifiers which do not correspond to arguments have the

 * following syntax:

 *

 * <blockquote><pre>

 *   %[flags][width]conversion

 * </pre></blockquote>

 *

 * <p> The optional <i>flags</i> and <i>width</i> is defined as above.

 *

 * <p> The required <i>conversion</i> is a character indicating content to be

 * inserted in the output.

 *

 * </ul>

 *

 * <h4> Conversions </h4>

 *

 * <p> Conversions are divided into the following categories:

 *

 * <ol>

 *

 * <li> <b>General</b> - may be applied to any argument

 * type

 *

 * <li> <b>Character</b> - may be applied to basic types which represent

 * Unicode characters: {@code char}, {@link Character}, {@code byte}, {@link

 * Byte}, {@code short}, and {@link Short}. This conversion may also be

 * applied to the types {@code int} and {@link Integer} when {@link

 * Character#isValidCodePoint} returns {@code true}

 *

 * <li> <b>Numeric</b>

 *

 * <ol>

 *

 * <li> <b>Integral</b> - may be applied to Java integral types: {@code byte},

 * {@link Byte}, {@code short}, {@link Short}, {@code int} and {@link

 * Integer}, {@code long}, {@link Long}, and {@link java.math.BigInteger

 * BigInteger}

 *

 * <li><b>Floating Point</b> - may be applied to Java floating-point types:

 * {@code float}, {@link Float}, {@code double}, {@link Double}, and {@link

 * java.math.BigDecimal BigDecimal}

 *

 * </ol>

 *

 * <li> <b>Date/Time</b> - may be applied to Java types which are capable of

 *

 * <li> <b>Percent</b> - produces a literal {@code '%'}

 * (<tt>'&#92;u0025'</tt>)

 *

 * <li> <b>Line Separator</b> - produces the platform-specific line separator

 *

 * </ol>

 *

 * <p> The following table summarizes the supported conversions.  Conversions

 * denoted by an upper-case character (i.e. {@code 'B'}, {@code 'H'},

 * {@code 'S'}, {@code 'C'}, {@code 'X'}, {@code 'E'}, {@code 'G'},

 * {@code 'A'}, and {@code 'T'}) are the same as those for the corresponding

 * lower-case conversion characters except that the result is converted to

 * upper case according to the rules of the prevailing {@link java.util.Locale

 * Locale}.  The result is equivalent to the following invocation of {@link

 * String#toUpperCase()}

 *

 * <pre>

 *    out.toUpperCase() </pre>

 *

 * <table cellpadding=5 summary="genConv">

 *

 * <tr><th valign="bottom"> Conversion

 *     <th valign="bottom"> Argument Category

 *     <th valign="bottom"> Description

 *

 * <tr><td valign="top"> {@code 'b'}, {@code 'B'}

 *     <td valign="top"> general

 *     <td> If the argument <i>arg</i> is {@code null}, then the result is

 *     "{@code false}".  If <i>arg</i> is a {@code boolean} or {@link

 *     Boolean}, then the result is the string returned by {@link

 *     String#valueOf(boolean) String.valueOf(arg)}.  Otherwise, the result is

 *     "true".

 *

 * <tr><td valign="top"> {@code 'h'}, {@code 'H'}

 *     <td valign="top"> general

 *     <td> If the argument <i>arg</i> is {@code null}, then the result is

 *     "{@code null}".  Otherwise, the result is obtained by invoking

 *     {@code Integer.toHexString(arg.hashCode())}.

 *

 * <tr><td valign="top"> {@code 's'}, {@code 'S'}

 *     <td valign="top"> general

 *     <td> If the argument <i>arg</i> is {@code null}, then the result is

 *     "{@code null}".  If <i>arg</i> implements {@link Formattable}, then

 *     {@link Formattable#formatTo arg.formatTo} is invoked. Otherwise, the

 *     result is obtained by invoking {@code arg.toString()}.

 *

 * <tr><td valign="top">{@code 'c'}, {@code 'C'}

 *     <td valign="top"> character

 *     <td> The result is a Unicode character

 *

 * <tr><td valign="top">{@code 'd'}

 *     <td valign="top"> integral

 *     <td> The result is formatted as a decimal integer

 *

 * <tr><td valign="top">{@code 'o'}

 *     <td valign="top"> integral

 *     <td> The result is formatted as an octal integer

 *

 * <tr><td valign="top">{@code 'x'}, {@code 'X'}

 *     <td valign="top"> integral

 *     <td> The result is formatted as a hexadecimal integer

 *

 * <tr><td valign="top">{@code 'e'}, {@code 'E'}

 *     <td valign="top"> floating point

 *     <td> The result is formatted as a decimal number in computerized

 *     scientific notation

 *

 * <tr><td valign="top">{@code 'f'}

 *     <td valign="top"> floating point

 *     <td> The result is formatted as a decimal number

 *

 * <tr><td valign="top">{@code 'g'}, {@code 'G'}

 *     <td valign="top"> floating point

 *     <td> The result is formatted using computerized scientific notation or

 *     decimal format, depending on the precision and the value after rounding.

 *

 * <tr><td valign="top">{@code 'a'}, {@code 'A'}

 *     <td valign="top"> floating point

 *     <td> The result is formatted as a hexadecimal floating-point number with

 *     a significand and an exponent

 *

 * <tr><td valign="top">{@code 't'}, {@code 'T'}

 *     <td valign="top"> date/time

 *     <td> Prefix for date and time conversion characters.  See <a

 *     href="#dt">Date/Time Conversions</a>.

 *

 * <tr><td valign="top">{@code '%'}

 *     <td valign="top"> percent

 *     <td> The result is a literal {@code '%'} (<tt>'&#92;u0025'</tt>)

 *

 * <tr><td valign="top">{@code 'n'}

 *     <td valign="top"> line separator

 *     <td> The result is the platform-specific line separator

 *

 * </table>

 *

 * <p> Any characters not explicitly defined as conversions are illegal and are

 * reserved for future extensions.

 *

 * <h4><a name="dt">Date/Time Conversions</a></h4>

 *

 * <p> The following date and time conversion suffix characters are defined for

 * the {@code 't'} and {@code 'T'} conversions.  The types are similar to but

 * not completely identical to those defined by GNU {@code date} and POSIX

 * {@code strftime(3c)}.  Additional conversion types are provided to access

 * Java-specific functionality (e.g. {@code 'L'} for milliseconds within the

 * second).

 *

 * <p> The following conversion characters are used for formatting times:

 *

 * <table cellpadding=5 summary="time">

 *

 * <tr><td valign="top"> {@code 'H'}

 *     <td> Hour of the day for the 24-hour clock, formatted as two digits with

 *     a leading zero as necessary i.e. {@code 00 - 23}.

 *

 * <tr><td valign="top">{@code 'I'}

 *     <td> Hour for the 12-hour clock, formatted as two digits with a leading

 *     zero as necessary, i.e.  {@code 01 - 12}.

 *

 * <tr><td valign="top">{@code 'k'}

 *     <td> Hour of the day for the 24-hour clock, i.e. {@code 0 - 23}.

 *

 * <tr><td valign="top">{@code 'l'}

 *     <td> Hour for the 12-hour clock, i.e. {@code 1 - 12}.

 *

 * <tr><td valign="top">{@code 'M'}

 *     <td> Minute within the hour formatted as two digits with a leading zero

 *     as necessary, i.e.  {@code 00 - 59}.

 *

 * <tr><td valign="top">{@code 'S'}

 *     <td> Seconds within the minute, formatted as two digits with a leading

 *     zero as necessary, i.e. {@code 00 - 60} ("{@code 60}" is a special

 *     value required to support leap seconds).

 *

 * <tr><td valign="top">{@code 'L'}

 *     <td> Millisecond within the second formatted as three digits with

 *     leading zeros as necessary, i.e. {@code 000 - 999}.

 *

 * <tr><td valign="top">{@code 'N'}

 *     <td> Nanosecond within the second, formatted as nine digits with leading

 *     zeros as necessary, i.e. {@code 000000000 - 999999999}.

 *

 * <tr><td valign="top">{@code 'p'}

 *     <td> Locale-specific {@linkplain

 *     java.text.DateFormatSymbols#getAmPmStrings morning or afternoon} marker

 *     in lower case, e.g."{@code am}" or "{@code pm}". Use of the conversion

 *     prefix {@code 'T'} forces this output to upper case.

 *

 * <tr><td valign="top">{@code 'z'}

 *     <td> <a href="http://www.ietf.org/rfc/rfc0822.txt">RFC&nbsp;822</a>

 *     style numeric time zone offset from GMT, e.g. {@code -0800}.  This

 *     value will be adjusted as necessary for Daylight Saving Time.  For

 *     {@code long}, {@link Long}, and {@link Date} the time zone used is

 *     the {@linkplain TimeZone#getDefault() default time zone} for this

 *     instance of the Java virtual machine.

 *

 * <tr><td valign="top">{@code 'Z'}

 *     <td> A string representing the abbreviation for the time zone.  This

 *     value will be adjusted as necessary for Daylight Saving Time.  For

 *     {@code long}, {@link Long}, and {@link Date} the  time zone used is

 *     the {@linkplain TimeZone#getDefault() default time zone} for this

 *     instance of the Java virtual machine.  The Formatter's locale will

 *     supersede the locale of the argument (if any).

 *

 * <tr><td valign="top">{@code 's'}

 *     <td> Seconds since the beginning of the epoch starting at 1 January 1970

 *     {@code 00:00:00} UTC, i.e. {@code Long.MIN_VALUE/1000} to

 *     {@code Long.MAX_VALUE/1000}.

 *

 * <tr><td valign="top">{@code 'Q'}

 *     <td> Milliseconds since the beginning of the epoch starting at 1 January

 *     1970 {@code 00:00:00} UTC, i.e. {@code Long.MIN_VALUE} to

 *     {@code Long.MAX_VALUE}.

 *

 * </table>

 *

 * <p> The following conversion characters are used for formatting dates:

 *

 * <table cellpadding=5 summary="date">

 *

 * <tr><td valign="top">{@code 'B'}

 *     <td> Locale-specific {@linkplain java.text.DateFormatSymbols#getMonths

 *     full month name}, e.g. {@code "January"}, {@code "February"}.

 *

 * <tr><td valign="top">{@code 'b'}

 *     <td> Locale-specific {@linkplain

 *     java.text.DateFormatSymbols#getShortMonths abbreviated month name},

 *     e.g. {@code "Jan"}, {@code "Feb"}.

 *

 * <tr><td valign="top">{@code 'h'}

 *     <td> Same as {@code 'b'}.

 *

 * <tr><td valign="top">{@code 'A'}

 *     <td> Locale-specific full name of the {@linkplain

 *     java.text.DateFormatSymbols#getWeekdays day of the week},

 *     e.g. {@code "Sunday"}, {@code "Monday"}

 *

 * <tr><td valign="top">{@code 'a'}

 *     <td> Locale-specific short name of the {@linkplain

 *     java.text.DateFormatSymbols#getShortWeekdays day of the week},

 *     e.g. {@code "Sun"}, {@code "Mon"}

 *

 * <tr><td valign="top">{@code 'C'}

 *     <td> Four-digit year divided by {@code 100}, formatted as two digits

 *     with leading zero as necessary, i.e. {@code 00 - 99}

 *

 * <tr><td valign="top">{@code 'Y'}

 *     <td> Year, formatted as at least four digits with leading zeros as

 *     necessary, e.g. {@code 0092} equals {@code 92} CE for the Gregorian

 *     calendar.

 *

 * <tr><td valign="top">{@code 'y'}

 *     <td> Last two digits of the year, formatted with leading zeros as

 *     necessary, i.e. {@code 00 - 99}.

 *

 * <tr><td valign="top">{@code 'j'}

 *     <td> Day of year, formatted as three digits with leading zeros as

 *     necessary, e.g. {@code 001 - 366} for the Gregorian calendar.

 *

 * <tr><td valign="top">{@code 'm'}

 *     <td> Month, formatted as two digits with leading zeros as necessary,

 *     i.e. {@code 01 - 13}.

 *

 * <tr><td valign="top">{@code 'd'}

 *     <td> Day of month, formatted as two digits with leading zeros as

 *     necessary, i.e. {@code 01 - 31}

 *

 * <tr><td valign="top">{@code 'e'}

 *     <td> Day of month, formatted as two digits, i.e. {@code 1 - 31}.

 *

 * </table>

 *

 * <p> The following conversion characters are used for formatting common

 * date/time compositions.