/*

 * Copyright (c) 1995, 2005, Oracle and/or its affiliates. All rights reserved.

 * 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).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package java.io;

import java.util.Arrays;

/**

 * The <code>StreamTokenizer</code> class takes an input stream and

 * parses it into "tokens", allowing the tokens to be

 * read one at a time. The parsing process is controlled by a table

 * and a number of flags that can be set to various states. The

 * stream tokenizer can recognize identifiers, numbers, quoted

 * strings, and various comment styles.

 * <p>

 * Each byte read from the input stream is regarded as a character

 * in the range <code>'&#92;u0000'</code> through <code>'&#92;u00FF'</code>.

 * The character value is used to look up five possible attributes of

 * the character: <i>white space</i>, <i>alphabetic</i>,

 * <i>numeric</i>, <i>string quote</i>, and <i>comment character</i>.

 * Each character can have zero or more of these attributes.

 * <p>

 * In addition, an instance has four flags. These flags indicate:

 * <ul>

 * <li>Whether line terminators are to be returned as tokens or treated

 *     as white space that merely separates tokens.

 * <li>Whether C-style comments are to be recognized and skipped.

 * <li>Whether C++-style comments are to be recognized and skipped.

 * <li>Whether the characters of identifiers are converted to lowercase.

 * </ul>

 * <p>

 * A typical application first constructs an instance of this class,

 * sets up the syntax tables, and then repeatedly loops calling the

 * <code>nextToken</code> method in each iteration of the loop until

 * it returns the value <code>TT_EOF</code>.

 *

 * @author  James Gosling

 * @see     java.io.StreamTokenizer#nextToken()

 * @see     java.io.StreamTokenizer#TT_EOF

 * @since   JDK1.0

 */

public class StreamTokenizer {

    /* Only one of these will be non-null */

    private Reader reader = null;

    private InputStream input = null;

    private char buf[] = new char[20];

    /**

     * The next character to be considered by the nextToken method.  May also

     * be NEED_CHAR to indicate that a new character should be read, or SKIP_LF

     * to indicate that a new character should be read and, if it is a '\n'

     * character, it should be discarded and a second new character should be

     * read.

     */

    private int peekc = NEED_CHAR;

    private static final int NEED_CHAR = Integer.MAX_VALUE;

    private static final int SKIP_LF = Integer.MAX_VALUE - 1;

    private boolean pushedBack;

    private boolean forceLower;

    /** The line number of the last token read */

    private int LINENO = 1;

    private boolean eolIsSignificantP = false;

    private boolean slashSlashCommentsP = false;

    private boolean slashStarCommentsP = false;

    private byte ctype[] = new byte[256];

    private static final byte CT_WHITESPACE = 1;

    private static final byte CT_DIGIT = 2;

    private static final byte CT_ALPHA = 4;

    private static final byte CT_QUOTE = 8;

    private static final byte CT_COMMENT = 16;

    /**

     * After a call to the <code>nextToken</code> method, this field

     * contains the type of the token just read. For a single character

     * token, its value is the single character, converted to an integer.

     * For a quoted string token, its value is the quote character.

     * Otherwise, its value is one of the following:

     * <ul>

     * <li><code>TT_WORD</code> indicates that the token is a word.

     * <li><code>TT_NUMBER</code> indicates that the token is a number.

     * <li><code>TT_EOL</code> indicates that the end of line has been read.

     *     The field can only have this value if the

     *     <code>eolIsSignificant</code> method has been called with the

     *     argument <code>true</code>.

     * <li><code>TT_EOF</code> indicates that the end of the input stream

     *     has been reached.

     * </ul>

     * <p>

     * The initial value of this field is -4.

     *

     * @see     java.io.StreamTokenizer#eolIsSignificant(boolean)

     * @see     java.io.StreamTokenizer#nextToken()

     * @see     java.io.StreamTokenizer#quoteChar(int)

     * @see     java.io.StreamTokenizer#TT_EOF

     * @see     java.io.StreamTokenizer#TT_EOL

     * @see     java.io.StreamTokenizer#TT_NUMBER

     * @see     java.io.StreamTokenizer#TT_WORD

     */

    public int ttype = TT_NOTHING;

    /**

     * A constant indicating that the end of the stream has been read.

     */

    public static final int TT_EOF = -1;

    /**

     * A constant indicating that the end of the line has been read.

     */

    public static final int TT_EOL = '\n';

    /**

     * A constant indicating that a number token has been read.

     */

    public static final int TT_NUMBER = -2;

    /**

     * A constant indicating that a word token has been read.

     */

    public static final int TT_WORD = -3;

    /* A constant indicating that no token has been read, used for

     * initializing ttype.  FIXME This could be made public and

     * made available as the part of the API in a future release.

     */

    private static final int TT_NOTHING = -4;

    /**

     * If the current token is a word token, this field contains a

     * string giving the characters of the word token. When the current

     * token is a quoted string token, this field contains the body of

     * the string.

     * <p>

     * The current token is a word when the value of the

     * <code>ttype</code> field is <code>TT_WORD</code>. The current token is

     * a quoted string token when the value of the <code>ttype</code> field is

     * a quote character.

     * <p>

     * The initial value of this field is null.

     *

     * @see     java.io.StreamTokenizer#quoteChar(int)

     * @see     java.io.StreamTokenizer#TT_WORD

     * @see     java.io.StreamTokenizer#ttype

     */

    public String sval;

    /**

     * If the current token is a number, this field contains the value

     * of that number. The current token is a number when the value of

     * the <code>ttype</code> field is <code>TT_NUMBER</code>.

     * <p>

     * The initial value of this field is 0.0.

     *

     * @see     java.io.StreamTokenizer#TT_NUMBER

     * @see     java.io.StreamTokenizer#ttype

     */

    public double nval;

    /** Private constructor that initializes everything except the streams. */

    private StreamTokenizer() {

        wordChars('a', 'z');

        wordChars('A', 'Z');

        wordChars(128 + 32, 255);

        whitespaceChars(0, ' ');

        commentChar('/');

        quoteChar('"');

        quoteChar('\'');

        parseNumbers();

    }

    /**

     * Creates a stream tokenizer that parses the specified input

     * stream. The stream tokenizer is initialized to the following

     * default state:

     * <ul>

     * <li>All byte values <code>'A'</code> through <code>'Z'</code>,

     *     <code>'a'</code> through <code>'z'</code>, and

     *     <code>'&#92;u00A0'</code> through <code>'&#92;u00FF'</code> are

     *     considered to be alphabetic.

     * <li>All byte values <code>'&#92;u0000'</code> through

     *     <code>'&#92;u0020'</code> are considered to be white space.

     * <li><code>'/'</code> is a comment character.

     * <li>Single quote <code>'&#92;''</code> and double quote <code>'"'</code>

     *     are string quote characters.

     * <li>Numbers are parsed.

     * <li>Ends of lines are treated as white space, not as separate tokens.

     * <li>C-style and C++-style comments are not recognized.

     * </ul>

     *

     * @deprecated As of JDK version 1.1, the preferred way to tokenize an

     * input stream is to convert it into a character stream, for example:

     * <blockquote><pre>

     *   Reader r = new BufferedReader(new InputStreamReader(is));

     *   StreamTokenizer st = new StreamTokenizer(r);

     * </pre></blockquote>

     *

     * @param      is        an input stream.

     * @see        java.io.BufferedReader

     * @see        java.io.InputStreamReader

     * @see        java.io.StreamTokenizer#StreamTokenizer(java.io.Reader)

     */

    @Deprecated

    public StreamTokenizer(InputStream is) {

        this();

        if (is == null) {

            throw new NullPointerException();

        }

        input = is;

    }

    /**

     * Create a tokenizer that parses the given character stream.

     *

     * @param r  a Reader object providing the input stream.

     * @since   JDK1.1

     */

    public StreamTokenizer(Reader r) {

        this();

        if (r == null) {

            throw new NullPointerException();

        }

        reader = r;

    }

    /**

     * Resets this tokenizer's syntax table so that all characters are

     * "ordinary." See the <code>ordinaryChar</code> method

     * for more information on a character being ordinary.

     *

     * @see     java.io.StreamTokenizer#ordinaryChar(int)

     */

    public void resetSyntax() {

        for (int i = ctype.length; --i >= 0;)

            ctype[i] = 0;

    }

    /**

     * Specifies that all characters <i>c</i> in the range

     * <code>low&nbsp;&lt;=&nbsp;<i>c</i>&nbsp;&lt;=&nbsp;high</code>

     * are word constituents. A word token consists of a word constituent

     * followed by zero or more word constituents or number constituents.

     *

     * @param   low   the low end of the range.

     * @param   hi    the high end of the range.

     */

    public void wordChars(int low, int hi) {

        if (low < 0)

            low = 0;

        if (hi >= ctype.length)

            hi = ctype.length - 1;

        while (low <= hi)

            ctype[low++] |= CT_ALPHA;

    }

    /**

     * Specifies that all characters <i>c</i> in the range

     * <code>low&nbsp;&lt;=&nbsp;<i>c</i>&nbsp;&lt;=&nbsp;high</code>

     * are white space characters. White space characters serve only to

     * separate tokens in the input stream.

     *

     * <p>Any other attribute settings for the characters in the specified

     * range are cleared.

     *

     * @param   low   the low end of the range.

     * @param   hi    the high end of the range.

     */

    public void whitespaceChars(int low, int hi) {

        if (low < 0)

            low = 0;

        if (hi >= ctype.length)

            hi = ctype.length - 1;

        while (low <= hi)

            ctype[low++] = CT_WHITESPACE;

    }

    /**

     * Specifies that all characters <i>c</i> in the range

     * <code>low&nbsp;&lt;=&nbsp;<i>c</i>&nbsp;&lt;=&nbsp;high</code>

     * are "ordinary" in this tokenizer. See the

     * <code>ordinaryChar</code> method for more information on a

     * character being ordinary.

     *

     * @param   low   the low end of the range.

     * @param   hi    the high end of the range.

     * @see     java.io.StreamTokenizer#ordinaryChar(int)

     */

    public void ordinaryChars(int low, int hi) {

        if (low < 0)

            low = 0;

        if (hi >= ctype.length)

            hi = ctype.length - 1;

        while (low <= hi)

            ctype[low++] = 0;

    }

    /**

     * Specifies that the character argument is "ordinary"

     * in this tokenizer. It removes any special significance the

     * character has as a comment character, word component, string

     * delimiter, white space, or number character. When such a character

     * is encountered by the parser, the parser treats it as a

     * single-character token and sets <code>ttype</code> field to the

     * character value.

     *

     * <p>Making a line terminator character "ordinary" may interfere

     * with the ability of a <code>StreamTokenizer</code> to count

     * lines. The <code>lineno</code> method may no longer reflect

     * the presence of such terminator characters in its line count.

     *

     * @param   ch   the character.

     * @see     java.io.StreamTokenizer#ttype

     */

    public void ordinaryChar(int ch) {

        if (ch >= 0 && ch < ctype.length)

            ctype[ch] = 0;

    }

    /**

     * Specified that the character argument starts a single-line

     * comment. All characters from the comment character to the end of

     * the line are ignored by this stream tokenizer.

     *

     * <p>Any other attribute settings for the specified character are cleared.

     *

     * @param   ch   the character.

     */

    public void commentChar(int ch) {

        if (ch >= 0 && ch < ctype.length)

            ctype[ch] = CT_COMMENT;

    }

    /**

     * Specifies that matching pairs of this character delimit string

     * constants in this tokenizer.

     * <p>

     * When the <code>nextToken</code> method encounters a string

     * constant, the <code>ttype</code> field is set to the string

     * delimiter and the <code>sval</code> field is set to the body of

     * the string.

     * <p>

     * If a string quote character is encountered, then a string is

     * recognized, consisting of all characters after (but not including)

     * the string quote character, up to (but not including) the next

     * occurrence of that same string quote character, or a line

     * terminator, or end of file. The usual escape sequences such as

     * <code>"&#92;n"</code> and <code>"&#92;t"</code> are recognized and

     * converted to single characters as the string is parsed.

     *

     * <p>Any other attribute settings for the specified character are cleared.

     *

     * @param   ch   the character.

     * @see     java.io.StreamTokenizer#nextToken()

     * @see     java.io.StreamTokenizer#sval

     * @see     java.io.StreamTokenizer#ttype

     */

    public void quoteChar(int ch) {

        if (ch >= 0 && ch < ctype.length)

            ctype[ch] = CT_QUOTE;

    }

    /**

     * Specifies that numbers should be parsed by this tokenizer. The

     * syntax table of this tokenizer is modified so that each of the twelve

     * characters:

     * <blockquote><pre>

     *      0 1 2 3 4 5 6 7 8 9 . -

     * </pre></blockquote>

     * <p>

     * has the "numeric" attribute.

     * <p>

     * When the parser encounters a word token that has the format of a

     * double precision floating-point number, it treats the token as a

     * number rather than a word, by setting the <code>ttype</code>

     * field to the value <code>TT_NUMBER</code> and putting the numeric

     * value of the token into the <code>nval</code> field.

     *

     * @see     java.io.StreamTokenizer#nval

     * @see     java.io.StreamTokenizer#TT_NUMBER

     * @see     java.io.StreamTokenizer#ttype

     */

    public void parseNumbers() {

        for (int i = '0'; i <= '9'; i++)

            ctype[i] |= CT_DIGIT;

        ctype['.'] |= CT_DIGIT;

        ctype['-'] |= CT_DIGIT;

    }

    /**

     * Determines whether or not ends of line are treated as tokens.

     * If the flag argument is true, this tokenizer treats end of lines

     * as tokens; the <code>nextToken</code> method returns

     * <code>TT_EOL</code> and also sets the <code>ttype</code> field to

     * this value when an end of line is read.

     * <p>

     * A line is a sequence of characters ending with either a

     * carriage-return character (<code>'&#92;r'</code>) or a newline

     * character (<code>'&#92;n'</code>). In addition, a carriage-return

     * character followed immediately by a newline character is treated

     * as a single end-of-line token.

     * <p>

     * If the <code>flag</code> is false, end-of-line characters are

     * treated as white space and serve only to separate tokens.

     *

     * @param   flag   <code>true</code> indicates that end-of-line characters

     *                 are separate tokens; <code>false</code> indicates that

     *                 end-of-line characters are white space.

     * @see     java.io.StreamTokenizer#nextToken()

     * @see     java.io.StreamTokenizer#ttype

     * @see     java.io.StreamTokenizer#TT_EOL

     */

    public void eolIsSignificant(boolean flag) {

        eolIsSignificantP = flag;

    }

    /**

     * Determines whether or not the tokenizer recognizes C-style comments.

     * If the flag argument is <code>true</code>, this stream tokenizer

     * recognizes C-style comments. All text between successive

     * occurrences of <code>/*</code> and <code>*&#47;</code> are discarded.

     * <p>

     * If the flag argument is <code>false</code>, then C-style comments

     * are not treated specially.

     *

     * @param   flag   <code>true</code> indicates to recognize and ignore

     *                 C-style comments.

     */

    public void slashStarComments(boolean flag) {

        slashStarCommentsP = flag;

    }

    /**

     * Determines whether or not the tokenizer recognizes C++-style comments.

     * If the flag argument is <code>true</code>, this stream tokenizer

     * recognizes C++-style comments. Any occurrence of two consecutive

     * slash characters (<code>'/'</code>) is treated as the beginning of

     * a comment that extends to the end of the line.

     * <p>

     * If the flag argument is <code>false</code>, then C++-style

     * comments are not treated specially.

     *

     * @param   flag   <code>true</code> indicates to recognize and ignore

     *                 C++-style comments.

     */

    public void slashSlashComments(boolean flag) {

        slashSlashCommentsP = flag;

    }

    /**

     * Determines whether or not word token are automatically lowercased.

     * If the flag argument is <code>true</code>, then the value in the

     * <code>sval</code> field is lowercased whenever a word token is

     * returned (the <code>ttype</code> field has the

     * value <code>TT_WORD</code> by the <code>nextToken</code> method

     * of this tokenizer.

     * <p>

     * If the flag argument is <code>false</code>, then the

     * <code>sval</code> field is not modified.

     *

     * @param   fl   <code>true</code> indicates that all word tokens should

     *               be lowercased.

     * @see     java.io.StreamTokenizer#nextToken()

     * @see     java.io.StreamTokenizer#ttype

     * @see     java.io.StreamTokenizer#TT_WORD

     */

    public void lowerCaseMode(boolean fl) {

        forceLower = fl;

    }

    /** Read the next character */

    private int read() throws IOException {

        if (reader != null)

            return reader.read();

        else if (input != null)

            return input.read();

        else

            throw new IllegalStateException();

    }

    /**

     * Parses the next token from the input stream of this tokenizer.

     * The type of the next token is returned in the <code>ttype</code>

     * field. Additional information about the token may be in the

     * <code>nval</code> field or the <code>sval</code> field of this

     * tokenizer.

     * <p>

     * Typical clients of this

     * class first set up the syntax tables and then sit in a loop

     * calling nextToken to parse successive tokens until TT_EOF

     * is returned.

     *

     * @return     the value of the <code>ttype</code> field.

     * @exception  IOException  if an I/O error occurs.

     * @see        java.io.StreamTokenizer#nval

     * @see        java.io.StreamTokenizer#sval

     * @see        java.io.StreamTokenizer#ttype

     */

    public int nextToken() throws IOException {

        if (pushedBack) {

            pushedBack = false;

            return ttype;