/*
 *        JacORB - a free Java ORB
 *
 *   Copyright (C) 1997-2004 Gerald Brose.
 *
 *   This library is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU Library General Public
 *   License as published by the Free Software Foundation; either
 *   version 2 of the License, or (at your option) any later version.
 *
 *   This library 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
 *   Library General Public License for more details.
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this library; if not, write to the Free
 *   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

package org.jacorb.idl;

import java.util.Hashtable;
import java.util.Stack;
import org.jacorb.idl.runtime.char_token;
import org.jacorb.idl.runtime.float_token;
import org.jacorb.idl.runtime.int_token;
import org.jacorb.idl.runtime.long_token;
import org.jacorb.idl.runtime.token;

/**
 *  This  class implements  a  scanner  (aka lexical  analyzer or
 *  lexer) for  IDL. The scanner reads characters  from a global input
 *  stream  and returns integers corresponding to  the terminal number
 *  of the next token.  Once the end of input is reached the EOF token
 *  is returned on every  subsequent call.<p>
 *
 *  All symbol constants are defined in sym.java which is generated by
 *  JavaCup from parser.cup.<p>
 *
 *  In  addition to the scanner  proper (called first  via init() then
 *  with  next_token() to get  each token) this class  provides simple
 *  error  and warning  routines  and keeps  a  count  of errors  and
 *  warnings that  is  publicly accessible.  It  also provides  basic
 *  preprocessing   facilties,  i.e.  it   does  handle  preprocessor
 *  directives  such as #define,  #undef, #include, etc.   although it
 *  does not provide full C++ preprocessing
 *
 *  This class is "static" (i.e., it has only static members and methods).
 *
 * @version $Id: lexer.java,v 1.54 2008-11-14 08:55:26 nick.cross Exp $
 * @author Gerald Brose
 *
 */

public class lexer
{
    private static org.apache.log.Logger logger = parser.getLogger();

    /** First and second character of lookahead. */
    protected static int next_char;
    protected static int next_char2;

    /** EOF constant. */
    protected static final int EOF_CHAR = -1;

    /**
     * Table   of  keywords.   Keywords  are   initially  treated  as
     * identifiers.  Just before they  are returned we look them up in
     * this table  to see  if they  match one  of the  keywords.  The
     * string of  the name  is the  key here,  which  indexes Integer
     * objects holding the symbol number.
     */

    protected static Hashtable keywords = new Hashtable();

    /** Table of keywords, stored in lower case.  Keys are the
     *  lower case version of the keywords used as keys for the keywords
     *  hash above, and the values are the case sensitive versions of
     *  the keywords.  This table is used for detecting collisions of
     *  identifiers with keywords.
     */
    protected static Hashtable keywords_lower_case = new Hashtable();


    /** Table of Java reserved names.
     */

    protected static Hashtable java_keywords = new Hashtable();

    /** Table of single character symbols.  For ease of implementation, we
     *  store all unambiguous single character tokens in this table of Integer
     *  objects keyed by Integer objects with the numerical value of the
     *  appropriate char (currently Character objects have a bug which precludes
     *  their use in tables).
     */
    protected static Hashtable char_symbols = new Hashtable( 25 );


    /** Defined symbols  (preprocessor) */

    protected static Hashtable defines = new Hashtable();
    protected static boolean conditionalCompilation = true;

    /** nested #ifdefs are pushed on this stack by the "preprocessor" */
    private static java.util.Stack ifStack = new Stack();

    private static java.util.Stack tokenStack = new Stack();

    /** Current line number for use in error messages. */
    protected static int current_line = 1;

    /** Current line  for use in error messages. */
    protected static StringBuffer line = new StringBuffer();

    /** Character position in current line. */
    protected static int current_position = 1;

    /** Have we already read a '"' ?  */
    protected static boolean in_string = false;

    /** Are we processing a wide char or string ?  */
    protected static boolean wide = false;

    /** Count of total errors detected so far. */
    static int error_count = 0;

    /** Count of warnings issued so far */
    public static int warning_count = 0;

    /** currently active pragma prefix */
    public static String currentPragmaPrefix = "";

    /** current file name */
    public static String currentFile = "";

    /** reset the scanner state */

    public static void reset()
    {
        current_position = 1;
        error_count = 0;
        warning_count = 0;
        currentPragmaPrefix = "";
        line = new StringBuffer();
        ifStack.removeAllElements();
        tokenStack.removeAllElements();
        defines.clear();
    }

    /**
     * Initialize the scanner.  This sets up the keywords and char_symbols
     * tables and reads the first two characters of lookahead.
     *
     * "Object" is listed as reserved in the OMG spec.
     * "int" is not, but I reserved it to bar its usage as a legal integer
     * type.
     */

    public static void init()
        throws java.io.IOException
    {
        /* set up standard symbols */
        defines.put( "JACORB_IDL_1_4", "" );

        /* set up the keyword table */

        keywords.put( "abstract", new Integer( sym.ABSTRACT ) );
        keywords.put( "any", new Integer( sym.ANY ) );
        keywords.put( "attribute", new Integer( sym.ATTRIBUTE ) );
        keywords.put( "boolean", new Integer( sym.BOOLEAN ) );
        keywords.put( "case", new Integer( sym.CASE ) );
        keywords.put( "char", new Integer( sym.CHAR ) );
        keywords.put( "const", new Integer( sym.CONST ) );
        keywords.put( "context", new Integer( sym.CONTEXT ) );
        keywords.put( "custom", new Integer( sym.CUSTOM ) );
        keywords.put( "default", new Integer( sym.DEFAULT ) );
        keywords.put( "double", new Integer( sym.DOUBLE ) );
        keywords.put( "enum", new Integer( sym.ENUM ) );
        keywords.put( "exception", new Integer( sym.EXCEPTION ) );
        keywords.put( "factory", new Integer( sym.FACTORY ) );
        keywords.put( "FALSE", new Integer( sym.FALSE ) );
        keywords.put( "fixed", new Integer( sym.FIXED ) );
        keywords.put( "float", new Integer( sym.FLOAT ) );
        keywords.put( "getraises", new Integer( sym.GETRAISES ) );
        keywords.put( "in", new Integer( sym.IN ) );
        keywords.put( "inout", new Integer( sym.INOUT ) );
        keywords.put( "interface", new Integer( sym.INTERFACE ) );
        keywords.put( "local", new Integer( sym.LOCAL ) );
        keywords.put( "long", new Integer( sym.LONG ) );
        keywords.put( "module", new Integer( sym.MODULE ) );
        keywords.put( "native", new Integer( sym.NATIVE ) );
        keywords.put( "Object", new Integer( sym.OBJECT ) );
        keywords.put( "octet", new Integer( sym.OCTET ) );
        keywords.put( "oneway", new Integer( sym.ONEWAY ) );
        keywords.put( "out", new Integer( sym.OUT ) );
        keywords.put( "private", new Integer( sym.PRIVATE ) );
        keywords.put( "public", new Integer( sym.PUBLIC ) );
        keywords.put( "pseudo", new Integer( sym.PSEUDO ) );
        keywords.put( "raises", new Integer( sym.RAISES ) );
        keywords.put( "readonly", new Integer( sym.READONLY ) );
        keywords.put( "sequence", new Integer( sym.SEQUENCE ) );
        keywords.put( "setraises", new Integer( sym.SETRAISES ) );
        keywords.put( "short", new Integer( sym.SHORT ) );
        keywords.put( "string", new Integer( sym.STRING ) );
        keywords.put( "struct", new Integer( sym.STRUCT ) );
        keywords.put( "supports", new Integer( sym.SUPPORTS ) );
        keywords.put( "switch", new Integer( sym.SWITCH ) );
        keywords.put( "TRUE", new Integer( sym.TRUE ) );
        keywords.put( "truncatable", new Integer( sym.TRUNCATABLE ) );
        keywords.put( "typedef", new Integer( sym.TYPEDEF ) );
        keywords.put( "unsigned", new Integer( sym.UNSIGNED ) );
        keywords.put( "union", new Integer( sym.UNION ) );
        keywords.put( "ValueBase", new Integer( sym.VALUEBASE ) );
        keywords.put( "valuetype", new Integer( sym.VALUETYPE ) );
        keywords.put( "void", new Integer( sym.VOID ) );
        keywords.put( "wchar", new Integer( sym.WCHAR ) );
        keywords.put( "wstring", new Integer( sym.WSTRING ) );

        keywords.put( "::", new Integer( sym.DBLCOLON ) );
        keywords.put( "<<", new Integer( sym.LSHIFT ) );
        keywords.put( ">>", new Integer( sym.RSHIFT ) );
        keywords.put( "L\"", new Integer( sym.LDBLQUOTE ) );

        // setup the mapping of lower case keywords to case sensitive
        // keywords

        for( java.util.Enumeration e = keywords.keys(); e.hasMoreElements(); )
        {
            String keyword = (String)e.nextElement();
            String keyword_lower_case = keyword.toLowerCase();
            keywords_lower_case.put( keyword_lower_case, keyword );
        }

        /* set up the table of single character symbols */
        char_symbols.put( new Integer( ';' ), new Integer( sym.SEMI ) );
        char_symbols.put( new Integer( ',' ), new Integer( sym.COMMA ) );
        char_symbols.put( new Integer( '*' ), new Integer( sym.STAR ) );
        char_symbols.put( new Integer( '.' ), new Integer( sym.DOT ) );
        char_symbols.put( new Integer( ':' ), new Integer( sym.COLON ) );
        char_symbols.put( new Integer( '=' ), new Integer( sym.EQUALS ) );
        char_symbols.put( new Integer( '+' ), new Integer( sym.PLUS ) );
        char_symbols.put( new Integer( '-' ), new Integer( sym.MINUS ) );
        char_symbols.put( new Integer( '{' ), new Integer( sym.LCBRACE ) );
        char_symbols.put( new Integer( '}' ), new Integer( sym.RCBRACE ) );
        char_symbols.put( new Integer( '(' ), new Integer( sym.LPAREN ) );
        char_symbols.put( new Integer( ')' ), new Integer( sym.RPAREN ) );
        char_symbols.put( new Integer( '[' ), new Integer( sym.LSBRACE ) );
        char_symbols.put( new Integer( ']' ), new Integer( sym.RSBRACE ) );
        char_symbols.put( new Integer( '<' ), new Integer( sym.LESSTHAN ) );
        char_symbols.put( new Integer( '>' ), new Integer( sym.GREATERTHAN ) );
        char_symbols.put( new Integer( '\'' ), new Integer( sym.QUOTE ) );
        char_symbols.put( new Integer( '\"' ), new Integer( sym.DBLQUOTE ) );
        char_symbols.put( new Integer( '\\' ), new Integer( sym.BSLASH ) );
        char_symbols.put( new Integer( '^' ), new Integer( sym.CIRCUM ) );
        char_symbols.put( new Integer( '&' ), new Integer( sym.AMPERSAND ) );
        char_symbols.put( new Integer( '/' ), new Integer( sym.SLASH ) );
        char_symbols.put( new Integer( '%' ), new Integer( sym.PERCENT ) );
        char_symbols.put( new Integer( '~' ), new Integer( sym.TILDE ) );
        char_symbols.put( new Integer( '|' ), new Integer( sym.BAR ) );
        char_symbols.put( new Integer( ' ' ), new Integer( sym.SPACE ) );

        /* set up reserved Java names */

        java_keywords.put( "abstract", "" );
        java_keywords.put( "boolean", "" );
        java_keywords.put( "break", "" );
        java_keywords.put( "byte", "" );
        java_keywords.put( "case", "" );
        java_keywords.put( "catch", "" );
        java_keywords.put( "char", "" );
        java_keywords.put( "class", "" );
        java_keywords.put( "const", "" );
        java_keywords.put( "continue", "" );
        java_keywords.put( "default", "" );
        java_keywords.put( "do", "" );
        java_keywords.put( "double", "" );
        java_keywords.put( "else", "" );
        java_keywords.put( "extends", "" );
        java_keywords.put( "false", "" );
        java_keywords.put( "final", "" );
        java_keywords.put( "finally", "" );
        java_keywords.put( "float", "" );
        java_keywords.put( "for", "" );
        java_keywords.put( "goto", "" );
        java_keywords.put( "if", "" );
        java_keywords.put( "implements", "" );
        java_keywords.put( "import", "" );
        java_keywords.put( "instanceof", "" );
        java_keywords.put( "int", "" );
        java_keywords.put( "interface", "" );
        java_keywords.put( "long", "" );
        java_keywords.put( "native", "" );
        java_keywords.put( "new", "" );
        java_keywords.put( "null", "" );
        java_keywords.put( "package", "" );
        java_keywords.put( "private", "" );
        java_keywords.put( "protected", "" );
        java_keywords.put( "public", "" );
        java_keywords.put( "return", "" );
        java_keywords.put( "short", "" );
        java_keywords.put( "static", "" );
        java_keywords.put( "super", "" );
        java_keywords.put( "switch", "" );
        java_keywords.put( "synchronized", "" );
        java_keywords.put( "true", "" );
        java_keywords.put( "this", "" );
        java_keywords.put( "throw", "" );
        java_keywords.put( "throws", "" );
        java_keywords.put( "transient", "" );
        java_keywords.put( "try", "" );
        java_keywords.put( "void", "" );
        java_keywords.put( "volatile", "" );
        java_keywords.put( "while", "" );

        java_keywords.put( "clone", "" );
        java_keywords.put( "equals", "" );
        java_keywords.put( "finalize", "" );
        java_keywords.put( "getClass", "" );
        java_keywords.put( "hashCode", "" );
        java_keywords.put( "notify", "" );
        java_keywords.put( "notifyAll", "" );
        java_keywords.put( "toString", "" );
        java_keywords.put( "wait", "" );



        /* stack needs a topmost value */
        ifStack.push( new Boolean( true ) );

        /* read two characters of lookahead */

        try
        {
            next_char = GlobalInputStream.read();
        }
        catch( Exception e )
        {
            org.jacorb.idl.parser.fatal_error( "Cannot read from file " +
                    GlobalInputStream.currentFile().getAbsolutePath() +
                    ", please check file name.", null );
        }

        if( next_char == EOF_CHAR )
            next_char2 = EOF_CHAR;
        else
            next_char2 = GlobalInputStream.read();
    }


    public static void define( String symbol, String value )
    {
        if( logger.isDebugEnabled() )
            logger.debug( "Defining: " + symbol + " as " + value );
        defines.put( symbol, value );
    }

    public static void undefine( String symbol )
    {
        if( logger.isDebugEnabled() )
            logger.debug( "Un-defining: " + symbol );
        defines.remove( symbol );
    }

    public static String defined( String symbol )
    {
        return (String)defines.get( symbol );
    }

    /**
     *   record information about the last lexical scope so that it can be
     *  restored later
     */

    public static int currentLine()
    {
        return current_line;
    }

    /**
     * return the current reading position
     */

    public static PositionInfo getPosition()
    {
        return new PositionInfo( current_line,
                                 current_position,
                                 currentPragmaPrefix,
                                 line.toString(),
                                 GlobalInputStream.currentFile() );
    }

    public static void restorePosition( PositionInfo p )
    {
        current_line = p.line_no;
        currentPragmaPrefix = p.pragma_prefix;
        current_position = 0;
    }

    /**
     * Advance the scanner one character in the input stream.  This moves
     * next_char2 to next_char and then reads a new next_char2.
     */

    protected static void advance()
        throws java.io.IOException
    {
        int old_char;

        old_char = next_char;
        next_char = next_char2;
        next_char2 = GlobalInputStream.read();

        line.append( (char)old_char );

        /* count this */

        current_position++;
        if( old_char == '\n' )
        {
            current_line++;
            current_position = 1;
            line = new StringBuffer();
        }
    }


    /**
     *  Emit an error message.  The message will be marked with both the
     *  current line number and the position in the line.  Error messages
     *  are printed on standard error (System.err).
     * @param message the message to print.
     */
    public static void emit_error( String message )
    {
        if (parser.getLogger().isErrorEnabled())
        {
            logger.error(  GlobalInputStream.currentFile().getAbsolutePath() +
                           ", line: " + current_line +
                           "(" + current_position + "): " +
                           message + "\n\t" +
                           line.toString() );
        }
        error_count++;
    }

    public static void emit_error( String message, str_token t )
    {
        if( t == null )
        {
            emit_error( message );
        }
        else
        {
            if (parser.getLogger().isErrorEnabled())
            {
                logger.error( t.fileName + ", line:" + t.line_no +
                              "(" + t.char_pos + "): " + message +
                              "\n\t" + t.line_val );
            }
            error_count++;
        }
    }


    /**
     *  Emit a warning message.  The message will be marked with both the
     *  current line number and the position in the line.  Messages are
     *  printed on standard error (System.err).
     *
     *  @param message the message to print.
     */

    public static void emit_warn( String message )
    {
        if (parser.getLogger().isWarnEnabled())
        {
            logger.warn( message + " at " + current_line + "(" + current_position +
                         "): \"" + line.toString() + "\"" );
        }
        warning_count++;
    }


    public static void emit_warn( String message, str_token t )
    {
        if( t == null )
        {
            emit_warn( message );
        }
        else
        {
            if (parser.getLogger().isWarnEnabled())
            {
                logger.warn( " at " + t.fileName + ", line:" + t.line_no + "(" +
                             t.char_pos + "): " + message  + "\n\t" + t.line_val );
            }

            warning_count++;
        }
    }


    /**
     * Determine if a character is ok to start an id.
     * @param ch the character in question.
     */
    protected static boolean id_start_char( int ch )
    {
        return
                ( ch >= 'a' && ch <= 'z' ) ||
                ( ch >= 'A' && ch <= 'Z' ) ||
                ( ch == '_' );
    }


    /**
     *  Determine if a character is ok for the middle of an id.
     * @param ch the character in question.
     */
    protected static boolean id_char( int ch )
    {
        return id_start_char( ch ) || ( ch == '_' ) || ( ch >= '0' && ch <= '9' );
    }


    /**
     * Try to look up a single character symbol, returns -1 for not found.
     * @param ch the character in question.
     */

    protected static int find_single_char( int ch )
    {
        Integer result;

        result = (Integer)char_symbols.get( new Integer( (char)ch ) );
        if( result == null )
            return -1;
        else
            return result.intValue();
    }

    /**
     * Handle swallowing up a comment.  Both old style C and new style C++
     * comments are handled.
     */
    protected static void swallow_comment()
            throws java.io.IOException
    {
        /* next_char == '/' at this point */

        /* is it a traditional comment */
        if( next_char2 == '*' )
        {
            /* swallow the opener */
            advance();
            advance();

            /* swallow the comment until end of comment or EOF */
            for( ; ; )
            {
                /* if its EOF we have an error */
                if( next_char == EOF_CHAR )
                {
                    emit_error( "Specification file ends inside a comment", null );
                    return;
                }

                /* if we can see the closer we are done */
                if( next_char == '*' && next_char2 == '/' )
                {
                    advance();
                    advance();
                    return;
                }

                /* otherwise swallow char and move on */
                advance();
            }
        }

        /* is its a new style comment */
        if( next_char2 == '/' )
        {
            /* swallow the opener */
            advance();
            advance();

            /* swallow to '\n', '\f', or EOF */
            while( next_char != '\n' && next_char != '\f' && next_char != '\r' && next_char != EOF_CHAR )
            {
                advance();
            }

            return;
        }

        /* shouldn't get here, but... if we get here we have an error */
        emit_error( "Malformed comment in specification -- ignored", null );
        advance();
    }


    /**
     *  Preprocessor directives are handled here.
     */

    protected static void preprocess()
        throws java.io.IOException
    {
        for( ; ; )
        {
            /* if its EOF we have an error */
            if( next_char == EOF_CHAR )
            {
                emit_error( "Specification file ends inside a preprocessor directive", null );
                return;
            }
            else if( next_char != '#' )
            {
                emit_error( "expected #, got " + (char)next_char + " instead!", null );
            }
            else
                advance();      // skip '#'

            // the following is done to allow for #   ifdef sloppiness
            while( ( ' ' == next_char ) || ( '\t' == next_char ) )
                advance();

            String dir = get_string();

            if( dir.equals( "include" ) )
            {
                if( !conditionalCompilation )
                    return;
                // Swallow between include and < or "
                swallow_whitespace();
                boolean useIncludePath = ( next_char == '<' );
                advance(); // skip `\"' or '<'

                String fname = get_string();

                if( useIncludePath && ( next_char != '>' ) )
                    emit_error( "Syntax error in #include directive, expecting '>'" );
                else if( !useIncludePath && ( next_char != '\"' ) )
                    emit_error( "Syntax error in #include directive, expecting \"" );

                /* swallow to '\n', '\f', or EOF */
                while( next_char != '\n' && next_char != '\f' && next_char != '\r' &&
                        next_char != EOF_CHAR )
                {
                    advance();
                }
                GlobalInputStream.include( fname, next_char2, useIncludePath );
                current_line = 0;
                advance();
                advance();
                return;
            }
            else if( dir.equals( "define" ) )
            {
                if( !conditionalCompilation )
                    return;
                swallow_whitespace();
                String name = get_string();
                StringBuffer text = new StringBuffer();
                if( next_char == ' ' )
                {
                    advance();
                }
                while( next_char != '\n' )
                {
                    if( next_char == '\\' )
                    {
                        advance();
                        advance();
                    }
                    text.append( (char)next_char );
                    advance();
                }
                define( name, text.toString() );
            }
            else if( dir.equals( "error" ) )
            {
                if( !conditionalCompilation )
                    return;
                advance();      // skip ' '
                String name = get_string();
                emit_error( name );
            }
            else if( dir.equals( "undef" ) )
            {
                // Undefining symbol
                if( !conditionalCompilation )
                    return;
                swallow_whitespace();
                String name = get_string();
                undefine( name );
            }
            else if( dir.equals( "if" ) || dir.equals( "elif" ) )
            {
                if (! dir.equals( "elif" ) )
                {
                    ifStack.push( new Boolean( conditionalCompilation ) );
                    if( !conditionalCompilation )
                        return;
                }

                swallow_whitespace();

                // the following snippet distinguishes between #if defined
                // and #if !defined

                boolean straightDefined = true;
                if( '!' == next_char )
                {
                    advance();
                    straightDefined = false;
                }

                String defineStr = get_string_no_paren();

                if (defineStr.equals ("defined"))
                {
                    swallow_whitespace();

                    boolean brackets = ( '(' == next_char );
                    if( brackets )
                    {
                        advance(); // skip '('
                        swallow_whitespace(); // any whitespace after ( ? skip it
                    }

                    String name = get_string_no_paren();

                    if( brackets )
                    {
                        swallow_whitespace();
                        if( logger.isDebugEnabled() )
                            logger.debug( "next char: " + next_char );

                        if( ')' != next_char )
                        {
                            emit_error( "Expected ) terminating #if defined", null );
                            return;
                        }
                        advance();
                    }

                    if( straightDefined )
                        conditionalCompilation = ( null != defined( name ) );
                    else
                        conditionalCompilation = ( null == defined( name ) );
                }
                else if (defineStr.equals("0"))
                {
                    conditionalCompilation = false;
                }
                else if (defineStr.equals("1"))
                {
                    conditionalCompilation = true;
                }
                else
                {
                    emit_error( "Expected \"defined\" following #if: " +
                                dir, null );
                    return;
                }
            }
            else if( dir.equals( "ifdef" ) )
            {
                ifStack.push( new Boolean( conditionalCompilation ) );
                if( !conditionalCompilation )
                    return;
                swallow_whitespace();
                String name = get_string();
                conditionalCompilation = ( defined( name ) != null );
            }
            else if( dir.equals( "ifndef" ) )
            {
                ifStack.push( new Boolean( conditionalCompilation ) );
                if( !conditionalCompilation )
                    return;
                swallow_whitespace();
                String name = get_string();
                conditionalCompilation = ( defined( name ) == null );
            }
            else if( dir.equals( "else" ) )
            {
                if( ( (Boolean)ifStack.peek() ).booleanValue() )
                    conditionalCompilation = !conditionalCompilation;
            }
            else if( dir.equals( "endif" ) )
            {
                boolean b = ( (Boolean)ifStack.pop() ).booleanValue();
                conditionalCompilation = b;
            }
            else if( dir.equals( "pragma" ) )
            {
                if( !conditionalCompilation )
                    return;
                swallow_whitespace();

                String name = get_string();
                if( name.equals( "prefix" ) )
                {
                    advance();
                    currentPragmaPrefix = get_string();
                }
                else if( name.equals( "version" ) )
                {
                    advance(); // skip ' '
                    String vname = get_string();
                    advance(); // skip ' '
                    String version = get_string();
                    String existingVersion = (String) parser.currentScopeData().versionMap.get (vname);
                    if (existingVersion == null)
                    {
                        // Set version
                        parser.currentScopeData().versionMap.put (vname, version);
                    }
                    else
                    {
                        // Check for version change
                        if (! existingVersion.equals (version))
                        {
                            emit_error
                            (
                                "Version re-declaration with different value: #pragma version " +
                                version,
                                null
                            );
                        }
                    }
                    String iname = (String)parser.currentScopeData().idMap.get (vname);
                    if (iname != null)
                    {
                        if (version.equals (iname.substring (1 + iname.lastIndexOf (':'))) == false)
                        {
                            emit_error ("Declaring version with different version to already declared ID for " + name, null);
                        }
                    }
                }
                else if( name.equals( "ID" ) )
                {
                    advance(); // skip ' '
                    String iname = get_string();
                    advance(); // skip ' '
                    String id = get_string();
                    String existingID = (String) parser.currentScopeData().idMap.get (iname);
                    if (existingID == null)
                    {
                        // Set id
                        parser.currentScopeData().idMap.put (iname, id);
                    }
                    else
                    {
                        // Check for id change
                        if (! existingID.equals (id))
                        {
                            emit_error
                            (
                                "ID re-declaration with different value: #pragma id " +
                                id,
                                null
                            );
                        }
                    }
                    if( parser.currentScopeData().versionMap.get( iname ) != null )
                    {
                        if( ((String)parser.currentScopeData().versionMap.get( iname )).equals
                            ( id.substring (1 + id.lastIndexOf (':'))) == false )
                        {
                            emit_error ("Declaring ID with different version to already declared version for " + name, null);
                        }
                    }
                }
                else if( name.equals( "inhibit_code_generation" ) )
                {
                    /* proprietary pragma of the JacORB IDL compiler */
                    parser.setInhibitionState( true );
                    // do something with it
                }
                else
                {
                    emit_warn( "Unknown pragma, ignoring: #pragma " + name, null );
                }
            }
            else
            {
                emit_error( "Unrecognized preprocessor directive " + dir, null );
            }


            /* swallow to '\n', '\f', or EOF */
            while( next_char != '\n' && next_char != '\f' && next_char != '\r' &&
                    next_char != EOF_CHAR )
            {
                advance();
            }
            return;
        }
    }


    // the following is used for parsing the #if defined(...) construct

    private static String get_string_no_paren()
            throws java.io.IOException
    {
        StringBuffer sb = new StringBuffer();
        char c = (char)next_char;
        while( c != ' ' && c != '\t' && c != '\r' && c != '\n' && c != '\f' && c != EOF_CHAR
                && c != '\"' && c != '<' && c != '>' && c != '(' && c != ')' )
        {
            sb.append( c );
            advance();
            c = (char)next_char;
        }
        return sb.toString();
    }


    private static String get_string()
            throws java.io.IOException
    {

        StringBuffer sb = new StringBuffer( "" );

        if( next_char == '\"' )
        {
            advance();
            while( next_char != '\"' )
            {
                if( next_char == EOF_CHAR )
                    emit_error( "Unexpected EOF in string" );
                sb.append( (char)next_char );
                advance();
            }
        }
        else
        {
            while( next_char != ' ' && next_char != '\t' && next_char != '\r' &&
                    next_char != '\n' && next_char != '\f' && next_char != EOF_CHAR &&
                    next_char != '\"' && next_char != '<' && next_char != '>' )
            {
                sb.append( (char)next_char );
                advance();
            }
        }
        return sb.toString();
    }


    /**
     *  Process  an identifier.
     *  <P>
     *  Identifiers  begin with a letter, underscore,  or dollar sign,
     *  which   is  followed  by  zero  or   more  letters,  numbers,
     *  underscores or dollar signs.  This routine returns a str_token
     *  suitable for return by the scanner or null, if the string that
     *  was read expanded to a symbol that was #defined. In this case,
     *  the symbol is expanded in place
     */

    protected static token do_symbol()
            throws java.io.IOException
    {
        StringBuffer result = new StringBuffer();
        String result_str;
        Integer keyword_num = null;
        char buffer[] = new char[ 1 ];

        /* next_char holds first character of id */
        buffer[ 0 ] = (char)next_char;
        result.append( buffer, 0, 1 );
        advance();

        /* collect up characters while they fit in id */
        while( id_char( next_char ) )
        {
            buffer[ 0 ] = (char)next_char;
            result.append( buffer, 0, 1 );
            advance();
        }

        /* extract a string */
        result_str = result.toString();

        /* try to look it up as a defined symbol... */

        String text = defined( result_str );
        if( text != null )
        {
            char[] next = {(char)next_char, (char)next_char2};
            GlobalInputStream.insert( text + ( new String( next ) ) );
            advance(); // restore lookahead
            advance(); // restore lookahead
            return null;
        }

        // check if it's a keyword
        keyword_num = (Integer)keywords.get( result_str );
        if( keyword_num != null )
        {
            if( isScope( result_str ) )
            {
                parser.openScope();
            }
            return new token( keyword_num.intValue() );
        }

        // not a keyword, so treat as identifier after verifying
        // case sensitivity rules and prefacing with an _
        // if it collides with a Java keyword.

        result_str = checkIdentifier( result_str );
        if( null != result_str )
            return new str_token( sym.ID, result_str, getPosition(),
                    GlobalInputStream.currentFile().getName() );
        else
            return null;
    }

    private static boolean isScope( String keyword )
    {
        return ( keyword.equals( "module" ) ||
                keyword.equals( "interface" ) ||
                keyword.equals( "struct" ) ||
                keyword.equals( "exception" ) ||
                keyword.equals( "union" )
                //                 keyword.equals("valuetype")
                );
    }


    /**
     * Checks whether Identifier str is legal and returns it. If the
     * identifier is escaped with a leading underscore, that
     * underscore is removed. If a the legal IDL identifier clashes
     * with a Java reserved word, an underscore is prepended.
     * <BR>
     * @param str - the IDL identifier <BR>
     * <BR>
     * Prints an error msg if the identifier collides with an IDL
     * keyword.
     */

    public static String checkIdentifier( String str )
    {

        if( logger.isInfoEnabled() )
            logger.info( "checking identifier " + str );

        /* if it is an escaped identifier, look it up as a keyword,
           otherwise remove the underscore. */

        if( str.charAt( 0 ) == '_' )
        {
            str = str.substring( 1 );
        }
        else
        {
            String colliding_keyword = null;

            if (org.jacorb.idl.parser.strict_names)
            {
                // check for name clashes strictly (i.e. case insensitive)
                colliding_keyword =
                    (String)keywords_lower_case.get(str.toLowerCase());
            }
            else
            {
                // check for name clashes only loosely (i.e. case sensitive)
                colliding_keyword =
                    (String)keywords.get(str);
            }

            if( colliding_keyword != null )
            {
                emit_error( "Identifier " + str + " collides with keyword " +
                            colliding_keyword + "." );
                return null;
            }


        }

        /* clashes with a Java reserved word? */
        if( needsJavaEscape( str ) )
        {
            str = "_" + str;
        }

        return str;
    }

    /**
     * Only the most general name clashes with Java keywords
     * are caught here. Identifiers need to be checked again
     * at different other places in the compiler!
     */

    private static boolean needsJavaEscape( String s )
    {
        return ( java_keywords.containsKey( s ) );
    }

    /**
     * called during the parse phase to catch clashes with
     * Java reserved words.
     */

    public static boolean strictJavaEscapeCheck( String s )
    {
        return ( ( !s.equals( "Helper" ) && s.endsWith( "Helper" ) ) ||
                ( !s.equals( "Holder" ) && s.endsWith( "Holder" ) ) ||
                ( !s.equals( "Operations" ) && s.endsWith( "Operations" ) ) ||
                ( !s.equals( "Package" ) && s.endsWith( "Package" ) ) ||
                ( !s.equals( "POA" ) && s.endsWith( "POA" ) ) ||
                ( !s.equals( "POATie" ) && s.endsWith( "POATie" ) ) );
    }

    public static boolean needsJavaEscape( Module m )
    {
        String s = m.pack_name;
        if( logger.isDebugEnabled() )
            logger.debug( "checking module name " + s );
        return ( strictJavaEscapeCheck( s ) );
    }


    /**
     *  Return one token.  This is the main external interface to the scanner.
     *  It consumes sufficient characters to determine the next input token
     *  and returns it.
     */

    public static token next_token()
        throws java.io.IOException
    {
        parser.set_included( GlobalInputStream.includeState() );
        token result = real_next_token();
        return result;
    }

    private static void swallow_whitespace()
        throws java.io.IOException
    {
        /* look for white space */
        while( next_char == ' ' || next_char == '\t' || next_char == '\n' ||
                next_char == '\f' || next_char == '\r' )
        {
            /* advance past it and try the next character */
            advance();
        }
    }

    /**
     * The actual routine to return one token.
     *
     * @return token
     * @throws java.io.IOException
     */

    protected static token real_next_token()
        throws java.io.IOException
    {
        int sym_num;

        /* if we found more than a single token last time, these
           tokens were remembered on the tokenStack - return the first
           one here */

        if( !tokenStack.empty() )
            return (token)tokenStack.pop();

        /* else */

        for( ; ; )
        {
            /* scan input until we return something */
            if( !in_string )
            {
                swallow_whitespace();

                /* look for preprocessor directives */
                if( (char)next_char == '#' )
                {
                    preprocess();
                    continue;
                }

                /* look for a comment */
                if( next_char == '/' && ( next_char2 == '*' || next_char2 == '/' ) )
                {
                    /* swallow then continue the scan */
                    swallow_comment();
                    continue;
                }

                if( !conditionalCompilation )
                {
                    advance();
                    if( next_char == EOF_CHAR )
                    {
                        emit_error( "EOF in conditional compilation!", null );
                        return null;
                    }
                    else
                        continue;
                }

                /* look for COLON or DBLCOLON */
                if( next_char == ':' )
                {
                    if( next_char2 == ':' )
                    {
                        advance();
                        advance();
                        return new token( sym.DBLCOLON );
                    }
                    else
                    {
                        advance();
                        return new token( sym.COLON );
                    }
                }

                /* leading L for wide strings */
                if( next_char == 'L' && ( next_char2 =='\"' || next_char2 =='\'') )
                {
                    wide = true;
                    advance();
                    if( next_char2 == '\"' )
                    {
                        advance();
                        in_string = true;
                        return new token( sym.LDBLQUOTE );
                    }
                    // wide char literal may follow, but detecting that
                    // is done below.
                }

                /* look for Shifts  */
                if( next_char == '<' )
                {
                    if( next_char2 == '<' )
                    {
                        advance();
                        advance();
                        return new token( sym.LSHIFT );
                    }
                    else
                    {
                        advance();
                        return new token( sym.LESSTHAN );
                    }
                }
                if( next_char == '>' )
                {
                    if( next_char2 == '>' )
                    {
                        advance();
                        advance();
                        return new token( sym.RSHIFT );
                    }
                    else
                    {
                        advance();
                        return new token( sym.GREATERTHAN );
                    }
                }


                /* leading 0: */
                /* Try to scan octal/hexadecimal numbers, might even find a float */
                if( next_char == '0' )
                {
                    long l_val = 0;
                    long l_val_old = 0;
                    int radix = 8;
                    int digit = 0;
                    advance();

                    if( next_char == '.' )
                    {
                        StringBuffer f_string = new StringBuffer( "0." );
                        advance();

                        while( next_char >= '0' && next_char <= '9' )
                        {
                            f_string.append( (char)next_char );
                            advance();
                        }

                        float f_val = ( new Float( f_string.toString() ) ).floatValue();
                        return new float_token( sym.FLOAT_NUMBER, f_val );
                    }
                    else
                    {
                        // See if hexadecimal value

                        if( next_char == 'x' || next_char == 'X' )
                        {
                            advance();
                            radix = 16;
                        }

                        StringBuffer val = new StringBuffer( "0" );
                        digit = Character.digit( (char)next_char, radix );
                        while( digit != -1 )
                        {
                            val.append( (char)next_char );
                            advance();
                            digit = Character.digit( (char)next_char, radix );
                        }

                        String str = val.toString();
                        try
                        {
                            return new int_token( sym.NUMBER,
                                                  Integer.parseInt( str, radix ) );
                        }
                        catch( NumberFormatException ex )
                        {
                            try
                            {
                                return new long_token( sym.LONG_NUMBER,
                                                       Long.parseLong( str, radix ) );
                            }
                            catch( NumberFormatException ex2 )
                            {
                                emit_error( "Invalid octal/hex value:  " + str );
                            }
                        }
                        return null;
                    }
                }

                /* Try to scan integer, floating point or fixed point literals */

                if (isDigit (((char)next_char)) ||
                    next_char == '.'    ||
                    (next_char == '-' && isDigit (((char)next_char2))))
                {
                    StringBuffer value = new StringBuffer();
                    StringBuffer fraction = null;
                    int exp = 0;

                    if ( next_char == '-' )
                    {
                        value.append( (char)next_char );
                        advance();
                    }
                    // Read integer part
                    while( next_char >= '0' && next_char <= '9' )
                    {
                        value.append( (char)next_char );
                        advance();
                    }

                    // Read fraction
                    if( next_char == '.' )
                    {
                        fraction = new StringBuffer();
                        advance();

                        while( next_char >= '0' && next_char <= '9' )
                        {
                            fraction.append( (char)next_char );
                            advance();
                        }
                    }

                    // Read exponent
                    if( next_char == 'e' || next_char == 'E' )
                    {
                        if( fraction == null )
                            fraction = new StringBuffer();

                        fraction.append( 'e' );
                        advance();
                        if( next_char == '-' || next_char == '+' )
                        {
                            fraction.append( (char)next_char );
                            advance();
                        }

                        while( next_char >= '0' && next_char <= '9' )
                        {
                            fraction.append( (char)next_char );
                            advance();
                        }

                        if( fraction.length() == 1 )
                        {
                            emit_error( "Empty exponent in float/double." );
                            continue;
                        }

                        return new float_token( sym.FLOAT_NUMBER,
                                Float.valueOf( value.toString() +
                                "." +
                                fraction.toString() ).floatValue() );
                    }

                    if( next_char == 'd' || next_char == 'D' )
                    {
                        advance();
                        if( fraction == null )
                            fraction = new StringBuffer();

                        java.math.BigDecimal bi =
                                new java.math.BigDecimal( value.toString() + "." +
                                fraction.toString() );
                        return new fixed_token( sym.FIXED_NUMBER, bi );

                    }

                    if( fraction == null )
                    {
                        /* integer or long */

                        token tok = null;
                        String str = value.toString();

                        try
                        {
                            tok = new int_token( sym.NUMBER, Integer.parseInt( str ) );
                        }
                        catch( NumberFormatException ex )
                        {
                            try
                            {
                                tok = new long_token
                                    ( sym.LONG_NUMBER, Long.parseLong( str ) );
                            }
                            catch( NumberFormatException ex2 )
                            {
                                try
                                {
                                    // Not quite critical yet - lets try stuffing it into
                                    // a bigdecimal for later checking.
                                    tok = new fixed_token
                                        (sym.FIXED_NUMBER, new java.math.BigDecimal (str));
                                }
                                catch (NumberFormatException ex3)
                                {
                                    emit_error( "Invalid long value:  " + str );
                                }
                            }
                        }

                        return tok;
                    }
                    else
                    {
                        try
                        {
                            float f =
                                    Float.valueOf( value.toString() + "." +
                                    fraction.toString() ).floatValue();
                            return new float_token( sym.FLOAT_NUMBER, f );
                        }
                        catch( NumberFormatException nf )
                        {
                            emit_error( "Unexpected symbol:  " +
                                    value.toString() + "." +
                                    fraction.toString() );
                        }
                    }
                }

                /* look for a single character symbol */
                sym_num = find_single_char( next_char );

                /* upon an opening double quote, return the
                   sym.DBLQUOTE token and continue scanning in the
                   in_string branch */

                if( (char)next_char == '\"' )
                {
                    in_string = true;
                    advance();
                    return new token( sym.DBLQUOTE );
                }

                if( (char)next_char == '\'' )
                {
                    advance();

                    token t = null;

                    if( next_char == '\\' )
                    {
                        // Now need to process escaped character.

                        advance();

                        if( isDigit( (char)next_char ) )
                        {
                            // Octal character
                            char octal1 = '0';
                            char octal2 = '0';
                            char octal3 = (char)next_char;

                            if( isDigit( (char)next_char2 ) )
                            {
                                advance();
                                octal2 = octal3;
                                octal3 = (char)next_char;

                                if( isDigit( (char)next_char2 ) )
                                {
                                    advance();
                                    octal1 = octal2;
                                    octal2 = octal3;
                                    octal3 = (char)next_char;
                                }
                            }

                            t = new char_token
                                    (
                                            sym.CH,
                                            (char)Integer.parseInt
                                    ( new String
                                            ( new char[]{octal1, octal2, octal3} ),
                                            8
                                    )
                                    );
                        }
                        else if( (char)next_char == 'x' )
                        {
                            // Hexadecimal character
                            advance();

                            char hex1 = '0';
                            char hex2 = (char)next_char;

                            if( isHexLetterOrDigit( (char)next_char2 ) )
                            {
                                advance();
                                hex1 = hex2;
                                hex2 = (char)next_char;
                            }
                            else if( (char)next_char2 != '\'' )
                            {
                                emit_error( "Illegal hex character" );
                                return null;
                            }

                            t = new char_token
                                    (
                                            sym.CH,
                                            (char)Integer.parseInt
                                    ( new String
                                            ( new char[]{hex1, hex2} ),
                                            16
                                    )
                                    );

                        }
                        else if( (char)next_char == 'u' )
                        {
                            if( wide == false )
                            {
                                emit_error( "Unicode characters are only legal with wide character" );
                                return null;
                            }
                            else
                            {
                                // Hexadecimal character
                                advance();

                                char uni1 = '0';
                                char uni2 = '0';
                                char uni3 = '0';
                                char uni4 = (char)next_char;

                                if( isHexLetterOrDigit( (char)next_char2 ) )
                                {
                                    advance();
                                    uni3 = uni4;
                                    uni4 = (char)next_char;

                                    if( isHexLetterOrDigit( (char)next_char2 ) )
                                    {
                                        advance();
                                        uni2 = uni3;
                                        uni3 = uni4;
                                        uni4 = (char)next_char;

                                        if( isHexLetterOrDigit( (char)next_char2 ) )
                                        {
                                            advance();
                                            uni1 = uni2;
                                            uni2 = uni3;
                                            uni3 = uni4;
                                            uni4 = (char)next_char;
                                        }
                                        else if( (char)next_char2 != '\'' )
                                        {
                                            emit_error( "Illegal unicode character" );
                                            return null;
                                        }
                                    }
                                    else if( (char)next_char2 != '\'' )
                                    {
                                        emit_error( "Illegal unicode character" );
                                        return null;
                                    }
                                }
                                else if( (char)next_char2 != '\'' )
                                {
                                    emit_error( "Illegal unicode character" );
                                    return null;
                                }

                                t = new char_token
                                        (
                                                sym.CH,
                                                (char)Integer.parseInt
                                        ( new String
                                                ( new char[]{uni1, uni2, uni3, uni4} ),
                                                16
                                        )
                                        );
                            }
                        }
                        else
                        {
                            switch( next_char )
                            {
                                case 'n':
                                    {
                                        t = new char_token( sym.CH, '\n' );
                                        break;
                                    }
                                case 't':
                                    {
                                        t = new char_token( sym.CH, '\t' );
                                        break;
                                    }
                                case 'v':
                                    {
                                        t = new char_token( sym.CH, '\013' );
                                        break;
                                    }
                                case 'b':
                                    {
                                        t = new char_token( sym.CH, '\b' );
                                        break;
                                    }
                                case 'r':
                                    {
                                        t = new char_token( sym.CH, '\r' );
                                        break;
                                    }
                                case 'f':
                                    {
                                        t = new char_token( sym.CH, '\f' );
                                        break;
                                    }
                                case 'a':
                                    {
                                        t = new char_token( sym.CH, '\007' );
                                        break;
                                    }
                                case '\\':
                                    {
                                        t = new char_token( sym.CH, '\\' );
                                        break;
                                    }
                                case '?':
                                    {
                                        t = new char_token( sym.CH, '?' );
                                        break;
                                    }
                                case '0':
                                    {
                                        t = new char_token( sym.CH, '\0' );
                                        break;
                                    }
                                case '\'':
                                    {
                                        t = new char_token( sym.CH, '\'' );
                                        break;
                                    }
                                case '\"':
                                    {
                                        t = new char_token( sym.CH, '\"' );
                                        break;
                                    }
                                default:
                                    {
                                        emit_error( "Invalid escape symbol \'" );
                                        return null;
                                    }
                            }
                        }
                    }
                    else
                    {
                        t = new char_token( sym.CH, (char)next_char );
                    }
                    advance();

                    if( (char)next_char == '\'' )
                    {
                        tokenStack.push( new token( sym.QUOTE ) );
                        tokenStack.push( t );
                        advance();
                    }
                    else
                    {
                        emit_error( "Expecting closing \'" );
                        return null;
                    }
                    wide = false;

                    return new token( sym.QUOTE );
                }


                if( sym_num != -1 )
                {
                    /* found one -- advance past it and return a token for it */
                    advance();

                    return new token( sym_num );
                }

                /* look for an id or keyword */
                if( id_start_char( next_char ) )
                {
                    token t = do_symbol();
                    if( t != null )
                        return t;
                    else
                        continue;
                }

                /* look for EOF */
                if( next_char == EOF_CHAR )
                {
                    return new token( sym.EOF );
                }
            }
            else // in_string
            {

                /* empty string ? */
                if( (char)next_char == '\"' )
                {
                    in_string = false;
                    advance();
                    return new token( sym.DBLQUOTE );
                }

                StringBuffer result = new StringBuffer();
                char previous = ' ';

                /* collect up characters while they fit in id */
                while( true )
                {
                    if( next_char == '\\' )
                    {
                        // Remap those characters that have no equivilant in java
                        switch( next_char2 )
                        {
                            case 'a':
                                {
                                    result.append( "\\007" );
                                    previous = 'a';
                                    advance();
                                    break;
                                }
                            case 'v':
                                {
                                    result.append( "\\013" );
                                    previous = 'v';
                                    advance();
                                    break;
                                }
                            case '?':
                                {
                                    result.append( "?" );
                                    previous = '?';
                                    advance();
                                    break;
                                }
                                // Replace \xA0 by octal equivilant
                            case 'x':
                                {
                                    advance();
                                    advance();

                                    // Now next_char will be A and next_char2 will be 0
                                    String octal = Integer.toOctalString
                                            (
                                                    Integer.parseInt
                                            (
                                                    new String
                                                            (
                                                                    new char[]{
                                                                        (char)next_char,
                                                                        (char)next_char2}
                                                            ),
                                                    16
                                            )
                                            );
                                    if( octal.length() != 3 )
                                    {
                                        if( octal.length() == 1 )
                                        {
                                            octal = "0" + octal;
                                        }
                                        octal = "0" + octal;
                                    }
                                    result.append( "\\" + octal );
                                    previous = (char)next_char2;

                                    advance();
                                    break;
                                }
                            case 'u':
                                {
                                    if( wide == false )
                                    {
                                        emit_error( "Unicode characters are only legal with wide strings" );
                                        return null;
                                    }
                                    else
                                    {
                                        result.append( (char)next_char );
                                        result.append( (char)next_char2 );
                                        advance();
                                        advance();

                                        char uni1 = (char)next_char;
                                        char uni2 = '0';
                                        char uni3 = '0';
                                        char uni4 = '0';

                                        if( isHexLetterOrDigit( (char)next_char2 ) )
                                        {
                                            advance();
                                            uni2 = (char)next_char;

                                            if( isHexLetterOrDigit( (char)next_char2 ) )
                                            {
                                                advance();
                                                uni3 = (char)next_char;

                                                if( isHexLetterOrDigit( (char)next_char2 ) )
                                                {
                                                    advance();
                                                    uni4 = (char)next_char;
                                                }
                                                else
                                                {
                                                    emit_error( "Illegal unicode character" );
                                                    return null;
                                                }
                                            }
                                            else
                                            {
                                                emit_error( "Illegal unicode character" );
                                                return null;
                                            }
                                        }
                                        else
                                        {
                                            emit_error( "Illegal unicode character" );
                                            return null;
                                        }

                                        previous = uni4;
                                        result.append( uni1 );
                                        result.append( uni2 );
                                        result.append( uni3 );
                                        result.append( uni4 );
                                    }
                                    break;
                                }
                            default:
                                {
                                    previous = (char)next_char;
                                    result.append( (char)next_char );
                                }
                        }
                    }
                    else
                    {
                        previous = (char)next_char;
                        result.append( (char)next_char );
                    }
                    advance();

                    // Handle backslash quote but exit if just quote
                    if( ( (char)next_char ) == '\"' && previous != '\\' )
                    {
                        break;
                    }
                }
                wide = false;

                String s = result.toString();

                /*  build and return an id token with an attached string */
                return new org.jacorb.idl.str_token( sym.ID, s,
                        getPosition(),
                        GlobalInputStream.currentFile().getName() );
            }

            /* if we get here, we have an unrecognized character */
            emit_warn( "Unrecognized character '" +
                    new Character( (char)next_char ) + "'(" + next_char + ") -- ignored" );

            /* advance past it */
            advance();
        }
    }

    /**
     * Returns true if character is US ASCII 0-9
     *
     * @param c a value of type 'char'
     * @return a value of type 'boolean'
     */
    static boolean isDigit( char c )
    {
        boolean result = false;

        if( c >= '\u0030' )
        {
            if( c <= '\u0039' )
            {
                // Range 0030 [0] -> 0039 [9]
                result = true;
            }
        }
        return result;
    }


    /**
     * Returns true if character is US ASCII 0-9, a-f, A-F
     *
     * @param c a value of type 'char'
     * @return a value of type 'boolean'
     */
    private static boolean isHexLetterOrDigit( char c )
    {
        boolean result = false;

        if( c >= '\u0030' )
        {
            if( c <= '\u0039' )
            {
                // Range 0030 [0] -> 0039 [9]
                result = true;
            }
            else
            {
                if( c >= '\u0041' )
                {
                    if( c <= '\u0046' )
                    {
                        // Range 0041 [A] -> 0046 [F]
                        result = true;
                    }
                    if( c >= '\u0061' )
                    {
                        if( c <= '\u0066' )
                        {
                            // Range 0061 [a] -> 0066 [f]
                            result = true;
                        }
                    }
                }
            }
        }
        return result;
    }
}
