/*
 * 11/07/2008
 *
 * PlainTextTokenMaker.flex - Scanner for plain text files.
 * 
 * This library is distributed under a modified BSD license.  See the included
 * RSyntaxTextArea.License.txt file for details.
 */
package org.fife.ui.rsyntaxtextarea.modes;

import java.io.*;
import javax.swing.text.Segment;

import org.fife.ui.rsyntaxtextarea.*;


/**
 * Scanner for plain text files.
 *
 * This implementation was created using
 * <a href="http://www.jflex.de/">JFlex</a> 1.4.1; however, the generated file
 * was modified for performance.  Memory allocation needs to be almost
 * completely removed to be competitive with the handwritten lexers (subclasses
 * of <code>AbstractTokenMaker</code>), so this class has been modified so that
 * Strings are never allocated (via yytext()), and the scanner never has to
 * worry about refilling its buffer (needlessly copying chars around).
 * We can achieve this because RText always scans exactly 1 line of tokens at a
 * time, and hands the scanner this line as an array of characters (a Segment
 * really).  Since tokens contain pointers to char arrays instead of Strings
 * holding their contents, there is no need for allocating new memory for
 * Strings.<p>
 *
 * The actual algorithm generated for scanning has, of course, not been
 * modified.<p>
 *
 * If you wish to regenerate this file yourself, keep in mind the following:
 * <ul>
 *   <li>The generated <code>PlainTextTokenMaker.java</code> file will contain
 *       two definitions of both <code>zzRefill</code> and <code>yyreset</code>.
 *       You should hand-delete the second of each definition (the ones
 *       generated by the lexer), as these generated methods modify the input
 *       buffer, which we'll never have to do.</li>
 *   <li>You should also change the declaration/definition of zzBuffer to NOT
 *       be initialized.  This is a needless memory allocation for us since we
 *       will be pointing the array somewhere else anyway.</li>
 *   <li>You should NOT call <code>yylex()</code> on the generated scanner
 *       directly; rather, you should use <code>getTokenList</code> as you would
 *       with any other <code>TokenMaker</code> instance.</li>
 * </ul>
 *
 * @author Robert Futrell
 * @version 0.5
 *
 */
%%

%public
%class PlainTextTokenMaker
%extends AbstractJFlexTokenMaker
%unicode
%type org.fife.ui.rsyntaxtextarea.Token


%{


	/**
	 * Constructor.  This must be here because JFlex does not generate a
	 * no-parameter constructor.
	 */
	public PlainTextTokenMaker() {
	}


	/**
	 * Adds the token specified to the current linked list of tokens.
	 *
	 * @param tokenType The token's type.
	 * @param link Whether this token is a hyperlink.
	 */
	private void addToken(int tokenType, boolean link) {
		int so = zzStartRead + offsetShift;
		super.addToken(zzBuffer, zzStartRead,zzMarkedPos-1, tokenType, so, link);
		zzStartRead = zzMarkedPos;
	}


	/**
	 * Always returns <code>Token.NULL</code>, as there are no multiline
	 * tokens in properties files.
	 *
	 * @param text The line of tokens to examine.
	 * @param initialTokenType The token type to start with (i.e., the value
	 *        of <code>getLastTokenTypeOnLine</code> for the line before
	 *        <code>text</code>).
	 * @return <code>Token.NULL</code>.
	 */
	public int getLastTokenTypeOnLine(Segment text, int initialTokenType) {
		return Token.NULL;
	}


	/**
	 * Returns the text to place at the beginning and end of a
	 * line to "comment" it in a this programming language.
	 *
	 * @return <code>null</code>, as there are no comments in plain text.
	 */
	@Override
	public String[] getLineCommentStartAndEnd() {
		return null;
	}


	/**
	 * Always returns <tt>false</tt>, as you never want "mark occurrences"
	 * working in plain text files.
	 *
	 * @param type The token type.
	 * @return Whether tokens of this type should have "mark occurrences"
	 *         enabled.
	 */
	public boolean getMarkOccurrencesOfTokenType(int type) {
		return false;
	}


	/**
	 * Returns the first token in the linked list of tokens generated
	 * from <code>text</code>.  This method must be implemented by
	 * subclasses so they can correctly implement syntax highlighting.
	 *
	 * @param text The text from which to get tokens.
	 * @param initialTokenType The token type we should start with.
	 * @param startOffset The offset into the document at which
	 *        <code>text</code> starts.
	 * @return The first <code>Token</code> in a linked list representing
	 *         the syntax highlighted text.
	 */
	public Token getTokenList(Segment text, int initialTokenType, int startOffset) {

		resetTokenList();
		this.offsetShift = -text.offset + startOffset;

		// Start off in the proper state.
		s = text;
		try {
			yyreset(zzReader);
			yybegin(YYINITIAL);
			return yylex();
		} catch (IOException ioe) {
			ioe.printStackTrace();
			return new TokenImpl();
		}

	}


	/**
	 * Refills the input buffer.
	 *
	 * @return      <code>true</code> if EOF was reached, otherwise
	 *              <code>false</code>.
	 * @exception   IOException  if any I/O-Error occurs.
	 */
	private boolean zzRefill() {
		return zzCurrentPos>=s.offset+s.count;
	}


	/**
	 * Resets the scanner to read from a new input stream.
	 * Does not close the old reader.
	 *
	 * All internal variables are reset, the old input stream 
	 * <b>cannot</b> be reused (internal buffer is discarded and lost).
	 * Lexical state is set to <tt>YY_INITIAL</tt>.
	 *
	 * @param reader   the new input stream 
	 */
	public final void yyreset(java.io.Reader reader) {
		// 's' has been updated.
		zzBuffer = s.array;
		/*
		 * We replaced the line below with the two below it because zzRefill
		 * no longer "refills" the buffer (since the way we do it, it's always
		 * "full" the first time through, since it points to the segment's
		 * array).  So, we assign zzEndRead here.
		 */
		//zzStartRead = zzEndRead = s.offset;
		zzStartRead = s.offset;
		zzEndRead = zzStartRead + s.count - 1;
		zzCurrentPos = zzMarkedPos = zzPushbackPos = s.offset;
		zzLexicalState = YYINITIAL;
		zzReader = reader;
		zzAtBOL  = true;
		zzAtEOF  = false;
	}


%}

LetterOrDigit	= ([a-zA-Z0-9])
Identifier		= ({LetterOrDigit}+)
Separator		= ([^a-zA-Z0-9 \t\n])
WhiteSpace		= ([ \t]+)
LineTerminator	= ([\n])

URLGenDelim				= ([:\/\?#\[\]@])
URLSubDelim				= ([\!\$&'\(\)\*\+,;=])
URLUnreserved			= ({LetterOrDigit}|[_\-\.\~])
URLCharacter			= ({URLGenDelim}|{URLSubDelim}|{URLUnreserved}|[%])
URLCharacters			= ({URLCharacter}*)
URLEndCharacter			= ([\/\$]|{LetterOrDigit})
URL						= (((https?|f(tp|ile))"://"|"www.")({URLCharacters}{URLEndCharacter})?)

%%

<YYINITIAL> {
	{URL}				{ addToken(Token.IDENTIFIER, true); }
	{Identifier}		{ addToken(Token.IDENTIFIER, false); }
	{Separator}			{ addToken(Token.IDENTIFIER, false); }
	{WhiteSpace}		{ addToken(Token.WHITESPACE, false); }
	{LineTerminator}	{ addNullToken(); return firstToken; }
	<<EOF>>				{ addNullToken(); return firstToken; }
	.					{ /* Never happens */ addToken(Token.IDENTIFIER, false); }
}
