/*
 * FortranTokenMarker.java - Fortran token marker
 * by Carl Smotricz
 * carl@smotricz.com
 * www.smotricz.com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or any later version.
 *
 * This program 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

package org.gjt.sp.jedit.syntax;

import javax.swing.text.Segment;

/**
 * Custom TokenMarker for UNISYS's ASCII FORTRAN 77.
 * Characteristics of this dialect are:

 *  
Fixed column format, with

 *   
comment character ( 'C'|'c'|'*' ) in column 1,
 *   
labels (numeric) in column 1-5,
 *   
continuation character ( any nonblank ) in column 6,
 *   
logical end of line after column 72.
 *   
 * 
Nonstandard block comment character ( '@' ) in any column,
 * 
Some nonstandard functions: BITS, BOOL,
 *   INDEX, TRMLEN
 * 
 * It should be easy enough to adapt this class for minor variations
 * in the dialect so long as the format is the classic fixed column format.
 * As this scanner is highly optimized for the fixed column format, it
 * is probably not readily adaptable for freeform FORTRAN code.
 */
 
public class FortranTokenMarker extends TokenMarker
{
  // private members

  private final static int MAYBE_KEYWORD_FIRST = Token.INTERNAL_FIRST;
  private final static int MAYBE_KEYWORD_MORE = 1 + MAYBE_KEYWORD_FIRST;
  private final static String S_E_P = "START EDIT PAGE";

  private static KeywordMap fortranKeywords;
  private KeywordMap keywords;

  private int lastOffset;

  /**
   * Constructor, with a wee bit of initialization.
   */
  public FortranTokenMarker()
  {
    this.keywords = getKeywords();
  }

  /**
   * Implementation of code to mark tokens.
   */
  public byte markTokensImpl(byte token, Segment line, int lineIndex)
  {
    byte lastLineToken = token;

    // --- Very quick check for empty line
    if (line.count < 1) return lastLineToken; // EXIT METHOD!

    char[] array = line.array;
    int offset = line.offset;
    char c = array[offset];

    // --- Very quick check for 'C' comment line
    if (c == 'C' || c == 'c' || c == '*') 
    { 
      addToken(line.count, Token.COMMENT1);
      return lastLineToken; // EXIT METHOD!
    }
    
    token = Token.NULL; // context usually ends on line boundary
    int lineEnd = offset + line.count;

    // --- Check for a label
    int limit = Math.min(lineEnd, offset + 5);
    int i;
    for (i=offset; i 0)
    {
      byte id = keywords.lookup(line, lastOffset, len);
      addToken(len, id);
      lastOffset = keywordEnd;
    }
  }

  /**
   * Call addToken only if the length of the token is not 0.
   */
  private void guardedAddToken(int len, byte token)
  {
    if (len > 0) addToken(len, token);
  }
  
  /**
   * Return the keyword map.
   * It's lazily initialized on the first call.
   */
  public static KeywordMap getKeywords()
  {
    if (fortranKeywords == null)
    {
      fortranKeywords = new KeywordMap(false);
      
      // === Commands ===        
      fortranKeywords.add("CALL", Token.KEYWORD1);
      fortranKeywords.add("CLOSE", Token.KEYWORD1);
      fortranKeywords.add("CONTINUE", Token.KEYWORD1);
      fortranKeywords.add("DO", Token.KEYWORD1);
      fortranKeywords.add("ELSE", Token.KEYWORD1);
      fortranKeywords.add("ELSEIF", Token.KEYWORD1);
      fortranKeywords.add("ENDIF", Token.KEYWORD1);
      fortranKeywords.add("GOTO", Token.KEYWORD1);
      fortranKeywords.add("GO TO", Token.KEYWORD1);
      fortranKeywords.add("IF", Token.KEYWORD1);
      fortranKeywords.add("INDEX", Token.KEYWORD1);
      fortranKeywords.add("INQUIRE", Token.KEYWORD1);
      fortranKeywords.add("OPEN", Token.KEYWORD1);
      fortranKeywords.add("PRINT", Token.KEYWORD1);
      fortranKeywords.add("READ", Token.KEYWORD1);
      fortranKeywords.add("RETURN", Token.KEYWORD1);
      fortranKeywords.add("THEN", Token.KEYWORD1);
      fortranKeywords.add("WRITE", Token.KEYWORD1);

      // === Compiler directives ===
      fortranKeywords.add("BLOCK DATA", Token.KEYWORD2);
      fortranKeywords.add("COMPILER", Token.KEYWORD2);
      fortranKeywords.add("END", Token.KEYWORD2);
      fortranKeywords.add("ENTRY", Token.KEYWORD2);
      fortranKeywords.add("FUNCTION", Token.KEYWORD2);
      fortranKeywords.add("INCLUDE", Token.KEYWORD2);
      fortranKeywords.add("SUBROUTINE", Token.KEYWORD2);

      // === Data types (etc.) ===
      fortranKeywords.add("CHARACTER", Token.KEYWORD3);
      fortranKeywords.add("DATA", Token.KEYWORD3);
      fortranKeywords.add("DEFINE", Token.KEYWORD3);
      fortranKeywords.add("EQUIVALENCE", Token.KEYWORD3);
      fortranKeywords.add("IMPLICIT", Token.KEYWORD3);
      fortranKeywords.add("INTEGER", Token.KEYWORD3);
      fortranKeywords.add("LOGICAL", Token.KEYWORD3);
      fortranKeywords.add("PARAMETER", Token.KEYWORD3);
      fortranKeywords.add("REAL", Token.KEYWORD3);

      // === Operators ===        
      fortranKeywords.add(".AND.", Token.OPERATOR);
      fortranKeywords.add(".EQ.", Token.OPERATOR);
      fortranKeywords.add(".NE.", Token.OPERATOR);
      fortranKeywords.add(".NOT.", Token.OPERATOR);
      fortranKeywords.add(".OR.", Token.OPERATOR);
      fortranKeywords.add("+", Token.OPERATOR);
      fortranKeywords.add("-", Token.OPERATOR);
      fortranKeywords.add("*", Token.OPERATOR);
      fortranKeywords.add("**", Token.OPERATOR);
      fortranKeywords.add("/", Token.OPERATOR);

      // === Literals ===
      fortranKeywords.add(".FALSE.", Token.LITERAL2);
      fortranKeywords.add(".TRUE.", Token.LITERAL2);

    }
    return fortranKeywords;
  }
}

// End of FortranTokenMarker.java