EMARS/mars/assembler/Token.java

   package mars.assembler;
   import mars.*;

/*
Copyright (c) 2003-2008,  Pete Sanderson and Kenneth Vollmar

Developed by Pete Sanderson (psanderson@otterbein.edu)
and Kenneth Vollmar (kenvollmar@missouristate.edu)

Permission is hereby granted, free of charge, to any person obtaining 
a copy of this software and associated documentation files (the 
"Software"), to deal in the Software without restriction, including 
without limitation the rights to use, copy, modify, merge, publish, 
distribute, sublicense, and/or sell copies of the Software, and to 
permit persons to whom the Software is furnished to do so, subject 
to the following conditions:

The above copyright notice and this permission notice shall be 
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR 
ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF 
CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

(MIT license, http://www.opensource.org/licenses/mit-license.html)
 */

/**
 * Represents one token in the input MIPS program.  Each Token carries, along with its
 * type and value, the position (line, column) in which its source appears in the MIPS program.
 * 
 * @author Pete Sanderson
 * @version August 2003
 **/

    public class Token {
   
      private TokenTypes type;
      private String value;
      private MIPSprogram sourceMIPSprogram;
      private int sourceLine, sourcePos;
   // original program and line will differ from the above if token was defined in an included file
      private MIPSprogram originalMIPSprogram;
      private int originalSourceLine;  
   /**
    * Constructor for Token class.
    * 
    * @param type The token type that this token has. (e.g. REGISTER_NAME)
    * @param value The source value for this token (e.g. $t3)
    * @param sourceMIPSprogram The MIPSprogram object containing this token
    * @param line The line number in source program in which this token appears.
    * @param start The starting position in that line number of this token's source value.
    * @see TokenTypes
    **/
    
       public Token(TokenTypes type, String value, MIPSprogram sourceMIPSprogram, int line, int start) {
         this.type = type;
         this.value = value;
         this.sourceMIPSprogram = sourceMIPSprogram;
         this.sourceLine = line;
         this.sourcePos = start; 
         this.originalMIPSprogram = sourceMIPSprogram;
         this.originalSourceLine = line;
      }

   
   /**
    * Set original program and line number for this token.
	 * Line number or both may change during pre-assembly as a result
	 * of the ".include" directive, and we need to keep the original
	 * for later reference (error messages, text segment display).
    * 
    * @param origProgram MIPS program containing this token.
    * @param origSourceLine Line within that program of this token.
    **/  		
       public void setOriginal(MIPSprogram origProgram, int origSourceLine) {
         this.originalMIPSprogram = origProgram;
         this.originalSourceLine = origSourceLine;
      }
		
   /**
    * Produces original program containing this token.
    * 
    * @return MIPSprogram of origin for this token.
    **/
       public MIPSprogram getOriginalProgram() {
         return this.originalMIPSprogram;
      }
		
   /**
    * Produces original line number of this token. It could change as result
	 * of ".include"
    * 
    * @return original line number of this token.
    **/   
       public int getOriginalSourceLine() {
         return this.originalSourceLine;
      }
   
   /**
    * Produces token type of this token.
    * 
    * @return TokenType of this token.
    **/
       public TokenTypes getType() {
         return type;
      }
   
   /**
    * Set or modify token type.  Generally used to note that
	 * an identifier that matches an instruction name is 
	 * actually being used as a label.
    * 
    * @param type new TokenTypes for this token.
    **/   
	    public void setType(TokenTypes type) {
		   this.type = type;
		}
		   
   /**
    * Produces source code of this token.
    * 
    * @return String containing source code of this token.
    **/
    
       public String getValue() {
         return value;
      }
   
   /**
    * Get a String representing the token.  This method is
    * equivalent to getValue().
    * 
    * @return     String version of the token. 
    */   
    
       public String toString() {
         return value;
      }
   
   /**
    * Produces MIPSprogram object associated with this token.
    * 
    * @return  MIPSprogram object associated with this token.
    **/
    
       public MIPSprogram getSourceMIPSprogram() {
         return sourceMIPSprogram;
      }
   
   /**
    * Produces line number of MIPS program of this token.
    * 
    * @return line number in source program of this token.
    **/
    
       public int getSourceLine() {
         return sourceLine;
      }
   
      /**
    * Produces position within source line of this token.
    * 
    * @return first character position within source program line of this token.
    **/
    
       public int getStartPos() {
         return sourcePos;
      }
       
   }