casestatement.java

一种将c高级语言转化给VHDL的编译器

/*
 *
 LA-CC 05-135 Trident 0.7.1

Copyright Notice
Copyright 2006 (c) the Regents of the University of California.

This Software was produced under a U.S. Government contract
(W-7405-ENG-36) by Los Alamos National Laboratory, which is operated
by the University of California for the U.S. Department of Energy. The
U.S. Government is licensed to use, reproduce, and distribute this
Software. Permission is granted to the public to copy and use this
Software without charge, provided that this Notice and any statement
of authorship are reproduced on all copies. Neither the Government nor
the University makes any warranty, express or implied, or assumes any
liability or responsibility for the user of this Software.

 
 */ 
package fp.util.vhdl.generator;

import java.util.*;

public class CaseStatement extends Statement implements VHDLout, SequentialStatement {
  
  private Expression _index;
  private LinkedHashMap _alternatives;

  public CaseStatement(Identifier label, Expression index) {
    super("case",label);
    _index = index;
    _alternatives = new LinkedHashMap();
  }

  public CaseStatement(Expression index) {
    this(null, index);
  }
    
  public SequentialStatementList addAlternative(ChoiceList cl, 
						SequentialStatementList ssl) {
    _alternatives.put(cl, ssl);
    return ssl;
  }

  public SequentialStatementList addAlternative(ChoiceList cl) {
    return addAlternative(cl, new SequentialStatementList());
  }

  public SequentialStatementList addAlternative(Choice choice) {
    return addAlternative(new ChoiceList(choice), 
			  new SequentialStatementList());
  }

  public SequentialStatementList addDefault() {
    return addAlternative(new ChoiceList(Identifier.OTHERS),
			  new SequentialStatementList());
  }

		       
  public StringBuffer toVHDL(StringBuffer s, String pre) {
    // label top.
    Identifier label = getLabel();
    if (label != null) {
      s.append(pre);
      pre += TAB;
      label.toVHDL(s,"");
      s.append(":\n");
    }

    s.append(pre).append("case ");
    _index.toVHDL(s,"");
    s.append(" is\n");

    int count = 0;
    for(Iterator iter = _alternatives.entrySet().iterator(); iter.hasNext();) {
      Map.Entry entry = (Map.Entry)iter.next();
      ChoiceList choices = (ChoiceList)entry.getKey();
      SequentialStatementList statements = (SequentialStatementList)entry.getValue();
      
      s.append(pre+TAB).append("when ");
      choices.toVHDL(s,"");
      s.append(" =>\n");
      
      statements.toVHDL(s, pre+TAB+TAB);
    }
    
    s.append(pre).append("end case ");
    if (label != null) {
      label.toVHDL(s,"");
    }
    s.append(";\n"); //?
    
    return s;
  }

  public String toString() {
    StringBuffer sbuf = new StringBuffer();
    return toVHDL(sbuf,"").toString();
  }



}