ifstatement.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 IfStatement extends Statement implements SequentialStatement, VHDLout {
  
  private LinkedHashMap _conditions;
  private SequentialStatementList _last_else; // ?
  
  public IfStatement(Identifier label, Expression condition, 
		     SequentialStatementList statements) {
    super("if", label);

    _conditions = new LinkedHashMap();
    _last_else = null;
    // this could be dangerous, what if you re-use the same condition
    // it will overwrite. 
    if (condition != null) 
      _conditions.put(condition, statements);
  }


  public IfStatement(Expression condition, SequentialStatementList statements) {
    this(null, condition, statements);
  }

  public IfStatement() {
    this(null, null, null);
  }
		      

  public SequentialStatementList addElseIf(Expression condition, 
					   SequentialStatementList statements) {
    _conditions.put(condition, statements);
    return statements;
  }

  public SequentialStatementList addElseIf(Expression condition) {
    return addElseIf(condition, new SequentialStatementList());
  }
    

  public SequentialStatementList addFinalElse(SequentialStatementList statements) {
    _last_else = statements;
    return _last_else;
  }

  public SequentialStatementList addFinalElse(SequentialStatement statement) {
    SequentialStatementList list = new SequentialStatementList();
    list.add(statement);
    return addFinalElse(list);
  }

  public SequentialStatementList addFinalElse() {
    return addFinalElse(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");
    }

    int count = 0;
    for(Iterator iter = _conditions.entrySet().iterator(); iter.hasNext();) {
      Map.Entry entry = (Map.Entry)iter.next();
      Expression condition = (Expression)entry.getKey();
      SequentialStatementList statements = (SequentialStatementList)entry.getValue();
      
      s.append(pre);
      if (count == 0) {
	s.append("if ");
      } else {
	s.append("elsif ");
      }
      condition.toVHDL(s, "");
      s.append(" then\n");
      count++;
      
      statements.toVHDL(s,pre+TAB);
    }

    if (_last_else != null) {
      s.append(pre).append("else\n");
      _last_else.toVHDL(s,pre+TAB);
    }

    s.append(pre).append("end if");
    if (label != null) {
      label.toVHDL(s," ");
    }
    s.append(";\n"); //?

    return s;
  }

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



}