// $Id: Statement.java,v 1.7 2000/04/10 04:10:22 msato Exp $
// $RWC_Release: Omni-1.6 $
// $RWC_Copyright:
//  Omni Compiler Software Version 1.5-1.6
//  Copyright (C) 2002 PC Cluster Consortium
//  
//  This software is free software; you can redistribute it and/or modify
//  it under the terms of the GNU Lesser General Public License version
//  2.1 published by the Free Software Foundation.
//  
//  Omni Compiler Software Version 1.0-1.4
//  Copyright (C) 1999, 2000, 2001.
//   Tsukuba Research Center, Real World Computing Partnership, Japan.
//  
//  Please check the Copyright and License information in the files named
//  COPYRIGHT and LICENSE under the top  directory of the Omni Compiler
//  Software release kit.
//  
//  
//  $
package exc.block;

import exc.object.*;

//
// statement
//
public class Statement {
  Statement prev,next;
  BasicBlock parent;
  Xobject statement;

  LineNo lineno;	// lineno information

  public Statement(Xobject statement){
    this.statement = statement;
  }

  public Statement getNext() { return next; }
  public Statement getPrev() { return prev; }
  public BasicBlock getParent() { return parent; }
  public Xobject getExpr() { return statement; }
  public void setExpr(Xobject x) { statement = x; }
  public void setLineNo(LineNo ln){ lineno = ln; }
  public LineNo getLineNo() { return lineno; }

  // remove itself
  public void remove(){
    if(parent == null) return; // already removed
    if(prev == null){ // head of double linked list 
      parent.head = next;
      if(next != null) next.prev = null;
    } else 
      prev.next = next;
    if(next == null) { // tail of double linked list 
      parent.tail = prev;
      if(prev != null) prev.next = null;
    } else
      next.prev = prev;
    parent = null;
    next = null;
    prev = null;
  }

  public boolean isRemoved(){
    return parent == null;
  }

  // add s after this 
  public Statement add(Xobject x){
    return add(new Statement(x));
  }
  public Statement add(Statement s){
    s.parent = parent;
    s.next = next;
    next = s;
    s.prev = this;
    if(s.next == null){ // tail of list
      parent.tail = s;
    } else {
      s.next.prev = s;
    }
    return s;
  }

  // insert s before this 
  public Statement insert(Xobject x){
    return insert(new Statement(x));
  }

  public Statement insert(Statement s){
    s.parent = parent;
    s.prev = prev;
    prev = s;
    s.next = this;
    if(s.prev == null){ // head of list
      parent.head = s;
    } else {
      s.prev.next = s;
    }
    return s;
  }

  // insert block before this statement
  public void insertBlock(Block b){
    Block b0 = parent.parent;
    if(parent.head != this){  // not head, then move precedings to new
      BasicBlock bb_new = new BasicBlock();
      bb_new.head = parent.head;
      for(Statement s = parent.head; s != this; s = s.next)
	s.parent = bb_new;
      this.prev.next = null; // tail
      this.prev = null;
      parent.head = this;    // this is head
      b0.insert(Bcons.BasicBlock(bb_new));
    }
    b0.insert(b);
  }
}