/*
* Copyright (C) 1996,1997 Morgan Stanley & Co., Inc.
* Copyright (C) 1997 Ilya Tilevich
*
* This file is part of C2J++.
* C2J++ 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, or (at your option) any later version.
* C2J++ 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 C2J;
* see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
import java.util.Vector;
/**
* A stack which can hold only m_iMaxSize elements
* Purpose: Stack used by Parser
*
*/
class TokenStack
{
private int m_iInsertLoc;
private int m_iSize;
private int m_iMask;
final static int m_iMaxSize = 32;
private static boolean m_bDebug = false;
/**
* Purpose:
* @return int
*/
private int GetStartPos(){ return (m_iInsertLoc -1) & m_iMask; }
/**
* Purpose:
* @return int
* @param iCurrent
*/
private int GetNext(int iCurrent) { return (iCurrent & m_iMask); }
Vector m_Vector;
/**
* Purpose: Constructor
*/
public TokenStack(){
int iTest = m_iMaxSize;
while((iTest & 1) != 1)
iTest = iTest >> 1;
if((iTest>>1)!=0){
System.out.println("m_iMaxSize should be a power of two");
System.exit(1);
}
m_Vector = new Vector(m_iMaxSize);
m_iSize = 0;
m_iInsertLoc = 0;
m_iMask = m_iMaxSize -1;
initialize();
}
/**
* Purpose:
*/
private void initialize(){
for(int i = 0; i < m_iMaxSize; i++)
m_Vector.addElement("");
}
/**
* Purpose: Returns the constant size of the stack
* @return int
*/
public int GetSize(){ return m_iMaxSize; }
/**
* Purpose: pushes the stack
* Note: if there m_iMaxSize elements on the stack, the bottom most element is
* removed
*
*/
public void push(String obj) {
m_Vector.setElementAt(obj, m_iInsertLoc);
m_iSize ++;
m_iInsertLoc = m_iSize % m_iMaxSize;
if(m_iSize == m_iMaxSize)
m_iSize = 0;
}
/**
* Purpose: Gets a token from the top of the stack
* Note: This function was written to maintain the compatability
* with ParseStack class that uses GetSize() to call TokenAt()
* Later, Parser should be modified to call ElementFromTopOfTheStack()
*/
public String TokenAt(int iIndex) {
if(iIndex < 0 || iIndex > m_iMaxSize-1)
return "";
iIndex = m_iMaxSize-iIndex-1;
return ElementFromTopOfTheStack(iIndex);
}
/**
* Purpose: gets an element from the top of the stack
* using zero-based iIndex
* @param iIndex
* @return String
*/
public String ElementFromTopOfTheStack(int iIndex){
if(iIndex < 0 || iIndex > (GetSize()-1) )
return "";
iIndex = (GetStartPos() - iIndex) & m_iMask;
return (String)m_Vector.elementAt(iIndex);
}
/**
* Purpose: prints the contents of the stack up the iDepth
* @param iDepth
*/
public void printStack(int iDepth){
int iSize = GetSize();
if( iDepth > iSize -1 ) System.out.println("Unable to print stack to " + String.valueOf(iDepth) + " depth");
else{
System.out.println("Printing the TokenStack: ");
for(int n = 0; n < iDepth; n++){
System.out.print(n + "th element from the top of the stack - ");
System.out.println(ElementFromTopOfTheStack(n));
}
}
}
/**
* Purpose: searches stack up to iDepth for a class name
* @param iDepth
* @return String
*/
public String getClassNameFromStack(int iDepth)
{
String strClassName = new String();
int iSize = GetSize(), n;
for(n = iDepth; n < iSize - iDepth -2; n+=3){
if( TokenAt(iSize-(n+1)).compareTo(":") != 0 ||
TokenAt(iSize-(n+2)).compareTo(":")!= 0 )
break;
}
if(m_bDebug)printStack(n);
for(; n > iDepth; n-=3)
strClassName += TokenAt(iSize-n);
strClassName+=TokenAt(iSize-iDepth);
return strClassName;
}
/**
* Purpose:
*/
public static void main(String[] args){
TokenStack stack = new TokenStack();
stack.push("A");
stack.push("B");
stack.push("C");
stack.push("D");
stack.push("E");
stack.push("F");
stack.push("G");
stack.push("H");
stack.push("I");
stack.push("J");
stack.push("K");
stack.push("L");
stack.printStack(5);
System.out.println(stack.TokenAt(stack.GetSize() - 1));
System.out.println(stack.TokenAt(stack.GetSize() -2));
System.out.println(stack.TokenAt(stack.GetSize() -3));
System.out.println(stack.ElementFromTopOfTheStack(0));
System.out.println(stack.ElementFromTopOfTheStack(1));
System.out.println(stack.ElementFromTopOfTheStack(2));
}
}
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