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/* 
 * TclList.java --
 *
 *	This file contains the native implementation of Tcl lists.
 *
 * Copyright (c) 1997 by Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: TclList.java,v 1.7 2006/06/08 07:44:51 mdejong Exp $
 */

package tcl.lang;

import java.util.*;

/*
 * This class implements the list object type in Tcl.  It is based on the
 * native list implementation, so it extends CObject to inherit the
 * shadowing behavior.
 */

public class TclList extends CObject {

/*
 *----------------------------------------------------------------------
 *
 * TclList --
 *
 *	This constructor creates a new Tcl_Obj.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

protected
TclList()
{
    super();

    if (TclObject.saveObjRecords) {
        String key = "TclList";
        Integer num = (Integer) TclObject.objRecordMap.get(key);
        if (num == null) {
            num = new Integer(1);
        } else {
            num = new Integer(num.intValue() + 1);
        }
        TclObject.objRecordMap.put(key, num);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclList --
 *
 *	Construct a new TclList from the given Tcl_Obj*.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Increments the reference count of the Tcl_Obj.
 *
 *----------------------------------------------------------------------
 */

protected
TclList(
    long objPtr)		// Tcl_Obj* from C.
{
    super(objPtr);

    if (TclObject.saveObjRecords) {
        String key = "TclList";
        Integer num = (Integer) TclObject.objRecordMap.get(key);
        if (num == null) {
            num = new Integer(1);
        } else {
            num = new Integer(num.intValue() + 1);
        }
        TclObject.objRecordMap.put(key, num);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * newInstance --
 *
 *	Construct a new TclObject containing an empty TclList.
 *
 * Results:
 *	Returns a new TclObject.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

public static TclObject
newInstance()
{
    return new TclObject(new TclList());
}

/*
 *----------------------------------------------------------------------
 *
 * newInstance --
 *
 *	Construct a new TclObject from a Tcl_Obj*.  This routine is only
 *	called from C. It is also the only TclList method that can be
 *	called from C.
 *
 * Results:
 *	Returns a newly allocated TclObject.
 *
 * Side effects:
 *	Constructs a new TclList.
 *
 *----------------------------------------------------------------------
 */

private static TclObject
newInstance(
    long objPtr)		// Tcl_Obj* to wrap.
{
    return new TclObject(new TclList(objPtr));
}

/*
 *----------------------------------------------------------------------
 *
 * setListFromAny --
 *
 *	Called to convert an object's internal rep to a list.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

private
static void
setListFromAny(
    Interp interp,		// Interp to report errors in, or null.
    TclObject tobj)		// Object to convert.
throws
    TclException		// Throws an exception of the object isn't a
				// valid Tcl list.
{
    InternalRep rep = tobj.getInternalRep();

    /*
     * If the object is already a Tcl_Obj reference, then we only need to check
     * to see if it is a valid list and copy the reference into a new TclList.
     * Otherwise we need to create a new Tcl_Obj to hold the list. Note that
     * this newly allocated list needs to be queued for cleanup. If tobj is
     * already a TclList just check to see if it was allocated by newInstance()
     * and needs to be added to the cleanup queue.
     */

    if (!tobj.isListType()) {
	TclList tlist;
	long interpPtr = (interp == null) ? 0 : interp.interpPtr;

	if (rep instanceof CObject) {
	    CObject cobj = (CObject) rep;
	    listLength(interpPtr, cobj.objPtr);
	    tlist = new TclList(cobj.objPtr);
	} else {
	    tlist = new TclList(splitList(interpPtr, tobj.toString()));
	    cleanupAdd(interp, tlist);
	}
	tobj.setInternalRep(tlist);

	if (TclObject.saveObjRecords) {
	    String key = "TclString -> TclList";
	    Integer num = (Integer) TclObject.objRecordMap.get(key);
	    if (num == null) {
	        num = new Integer(1);
	    } else {
	        num = new Integer(num.intValue() + 1);
	    }
	    TclObject.objRecordMap.put(key, num);
	}
    } else {
	TclList tlist = (TclList) rep;
	if (interp != null && tlist.emptyNeedsCleanup) {
	    cleanupAdd(interp, tlist);
	    tlist.emptyNeedsCleanup = false;
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ListObjAppendElement -> TclList.append()
 *
 *	Appends a list element to a TclObject.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Modifies the underlying Tcl_Obj list.
 *
 *----------------------------------------------------------------------
 */

public static final void
append(
    Interp interp,		// Current interpreter.
    TclObject tobj,		// The TclObject to append an element to.
    TclObject elemObj)		// The element to append to the object.
throws
    TclException		// If tobj cannot be converted into a list.
{
    if (tobj.isShared()) {
        throw new TclRuntimeError("TclList.append() called with shared object");
    }
    setListFromAny(interp, tobj);
    tobj.invalidateStringRep();

    TclList tlist = (TclList)tobj.getInternalRep();

    // If the append command duplicated a shared C list
    // then create a new internal rep to hold the
    // new pointer from C. A duplicated C list will have
    // a ref count of 0 when append returns. Avoid a
    // memory leak in C by adding to the cleanup queue.

    long newPtr = append(tlist.objPtr, elemObj);

    if (tlist.objPtr != newPtr) {
        TclList newList = new TclList(newPtr);
        tobj.setInternalRep(newList);
        cleanupAdd(interp, newList);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * getLength --
 *
 *	Queries the length of the list. If tobj is not a list object,
 *	an attempt will be made to convert it to a list.
 *
 * Results:
 *	The length of the list.
 *
 * Side effects:
 *	Will attempt to convert the object into a TclList.
 *
 *----------------------------------------------------------------------
 */

public static final int
getLength(
    Interp interp,		// Current interpreter.
    TclObject tobj)		// The TclObject to append an element to.
throws
    TclException		// If tobj is not a valid list.
{
    long interpPtr = (interp == null) ? 0 : interp.interpPtr;
    setListFromAny(interp, tobj);

    TclList tlist = (TclList)tobj.getInternalRep();
    return listLength(interpPtr, tlist.objPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * getElements --
 *
 *	Retrieve all of the elements of a list.  The objects referenced
 *	by the returned array should be treated as readonly and their
 *	ref counts are _not_ incremented; the caller must do that if
 *	it holds on to a reference.
 *
 * Results:
 *	Returns a TclObject array of the elements in the list object.
 *
 * Side effects:
 *	Attempts to convert the object to a list and may throw an
 *	exception if the object isn't a list.  
 *
 *----------------------------------------------------------------------
 */

public static TclObject[]
getElements(
    Interp interp,		// Current interpreter.
    TclObject tobj)		// The TclObject to get the elements of.
throws
    TclException		// If tobj is not a valid list.
{
    setListFromAny(interp, tobj);
    TclList tlist = (TclList)tobj.getInternalRep();
    return getElements(tlist.objPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * index --
 *
 *	Retrieve the index'th object from the list. The first element has
 *	index 0. If index is negative or greater than or equal to the
 *	number of elements in the list, a null is returned.
 *
 * Results:
 *	Returns the index'th TclObject in the list. The returned
 *	object should be treated as readonly and its ref count is
 *	_not_ incremented; the caller must do that if it holds
 *	on to the reference.
 *
 * Side effects:
 *	Attempts to convert the object to a list and may throw an
 *	exception if the object isn't a list.  
 *
 *----------------------------------------------------------------------
 */

public static final TclObject
index(
    Interp interp,		// Current interpreter.
    TclObject tobj,		// The TclObject to get the element from.
    int index)			// The index of the requested element.
throws
    TclException		// If tobj is not a valid list.
{
    setListFromAny(interp, tobj);
    TclList tlist = (TclList)tobj.getInternalRep();
    return index(tlist.objPtr, index);
}

/*
 *----------------------------------------------------------------------
 *
 * replace --
 *
 *	This procedure replaces zero or more elements of the list
 *	referenced by tobj with the objects from an TclObject array.
 *	If tobj is not a list object, an attempt will
 *	be made to convert it to a list.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Updates the Tcl_Obj list.
 *
 *----------------------------------------------------------------------
 */

public static final void
replace(
    Interp interp,		// Current interpreter.
    TclObject tobj,		// The TclObject to get the element from.
    int index,			// The starting index of the replace
				// operation. <=0 means the beginning of the
				// list. >= TclList.getLength(tobj) means the
				// end of the list.
    int count,			// the number of elements to delete from the
				// list. <=0 means no elements should be
				// deleted and the operation is equivalent to
				// an insertion operation.
    TclObject elements[],	// The element(s) to insert.
    int from,			// Insert starting at elements[from]
    int to)			// Insert up to elements[to] (inclusive)
throws
    TclException		// If tobj is not a valid list.
{
    if (tobj.isShared()) {
        throw new TclRuntimeError("TclList.replace() called with shared object");
    }
    setListFromAny(interp, tobj);
    tobj.invalidateStringRep();
    TclList tlist = (TclList)tobj.getInternalRep();

    // If the replace command duplicated a shared C list
    // then create a new internal rep to hold the
    // new pointer from C. A duplicated C list will have
    // a ref count of 0 when append returns. Avoid a
    // memory leak in C by adding to the cleanup queue.

    long newPtr = replace(tlist.objPtr, index, count, elements, from, to);

    if (tlist.objPtr != newPtr) {
        TclList newList = new TclList(newPtr);
        tobj.setInternalRep(newList);
        cleanupAdd(interp, newList);
    }
}

/*
 * Native method declarations.
 */

private static final native long append(long objPtr, TclObject element);
private static final native TclObject[] getElements(long objPtr);
private static final native TclObject index(long objPtr, int index);
private static final native int listLength(long interp, long objPtr)
	throws TclException;
private static final native long replace(long objPtr, int index, int count,
	TclObject elements[], int from, int to);
private static final native long splitList(long interp, String s);

} // end TclList