gecko-dev/xpcom/ds/nsSupportsArrayEnumerator.cpp

131 lines
3.2 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
#include "nsSupportsArrayEnumerator.h"
#include "nsISupportsArray.h"
nsSupportsArrayEnumerator::nsSupportsArrayEnumerator(nsISupportsArray* array)
: mArray(array), mCursor(0)
{
NS_INIT_REFCNT();
NS_ASSERTION(array, "null array");
NS_ADDREF(mArray);
}
nsSupportsArrayEnumerator::~nsSupportsArrayEnumerator()
{
NS_RELEASE(mArray);
}
NS_IMPL_ISUPPORTS2(nsSupportsArrayEnumerator, nsIBidirectionalEnumerator, nsIEnumerator)
NS_IMETHODIMP
nsSupportsArrayEnumerator::First()
{
mCursor = 0;
PRUint32 cnt;
nsresult rv = mArray->Count(&cnt);
if (NS_FAILED(rv)) return rv;
PRInt32 end = (PRInt32)cnt;
if (mCursor < end)
return NS_OK;
else
return NS_ERROR_FAILURE;
}
NS_IMETHODIMP
nsSupportsArrayEnumerator::Next()
{
PRUint32 cnt;
nsresult rv = mArray->Count(&cnt);
if (NS_FAILED(rv)) return rv;
PRInt32 end = (PRInt32)cnt;
if (mCursor < end) // don't count upward forever
mCursor++;
if (mCursor < end)
return NS_OK;
else
return NS_ERROR_FAILURE;
}
NS_IMETHODIMP
nsSupportsArrayEnumerator::CurrentItem(nsISupports **aItem)
{
NS_ASSERTION(aItem, "null out parameter");
PRUint32 cnt;
nsresult rv = mArray->Count(&cnt);
if (NS_FAILED(rv)) return rv;
if (mCursor >= 0 && mCursor < (PRInt32)cnt) {
*aItem = mArray->ElementAt(mCursor);
return NS_OK;
}
return NS_ERROR_FAILURE;
}
NS_IMETHODIMP
nsSupportsArrayEnumerator::IsDone()
{
PRUint32 cnt;
nsresult rv = mArray->Count(&cnt);
if (NS_FAILED(rv)) return rv;
return (mCursor >= 0 && mCursor < (PRInt32)cnt)
? NS_COMFALSE : NS_OK;
}
////////////////////////////////////////////////////////////////////////////////
NS_IMETHODIMP
nsSupportsArrayEnumerator::Last()
{
PRUint32 cnt;
nsresult rv = mArray->Count(&cnt);
if (NS_FAILED(rv)) return rv;
mCursor = cnt - 1;
return NS_OK;
}
NS_IMETHODIMP
nsSupportsArrayEnumerator::Prev()
{
if (mCursor >= 0)
--mCursor;
if (mCursor >= 0)
return NS_OK;
else
return NS_ERROR_FAILURE;
}
////////////////////////////////////////////////////////////////////////////////
NS_COM nsresult
NS_NewISupportsArrayEnumerator(nsISupportsArray* array,
nsIBidirectionalEnumerator* *aInstancePtrResult)
{
if (aInstancePtrResult == 0)
return NS_ERROR_NULL_POINTER;
nsSupportsArrayEnumerator* e = new nsSupportsArrayEnumerator(array);
if (e == 0)
return NS_ERROR_OUT_OF_MEMORY;
NS_ADDREF(e);
*aInstancePtrResult = e;
return NS_OK;
}
////////////////////////////////////////////////////////////////////////////////