/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "txList.h"

  //----------------------------/

 //- Implementation of txList -/

//----------------------------/

/**

 * Default constructor for a txList;

**/

txList::txList() {

   firstItem  = 0;

   lastItem   = 0;

   itemCount  = 0;

} //-- txList;

/**

 * txList destructor, cleans up ListItems, but will not delete the Object

 * references

*/

txList::~txList() {

    clear();

} //-- ~txList

nsresult txList::add(void* objPtr)

{

    return insertBefore(objPtr, 0);

} //-- add

/**

 * Returns the number of items in this txList

**/

int32_t List::getLength() {

   return itemCount;

} //-- getLength

/**

 * Inserts the given Object pointer as the item just after refItem.

 * If refItem is a null pointer the Object will be inserted at the

 * beginning of the txList (ie, insert after nothing).

 * This method assumes refItem is a member of this list, and since this

 * is a private method, I feel that's a valid assumption

**/

nsresult txList::insertAfter(void* objPtr, ListItem* refItem)

{

    //-- if refItem == null insert at front

    if (!refItem)

        return insertBefore(objPtr, firstItem);

    return insertBefore(objPtr, refItem->nextItem);

} //-- insertAfter

/**

 * Inserts the given Object pointer as the item just before refItem.

 * If refItem is a null pointer the Object will be inserted at the

 * end of the txList (ie, insert before nothing).

 * This method assumes refItem is a member of this list, and since this

 * is a private method, I feel that's a valid assumption

**/

nsresult txList::insertBefore(void* objPtr, ListItem* refItem)

{

    ListItem* item = new ListItem;

    item->objPtr = objPtr;

    item->nextItem = 0;

    item->prevItem = 0;

    //-- if refItem == null insert at end

    if (!refItem) {

        //-- add to back of list

        if (lastItem) {

            lastItem->nextItem = item;

            item->prevItem = lastItem;

        }

        lastItem = item;

        if (!firstItem)

            firstItem = item;

    }

    else {

        //-- insert before given item

        item->nextItem = refItem;

        item->prevItem = refItem->prevItem;

        refItem->prevItem = item;

        if (item->prevItem)

            item->prevItem->nextItem = item;

        else

            firstItem = item;

    }

    // increase the item count

    ++itemCount;

    return NS_OK;

} //-- insertBefore

txList::ListItem* txList::remove(ListItem* item) {

    if (!item)

        return item;

    //-- adjust the previous item's next pointer

    if (item->prevItem) {

        item->prevItem->nextItem = item->nextItem;

    }

    //-- adjust the next item's previous pointer

    if (item->nextItem) {

        item->nextItem->prevItem = item->prevItem;

    }

    //-- adjust first and last items

    if (item == firstItem)

        firstItem = item->nextItem;

    if (item == lastItem)

        lastItem = item->prevItem;

    //-- decrease Item count

    --itemCount;

    return item;

} //-- remove

void txList::clear()

{

    ListItem* item = firstItem;

    while (item) {

        ListItem* tItem = item;

        item = item->nextItem;

        delete tItem;

    }

    firstItem  = 0;

    lastItem   = 0;

    itemCount  = 0;

}

  //------------------------------------/

 //- Implementation of txListIterator -/

//------------------------------------/

/**

 * Creates a new txListIterator for the given txList

 * @param list, the txList to create an Iterator for

**/

txListIterator::txListIterator(txList* list) {

   this->list   = list;

   currentItem  = 0;

   atEndOfList  = false;

} //-- txListIterator

/**

 * Adds the Object pointer to the txList pointed to by this txListIterator.

 * The Object pointer is inserted as the next item in the txList

 * based on the current position within the txList

 * @param objPtr the Object pointer to add to the list

**/

nsresult txListIterator::addAfter(void* objPtr)

{

    if (currentItem || !atEndOfList)

        return list->insertAfter(objPtr, currentItem);

    return list->insertBefore(objPtr, 0);

} //-- addAfter

/**

 * Adds the Object pointer to the txList pointed to by this txListIterator.

 * The Object pointer is inserted as the previous item in the txList

 * based on the current position within the txList

 * @param objPtr the Object pointer to add to the list

**/

nsresult txListIterator::addBefore(void* objPtr)

{

    if (currentItem || atEndOfList)

        return list->insertBefore(objPtr, currentItem);

    return list->insertAfter(objPtr, 0);

} //-- addBefore

/**

 * Returns true if a successful call to the next() method can be made

 * @return true if a successful call to the next() method can be made,

 * otherwise false

**/

bool txListIterator::hasNext() {

    bool hasNext = false;

    if (currentItem)

        hasNext = (currentItem->nextItem != 0);

    else if (!atEndOfList)

        hasNext = (list->firstItem != 0);

    return hasNext;

} //-- hasNext

/**

 * Returns the next Object pointer in the list

**/

void* txListIterator::next() {

    void* obj = 0;

    if (currentItem)

        currentItem = currentItem->nextItem;

    else if (!atEndOfList)

        currentItem = list->firstItem;

    if (currentItem)

        obj = currentItem->objPtr;

    else

        atEndOfList = true;

    return obj;

} //-- next

/**

 * Returns the previous Object in the list

**/

void* txListIterator::previous() {

    void* obj = 0;

    if (currentItem)

        currentItem = currentItem->prevItem;

    else if (atEndOfList)

        currentItem = list->lastItem;

    if (currentItem)

        obj = currentItem->objPtr;

    atEndOfList = false;

    return obj;

} //-- previous

/**

 * Returns the current Object

**/

void* txListIterator::current() {

    if (currentItem)

        return currentItem->objPtr;

    return 0;

} //-- current

/**

 * Removes the Object last returned by the next() or previous() methods;

 * @return the removed Object pointer

**/

void* txListIterator::remove() {

    void* obj = 0;

    if (currentItem) {

        obj = currentItem->objPtr;

        txList::ListItem* item = currentItem;

        previous(); //-- make previous item the current item

        list->remove(item);

        delete item;

    }

    return obj;

} //-- remove

/**

 * Resets the current location within the txList to the beginning of the txList

**/

void txListIterator::reset() {

   atEndOfList = false;

   currentItem = 0;

} //-- reset

/**

 * Move the iterator to right after the last element

**/

void txListIterator::resetToEnd() {

   atEndOfList = true;

   currentItem = 0;

} //-- moveToEnd