/**********************************************************************
 * $Id: cpl_list.cpp 14693 2008-06-12 18:21:54Z rouault $
 *
 * Name:     cpl_list.cpp
 * Project:  CPL - Common Portability Library
 * Purpose:  List functions.
 * Author:   Andrey Kiselev, dron@remotesensing.org
 *
 **********************************************************************
 * Copyright (c) 2003, Andrey Kiselev <dron@remotesensing.org>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
 * DEALINGS IN THE SOFTWARE.
 ****************************************************************************/

#include "cpl_list.h"
#include "cpl_conv.h"

CPL_CVSID("$Id: cpl_list.cpp 14693 2008-06-12 18:21:54Z rouault $");

/*=====================================================================
                    List manipulation functions.
 =====================================================================*/

/************************************************************************/
/*                          CPLListAppend()                             */
/************************************************************************/

/**
 * Append an object list and return a pointer to the modified list.
 * If the input list is NULL, then a new list is created.
 * 
 * @param psList pointer to list head.
 * @param pData pointer to inserted data object. May be NULL.
 *
 * @return pointer to the head of modified list.
 */

CPLList *CPLListAppend( CPLList *psList, void *pData )
{
    CPLList *psLast;
    
    /* Allocate room for the new object */
    if ( psList == NULL )
    {
        psLast = psList = (CPLList *)CPLMalloc( sizeof(CPLList) );
    }
    else
    {
        psLast = CPLListGetLast( psList );
        psLast = psLast->psNext = (CPLList *)CPLMalloc( sizeof(CPLList) );
    }

    /* Append object to the end of list */
    psLast->pData = pData;
    psLast->psNext = NULL;

    return psList;
}

/************************************************************************/
/*                          CPLListInsert()                             */
/************************************************************************/

/**
 * Insert an object into list at specified position (zero based).
 * If the input list is NULL, then a new list is created.
 * 
 * @param psList pointer to list head.
 * @param pData pointer to inserted data object. May be NULL.
 * @param nPosition position number to insert an object.
 *
 * @return pointer to the head of modified list.
 */

CPLList *CPLListInsert( CPLList *psList, void *pData, int nPosition )
{
    CPLList *psCurrent;
    int     i, nCount;
    
    if ( nPosition < 0 )
        return psList;      /* Nothing to do!*/

    nCount = CPLListCount( psList );

    if ( nPosition == 0)
    {
        CPLList *psNew = (CPLList *)CPLMalloc( sizeof(CPLList) );
        psNew->pData = pData;
        psNew->psNext = psList;
        psList = psNew;
    }
    else if ( nCount < nPosition )
    {
        /* Allocate room for the new object */
        CPLList* psLast = CPLListGetLast(psList);
        for ( i = nCount; i <= nPosition - 1; i++ )
        {
            psLast = CPLListAppend( psLast, NULL );
            if (psList == NULL)
                psList = psLast;
            else
                psLast = psLast->psNext;
        }
        psLast = CPLListAppend( psLast, pData );
        if (psList == NULL)
            psList = psLast;
    }
    else
    {
        CPLList *psNew = (CPLList *)CPLMalloc( sizeof(CPLList) );
        psNew->pData = pData;

        psCurrent = psList;
        for ( i = 0; i < nPosition - 1; i++ )
            psCurrent = psCurrent->psNext;
        psNew->psNext = psCurrent->psNext;
        psCurrent->psNext = psNew;
    }

    return psList;
}

/************************************************************************/
/*                          CPLListGetLast()                            */
/************************************************************************/

/**
 * Return the pointer to last element in a list.
 * 
 * @param psList pointer to list head.
 *
 * @return pointer to last element in a list.
 */

CPLList *CPLListGetLast( CPLList *psList )
{
    CPLList *psCurrent = psList;

    if ( psList == NULL )
        return NULL;

    while ( psCurrent->psNext )
        psCurrent = psCurrent->psNext;

    return psCurrent;
}

/************************************************************************/
/*                          CPLListGet()                                */
/************************************************************************/

/**
 * Return the pointer to the specified element in a list.
 * 
 * @param psList pointer to list head.
 * @param nPosition the index of the element in the list, 0 being the first element
 *
 * @return pointer to the specified element in a list.
 */

CPLList *CPLListGet( CPLList *psList, int nPosition )
{
    int     iItem = 0;
    CPLList *psCurrent = psList;

    if ( nPosition < 0 )
        return NULL;

    while ( iItem < nPosition && psCurrent )
    {
        psCurrent = psCurrent->psNext;
        iItem++;
    }

    return psCurrent;
}

/************************************************************************/
/*                          CPLListCount()                              */
/************************************************************************/

/**
 * Return the number of elements in a list.
 * 
 * @param psList pointer to list head.
 *
 * @return number of elements in a list.
 */

int CPLListCount( CPLList *psList )
{
    int     nItems = 0;
    CPLList *psCurrent = psList;

    while ( psCurrent )
    {
        nItems++;
        psCurrent = psCurrent->psNext;
    }

    return nItems;
}

/************************************************************************/
/*                          CPLListRemove()                             */
/************************************************************************/

/**
 * Remove the element from the specified position (zero based) in a list. Data
 * object contained in removed element must be freed by the caller first.
 * 
 * @param psList pointer to list head.
 * @param nPosition position number to delet an element.
 *
 * @return pointer to the head of modified list.
 */

CPLList *CPLListRemove( CPLList *psList, int nPosition )
{
    CPLList *psCurrent, *psRemoved;
    int     i;

    if ( psList == NULL)
    {
        return NULL;
    }
    else if ( nPosition < 0)
    {
        return psList;      /* Nothing to do!*/
    }
    else if ( nPosition == 0 )
    {
        psCurrent = psList->psNext;
        CPLFree( psList );
        psList = psCurrent;
    }
    else
    {
        psCurrent = psList;
        for ( i = 0; i < nPosition - 1; i++ )
        {
            psCurrent = psCurrent->psNext;
            /* psCurrent == NULL if nPosition >= CPLListCount(psList) */
            if (psCurrent == NULL)
                return psList;
        }
        psRemoved = psCurrent->psNext;
        /* psRemoved == NULL if nPosition >= CPLListCount(psList) */
        if (psRemoved == NULL)
            return psList;
        psCurrent->psNext = psRemoved->psNext;
        CPLFree( psRemoved );
    }

    return psList;
}

/************************************************************************/
/*                          CPLListDestroy()                            */
/************************************************************************/

/**
 * Destroy a list. Caller responsible for freeing data objects contained in
 * list elements.
 * 
 * @param psList pointer to list head.
 *
 */

void CPLListDestroy( CPLList *psList )
{
    CPLList *psNext;
    CPLList *psCurrent = psList;

    while ( psCurrent )
    {
        psNext = psCurrent->psNext;
        CPLFree( psCurrent );
        psCurrent = psNext;
    }
}

/************************************************************************/
/*                          CPLListGetNext()                            */
/************************************************************************/

/**
 * Return the pointer to next element in a list.
 * 
 * @param psElement pointer to list element.
 *
 * @return pointer to the list element preceded by the given element.
 */

CPLList *CPLListGetNext( CPLList *psElement )
{
    if ( psElement == NULL )
        return NULL;
    else
        return psElement->psNext;
}

/************************************************************************/
/*                          CPLListGetData()                            */
/************************************************************************/

/**
 * Return pointer to the data object contained in given list element.
 * 
 * @param psElement pointer to list element.
 *
 * @return pointer to the data object contained in given list element.
 */

void *CPLListGetData( CPLList *psElement )
{
    if ( psElement == NULL )
        return NULL;
    else
        return psElement->pData;
}

