/*
    Copyright (C) 1995-1997 AROS - The Amiga Replacement OS
    $Id: clonetagitems.c,v 1.7 1997/02/03 02:58:31 ldp Exp $

    Desc: CloneTagItems()
    Lang: english
*/
#include "utility_intern.h"

/*****************************************************************************

    NAME */
#include <utility/tagitem.h>
#include <proto/utility.h>

        AROS_LH1(struct TagItem *, CloneTagItems,

/*  SYNOPSIS */
        AROS_LHA(struct TagItem *, tagList, A0),

/*  LOCATION */
        struct UtilityBase *, UtilityBase, 12, Utility)

/*  FUNCTION
        Duplicates a TagList. The input TagList can be NULL, in which
        case an empty TagList will be returned.

    INPUTS
        tagList     -   The TagList that you want to clone

    RESULT
        A TagList which contains a copy of the TagItems contained in the
        original list. The list is cloned so that calling FindTagItem()
        on a tag in the clone will return the same value as that in the
        original list (assuming the original has not been modified).

    NOTES

    EXAMPLE
        struct TagItem *tagList, *tagListClone;

        \* Set up the original taglist tagList *\

        tagListClone = CloneTagItems( tagList );

        \* Do what you want with your TagList here *\

        FreeTagItems( tagListClone );

    BUGS

    SEE ALSO
        AllocateTagItems(), FreeTagItems(), RefreshTagItemClones()

    INTERNALS

    HISTORY
        29-10-95    digulla automatically created from
                            utility_lib.fd and clib/utility_protos.h
        11-08-96    iaint   Implemented as AROS function.
        01-09-96    iaint   Updated the docs to give the same warnings
                            as the autodocs.
        05-09-96    iaint   Bit of optimisation (one variable :( )
        23-01-97    iaint   Corrected NULL TagList handling.

*****************************************************************************/
{
    AROS_LIBFUNC_INIT

    struct TagItem *newList;
    LONG numTags = 1;

    /*
        This is rather strange, if we have a NULL input, then we still
        have to allocate a list. This is to circumvent a bug in SID v2,
        which for some unknown reason is the only program I have seen
        that has this problem.

        Had to alter RefreshTagItemClones as well.
        However, that is also what the autodoc says...
    */
    if (tagList)
    {
        /*
            We start the counter at 1 since this count will not include the
            TAG_DONE TagItem

            newList is used here to save a variable. We don't need to do
            anything to the value of newList afterwards, since AllocateTagitems()
            will take care of setting it to NULL if the allocation fails.
        */
        newList = tagList;
        while (NextTagItem (&newList) != NULL)
            numTags++;
    }

    /*
        Then we shall allocate the TagList.
        If we can actually allocate a clone tag list, then we shall copy
        the tag values from one tag to another, the function
        "RefreshTagItemClones()" is used here to help re-use code.

        Of course we don't have to worry about the if and only if
        statement, since the original is guaranteed to have not
        been changed since CloneTagItems() :)
    */

    if ((newList = AllocateTagItems(numTags)))
        RefreshTagItemClones (newList, tagList);

    /* newList == 0 when allocation failed - AllocateTagItems handles this*/
    return newList;

    AROS_LIBFUNC_EXIT
} /* CloneTagItems */