/*

x.movscn.c - implementation of the elfx_movscn(3) function.

Copyright (C) 1995 - 2001, 2003 Michael Riepe

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Library General Public

License as published by the Free Software Foundation; either

version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

Library General Public License for more details.

You should have received a copy of the GNU Library General Public

License along with this library; if not, write to the Free Software

Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*/

#include <private.h>

#ifndef lint

static const char rcsid[] = "@(#) $Id: x.movscn.c,v 1.13 2005/05/21 15:39:27 michael Exp $";

#endif /* lint */

size_t

elfx_movscn(Elf *elf, Elf_Scn *scn, Elf_Scn *after) {

    Elf_Scn *prev;

    Elf_Scn *tmp;

    int off;

    if (!elf || !scn || !after) {

	return SHN_UNDEF;

    }

    elf_assert(elf->e_magic == ELF_MAGIC);

    if (elf->e_kind != ELF_K_ELF) {

	seterr(ERROR_NOTELF);

	return SHN_UNDEF;

    }

    elf_assert(scn->s_magic == SCN_MAGIC);

    elf_assert(after->s_magic == SCN_MAGIC);

    if (scn->s_elf != elf || after->s_elf != elf) {

	seterr(ERROR_ELFSCNMISMATCH);

	return SHN_UNDEF;

    }

    elf_assert(elf->e_scn_1);

    if (scn == elf->e_scn_1) {

	seterr(ERROR_NULLSCN);

	return SHN_UNDEF;

    }

    if (scn == after || scn == after->s_link) {

	/* nothing to do */

	return scn->s_index;

    }

    /*

     * Find previous section.

     */

    prev = NULL;

    for (tmp = elf->e_scn_1; tmp->s_link; tmp = tmp->s_link) {

	if (tmp->s_link == scn) {

	    prev = tmp;

	    break;

	}

    }

    elf_assert(prev != NULL);

    /*

     * Update section indices

     */

    off = 0;

    for (tmp = elf->e_scn_1; tmp; tmp = tmp->s_link) {

	if (off) {

	    tmp->s_index += off;

	}

	if (tmp == after) {

	    off++;

	}

	else if (tmp == scn) {

	    off--;

	}

    }

    elf_assert(off == 0);

    /*

     * Move section.

     */

    prev->s_link = scn->s_link;

    scn->s_link = after->s_link;

    after->s_link = scn;

    scn->s_index = after->s_index + 1;

    if (elf->e_scn_n == scn) {

	elf->e_scn_n = prev;

    }

    else if (elf->e_scn_n == after) {

	elf->e_scn_n = scn;

    }

#if ENABLE_DEBUG

    /*

     * Check section indices

     */

    tmp = elf->e_scn_1;

    elf_assert(tmp->s_index == 0);

    while (tmp->s_link) {

	elf_assert(tmp->s_link->s_index == tmp->s_index + 1);

	tmp = tmp->s_link;

    }

#endif /* ENABLE_DEBUG */

    return scn->s_index;

}