/* mpiutil.ac  -  Utility functions for MPI
 * Copyright (C) 1998, 1999 Free Software Foundation, Inc.
 *
 * This file is part of GnuPG.
 *
 * GnuPG is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * GnuPG 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

#include <linux/export.h>

#include "mpi-internal.h"

/****************
 * Note:  It was a bad idea to use the number of limbs to allocate
 *        because on a alpha the limbs are large but we normally need
 *        integers of n bits - So we should change this to bits (or bytes).
 *
 *        But mpi_alloc is used in a lot of places :-)
 */
MPI mpi_alloc(unsigned nlimbs)
{
        MPI a;

        a = kmalloc_obj(*a);
        if (!a)
                return a;

        if (nlimbs) {
                a->d = mpi_alloc_limb_space(nlimbs);
                if (!a->d) {
                        kfree(a);
                        return NULL;
                }
        } else {
                a->d = NULL;
        }

        a->alloced = nlimbs;
        a->nlimbs = 0;
        a->sign = 0;
        a->flags = 0;
        a->nbits = 0;
        return a;
}
EXPORT_SYMBOL_GPL(mpi_alloc);

mpi_ptr_t mpi_alloc_limb_space(unsigned nlimbs)
{
        size_t len = nlimbs * sizeof(mpi_limb_t);

        if (!len)
                return NULL;

        return kmalloc(len, GFP_KERNEL);
}

void mpi_free_limb_space(mpi_ptr_t a)
{
        if (!a)
                return;

        kfree_sensitive(a);
}

void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs)
{
        mpi_free_limb_space(a->d);
        a->d = ap;
        a->alloced = nlimbs;
}

/****************
 * Resize the array of A to NLIMBS. the additional space is cleared
 * (set to 0) [done by m_realloc()]
 */
int mpi_resize(MPI a, unsigned nlimbs)
{
        void *p;

        if (nlimbs <= a->alloced)
                return 0;       /* no need to do it */

        if (a->d) {
                p = kzalloc_objs(mpi_limb_t, nlimbs);
                if (!p)
                        return -ENOMEM;
                memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t));
                kfree_sensitive(a->d);
                a->d = p;
        } else {
                a->d = kzalloc_objs(mpi_limb_t, nlimbs);
                if (!a->d)
                        return -ENOMEM;
        }
        a->alloced = nlimbs;
        return 0;
}

void mpi_free(MPI a)
{
        if (!a)
                return;

        if (a->flags & 4)
                kfree_sensitive(a->d);
        else
                mpi_free_limb_space(a->d);

        if (a->flags & ~7)
                pr_info("invalid flag value in mpi\n");
        kfree(a);
}
EXPORT_SYMBOL_GPL(mpi_free);

/****************
 * Note: This copy function should not interpret the MPI
 *       but copy it transparently.
 */
MPI mpi_copy(MPI a)
{
        int i;
        MPI b;

        if (a) {
                b = mpi_alloc(a->nlimbs);
                if (!b)
                        return NULL;
                b->nlimbs = a->nlimbs;
                b->sign = a->sign;
                b->flags = a->flags;
                b->flags &= ~(16|32); /* Reset the immutable and constant flags. */
                for (i = 0; i < b->nlimbs; i++)
                        b->d[i] = a->d[i];
        } else
                b = NULL;
        return b;
}

MODULE_DESCRIPTION("Multiprecision maths library");
MODULE_LICENSE("GPL");