LXR linux/lib/mpi/mpiutil.c

   1/* mpiutil.ac  -  Utility functions for MPI
   2 * Copyright (C) 1998, 1999 Free Software Foundation, Inc.
   3 *
   4 * This file is part of GnuPG.
   5 *
   6 * GnuPG is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * GnuPG is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  19 */
  20
  21#include "mpi-internal.h"
  22
  23/****************
  24 * Note:  It was a bad idea to use the number of limbs to allocate
  25 *        because on a alpha the limbs are large but we normally need
  26 *        integers of n bits - So we should chnage this to bits (or bytes).
  27 *
  28 *        But mpi_alloc is used in a lot of places :-)
  29 */
  30MPI mpi_alloc(unsigned nlimbs)
  31{
  32        MPI a;
  33
  34        a = kmalloc(sizeof *a, GFP_KERNEL);
  35        if (!a)
  36                return a;
  37
  38        if (nlimbs) {
  39                a->d = mpi_alloc_limb_space(nlimbs);
  40                if (!a->d) {
  41                        kfree(a);
  42                        return NULL;
  43                }
  44        } else {
  45                a->d = NULL;
  46        }
  47
  48        a->alloced = nlimbs;
  49        a->nlimbs = 0;
  50        a->sign = 0;
  51        a->flags = 0;
  52        a->nbits = 0;
  53        return a;
  54}
  55EXPORT_SYMBOL_GPL(mpi_alloc);
  56
  57mpi_ptr_t mpi_alloc_limb_space(unsigned nlimbs)
  58{
  59        size_t len = nlimbs * sizeof(mpi_limb_t);
  60
  61        if (!len)
  62                return NULL;
  63
  64        return kmalloc(len, GFP_KERNEL);
  65}
  66
  67void mpi_free_limb_space(mpi_ptr_t a)
  68{
  69        if (!a)
  70                return;
  71
  72        kfree(a);
  73}
  74
  75void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs)
  76{
  77        mpi_free_limb_space(a->d);
  78        a->d = ap;
  79        a->alloced = nlimbs;
  80}
  81
  82/****************
  83 * Resize the array of A to NLIMBS. the additional space is cleared
  84 * (set to 0) [done by m_realloc()]
  85 */
  86int mpi_resize(MPI a, unsigned nlimbs)
  87{
  88        void *p;
  89
  90        if (nlimbs <= a->alloced)
  91                return 0;       /* no need to do it */
  92
  93        if (a->d) {
  94                p = kmalloc(nlimbs * sizeof(mpi_limb_t), GFP_KERNEL);
  95                if (!p)
  96                        return -ENOMEM;
  97                memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t));
  98                kfree(a->d);
  99                a->d = p;
 100        } else {
 101                a->d = kzalloc(nlimbs * sizeof(mpi_limb_t), GFP_KERNEL);
 102                if (!a->d)
 103                        return -ENOMEM;
 104        }
 105        a->alloced = nlimbs;
 106        return 0;
 107}
 108
 109void mpi_clear(MPI a)
 110{
 111        a->nlimbs = 0;
 112        a->nbits = 0;
 113        a->flags = 0;
 114}
 115
 116void mpi_free(MPI a)
 117{
 118        if (!a)
 119                return;
 120
 121        if (a->flags & 4)
 122                kfree(a->d);
 123        else
 124                mpi_free_limb_space(a->d);
 125
 126        if (a->flags & ~7)
 127                pr_info("invalid flag value in mpi\n");
 128        kfree(a);
 129}
 130EXPORT_SYMBOL_GPL(mpi_free);
 131
 132/****************
 133 * Note: This copy function should not interpret the MPI
 134 *       but copy it transparently.
 135 */
 136int mpi_copy(MPI *copied, const MPI a)
 137{
 138        size_t i;
 139        MPI b;
 140
 141        *copied = NULL;
 142
 143        if (a) {
 144                b = mpi_alloc(a->nlimbs);
 145                if (!b)
 146                        return -ENOMEM;
 147
 148                b->nlimbs = a->nlimbs;
 149                b->sign = a->sign;
 150                b->flags = a->flags;
 151                b->nbits = a->nbits;
 152
 153                for (i = 0; i < b->nlimbs; i++)
 154                        b->d[i] = a->d[i];
 155
 156                *copied = b;
 157        }
 158
 159        return 0;
 160}
 161
 162int mpi_set(MPI w, const MPI u)
 163{
 164        mpi_ptr_t wp, up;
 165        mpi_size_t usize = u->nlimbs;
 166        int usign = u->sign;
 167
 168        if (RESIZE_IF_NEEDED(w, (size_t) usize) < 0)
 169                return -ENOMEM;
 170
 171        wp = w->d;
 172        up = u->d;
 173        MPN_COPY(wp, up, usize);
 174        w->nlimbs = usize;
 175        w->nbits = u->nbits;
 176        w->flags = u->flags;
 177        w->sign = usign;
 178        return 0;
 179}
 180
 181int mpi_set_ui(MPI w, unsigned long u)
 182{
 183        if (RESIZE_IF_NEEDED(w, 1) < 0)
 184                return -ENOMEM;
 185        w->d[0] = u;
 186        w->nlimbs = u ? 1 : 0;
 187        w->sign = 0;
 188        w->nbits = 0;
 189        w->flags = 0;
 190        return 0;
 191}
 192
 193MPI mpi_alloc_set_ui(unsigned long u)
 194{
 195        MPI w = mpi_alloc(1);
 196        if (!w)
 197                return w;
 198        w->d[0] = u;
 199        w->nlimbs = u ? 1 : 0;
 200        w->sign = 0;
 201        return w;
 202}
 203
 204void mpi_swap(MPI a, MPI b)
 205{
 206        struct gcry_mpi tmp;
 207
 208        tmp = *a;
 209        *a = *b;
 210        *b = tmp;
 211}
 212