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  */
  30 MPI 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 }
  55 EXPORT_SYMBOL_GPL(mpi_alloc);
  56
  57 mpi_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
  67 void mpi_free_limb_space(mpi_ptr_t a)
  68 {
  69         if (!a)
  70                 return;
  71
  72         kfree(a);
  73 }
  74
  75 void 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  */
  86 int 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
 109 void mpi_clear(MPI a)
 110 {
 111         a->nlimbs = 0;
 112         a->nbits = 0;
 113         a->flags = 0;
 114 }
 115
 116 void 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 }
 130 EXPORT_SYMBOL_GPL(mpi_free);
 131
 132 /****************
 133  * Note: This copy function should not interpret the MPI
 134  *       but copy it transparently.
 135  */
 136 int 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
 162 int 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
 181 int 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
 193 MPI 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
 204 void mpi_swap(MPI a, MPI b)
 205 {
 206         struct gcry_mpi tmp;
 207
 208         tmp = *a;
 209         *a = *b;
 210         *b = tmp;
 211 }