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         return kmalloc(len, GFP_KERNEL);
  62 }
  63
  64 void mpi_free_limb_space(mpi_ptr_t a)
  65 {
  66         if (!a)
  67                 return;
  68
  69         kfree(a);
  70 }
  71
  72 void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs)
  73 {
  74         mpi_free_limb_space(a->d);
  75         a->d = ap;
  76         a->alloced = nlimbs;
  77 }
  78
  79 /****************
  80  * Resize the array of A to NLIMBS. the additional space is cleared
  81  * (set to 0) [done by m_realloc()]
  82  */
  83 int mpi_resize(MPI a, unsigned nlimbs)
  84 {
  85         void *p;
  86
  87         if (nlimbs <= a->alloced)
  88                 return 0;       /* no need to do it */
  89
  90         if (a->d) {
  91                 p = kmalloc(nlimbs * sizeof(mpi_limb_t), GFP_KERNEL);
  92                 if (!p)
  93                         return -ENOMEM;
  94                 memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t));
  95                 kfree(a->d);
  96                 a->d = p;
  97         } else {
  98                 a->d = kzalloc(nlimbs * sizeof(mpi_limb_t), GFP_KERNEL);
  99                 if (!a->d)
 100                         return -ENOMEM;
 101         }
 102         a->alloced = nlimbs;
 103         return 0;
 104 }
 105
 106 void mpi_clear(MPI a)
 107 {
 108         a->nlimbs = 0;
 109         a->nbits = 0;
 110         a->flags = 0;
 111 }
 112
 113 void mpi_free(MPI a)
 114 {
 115         if (!a)
 116                 return;
 117
 118         if (a->flags & 4)
 119                 kfree(a->d);
 120         else
 121                 mpi_free_limb_space(a->d);
 122
 123         if (a->flags & ~7)
 124                 pr_info("invalid flag value in mpi\n");
 125         kfree(a);
 126 }
 127 EXPORT_SYMBOL_GPL(mpi_free);
 128
 129 /****************
 130  * Note: This copy function should not interpret the MPI
 131  *       but copy it transparently.
 132  */
 133 int mpi_copy(MPI *copied, const MPI a)
 134 {
 135         size_t i;
 136         MPI b;
 137
 138         *copied = MPI_NULL;
 139
 140         if (a) {
 141                 b = mpi_alloc(a->nlimbs);
 142                 if (!b)
 143                         return -ENOMEM;
 144
 145                 b->nlimbs = a->nlimbs;
 146                 b->sign = a->sign;
 147                 b->flags = a->flags;
 148                 b->nbits = a->nbits;
 149
 150                 for (i = 0; i < b->nlimbs; i++)
 151                         b->d[i] = a->d[i];
 152
 153                 *copied = b;
 154         }
 155
 156         return 0;
 157 }
 158
 159 int mpi_set(MPI w, const MPI u)
 160 {
 161         mpi_ptr_t wp, up;
 162         mpi_size_t usize = u->nlimbs;
 163         int usign = u->sign;
 164
 165         if (RESIZE_IF_NEEDED(w, (size_t) usize) < 0)
 166                 return -ENOMEM;
 167
 168         wp = w->d;
 169         up = u->d;
 170         MPN_COPY(wp, up, usize);
 171         w->nlimbs = usize;
 172         w->nbits = u->nbits;
 173         w->flags = u->flags;
 174         w->sign = usign;
 175         return 0;
 176 }
 177
 178 int mpi_set_ui(MPI w, unsigned long u)
 179 {
 180         if (RESIZE_IF_NEEDED(w, 1) < 0)
 181                 return -ENOMEM;
 182         w->d[0] = u;
 183         w->nlimbs = u ? 1 : 0;
 184         w->sign = 0;
 185         w->nbits = 0;
 186         w->flags = 0;
 187         return 0;
 188 }
 189
 190 MPI mpi_alloc_set_ui(unsigned long u)
 191 {
 192         MPI w = mpi_alloc(1);
 193         if (!w)
 194                 return w;
 195         w->d[0] = u;
 196         w->nlimbs = u ? 1 : 0;
 197         w->sign = 0;
 198         return w;
 199 }
 200
 201 void mpi_swap(MPI a, MPI b)
 202 {
 203         struct gcry_mpi tmp;
 204
 205         tmp = *a;
 206         *a = *b;
 207         *b = tmp;
 208 }