git.distorted.org.uk Git - u/mdw/catacomb/blob - math/mp-io.c

   1 /* -*-c-*-
   2  *
   3  * Loading and storing of multiprecision integers
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include "mp.h"
  31
  32 /*----- Main code ---------------------------------------------------------*/
  33
  34 /* --- @mp_octets@ --- *
  35  *
  36  * Arguments:   @const mp *m@ = a multiprecision integer
  37  *
  38  * Returns:     The number of octets required to represent @m@.
  39  *
  40  * Use:         Calculates the external storage required for a multiprecision
  41  *              integer.
  42  */
  43
  44 size_t mp_octets(const mp *m)
  45 {
  46   size_t sz;
  47   MPX_OCTETS(sz, m->v, m->vl);
  48   return (sz);
  49 }
  50
  51 /* --- @mp_octets2c@ --- *
  52  *
  53  * Arguments:   @const mp *m@ = a multiprecision integer
  54  *
  55  * Returns:     The number of octets required to represent @m@.
  56  *
  57  * Use:         Calculates the external storage required for a multiprecision
  58  *              integer represented as two's complement.
  59  */
  60
  61 size_t mp_octets2c(const mp *m)
  62 {
  63   size_t sz;
  64   MPX_OCTETS2C(sz, m->v, m->vl);
  65   return (sz);
  66 }
  67
  68 /* --- @mp_bits@ --- *
  69  *
  70  * Arguments:   @const mp *m@ = a multiprecision integer
  71  *
  72  * Returns:     The number of bits required to represent @m@.
  73  *
  74  * Use:         Calculates the external storage required for a multiprecision
  75  *              integer.
  76  */
  77
  78 unsigned long mp_bits(const mp *m)
  79 {
  80   unsigned long bits;
  81   MPX_BITS(bits, m->v, m->vl);
  82   return (bits);
  83 }
  84
  85 /* --- @mp_loadl@ --- *
  86  *
  87  * Arguments:   @mp *d@ = destination
  88  *              @const void *pv@ = pointer to source data
  89  *              @size_t sz@ = size of the source data
  90  *
  91  * Returns:     Resulting multiprecision number.
  92  *
  93  * Use:         Loads a multiprecision number from an array of octets.  The
  94  *              first byte in the array is the least significant.  More
  95  *              formally, if the bytes are %$b_0, b_1, \ldots, b_{n-1}$%
  96  *              then the result is %$N = \sum_{0 \le i < n} b_i 2^{8i}$%.
  97  */
  98
  99 mp *mp_loadl(mp *d, const void *pv, size_t sz)
 100 {
 101   MP_DEST(d, MPW_RQ(sz), MP_UNDEF);
 102   mpx_loadl(d->v, d->vl, pv, sz);
 103   d->f &= ~(MP_UNDEF | MP_NEG);
 104   mp_shrink(d);
 105   return (d);
 106 }
 107
 108 /* --- @mp_storel@ --- *
 109  *
 110  * Arguments:   @const mp *m@ = source
 111  *              @void *pv@ = pointer to output array
 112  *              @size_t sz@ = size of the output array
 113  *
 114  * Returns:     ---
 115  *
 116  * Use:         Stores a multiprecision number in an array of octets.  The
 117  *              first byte in the array is the least significant.  If the
 118  *              array is too small to represent the number, high-order bits
 119  *              are truncated; if the array is too large, high order bytes
 120  *              are filled with zeros.  More formally, if the number is
 121  *              %$N = \sum{0 \le i} b_i 2^{8i}$% where %$0 \le b_i < 256$%,
 122  *              then the array is %$b_0, b_1, \ldots, b_{n-1}$%.
 123  */
 124
 125 void mp_storel(const mp *m, void *pv, size_t sz)
 126 {
 127   mpx_storel(m->v, m->vl, pv, sz);
 128 }
 129
 130 /* --- @mp_loadb@ --- *
 131  *
 132  * Arguments:   @mp *d@ = destination
 133  *              @const void *pv@ = pointer to source data
 134  *              @size_t sz@ = size of the source data
 135  *
 136  * Returns:     Resulting multiprecision number.
 137  *
 138  * Use:         Loads a multiprecision number from an array of octets.  The
 139  *              last byte in the array is the least significant.  More
 140  *              formally, if the bytes are %$b_{n-1}, b_{n-2}, \ldots, b_0$%
 141  *              then the result is %$N = \sum_{0 \le i < n} b_i 2^{8i}$%.
 142  */
 143
 144 mp *mp_loadb(mp *d, const void *pv, size_t sz)
 145 {
 146   MP_DEST(d, MPW_RQ(sz), MP_UNDEF);
 147   mpx_loadb(d->v, d->vl, pv, sz);
 148   d->f &= ~(MP_UNDEF | MP_NEG);
 149   mp_shrink(d);
 150   return (d);
 151 }
 152
 153 /* --- @mp_storeb@ --- *
 154  *
 155  * Arguments:   @const mp *m@ = source
 156  *              @void *pv@ = pointer to output array
 157  *              @size_t sz@ = size of the output array
 158  *
 159  * Returns:     ---
 160  *
 161  * Use:         Stores a multiprecision number in an array of octets.  The
 162  *              last byte in the array is the least significant.  If the
 163  *              array is too small to represent the number, high-order bits
 164  *              are truncated; if the array is too large, high order bytes
 165  *              are filled with zeros.  More formally, if the number is
 166  *              %$N = \sum{0 \le i} b_i 2^{8i}$% where %$0 \le b_i < 256$%,
 167  *              then the array is %$b_{n-1}, b_{n-2}, \ldots, b_0$%.
 168  */
 169
 170 void mp_storeb(const mp *m, void *pv, size_t sz)
 171 {
 172   mpx_storeb(m->v, m->vl, pv, sz);
 173 }
 174
 175 /* --- @mp_loadl2c@ --- *
 176  *
 177  * Arguments:   @mp *d@ = destination
 178  *              @const void *pv@ = pointer to source data
 179  *              @size_t sz@ = size of the source data
 180  *
 181  * Returns:     Resulting multiprecision number.
 182  *
 183  * Use:         Loads a multiprecision number from an array of octets as
 184  *              two's complement.  The first byte in the array is the least
 185  *              significant.
 186  */
 187
 188 mp *mp_loadl2c(mp *d, const void *pv, size_t sz)
 189 {
 190   const octet *ov = pv;
 191   MP_DEST(d, MPW_RQ(sz), MP_UNDEF);
 192   if (!sz || !(ov[sz - 1] & 0x80)) {
 193     mpx_loadl(d->v, d->vl, pv, sz);
 194     d->f &= ~MP_NEG;
 195   } else {
 196     mpx_loadl2cn(d->v, d->vl, pv, sz);
 197     d->f |= MP_NEG;
 198   }
 199   d->f &= ~MP_UNDEF;
 200   mp_shrink(d);
 201   return (d);
 202 }
 203
 204 /* --- @mp_storel2c@ --- *
 205  *
 206  * Arguments:   @const mp *m@ = source
 207  *              @void *pv@ = pointer to output array
 208  *              @size_t sz@ = size of the output array
 209  *
 210  * Returns:     ---
 211  *
 212  * Use:         Stores a multiprecision number in an array of octets as two's
 213  *              complement.  The first byte in the array is the least
 214  *              significant.  If the array is too small to represent the
 215  *              number, high-order bits are truncated; if the array is too
 216  *              large, high order bytes are sign-extended.
 217  */
 218
 219 void mp_storel2c(const mp *m, void *pv, size_t sz)
 220 {
 221   if (MP_NEGP(m))
 222     mpx_storel2cn(m->v, m->vl, pv, sz);
 223   else
 224     mpx_storel(m->v, m->vl, pv, sz);
 225 }
 226
 227 /* --- @mp_loadb2c@ --- *
 228  *
 229  * Arguments:   @mp *d@ = destination
 230  *              @const void *pv@ = pointer to source data
 231  *              @size_t sz@ = size of the source data
 232  *
 233  * Returns:     Resulting multiprecision number.
 234  *
 235  * Use:         Loads a multiprecision number from an array of octets as
 236  *              two's complement.  The last byte in the array is the least
 237  *              significant.
 238  */
 239
 240 mp *mp_loadb2c(mp *d, const void *pv, size_t sz)
 241 {
 242   const octet *ov = pv;
 243   MP_DEST(d, MPW_RQ(sz), MP_UNDEF);
 244   if (!sz || !(ov[0] & 0x80)) {
 245     mpx_loadb(d->v, d->vl, pv, sz);
 246     d->f &= ~MP_NEG;
 247   } else {
 248     mpx_loadb2cn(d->v, d->vl, pv, sz);
 249     d->f |= MP_NEG;
 250   }
 251   d->f &= ~MP_UNDEF;
 252   mp_shrink(d);
 253   return (d);
 254 }
 255
 256 /* --- @mp_storeb2c@ --- *
 257  *
 258  * Arguments:   @const mp *m@ = source
 259  *              @void *pv@ = pointer to output array
 260  *              @size_t sz@ = size of the output array
 261  *
 262  * Returns:     ---
 263  *
 264  * Use:         Stores a multiprecision number in an array of octets, as
 265  *              two's complement.  The last byte in the array is the least
 266  *              significant.  If the array is too small to represent the
 267  *              number, high-order bits are truncated; if the array is too
 268  *              large, high order bytes are sign-extended.
 269  */
 270
 271 void mp_storeb2c(const mp *m, void *pv, size_t sz)
 272 {
 273   if (MP_NEGP(m))
 274     mpx_storeb2cn(m->v, m->vl, pv, sz);
 275   else
 276     mpx_storeb(m->v, m->vl, pv, sz);
 277 }
 278
 279 /*----- That's all, folks -------------------------------------------------*/