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

   1 /* -*-c-*-
   2  *
   3  * $Id: mp-io.c,v 1.3 1999/11/21 22:13:02 mdw Exp $
   4  *
   5  * Loading and storing of multiprecision integers
   6  *
   7  * (c) 1999 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: mp-io.c,v $
  33  * Revision 1.3  1999/11/21 22:13:02  mdw
  34  * Add mp version of MPX_BITS.
  35  *
  36  * Revision 1.2  1999/11/19 13:19:06  mdw
  37  * Set flags on results correctly.
  38  *
  39  * Revision 1.1  1999/11/17 18:02:16  mdw
  40  * New multiprecision integer arithmetic suite.
  41  *
  42  */
  43
  44 /*----- Header files ------------------------------------------------------*/
  45
  46 #include "mp.h"
  47
  48 /*----- Main code ---------------------------------------------------------*/
  49
  50 /* --- @mp_octets@ --- *
  51  *
  52  * Arguments:   @const mp *m@ = a multiprecision integer
  53  *
  54  * Returns:     The number of octets required to represent @m@.
  55  *
  56  * Use:         Calculates the external storage required for a multiprecision
  57  *              integer.
  58  */
  59
  60 size_t mp_octets(const mp *m)
  61 {
  62   size_t sz;
  63   MPX_OCTETS(sz, m->v, m->vl);
  64   return (sz);
  65 }
  66
  67 /* --- @mp_bits@ --- *
  68  *
  69  * Arguments:   @const mp *m@ = a multiprecision integer
  70  *
  71  * Returns:     The number of bits required to represent @m@.
  72  *
  73  * Use:         Calculates the external storage required for a multiprecision
  74  *              integer.
  75  */
  76
  77 unsigned long mp_bits(const mp *m)
  78 {
  79   unsigned long bits;
  80   MPX_BITS(bits, m->v, m->vl);
  81   return (bits);
  82 }
  83
  84 /* --- @mp_loadl@ --- *
  85  *
  86  * Arguments:   @mp *d@ = destination
  87  *              @const void *pv@ = pointer to source data
  88  *              @size_t sz@ = size of the source data
  89  *
  90  * Returns:     Resulting multiprecision number.
  91  *
  92  * Use:         Loads a multiprecision number from an array of octets.  The
  93  *              first byte in the array is the least significant.  More
  94  *              formally, if the bytes are %$b_0, b_1, \ldots, b_{n-1}$%
  95  *              then the result is %$N = \sum_{0 \le i < n} b_i 2^{8i}$%.
  96  */
  97
  98 mp *mp_loadl(mp *d, const void *pv, size_t sz)
  99 {
 100   MP_MODIFY(d, MPW_RQ(sz));
 101   mpx_loadl(d->v, d->vl, pv, sz);
 102   d->f &= ~(MP_UNDEF | MP_NEG);
 103   mp_shrink(d);
 104   return (d);
 105 }
 106
 107 /* --- @mp_storel@ --- *
 108  *
 109  * Arguments:   @const mp *m@ = source
 110  *              @void *pv@ = pointer to output array
 111  *              @size_t sz@ = size of the output array
 112  *
 113  * Returns:     ---
 114  *
 115  * Use:         Stores a multiprecision number in an array of octets.  The
 116  *              first byte in the array is the least significant.  If the
 117  *              array is too small to represent the number, high-order bits
 118  *              are truncated; if the array is too large, high order bytes
 119  *              are filled with zeros.  More formally, if the number is
 120  *              %$N = \sum{0 \le i} b_i 2^{8i}$% where %$0 \le b_i < 256$%,
 121  *              then the array is %$b_0, b_1, \ldots, b_{n-1}$%.
 122  */
 123
 124 void mp_storel(const mp *m, void *pv, size_t sz)
 125 {
 126   mpx_storel(m->v, m->vl, pv, sz);
 127 }
 128
 129 /* --- @mp_loadb@ --- *
 130  *
 131  * Arguments:   @mp *d@ = destination
 132  *              @const void *pv@ = pointer to source data
 133  *              @size_t sz@ = size of the source data
 134  *
 135  * Returns:     Resulting multiprecision number.
 136  *
 137  * Use:         Loads a multiprecision number from an array of octets.  The
 138  *              last byte in the array is the least significant.  More
 139  *              formally, if the bytes are %$b_{n-1}, b_{n-2}, \ldots, b_0$%
 140  *              then the result is %$N = \sum_{0 \le i < n} b_i 2^{8i}$%.
 141  */
 142
 143 mp *mp_loadb(mp *d, const void *pv, size_t sz)
 144 {
 145   MP_MODIFY(d, MPW_RQ(sz));
 146   mpx_loadb(d->v, d->vl, pv, sz);
 147   d->f &= ~(MP_UNDEF | MP_NEG);
 148   mp_shrink(d);
 149   return (d);
 150 }
 151
 152 /* --- @mp_storeb@ --- *
 153  *
 154  * Arguments:   @const mp *m@ = source
 155  *              @void *pv@ = pointer to output array
 156  *              @size_t sz@ = size of the output array
 157  *
 158  * Returns:     ---
 159  *
 160  * Use:         Stores a multiprecision number in an array of octets.  The
 161  *              last byte in the array is the least significant.  If the
 162  *              array is too small to represent the number, high-order bits
 163  *              are truncated; if the array is too large, high order bytes
 164  *              are filled with zeros.  More formally, if the number is
 165  *              %$N = \sum{0 \le i} b_i 2^{8i}$% where %$0 \le b_i < 256$%,
 166  *              then the array is %$b_{n-1}, b_{n-2}, \ldots, b_0$%.
 167  */
 168
 169 void mp_storeb(const mp *m, void *pv, size_t sz)
 170 {
 171   mpx_storeb(m->v, m->vl, pv, sz);
 172 }
 173
 174 /*----- That's all, folks -------------------------------------------------*/