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

   1 /* -*-c-*-
   2  *
   3  * $Id: mp-mem.c,v 1.2 1999/12/10 23:19:02 mdw Exp $
   4  *
   5  * Memory management for multiprecision numbers
   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-mem.c,v $
  33  * Revision 1.2  1999/12/10 23:19:02  mdw
  34  * Improve error-checking.
  35  *
  36  * Revision 1.1  1999/11/17 18:02:16  mdw
  37  * New multiprecision integer arithmetic suite.
  38  *
  39  */
  40
  41 /*----- Header files ------------------------------------------------------*/
  42
  43 #include "mp.h"
  44
  45 /*----- Main code ---------------------------------------------------------*/
  46
  47 /* --- @mp_create@ --- *
  48  *
  49  * Arguments:   @size_t sz@ = size of vector required
  50  *
  51  * Returns:     Pointer to pristine new MP structure with enough memory
  52  *              bolted onto it.
  53  *
  54  * Use:         Creates a new multiprecision integer, initially zero.  The
  55  *              integer has a single reference.
  56  */
  57
  58 mp *mp_create(size_t sz)
  59 {
  60   mp *m = CREATE(mp);
  61   m->v = MP_ALLOC(sz);
  62   m->vl = m->v + sz;
  63   m->sz = sz;
  64   m->f = MP_UNDEF;
  65   m->ref = 1;
  66   return (m);
  67 }
  68
  69 /* --- @mp_build@ --- *
  70  *
  71  * Arguments:   @mp *m@ = pointer to an MP block to fill in
  72  *              @mpw *v@ = pointer to a word array
  73  *              @mpw *vl@ = pointer just past end of array
  74  *
  75  * Returns:     ---
  76  *
  77  * Use:         Creates a multiprecision integer representing some smallish
  78  *              number.  You must provide storage for the number and dispose
  79  *              of it when you've finished with it.  The number is marked as
  80  *              constant while it exists.
  81  */
  82
  83 void mp_build(mp *m, mpw *v, mpw *vl)
  84 {
  85   m->v = v;
  86   m->vl = vl;
  87   m->sz = vl - v;
  88   m->f = MP_CONST;
  89   m->ref = 1;
  90 }
  91
  92 /* --- @mp_destroy@ --- *
  93  *
  94  * Arguments:   @mp *m@ = pointer to a multiprecision integer
  95  *
  96  * Returns:     ---
  97  *
  98  * Use:         Destroys a multiprecision integer. The reference count isn't
  99  *              checked.  Don't use this function if you don't know what
 100  *              you're doing: use @mp_drop@ instead.
 101  */
 102
 103 void mp_destroy(mp *m)
 104 {
 105   assert(((void)"Destroying a free integer", !(m->f & MP_DESTROYED)));
 106   assert(((void)"Attempted to destroy a constant", !(m->f & MP_CONST)));
 107   if (m->f & MP_BURN)
 108     memset(m->v, 0, MPWS(m->sz));
 109   MP_FREE(m->v);
 110   m->f |= MP_DESTROYED;
 111   DESTROY(m);
 112 }
 113
 114 /* --- @mp_copy@ --- *
 115  *
 116  * Arguments:   @mp *m@ = pointer to a multiprecision integer
 117  *
 118  * Returns:     A copy of the given multiprecision integer.
 119  *
 120  * Use:         Copies the given integer.  In fact you just get another
 121  *              reference to the same old one again.
 122  */
 123
 124 mp *mp_copy(mp *m) { return MP_COPY(m); }
 125
 126 /* --- @mp_drop@ --- *
 127  *
 128  * Arguments:   @mp *m@ = pointer to a multiprecision integer
 129  *
 130  * Returns:     ---
 131  *
 132  * Use:         Drops a reference to an integer which isn't wanted any more.
 133  *              If there are no more references, the integer is destroyed.
 134  */
 135
 136 void mp_drop(mp *m) { MP_DROP(m); }
 137
 138 /* --- @mp_split@ --- *
 139  *
 140  * Arguments:   @mp *m@ = pointer to a multiprecision integer
 141  *
 142  * Returns:     A reference to the same integer, possibly with a different
 143  *              address.
 144  *
 145  * Use:         Splits off a modifiable version of the integer referred to.
 146  */
 147
 148 mp *mp_split(mp *m) { MP_SPLIT(m); return (m); }
 149
 150 /* --- @mp_resize@ --- *
 151  *
 152  * Arguments:   @mp *m@ = pointer to a multiprecision integer
 153  *              @size_t sz@ = new size
 154  *
 155  * Returns:     ---
 156  *
 157  * Use:         Resizes the vector containing the integer's digits.  The new
 158  *              size must be at least as large as the current integer's
 159  *              length.  This isn't really intended for client use.
 160  */
 161
 162 void mp_resize(mp *m, size_t sz) { MP_RESIZE(m, sz); }
 163
 164 /* --- @mp_ensure@ --- *
 165  *
 166  * Arguments:   @mp *m@ = pointer to a multiprecision integer
 167  *              @size_t sz@ = required size
 168  *
 169  * Returns:     ---
 170  *
 171  * Use:         Ensures that the integer has enough space for @sz@ digits.
 172  *              The value is not changed.
 173  */
 174
 175 void mp_ensure(mp *m, size_t sz) { MP_ENSURE(m, sz); }
 176
 177 /* --- @mp_modify@ --- *
 178  *
 179  * Arguments:   @mp *m@ = pointer to a multiprecision integer
 180  *              @size_t sz@ = size required
 181  *
 182  * Returns:     Pointer to the integer (possibly different).
 183  *
 184  * Use:         Prepares an integer to be overwritten.  It's split off from
 185  *              other references to the same integer, and sufficient space is
 186  *              allocated.
 187  */
 188
 189 mp *mp_modify(mp *m, size_t sz) { MP_MODIFY(m, sz); return (m); }
 190
 191 /*----- That's all, folks -------------------------------------------------*/