3 * $Id: mpint.h,v 1.3 2000/06/17 11:45:09 mdw Exp $
5 * Conversion between MPs and standard C integers
7 * (c) 1999 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
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.
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.
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,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.3 2000/06/17 11:45:09 mdw
34 * Major memory management overhaul. Added arena support. Use the secure
35 * arena for secret integers. Replace and improve the MP management macros
36 * (e.g., replace MP_MODIFY by MP_DEST).
38 * Revision 1.2 1999/12/10 23:22:53 mdw
41 * Revision 1.1 1999/11/25 11:38:31 mdw
42 * Support for conversions between MPs and C integers.
46 #ifndef CATACOMB_MPINT_H
47 #define CATACOMB_MPINT_H
53 /*----- Header files ------------------------------------------------------*/
61 /*----- Generic translation macros ----------------------------------------*/
63 /* --- @MP_FROMINT@ --- *
65 * Arguments: @d@ = destination multiprecision integer
66 * @type@ = type of integer which @i@ is
67 * @i@ = a standard C integer
69 * Use: Stores the value of @i@ in @d@. This macro is actually
70 * rather subtle in places. Be careful what you change.
73 #define MP_FROMINT(d, type, i) do { \
79 MP_DEST(_d, _sz, 0); \
80 _d->f &= ~(MP_NEG | MP_UNDEF); \
82 /* --- Set the sign on the MP --- * \
84 * If the input integer is *not* negative, then negate it. This \
85 * fixes a problem with two's complement machines where the most \
86 * negative value actually has larger magnitude than the most \
87 * positive, and hence -TYPE_MIN == TYPE_MIN but TYPE_MIN != 0. If \
88 * all the work is carried out on negative numbers there isn't a \
100 MP_ENSURE(_d, _sz); \
102 _d->v[_o++] = MPW(-_i); \
104 /* --- More subtlety --- * \
106 * Ideally, I'd like to just shift @i@ right by @MPW_BITS@. But I \
107 * can't, because that might be more than I'm allowed. I can't \
108 * divide by @MPW_MAX + 1@ because that might turn out to be zero \
109 * in my current type, and besides which it's unsigned which messes \
110 * up all of my negative arithmetic. So do an explicit test here. \
116 _i /= (type)MPW_MAX + 1; \
118 _d->vl = _d->v + _o; \
122 /* --- @MP_TOINT@ --- *
124 * Arguments: @m@ = a multiprecision integer
125 * @type@ = the type of @i@
126 * @max@ = the largest value @i@ can represent
127 * @i@ = an integer variable
129 * Use: Stores the value of a multiprecision integer in a standard C
130 * integer. If the value won't fit, the behaviour is determined
131 * by the type of @i@: if @i@ is unsigned, the value of the
132 * multiprecision integer modulo @max + 1@ is stored; if @i@ is
133 * signed, the behaviour is undefined.
135 * If you don't want to be bitten by these sorts of things, keep
136 * copies of @INT_MAX@ or whatever is appropriate in
137 * multiprecision form and compare before conversion.
140 #define MP_TOINT(m, type, max, i) do { \
144 const mp *_m = (m); \
145 const mpw *_v = _m->v, *_vl = _m->vl; \
147 /* --- Do all the arithmetic in negative numbers --- */ \
149 while (_v < _vl && _max > 0) { \
153 _max /= (mpd)MPW_MAX + 1; \
155 if (!(_m->f & MP_NEG)) \
160 /*----- Functions provided ------------------------------------------------*/
162 /* --- @mp_fromINT@ --- *
164 * Arguments: @mp *d@ = pointer to destination multiprecision integer
165 * @INT i@ = standard C integer to convert
167 * Returns: The resulting multiprecision integer.
169 * Use: Converts a standard C integer to a multiprecision integer.
172 #define mp_fromINT(name, type) \
173 extern mp *mp_from##name(mp */*d*/, type /*i*/)
175 mp_fromINT(short, short);
176 mp_fromINT(ushort
, unsigned short);
177 mp_fromINT(int, int);
178 mp_fromINT(uint
, unsigned);
179 mp_fromINT(uint32
, uint32
);
180 mp_fromINT(long, long);
181 mp_fromINT(ulong
, unsigned long);
185 /* --- @mp_toINT@ --- *
187 * Arguments: @const mp *m@ = pointer to a multiprecision integer
189 * Returns: The value of the integer @m@ as a C integer.
191 * Use: Converts a multiprecision integer to a standard C integer.
192 * If the value of the multiprecision integer cannot be
193 * represented in the return type, and the return type is
194 * unsigned, it is reduced modulo @TYPE_MAX + 1@; if the return
195 * type is signed, the behaviour is undefined.
198 #define mp_toINT(name, type) \
199 extern type mp_to##name(const mp */*m*/);
201 mp_toINT(short, short);
202 mp_toINT(ushort
, unsigned short);
204 mp_toINT(uint
, unsigned);
205 mp_toINT(uint32
, uint32
);
206 mp_toINT(long, long);
207 mp_toINT(ulong
, unsigned long);
211 /*----- That's all, folks -------------------------------------------------*/