| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Conversion between MPs and standard C 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 | #ifndef CATACOMB_MPINT_H |
| 29 | #define CATACOMB_MPINT_H |
| 30 | |
| 31 | #ifdef __cplusplus |
| 32 | extern "C" { |
| 33 | #endif |
| 34 | |
| 35 | /*----- Header files ------------------------------------------------------*/ |
| 36 | |
| 37 | #include <limits.h> |
| 38 | |
| 39 | #include <mLib/macros.h> |
| 40 | |
| 41 | #ifndef CATACOMB_MP_H |
| 42 | # include "mp.h" |
| 43 | #endif |
| 44 | |
| 45 | /*----- Generic translation macros ----------------------------------------*/ |
| 46 | |
| 47 | /* --- Warning damage control --- * |
| 48 | * |
| 49 | * GCC (at least) isn't clever enough to work out that the division in |
| 50 | * @MP_FROMINT@ is actually safe (since it will only be executed if @_i > |
| 51 | * MPW_MAX@, which would prove that @(type)MPW_MAX + 1 != 0@). |
| 52 | */ |
| 53 | |
| 54 | /* --- @MP_FROMINT@ --- * |
| 55 | * |
| 56 | * Arguments: @d@ = destination multiprecision integer |
| 57 | * @type@ = type of integer which @i@ is |
| 58 | * @i@ = a standard C integer |
| 59 | * |
| 60 | * Use: Stores the value of @i@ in @d@. This macro is actually |
| 61 | * rather subtle in places. Be careful what you change. |
| 62 | */ |
| 63 | |
| 64 | #define MP_FROMINT(d, type, i) do { \ |
| 65 | type _i = (i); \ |
| 66 | size_t _o = 0; \ |
| 67 | mp *_d = (d); \ |
| 68 | size_t _sz = 4; \ |
| 69 | \ |
| 70 | MP_DEST(_d, _sz, 0); \ |
| 71 | _d->f &= ~(MP_NEG | MP_UNDEF); \ |
| 72 | \ |
| 73 | if (_i >= 0) { \ |
| 74 | while (_i) { \ |
| 75 | if (_o == _sz) { \ |
| 76 | _sz <<= 1; \ |
| 77 | MP_ENSURE(_d, _sz); \ |
| 78 | } \ |
| 79 | _d->v[_o++] = MPW(_i); \ |
| 80 | if (_i <= MPW_MAX) \ |
| 81 | break; \ |
| 82 | else \ |
| 83 | MUFFLE_WARNINGS_STMT(GCC_WARNING("-Wdiv-by-zero"), { \ |
| 84 | _i /= (type)MPW_MAX + 1; \ |
| 85 | }); \ |
| 86 | } \ |
| 87 | } else { \ |
| 88 | _d->f |= MP_NEG; \ |
| 89 | while (_i) { \ |
| 90 | if (_o == _sz) { \ |
| 91 | _sz <<= 1; \ |
| 92 | MP_ENSURE(_d, _sz); \ |
| 93 | } \ |
| 94 | _d->v[_o++] = MPW(-_i); \ |
| 95 | if (_i >= -MPW_MAX) \ |
| 96 | break; \ |
| 97 | else \ |
| 98 | MUFFLE_WARNINGS_STMT(GCC_WARNING("-Wdiv-by-zero"), { \ |
| 99 | _i /= (type)MPW_MAX + 1; \ |
| 100 | }); \ |
| 101 | } \ |
| 102 | } \ |
| 103 | \ |
| 104 | _d->vl = _d->v + _o; \ |
| 105 | (d) = _d; \ |
| 106 | } while (0) |
| 107 | |
| 108 | /* --- @MP_TOINT@ --- * |
| 109 | * |
| 110 | * Arguments: @m@ = a multiprecision integer |
| 111 | * @type@ = the type of @i@ |
| 112 | * @max@ = the largest value @i@ can represent |
| 113 | * @i@ = an integer variable |
| 114 | * |
| 115 | * Use: Stores the value of a multiprecision integer in a standard C |
| 116 | * integer. If the value won't fit, the behaviour is determined |
| 117 | * by the type of @i@: if @i@ is unsigned, the value of the |
| 118 | * multiprecision integer modulo @max + 1@ is stored; if @i@ is |
| 119 | * signed, the behaviour is undefined. |
| 120 | * |
| 121 | * If you don't want to be bitten by these sorts of things, keep |
| 122 | * copies of @INT_MAX@ or whatever is appropriate in |
| 123 | * multiprecision form and compare before conversion. |
| 124 | */ |
| 125 | |
| 126 | #define MP_TOINT(m, type, max, i) do { \ |
| 127 | type _i = 0; \ |
| 128 | type _max = (max); \ |
| 129 | unsigned _s = 0; \ |
| 130 | const mp *_m = (m); \ |
| 131 | const mpw *_v = _m->v, *_vl = _m->vl; \ |
| 132 | \ |
| 133 | /* --- Do all the arithmetic in negative numbers --- */ \ |
| 134 | \ |
| 135 | while (_v < _vl && _max > 0) { \ |
| 136 | _i -= *_v << _s; \ |
| 137 | _s += MPW_BITS; \ |
| 138 | _v++; \ |
| 139 | _max /= (mpd)MPW_MAX + 1; \ |
| 140 | } \ |
| 141 | if (!MP_NEGP(_m)) \ |
| 142 | _i = -_i; \ |
| 143 | (i) = _i; \ |
| 144 | } while (0) |
| 145 | |
| 146 | /*----- Functions provided ------------------------------------------------*/ |
| 147 | |
| 148 | /* --- @mp_fromINT@ --- * |
| 149 | * |
| 150 | * Arguments: @mp *d@ = pointer to destination multiprecision integer |
| 151 | * @INT i@ = standard C integer to convert |
| 152 | * |
| 153 | * Returns: The resulting multiprecision integer. |
| 154 | * |
| 155 | * Use: Converts a standard C integer to a multiprecision integer. |
| 156 | */ |
| 157 | |
| 158 | #define mp_fromINT(name, type) \ |
| 159 | extern mp *mp_from##name(mp */*d*/, type /*i*/) |
| 160 | |
| 161 | mp_fromINT(short, short); |
| 162 | mp_fromINT(ushort, unsigned short); |
| 163 | mp_fromINT(int, int); |
| 164 | mp_fromINT(uint, unsigned); |
| 165 | mp_fromINT(uint32, uint32); |
| 166 | mp_fromINT(long, long); |
| 167 | mp_fromINT(ulong, unsigned long); |
| 168 | |
| 169 | #undef mp_fromINT |
| 170 | |
| 171 | /* --- @mp_toINT@ --- * |
| 172 | * |
| 173 | * Arguments: @const mp *m@ = pointer to a multiprecision integer |
| 174 | * |
| 175 | * Returns: The value of the integer @m@ as a C integer. |
| 176 | * |
| 177 | * Use: Converts a multiprecision integer to a standard C integer. |
| 178 | * If the value of the multiprecision integer cannot be |
| 179 | * represented in the return type, and the return type is |
| 180 | * unsigned, it is reduced modulo @TYPE_MAX + 1@; if the return |
| 181 | * type is signed, the behaviour is undefined. |
| 182 | */ |
| 183 | |
| 184 | #define mp_toINT(name, type) \ |
| 185 | extern type mp_to##name(const mp */*m*/) |
| 186 | |
| 187 | mp_toINT(short, short); |
| 188 | mp_toINT(ushort, unsigned short); |
| 189 | mp_toINT(int, int); |
| 190 | mp_toINT(uint, unsigned); |
| 191 | mp_toINT(uint32, uint32); |
| 192 | mp_toINT(long, long); |
| 193 | mp_toINT(ulong, unsigned long); |
| 194 | |
| 195 | #undef mp_toINT |
| 196 | |
| 197 | /*----- That's all, folks -------------------------------------------------*/ |
| 198 | |
| 199 | #ifdef __cplusplus |
| 200 | } |
| 201 | #endif |
| 202 | |
| 203 | #endif |