--- /dev/null
+/* -*-c-*-
+ *
+ * $Id: mpint.h,v 1.1 1999/11/25 11:38:31 mdw Exp $
+ *
+ * Conversion between MPs and standard C integers
+ *
+ * (c) 1999 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of Catacomb.
+ *
+ * Catacomb is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * Catacomb is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with Catacomb; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+/*----- Revision history --------------------------------------------------*
+ *
+ * $Log: mpint.h,v $
+ * Revision 1.1 1999/11/25 11:38:31 mdw
+ * Support for conversions between MPs and C integers.
+ *
+ */
+
+#ifndef MPINT_H
+#define MPINT_H
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <limits.h>
+
+#ifndef MP_H
+# include "mp.h"
+#endif
+
+/*----- Generic translation macros ----------------------------------------*/
+
+/* --- @MP_FROMINT@ --- *
+ *
+ * Arguments: @d@ = destination multiprecision integer
+ * @type@ = type of integer which @i@ is
+ * @i@ = a standard C integer
+ *
+ * Use: Stores the value of @i@ in @d@. This macro is actually
+ * rather subtle in places. Be careful what you change.
+ */
+
+#define MP_FROMINT(d, type, i) do { \
+ type _i = (i); \
+ size_t _o = 0; \
+ mp *_d = (d); \
+ size_t _sz = 4; \
+ \
+ MP_MODIFY(_d, _sz); \
+ _d->f &= ~(MP_NEG | MP_UNDEF); \
+ \
+ /* --- Set the sign on the MP --- * \
+ * \
+ * If the input integer is *not* negative, then negate it. This \
+ * fixes a problem with two's complement machines where the most \
+ * negative value actually has larger magnitude than the most \
+ * positive, and hence -TYPE_MIN == TYPE_MIN but TYPE_MIN != 0. If \
+ * all the work is carried out on negative numbers there isn't a \
+ * problem. \
+ */ \
+ \
+ if (_i >= 0) \
+ _i = -_i; \
+ else \
+ _d->f |= MP_NEG; \
+ \
+ while (_i) { \
+ if (_o == _sz) { \
+ _sz <<= 1; \
+ MP_ENSURE(_d, _sz); \
+ } \
+ _d->v[_o++] = MPW(-_i); \
+ \
+ /* --- More subtlety --- * \
+ * \
+ * Ideally, I'd like to just shift @i@ right by @MPW_BITS@. But I \
+ * can't, because that might be more than I'm allowed. I can't \
+ * divide by @MPW_MAX + 1@ because that might turn out to be zero \
+ * in my current type, and besides which it's unsigned which messes \
+ * up all of my negative arithmetic. So do an explicit test here. \
+ */ \
+ \
+ if (_i > -MPW_MAX) \
+ break; \
+ else \
+ _i /= (type)MPW_MAX + 1; \
+ } \
+ _d->vl = _d->v + _o; \
+ (d) = _d; \
+} while (0)
+
+/* --- @MP_TOINT@ --- *
+ *
+ * Arguments: @m@ = a multiprecision integer
+ * @type@ = the type of @i@
+ * @max@ = the largest value @i@ can represent
+ * @i@ = an integer variable
+ *
+ * Use: Stores the value of a multiprecision integer in a standard C
+ * integer. If the value won't fit, the behaviour is determined
+ * by the type of @i@: if @i@ is unsigned, the value of the
+ * multiprecision integer modulo @max + 1@ is stored; if @i@ is
+ * signed, the behaviour is undefined.
+ *
+ * If you don't want to be bitten by these sorts of things, keep
+ * copies of @INT_MAX@ or whatever is appropriate in
+ * multiprecision form and compare before conversion.
+ */
+
+#define MP_TOINT(m, type, max, i) do { \
+ type _i = 0; \
+ type _max = (max); \
+ unsigned _s = 0; \
+ const mp *_m = (m); \
+ const mpw *_v = _m->v, *_vl = _m->vl; \
+ \
+ /* --- Do all the arithmetic in negative numbers --- */ \
+ \
+ while (_v < _vl && _max > 0) { \
+ _i -= *_v << _s; \
+ _s += MPW_BITS; \
+ _v++; \
+ _max /= (mpd)MPW_MAX + 1; \
+ } \
+ if (!(_m->f & MP_NEG)) \
+ _i = -_i; \
+ (i) = _i; \
+} while (0)
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @mp_fromINT@ --- *
+ *
+ * Arguments: @mp *d@ = pointer to destination multiprecision integer
+ * @INT i@ = standard C integer to convert
+ *
+ * Returns: The resulting multiprecision integer.
+ *
+ * Use: Converts a standard C integer to a multiprecision integer.
+ */
+
+#define mp_fromINT(name, type) \
+ extern mp *mp_from##name(mp */*d*/, type /*i*/)
+
+mp_fromINT(short, short);
+mp_fromINT(ushort, unsigned short);
+mp_fromINT(int, int);
+mp_fromINT(uint, unsigned);
+mp_fromINT(long, long);
+mp_fromINT(ulong, unsigned long);
+
+#undef mp_fromINT
+
+/* --- @mp_toINT@ --- *
+ *
+ * Arguments: @const mp *m@ = pointer to a multiprecision integer
+ *
+ * Returns: The value of the integer @m@ as a C integer.
+ *
+ * Use: Converts a multiprecision integer to a standard C integer.
+ * If the value of the multiprecision integer cannot be
+ * represented in the return type, and the return type is
+ * unsigned, it is reduced modulo @TYPE_MAX + 1@; if the return
+ * type is signed, the behaviour is undefined.
+ */
+
+#define mp_toINT(name, type) \
+ extern type mp_to##name(const mp */*m*/);
+
+mp_toINT(short, short);
+mp_toINT(ushort, unsigned short);
+mp_toINT(int, int);
+mp_toINT(uint, unsigned);
+mp_toINT(long, long);
+mp_toINT(ulong, unsigned long);
+
+#undef mp_toINT
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif
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