+++ /dev/null
-/* -*-c-*-
- *
- * $Id: mp-mem.c,v 1.8 2004/04/08 16:17:32 mdw Exp $
- *
- * Memory management for multiprecision numbers
- *
- * (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.
- */
-
-/*----- Header files ------------------------------------------------------*/
-
-#include <mLib/sub.h>
-
-
-#include "mp.h"
-
-/*----- Main code ---------------------------------------------------------*/
-
-/* --- @mp_new@ --- *
- *
- * Arguments: @size_t sz@ = size of vector required
- * @unsigned f@ = flags to set
- *
- * Returns: Pointer to a new MP structure.
- *
- * Use: Allocates a new multiprecision integer. The data space is
- * allocated from either the standard global or secret arena,
- * depending on the initial flags requested.
- */
-
-mp *mp_new(size_t sz, unsigned f)
-{
- mp *m = CREATE(mp);
- m->a = (f & MP_BURN) ? MPARENA_SECURE : MPARENA_GLOBAL;
- m->v = mpalloc(m->a, sz);
- m->vl = m->v + sz;
- m->sz = sz;
- m->f = f & ~(MP_CONST | MP_DESTROYED);
- m->ref = 1;
- return (m);
-}
-
-/* --- @mp_create@ --- *
- *
- * Arguments: @size_t sz@ = size of vector required
- *
- * Returns: Pointer to pristine new MP structure with enough memory
- * bolted onto it.
- *
- * Use: Creates a new multiprecision integer, initially zero. The
- * integer has a single reference.
- */
-
-mp *mp_create(size_t sz)
-{
- mp *m = CREATE(mp);
- m->v = mpalloc(MPARENA_GLOBAL, sz);
- m->vl = m->v + sz;
- m->sz = sz;
- m->a = MPARENA_GLOBAL;
- m->f = MP_UNDEF;
- m->ref = 1;
- return (m);
-}
-
-/* --- @mp_createsecure@ --- *
- *
- * Arguments: @size_t sz@ = size of vector required
- *
- * Returns: Pointer to pristine new MP structure with enough memory
- * bolted onto it.
- *
- * Use: Creates a new multiprecision integer with indeterminate
- * contents. The integer has a single reference. The integer's
- * data space is allocated from the secure arena. Its burn flag
- * is set.
- */
-
-mp *mp_createsecure(size_t sz)
-{
- mp *m = CREATE(mp);
- m->v = mpalloc(MPARENA_SECURE, sz);
- m->vl = m->v + sz;
- m->sz = sz;
- m->a = MPARENA_SECURE;
- m->f = MP_UNDEF | MP_BURN;
- m->ref = 1;
- return (m);
-}
-
-/* --- @mp_build@ --- *
- *
- * Arguments: @mp *m@ = pointer to an MP block to fill in
- * @mpw *v@ = pointer to a word array
- * @mpw *vl@ = pointer just past end of array
- *
- * Returns: ---
- *
- * Use: Creates a multiprecision integer representing some smallish
- * number. You must provide storage for the number and dispose
- * of it when you've finished with it. The number is marked as
- * constant while it exists.
- */
-
-void mp_build(mp *m, mpw *v, mpw *vl)
-{
- m->v = v;
- m->vl = vl;
- m->sz = vl - v;
- m->a = MPARENA_GLOBAL;
- m->f = MP_CONST;
- m->ref = 1;
-}
-
-/* --- @mp_destroy@ --- *
- *
- * Arguments: @mp *m@ = pointer to a multiprecision integer
- *
- * Returns: ---
- *
- * Use: Destroys a multiprecision integer. The reference count isn't
- * checked. Don't use this function if you don't know what
- * you're doing: use @mp_drop@ instead.
- */
-
-void mp_destroy(mp *m)
-{
- assert(((void)"Destroying a free integer", !(m->f & MP_DESTROYED)));
- assert(((void)"Attempted to destroy a constant", !(m->f & MP_CONST)));
- if (m->f & MP_BURN)
- memset(m->v, 0, MPWS(m->sz));
- mpfree(m->a, m->v);
- m->f |= MP_DESTROYED;
- DESTROY(m);
-}
-
-/* --- @mp_copy@ --- *
- *
- * Arguments: @mp *m@ = pointer to a multiprecision integer
- *
- * Returns: A copy of the given multiprecision integer.
- *
- * Use: Copies the given integer. In fact you just get another
- * reference to the same old one again.
- */
-
-mp *mp_copy(mp *m) { return MP_COPY(m); }
-
-/* --- @mp_drop@ --- *
- *
- * Arguments: @mp *m@ = pointer to a multiprecision integer
- *
- * Returns: ---
- *
- * Use: Drops a reference to an integer which isn't wanted any more.
- * If there are no more references, the integer is destroyed.
- */
-
-void mp_drop(mp *m) { if (m) MP_DROP(m); }
-
-/* --- @mp_split@ --- *
- *
- * Arguments: @mp *m@ = pointer to a multiprecision integer
- *
- * Returns: A reference to the same integer, possibly with a different
- * address.
- *
- * Use: Splits off a modifiable version of the integer referred to.
- */
-
-mp *mp_split(mp *m) { MP_SPLIT(m); return (m); }
-
-/* --- @mp_resize@ --- *
- *
- * Arguments: @mp *m@ = pointer to a multiprecision integer
- * @size_t sz@ = new size
- *
- * Returns: ---
- *
- * Use: Changes an integer's size. The length and value are not
- * changed. It is an error to
- */
-
-void mp_resize(mp *m, size_t sz) { MP_RESIZE(m, sz); }
-
-/* --- @mp_ensure@ --- *
- *
- * Arguments: @mp *m@ = pointer to a multiprecision integer
- * @size_t sz@ = required length
- *
- * Returns: ---
- *
- * Use: Changes an integer's length. If there is not enough space
- * allocated for the new length then the size is increased. It
- */
-
-void mp_ensure(mp *m, size_t sz) { MP_ENSURE(m, sz); }
-
-/* --- @mp_dest@ --- *
- *
- * Arguments: @mp *m@ = a suggested destination integer
- * @size_t sz@ = size required for result, in digits
- * @unsigned f@ = various flags
- *
- * Returns: A pointer to an appropriate destination.
- *
- * Use: Converts a suggested destination into a real destination with
- * the required properties. If the real destination is @d@,
- * then the following properties will hold:
- *
- * * @d@ will have exactly one reference.
- *
- * * If @m@ is not @MP_NEW@, then the contents of @m@ will not
- * change, unless @f@ has the @MP_UNDEF@ flag set.
- *
- * * If @m@ is not @MP_NEW@, then he reference count of @m@ on
- * entry is equal to the sum of the counts of @d@ and @m@ on
- * exit.
- *
- * * The size of @d@ will be at least @sz@.
- *
- * * If @f@ has the @MP_BURN@ flag set, then @d@ will be
- * allocated from @MPARENA_SECURE@.
- *
- * Understanding this function is crucial to using Catacomb's
- * multiprecision integer library effectively.
- */
-
-mp *mp_dest(mp *m, size_t sz, unsigned f)
-{
- /* --- If no destination, make one --- */
-
- if (m == MP_NEWSEC)
- m = mp_new(sz, f | MP_UNDEF | MP_BURN);
- else if (m == MP_NEW)
- m = mp_new(sz, f | MP_UNDEF);
- else {
- size_t len = MP_LEN(m);
- unsigned undef = (m->f | f) & MP_UNDEF;
-
- /* --- If the value must be preserved, the block can't shrink --- */
-
- if (!undef && sz < len)
- sz = len;
-
- /* --- Otherwise check whether the destination is suitable --- */
-
- if (m->ref > 1 || (m->f & MP_CONST) ||
- sz > m->sz || ((f & ~m->f) & MP_BURN)) {
-
- /* --- No -- allocate a new buffer --- *
- *
- * The buffer must be secure if (a) the caller requested a secure
- * buffer, or (b) the old buffer is secure and I'm not allowed to
- * discard the old contents.
- */
-
- mparena *a;
- mpw *v;
-
- if ((f & MP_BURN) || (!undef && (m->f & MP_BURN)))
- a = MPARENA_SECURE;
- else
- a = MPARENA_GLOBAL;
- v = mpalloc(a, sz);
-
- /* --- Copy the data over --- */
-
- if (!undef) {
- memcpy(v, m->v, MPWS(len));
- if (sz - len > 0)
- memset(v + len, 0, MPWS(sz - len));
- }
-
- /* --- If @m@ has other references, make a new node --- *
- *
- * Otherwise dispose of the old buffer.
- */
-
- if (!(m->f & MP_CONST) && m->ref == 1) {
- if (m->f & MP_BURN)
- memset(m->v, 0, MPWS(m->sz));
- mpfree(m->a, m->v);
- } else {
- mp *mm = CREATE(mp);
- mm->ref = 1;
- mm->f = m->f;
- m->ref--;
- m = mm;
- }
-
- /* --- Fix up the node --- */
-
- m->v = v;
- m->vl = v + sz;
- m->sz = sz;
- m->f = ((m->f & ~(MP_CONST | MP_BURN)) |
- (f & (MP_BURN | MP_UNDEF)));
- m->a = a;
- }
-
- /* --- If the number is growing in its buffer, fix it up --- */
-
- else if (sz > len) {
- if (!undef)
- memset(m->vl, 0, MPWS(sz - len));
- m->vl = m->v + sz;
- }
- }
-
- /* --- Done --- */
-
- return (m);
-}
-
-/*----- That's all, folks -------------------------------------------------*/
projects / u / mdw / catacomb / blobdiff