+++ /dev/null
-/* Copyright (C) 1995,1996,1998,2000,2001, 2003, 2006, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public License
- * as published by the Free Software Foundation; either version 3 of
- * the License, or (at your option) any later version.
- *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301 USA
- */
-
-
-\f
-#ifdef HAVE_CONFIG_H
-# include <config.h>
-#endif
-
-#include <stdio.h>
-
-#include "libguile/_scm.h"
-#include "libguile/vectors.h"
-#include "libguile/hashtab.h"
-
-#include "libguile/validate.h"
-#include "libguile/weaks.h"
-
-#include "libguile/bdw-gc.h"
-#include <gc/gc_typed.h>
-
-
-\f
-/* Weak pairs for use in weak alist vectors and weak hash tables.
-
- We have weal-car pairs, weak-cdr pairs, and doubly weak pairs. In weak
- pairs, the weak component(s) are not scanned for pointers and are
- registered as disapperaring links; therefore, the weak component may be
- set to NULL by the garbage collector when no other reference to that word
- exist. Thus, users should only access weak pairs via the
- `SCM_WEAK_PAIR_C[AD]R ()' macros. See also `scm_fixup_weak_alist ()' in
- `hashtab.c'. */
-
-/* Type descriptors for weak-c[ad]r pairs. */
-static GC_descr wcar_pair_descr, wcdr_pair_descr;
-
-
-SCM
-scm_weak_car_pair (SCM car, SCM cdr)
-{
- scm_t_cell *cell;
-
- cell = (scm_t_cell *)GC_malloc_explicitly_typed (sizeof (*cell),
- wcar_pair_descr);
-
- cell->word_0 = car;
- cell->word_1 = cdr;
-
- if (SCM_NIMP (car))
- /* Weak car cells make sense iff the car is non-immediate. */
- SCM_I_REGISTER_DISAPPEARING_LINK ((GC_PTR) &cell->word_0,
- (GC_PTR) SCM2PTR (car));
-
- return (SCM_PACK (cell));
-}
-
-SCM
-scm_weak_cdr_pair (SCM car, SCM cdr)
-{
- scm_t_cell *cell;
-
- cell = (scm_t_cell *)GC_malloc_explicitly_typed (sizeof (*cell),
- wcdr_pair_descr);
-
- cell->word_0 = car;
- cell->word_1 = cdr;
-
- if (SCM_NIMP (cdr))
- /* Weak cdr cells make sense iff the cdr is non-immediate. */
- SCM_I_REGISTER_DISAPPEARING_LINK ((GC_PTR) &cell->word_1,
- (GC_PTR) SCM2PTR (cdr));
-
- return (SCM_PACK (cell));
-}
-
-SCM
-scm_doubly_weak_pair (SCM car, SCM cdr)
-{
- /* Doubly weak cells shall not be scanned at all for pointers. */
- scm_t_cell *cell = (scm_t_cell *)scm_gc_malloc_pointerless (sizeof (*cell),
- "weak cell");
-
- cell->word_0 = car;
- cell->word_1 = cdr;
-
- if (SCM_NIMP (car))
- SCM_I_REGISTER_DISAPPEARING_LINK ((GC_PTR) &cell->word_0,
- (GC_PTR) SCM2PTR (car));
- if (SCM_NIMP (cdr))
- SCM_I_REGISTER_DISAPPEARING_LINK ((GC_PTR) &cell->word_1,
- (GC_PTR) SCM2PTR (cdr));
-
- return (SCM_PACK (cell));
-}
-
-
-\f
-
-/* 1. The current hash table implementation in hashtab.c uses weak alist
- * vectors (formerly called weak hash tables) internally.
- *
- * 2. All hash table operations still work on alist vectors.
- *
- * 3. The weak vector and alist vector Scheme API is accessed through
- * the module (ice-9 weak-vector).
- */
-
-
-/* {Weak Vectors}
- */
-
-
-SCM_DEFINE (scm_make_weak_vector, "make-weak-vector", 1, 1, 0,
- (SCM size, SCM fill),
- "Return a weak vector with @var{size} elements. If the optional\n"
- "argument @var{fill} is given, all entries in the vector will be\n"
- "set to @var{fill}. The default value for @var{fill} is the\n"
- "empty list.")
-#define FUNC_NAME s_scm_make_weak_vector
-{
- return scm_i_make_weak_vector (0, size, fill);
-}
-#undef FUNC_NAME
-
-
-SCM_REGISTER_PROC(s_list_to_weak_vector, "list->weak-vector", 1, 0, 0, scm_weak_vector);
-
-SCM_DEFINE (scm_weak_vector, "weak-vector", 0, 0, 1,
- (SCM l),
- "@deffnx {Scheme Procedure} list->weak-vector l\n"
- "Construct a weak vector from a list: @code{weak-vector} uses\n"
- "the list of its arguments while @code{list->weak-vector} uses\n"
- "its only argument @var{l} (a list) to construct a weak vector\n"
- "the same way @code{list->vector} would.")
-#define FUNC_NAME s_scm_weak_vector
-{
- return scm_i_make_weak_vector_from_list (0, l);
-}
-#undef FUNC_NAME
-
-
-SCM_DEFINE (scm_weak_vector_p, "weak-vector?", 1, 0, 0,
- (SCM obj),
- "Return @code{#t} if @var{obj} is a weak vector. Note that all\n"
- "weak hashes are also weak vectors.")
-#define FUNC_NAME s_scm_weak_vector_p
-{
- return scm_from_bool (SCM_I_WVECTP (obj) && !SCM_IS_WHVEC (obj));
-}
-#undef FUNC_NAME
-
-\f
-/* Weak alist vectors, i.e., vectors of alists.
-
- The alist vector themselves are _not_ weak. The `car' (or `cdr', or both)
- of the pairs within it are weak. See `hashtab.c' for details. */
-
-
-/* FIXME: We used to have two implementations of weak hash tables: the one in
- here and the one in `hashtab.c'. The difference is that weak alist
- vectors could be used as vectors while (weak) hash tables can't. We need
- to unify that. */
-
-SCM_DEFINE (scm_make_weak_key_alist_vector, "make-weak-key-alist-vector", 0, 1, 0,
- (SCM size),
- "@deffnx {Scheme Procedure} make-weak-value-alist-vector size\n"
- "@deffnx {Scheme Procedure} make-doubly-weak-alist-vector size\n"
- "Return a weak hash table with @var{size} buckets. As with any\n"
- "hash table, choosing a good size for the table requires some\n"
- "caution.\n"
- "\n"
- "You can modify weak hash tables in exactly the same way you\n"
- "would modify regular hash tables. (@pxref{Hash Tables})")
-#define FUNC_NAME s_scm_make_weak_key_alist_vector
-{
- return scm_make_weak_key_hash_table (size);
-}
-#undef FUNC_NAME
-
-
-SCM_DEFINE (scm_make_weak_value_alist_vector, "make-weak-value-alist-vector", 0, 1, 0,
- (SCM size),
- "Return a hash table with weak values with @var{size} buckets.\n"
- "(@pxref{Hash Tables})")
-#define FUNC_NAME s_scm_make_weak_value_alist_vector
-{
- return scm_make_weak_value_hash_table (size);
-}
-#undef FUNC_NAME
-
-
-SCM_DEFINE (scm_make_doubly_weak_alist_vector, "make-doubly-weak-alist-vector", 1, 0, 0,
- (SCM size),
- "Return a hash table with weak keys and values with @var{size}\n"
- "buckets. (@pxref{Hash Tables})")
-#define FUNC_NAME s_scm_make_doubly_weak_alist_vector
-{
- return scm_make_doubly_weak_hash_table (size);
-}
-#undef FUNC_NAME
-
-
-SCM_DEFINE (scm_weak_key_alist_vector_p, "weak-key-alist-vector?", 1, 0, 0,
- (SCM obj),
- "@deffnx {Scheme Procedure} weak-value-alist-vector? obj\n"
- "@deffnx {Scheme Procedure} doubly-weak-alist-vector? obj\n"
- "Return @code{#t} if @var{obj} is the specified weak hash\n"
- "table. Note that a doubly weak hash table is neither a weak key\n"
- "nor a weak value hash table.")
-#define FUNC_NAME s_scm_weak_key_alist_vector_p
-{
- return scm_from_bool (SCM_I_WVECTP (obj) && SCM_IS_WHVEC (obj));
-}
-#undef FUNC_NAME
-
-
-SCM_DEFINE (scm_weak_value_alist_vector_p, "weak-value-alist-vector?", 1, 0, 0,
- (SCM obj),
- "Return @code{#t} if @var{obj} is a weak value hash table.")
-#define FUNC_NAME s_scm_weak_value_alist_vector_p
-{
- return scm_from_bool (SCM_I_WVECTP (obj) && SCM_IS_WHVEC_V (obj));
-}
-#undef FUNC_NAME
-
-
-SCM_DEFINE (scm_doubly_weak_alist_vector_p, "doubly-weak-alist-vector?", 1, 0, 0,
- (SCM obj),
- "Return @code{#t} if @var{obj} is a doubly weak hash table.")
-#define FUNC_NAME s_scm_doubly_weak_alist_vector_p
-{
- return scm_from_bool (SCM_I_WVECTP (obj) && SCM_IS_WHVEC_B (obj));
-}
-#undef FUNC_NAME
-
-
-
-\f
-SCM
-scm_init_weaks_builtins ()
-{
-#include "libguile/weaks.x"
- return SCM_UNSPECIFIED;
-}
-
-void
-scm_weaks_prehistory ()
-{
- /* Initialize weak pairs. */
- GC_word wcar_pair_bitmap[GC_BITMAP_SIZE (scm_t_cell)] = { 0 };
- GC_word wcdr_pair_bitmap[GC_BITMAP_SIZE (scm_t_cell)] = { 0 };
-
- /* In a weak-car pair, only the second word must be scanned for
- pointers. */
- GC_set_bit (wcar_pair_bitmap, GC_WORD_OFFSET (scm_t_cell, word_1));
- wcar_pair_descr = GC_make_descriptor (wcar_pair_bitmap,
- GC_WORD_LEN (scm_t_cell));
-
- /* Conversely, in a weak-cdr pair, only the first word must be scanned for
- pointers. */
- GC_set_bit (wcdr_pair_bitmap, GC_WORD_OFFSET (scm_t_cell, word_0));
- wcdr_pair_descr = GC_make_descriptor (wcdr_pair_bitmap,
- GC_WORD_LEN (scm_t_cell));
-
-}
-
-void
-scm_init_weaks ()
-{
- scm_c_define_gsubr ("%init-weaks-builtins", 0, 0, 0,
- scm_init_weaks_builtins);
-}
-
-
-/*
- Local Variables:
- c-file-style: "gnu"
- End:
-*/
HCoop / bpt / guile.git / blobdiff