*
* You should have received a copy of the GNU General Public License
* along with this software; see the file COPYING. If not, write to
- * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
- * Boston, MA 02111-1307 USA
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA
*
* As a special exception, Free Software Foundation gives permission
* for additional uses of the text contained in its release of this library.
\f
+#include <stdio.h>
+
#include "libguile/_scm.h"
#include "libguile/vectors.h"
#include "libguile/lang.h"
\f
-/* {Weak Vectors}
+/* 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).
*/
-/* Allocate memory for a weak vector on behalf of the caller. The allocated
- * vector will be of the given weak vector subtype. It will contain size
- * elements which are initialized with the 'fill' object, or, if 'fill' is
- * undefined, with an unspecified object.
+/* {Weak Vectors}
*/
-static SCM
-allocate_weak_vector (scm_t_bits type, SCM size, SCM fill, const char* caller)
-#define FUNC_NAME caller
-{
- if (SCM_INUMP (size))
- {
- size_t c_size;
- SCM v;
-
- SCM_ASSERT_RANGE (1, size, SCM_INUM (size) >= 0);
- c_size = SCM_INUM (size);
-
- if (c_size > 0)
- {
- scm_t_bits *base;
- size_t j;
-
- if (SCM_UNBNDP (fill))
- fill = SCM_UNSPECIFIED;
-
- SCM_ASSERT_RANGE (1, size, c_size <= SCM_VECTOR_MAX_LENGTH);
- base = scm_gc_malloc (c_size * sizeof (scm_t_bits), "weak vector");
- for (j = 0; j != c_size; ++j)
- base[j] = SCM_UNPACK (fill);
- v = scm_double_cell (SCM_MAKE_VECTOR_TAG (c_size, scm_tc7_wvect),
- (scm_t_bits) base,
- type,
- SCM_UNPACK (SCM_EOL));
- scm_remember_upto_here_1 (fill);
- }
- else
- {
- v = scm_double_cell (SCM_MAKE_VECTOR_TAG (0, scm_tc7_wvect),
- (scm_t_bits) NULL,
- type,
- SCM_UNPACK (SCM_EOL));
- }
-
- return v;
- }
- else if (SCM_BIGP (size))
- SCM_OUT_OF_RANGE (1, size);
- else
- SCM_WRONG_TYPE_ARG (1, size);
-}
-#undef FUNC_NAME
SCM_DEFINE (scm_make_weak_vector, "make-weak-vector", 1, 1, 0,
"empty list.")
#define FUNC_NAME s_scm_make_weak_vector
{
- return allocate_weak_vector (0, size, fill, FUNC_NAME);
+ return scm_i_allocate_weak_vector (0, size, fill);
}
#undef FUNC_NAME
"the same way @code{list->vector} would.")
#define FUNC_NAME s_scm_weak_vector
{
- SCM res;
- SCM *data;
+ scm_t_array_handle handle;
+ SCM res, *data;
long i;
- /* Dirk:FIXME:: In case of multiple threads, the list might get corrupted
- while the vector is being created. */
i = scm_ilength (l);
SCM_ASSERT (i >= 0, l, SCM_ARG1, FUNC_NAME);
- res = scm_make_weak_vector (SCM_MAKINUM (i), SCM_UNSPECIFIED);
- /*
- no alloc, so this loop is safe.
- */
- data = SCM_WRITABLE_VELTS (res);
- while (!SCM_NULL_OR_NIL_P (l))
+ res = scm_make_weak_vector (scm_from_int (i), SCM_UNSPECIFIED);
+ data = scm_vector_writable_elements (res, &handle, NULL, NULL);
+
+ while (scm_is_pair (l) && i > 0)
{
*data++ = SCM_CAR (l);
l = SCM_CDR (l);
+ i--;
}
+ scm_array_handle_release (&handle);
+
return res;
}
#undef FUNC_NAME
"weak hashes are also weak vectors.")
#define FUNC_NAME s_scm_weak_vector_p
{
- return SCM_BOOL (SCM_WVECTP (obj) && !SCM_IS_WHVEC (obj));
+ return scm_from_bool (SCM_I_WVECTP (obj) && !SCM_IS_WHVEC (obj));
}
#undef FUNC_NAME
\f
-SCM_DEFINE (scm_make_weak_key_hash_table, "make-weak-key-hash-table", 0, 1, 0,
+SCM_DEFINE (scm_make_weak_key_alist_vector, "make-weak-key-alist-vector", 0, 1, 0,
(SCM size),
- "@deffnx {Scheme Procedure} make-weak-value-hash-table size\n"
- "@deffnx {Scheme Procedure} make-doubly-weak-hash-table size\n"
+ "@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_hash_table
+#define FUNC_NAME s_scm_make_weak_key_alist_vector
{
- if (SCM_UNBNDP (size))
- return scm_vector_to_hash_table (allocate_weak_vector (1, SCM_MAKINUM (31),
- SCM_EOL, FUNC_NAME));
- else
- return allocate_weak_vector (1, size, SCM_EOL, FUNC_NAME);
+ return scm_i_allocate_weak_vector
+ (1, SCM_UNBNDP (size) ? scm_from_int (31) : size, SCM_EOL);
}
#undef FUNC_NAME
-SCM_DEFINE (scm_make_weak_value_hash_table, "make-weak-value-hash-table", 0, 1, 0,
+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_hash_table
+#define FUNC_NAME s_scm_make_weak_value_alist_vector
{
- if (SCM_UNBNDP (size))
- return scm_vector_to_hash_table (allocate_weak_vector (2, SCM_MAKINUM (31),
- SCM_EOL, FUNC_NAME));
- else
- return allocate_weak_vector (2, size, SCM_EOL, FUNC_NAME);
+ return scm_i_allocate_weak_vector
+ (2, SCM_UNBNDP (size) ? scm_from_int (31) : size, SCM_EOL);
}
#undef FUNC_NAME
-SCM_DEFINE (scm_make_doubly_weak_hash_table, "make-doubly-weak-hash-table", 1, 0, 0,
+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_hash_table
+#define FUNC_NAME s_scm_make_doubly_weak_alist_vector
{
- if (SCM_UNBNDP (size))
- return scm_vector_to_hash_table (allocate_weak_vector (3, SCM_MAKINUM (31),
- SCM_EOL, FUNC_NAME));
- else
- return allocate_weak_vector (3, size, SCM_EOL, FUNC_NAME);
+ return scm_i_allocate_weak_vector
+ (3, SCM_UNBNDP (size) ? scm_from_int (31) : size, SCM_EOL);
}
#undef FUNC_NAME
-SCM_DEFINE (scm_weak_key_hash_table_p, "weak-key-hash-table?", 1, 0, 0,
+SCM_DEFINE (scm_weak_key_alist_vector_p, "weak-key-alist-vector?", 1, 0, 0,
(SCM obj),
- "@deffnx {Scheme Procedure} weak-value-hash-table? obj\n"
- "@deffnx {Scheme Procedure} doubly-weak-hash-table? obj\n"
+ "@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_hash_table_p
+#define FUNC_NAME s_scm_weak_key_alist_vector_p
{
- return SCM_BOOL (SCM_WVECTP (obj) && SCM_IS_WHVEC (obj));
+ return scm_from_bool (SCM_I_WVECTP (obj) && SCM_IS_WHVEC (obj));
}
#undef FUNC_NAME
-SCM_DEFINE (scm_weak_value_hash_table_p, "weak-value-hash-table?", 1, 0, 0,
+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_hash_table_p
+#define FUNC_NAME s_scm_weak_value_alist_vector_p
{
- return SCM_BOOL (SCM_WVECTP (obj) && SCM_IS_WHVEC_V (obj));
+ return scm_from_bool (SCM_I_WVECTP (obj) && SCM_IS_WHVEC_V (obj));
}
#undef FUNC_NAME
-SCM_DEFINE (scm_doubly_weak_hash_table_p, "doubly-weak-hash-table?", 1, 0, 0,
+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_hash_table_p
+#define FUNC_NAME s_scm_doubly_weak_alist_vector_p
{
- return SCM_BOOL (SCM_WVECTP (obj) && SCM_IS_WHVEC_B (obj));
+ return scm_from_bool (SCM_I_WVECTP (obj) && SCM_IS_WHVEC_B (obj));
}
#undef FUNC_NAME
+#define UNMARKED_CELL_P(x) (SCM_NIMP(x) && !SCM_GC_MARK_P (x))
-static void *
-scm_weak_vector_gc_init (void *dummy1 SCM_UNUSED,
- void *dummy2 SCM_UNUSED,
- void *dummy3 SCM_UNUSED)
-{
- scm_weak_vectors = SCM_EOL;
+static SCM weak_vectors;
- return 0;
+void
+scm_i_init_weak_vectors_for_gc ()
+{
+ weak_vectors = SCM_EOL;
}
+void
+scm_i_mark_weak_vector (SCM w)
+{
+ SCM_I_SET_WVECT_GC_CHAIN (w, weak_vectors);
+ weak_vectors = w;
+}
-static void *
-scm_mark_weak_vector_spines (void *dummy1 SCM_UNUSED,
- void *dummy2 SCM_UNUSED,
- void *dummy3 SCM_UNUSED)
+static int
+scm_i_mark_weak_vector_non_weaks (SCM w)
{
- SCM w;
+ int again = 0;
- for (w = scm_weak_vectors; !SCM_NULLP (w); w = SCM_WVECT_GC_CHAIN (w))
+ if (SCM_IS_WHVEC_ANY (w))
{
- if (SCM_IS_WHVEC_ANY (w))
+ SCM *ptr;
+ long n = SCM_I_WVECT_LENGTH (w);
+ long j;
+ int weak_keys = SCM_IS_WHVEC (w) || SCM_IS_WHVEC_B (w);
+ int weak_values = SCM_IS_WHVEC_V (w) || SCM_IS_WHVEC_B (w);
+
+ ptr = SCM_I_WVECT_GC_WVELTS (w);
+
+ for (j = 0; j < n; ++j)
{
- SCM const *ptr;
- SCM obj;
- long j;
- long n;
-
- obj = w;
- ptr = SCM_VELTS (w);
- n = SCM_VECTOR_LENGTH (w);
- for (j = 0; j < n; ++j)
+ SCM alist, slow_alist;
+ int slow_toggle = 0;
+
+ /* We do not set the mark bits of the alist spine cells here
+ since we do not want to ever create the situation where a
+ marked cell references an unmarked cell (except in
+ scm_gc_mark, where the referenced cells will be marked
+ immediately). Thus, we can not use mark bits to stop us
+ from looping indefinitely over a cyclic alist. Instead,
+ we use the standard tortoise and hare trick to catch
+ cycles. The fast walker does the work, and stops when it
+ catches the slow walker to ensure that the whole cycle
+ has been worked on.
+ */
+
+ alist = slow_alist = ptr[j];
+
+ while (scm_is_pair (alist))
{
- SCM alist;
+ SCM elt = SCM_CAR (alist);
- alist = ptr[j];
- while ( SCM_CONSP (alist)
- && !SCM_GC_MARK_P (alist)
- && SCM_CONSP (SCM_CAR (alist)))
+ if (UNMARKED_CELL_P (elt))
{
- SCM_SET_GC_MARK (alist);
- SCM_SET_GC_MARK (SCM_CAR (alist));
- alist = SCM_CDR (alist);
+ if (scm_is_pair (elt))
+ {
+ SCM key = SCM_CAR (elt);
+ SCM value = SCM_CDR (elt);
+
+ if (!((weak_keys && UNMARKED_CELL_P (key))
+ || (weak_values && UNMARKED_CELL_P (value))))
+ {
+ /* The item should be kept. We need to mark it
+ recursively.
+ */
+ scm_gc_mark (elt);
+ again = 1;
+ }
+ }
+ else
+ {
+ /* A non-pair cell element. This should not
+ appear in a real alist, but when it does, we
+ need to keep it.
+ */
+ scm_gc_mark (elt);
+ again = 1;
+ }
+ }
+
+ alist = SCM_CDR (alist);
+
+ if (slow_toggle && scm_is_pair (slow_alist))
+ {
+ slow_alist = SCM_CDR (slow_alist);
+ slow_toggle = !slow_toggle;
+ if (scm_is_eq (slow_alist, alist))
+ break;
}
}
+ if (!scm_is_pair (alist))
+ scm_gc_mark (alist);
}
}
- return 0;
+ return again;
}
-#define UNMARKED_CELL_P(x) (SCM_NIMP(x) && !SCM_GC_MARK_P (x))
+int
+scm_i_mark_weak_vectors_non_weaks ()
+{
+ int again = 0;
+ SCM w = weak_vectors;
+ while (!scm_is_null (w))
+ {
+ if (scm_i_mark_weak_vector_non_weaks (w))
+ again = 1;
+ w = SCM_I_WVECT_GC_CHAIN (w);
+ }
+ return again;
+}
-static void *
-scm_scan_weak_vectors (void *dummy1 SCM_UNUSED,
- void *dummy2 SCM_UNUSED,
- void *dummy3 SCM_UNUSED)
+static void
+scm_i_remove_weaks (SCM w)
{
- SCM *ptr, w;
- for (w = scm_weak_vectors; !SCM_NULLP (w); w = SCM_WVECT_GC_CHAIN (w))
+ SCM *ptr = SCM_I_WVECT_GC_WVELTS (w);
+ size_t n = SCM_I_WVECT_LENGTH (w);
+ size_t i;
+
+ if (!SCM_IS_WHVEC_ANY (w))
{
- if (!SCM_IS_WHVEC_ANY (w))
- {
- register long j, n;
+ for (i = 0; i < n; ++i)
+ if (UNMARKED_CELL_P (ptr[i]))
+ ptr[i] = SCM_BOOL_F;
+ }
+ else
+ {
+ size_t delta = 0;
- ptr = SCM_GC_WRITABLE_VELTS (w);
- n = SCM_VECTOR_LENGTH (w);
- for (j = 0; j < n; ++j)
- if (UNMARKED_CELL_P (ptr[j]))
- ptr[j] = SCM_BOOL_F;
- }
- else /* if (SCM_IS_WHVEC_ANY (scm_weak_vectors[i])) */
+ for (i = 0; i < n; ++i)
{
- SCM obj = w;
- register long n = SCM_VECTOR_LENGTH (w);
- register long j;
- int weak_keys = SCM_IS_WHVEC (obj) || SCM_IS_WHVEC_B (obj);
- int weak_values = SCM_IS_WHVEC_V (obj) || SCM_IS_WHVEC_B (obj);
-
- ptr = SCM_GC_WRITABLE_VELTS (w);
+ SCM alist, *fixup;
- for (j = 0; j < n; ++j)
+ fixup = ptr + i;
+ alist = *fixup;
+ while (scm_is_pair (alist) && !SCM_GC_MARK_P (alist))
{
- SCM * fixup;
- SCM alist;
-
- fixup = ptr + j;
- alist = *fixup;
-
- while (SCM_CONSP (alist)
- && SCM_CONSP (SCM_CAR (alist)))
+ if (UNMARKED_CELL_P (SCM_CAR (alist)))
{
- SCM key;
- SCM value;
-
- key = SCM_CAAR (alist);
- value = SCM_CDAR (alist);
- if ( (weak_keys && UNMARKED_CELL_P (key))
- || (weak_values && UNMARKED_CELL_P (value)))
- {
- *fixup = SCM_CDR (alist);
- }
- else
- fixup = SCM_CDRLOC (alist);
- alist = SCM_CDR (alist);
+ *fixup = SCM_CDR (alist);
+ delta++;
}
+ else
+ {
+ SCM_SET_GC_MARK (alist);
+ fixup = SCM_CDRLOC (alist);
+ }
+ alist = *fixup;
}
}
+#if 0
+ if (delta)
+ fprintf (stderr, "vector %p, delta %d\n", w, delta);
+#endif
+ SCM_I_SET_WVECT_DELTA (w, delta);
}
+}
- return 0;
+void
+scm_i_remove_weaks_from_weak_vectors ()
+{
+ SCM w = weak_vectors;
+ while (!scm_is_null (w))
+ {
+ scm_i_remove_weaks (w);
+ w = SCM_I_WVECT_GC_CHAIN (w);
+ }
}
\f
-void
-scm_weaks_prehistory ()
+SCM
+scm_init_weaks_builtins ()
{
- scm_c_hook_add (&scm_before_mark_c_hook, scm_weak_vector_gc_init, 0, 0);
- scm_c_hook_add (&scm_before_sweep_c_hook, scm_mark_weak_vector_spines, 0, 0);
- scm_c_hook_add (&scm_after_sweep_c_hook, scm_scan_weak_vectors, 0, 0);
+#include "libguile/weaks.x"
+ return SCM_UNSPECIFIED;
}
-
void
scm_init_weaks ()
{
-#include "libguile/weaks.x"
+ scm_c_define_gsubr ("%init-weaks-builtins", 0, 0, 0,
+ scm_init_weaks_builtins);
}
HCoop / bpt / guile.git / blobdiff