dmbcs/guile
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

* hashtab.c (scm_i_rehash): Cope with the case that a GC modifies

Browse source 
the hashtable.
(scm_hash_fn_create_handle_x): Likewise.
* vectors.h (SCM_I_SET_WVECT_TYPE): New, for use in scm_i_rehash.
This commit is contained in:
Marius Vollmer 2005-02-23 17:24:19 +00:00
commit bc6580eb22
2 changed files with 32 additions and 13 deletions
Download patch file Download diff file Expand all files Collapse all files

40
libguile/hashtab.c
View file

@ -162,25 +162,40 @@ scm_i_rehash (SCM table,
else
new_buckets = scm_c_make_vector (new_size, SCM_EOL);
/* When this is a weak hashtable, running the GC might change it.
We need to cope with this while rehashing its elements. We do
this by first installing the new, empty bucket vector and turning
the old bucket vector into a regularily scanned weak vector.
Then we iterate over the elements in the old bucket vector.
While iterating, the elements in LS will not disappear since they
are protected.
*/
SCM_SET_HASHTABLE_VECTOR (table, new_buckets);
SCM_SET_HASHTABLE_N_ITEMS (table, 0);
if (SCM_HASHTABLE_WEAK_P (table))
SCM_I_SET_WVECT_TYPE (buckets, (SCM_HASHTABLE_FLAGS (table)));
old_size = SCM_SIMPLE_VECTOR_LENGTH (buckets);
for (i = 0; i < old_size; ++i)
{
SCM ls = SCM_SIMPLE_VECTOR_REF (buckets, i), handle;
while (!scm_is_null (ls))
SCM ls, cell, handle;
ls = SCM_SIMPLE_VECTOR_REF (buckets, i);
while (scm_is_pair (ls))
{
unsigned long h;
handle = SCM_CAR (ls);
cell = ls;
handle = SCM_CAR (cell);
ls = SCM_CDR (ls);
h = hash_fn (SCM_CAR (handle), new_size, closure);
if (h >= new_size)
scm_out_of_range (func_name, scm_from_ulong (h));
SCM_SIMPLE_VECTOR_SET
(new_buckets, h,
scm_cons (handle,
SCM_SIMPLE_VECTOR_REF (new_buckets, h)));
ls = SCM_CDR (ls);
SCM_SETCDR (cell, SCM_SIMPLE_VECTOR_REF (new_buckets, h));
SCM_SIMPLE_VECTOR_SET (new_buckets, h, cell);
SCM_HASHTABLE_INCREMENT (table);
}
}
SCM_SET_HASHTABLE_VECTOR (table, new_buckets);
}
@ -475,8 +490,11 @@ scm_hash_fn_create_handle_x (SCM table, SCM obj, SCM init, unsigned long (*hash_
return it;
else
{
SCM old_bucket = SCM_SIMPLE_VECTOR_REF (buckets, k);
SCM new_bucket = scm_acons (obj, init, old_bucket);
/* We need to take care not to run the GC while linking the new
bucket into its chain. A GC might change a weak hashtable.
*/
SCM new_bucket = scm_acons (obj, init, SCM_EOL);
SCM_SETCDR (new_bucket, SCM_SIMPLE_VECTOR_REF (buckets, k));
SCM_SIMPLE_VECTOR_SET (buckets, k, new_bucket);
if (table != buckets)
{