Reduce work done by hashing.

Curtail traversal of objects and strings.

* hash.c (struct hash): hash_fun member takes int *
parameter now.
(HASH_STR_LIMIT, HASH_REC_LIMIT): New macros.
(hash_c_str): Hash only HASH_STR_LIMIT characters.
(equal_hash): Becomes extern function. Takes pointer-to-int
count argument, which is decremented. Function stops
recursing and returns zero when this hits zero.
(eql_hash): Also takes int * param, for compatibility
with function pointer in struct hash. This parameter
is not used, though.
(cobj_hash_op): Take pointer-to-count parameter,
but ignore it.
(hash_hash_op): Take pointer-to-count parameter,
decrement and check that it has not hit zero,
pass down to equal hash.
(hash_grow, gethash_c, gethash, gethash_f, gethash_n,
remhash): Initialize a counter to HASH_REC_LIMIT and
pass down to hashing function.
(hash_eql): Pass down a pointer to a dummy counter
to eql_hash.
(hash_equal): Initialize a counter to HASH_REC_LIMIT
and pass down to hash_equal.

* hash.h (equal_hash): Declared.

* lib.h (cobj_ops): hash member takes int * parameter.
(cobj_hash_op): Declaration updated with new param.

* struct.c (struct_inst_hash): Takes new int * parameter
for count. Calls equal_hash instead of hash_equal,
eliminating c_num calls; pointer to count is
passed to equal_hash.

1 files changed, 4 insertions, 4 deletions

diff --git a/struct.c b/struct.c
index 7cfdee24..2318ee8b 100644
--- a/struct.c
+++ b/struct.c
@@ -1044,17 +1044,17 @@ static val struct_inst_equal(val left, val right)
   return t;
 }
 
-static cnum struct_inst_hash(val obj)
+static cnum struct_inst_hash(val obj, int *count)
 {
   struct struct_inst *si = coerce(struct struct_inst *, obj->co.handle);
   struct struct_type *st = si->type;
-  cnum nslots = st->nslots, sl, out = c_num(hash_equal(st->self));
+  cnum nslots = st->nslots, sl, out = equal_hash(st->self, count);
 
   check_init_lazy_struct(obj, si);
 
   for (sl = 0; sl < nslots; sl++) {
-    val hash = hash_equal(si->slot[sl]);
-    out += c_num(hash);
+    cnum hash = equal_hash(si->slot[sl], count);
+    out += hash;
     out &= NUM_MAX;
   }