hash: use full width unsigned type for hash values.

Throughout the hashing framework, hashes are reduced into the
fixnum range, and returned as cnum.  This is not necessary;
only the hash-eql and hash-equal functions need to reduce
hashes to fixnums. Let's make it ucnum everywhere else, using
its full range (no reduction into the [0, NUM_MAX) range).

* hash.c (struct hash_ops): hash_fun function pointer returns
ucnum instead of cnum.
(hash_double): Return unreduced ucnum. Obsolete #ifdef-s
removed; the ucnum type gives us a pointer-wide unsigned
integer on all platforms.
(equal_hash, eql_hash): Return ucnum. Don't reduce values to
fixnum range. Some of the way we combine hashes from recursive
calls changes; we multiply by at most 2 not to lose too many
bits.
(eql_hash_op, cobj_eq_hash_op, hash_hash_op): Return ucnum.

* hash.h (equal_hash): Declaration updated.

* lib.c (cobj_handle_hash_op): Return value changes to ucnum.

* lib.h (struct cobj_ops): Hash function pointer's return
type changes.
(cobj_eq_hash_op, cobj_handle_hash_op): Declarations updated.

* struct.c (struct_inst_hash): Return value changes to ucnum.

1 files changed, 1 insertions, 1 deletions

diff --git a/hash.h b/hash.h
index 2b8f70b2..c4181699 100644
--- a/hash.h
+++ b/hash.h
@@ -27,7 +27,7 @@
 
 extern val weak_keys_k, weak_vals_k, equal_based_k, eql_based_k, userdata_k;
 
-cnum equal_hash(val obj, int *count, ucnum);
+ucnum equal_hash(val obj, int *count, ucnum);
 val make_seeded_hash(val weak_keys, val weak_vals, val equal_based, val seed);
 val make_hash(val weak_keys, val weak_vals, val equal_based);
 val make_similar_hash(val existing);