summaryrefslogtreecommitdiff
path: root/hash.c
diff options
context:
space:
mode:
authornobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2015-01-23 02:36:50 (GMT)
committernobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2015-01-23 02:36:50 (GMT)
commit059ea6e4d8233606d7dd522155744501b274acd4 (patch)
tree5f566d568fa09d85ad8e732f0d36167a53bed788 /hash.c
parent51efda1ef3f17ff87e23d56bb40939d90b0e921c (diff)
hash.c: move Hash specific functions
* hash.c (rb_ident_hash): move compare_by_identity specific function from st.c. * hash.c (rb_ident_hash_new): ditto from thread.c. * st.c (st_numhash): remove ruby's Hash specific implementation. * thread.c (recursive_list_access): use rb_ident_hash_new(). git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49386 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'hash.c')
-rw-r--r--hash.c42
1 files changed, 41 insertions, 1 deletions
diff --git a/hash.c b/hash.c
index b7e2c66..bae417c 100644
--- a/hash.c
+++ b/hash.c
@@ -177,7 +177,39 @@ static const struct st_hash_type objhash = {
rb_any_hash,
};
-#define identhash st_hashtype_num
+#define rb_ident_cmp st_numcmp
+
+static st_index_t
+rb_ident_hash(st_data_t n)
+{
+ /*
+ * This hash function is lightly-tuned for Ruby. Further tuning
+ * should be possible. Notes:
+ *
+ * - (n >> 3) alone is great for heap objects and OK for fixnum,
+ * however symbols perform poorly.
+ * - (n >> (RUBY_SPECIAL_SHIFT+3)) was added to make symbols hash well,
+ * n.b.: +3 to remove ID scope, +1 worked well initially, too
+ * - (n << 3) was finally added to avoid losing bits for fixnums
+ * - avoid expensive modulo instructions, it is currently only
+ * shifts and bitmask operations.
+ * - flonum (on 64-bit) is pathologically bad, mix the actual
+ * float value in, but do not use the float value as-is since
+ * many integers get interpreted as 2.0 or -2.0 [Bug #10761]
+ */
+#ifdef USE_FLONUM /* RUBY */
+ if (FLONUM_P(n)) {
+ n ^= (st_data_t)rb_float_value(n);
+ }
+#endif
+
+ return (st_index_t)((n>>(RUBY_SPECIAL_SHIFT+3)|(n<<3)) ^ (n>>3));
+}
+
+static const struct st_hash_type identhash = {
+ rb_ident_cmp,
+ rb_ident_hash,
+};
typedef int st_foreach_func(st_data_t, st_data_t, st_data_t);
@@ -2509,6 +2541,14 @@ rb_hash_compare_by_id_p(VALUE hash)
return Qfalse;
}
+VALUE
+rb_ident_hash_new(void)
+{
+ VALUE hash = rb_hash_new();
+ RHASH(hash)->ntbl = st_init_table(&identhash);
+ return hash;
+}
+
static int
any_p_i(VALUE key, VALUE value, VALUE arg)
{