diff options
Diffstat (limited to 'hash.c')
-rw-r--r-- | hash.c | 44 |
1 files changed, 44 insertions, 0 deletions
@@ -1519,6 +1519,49 @@ rb_hash_eql(hash1, hash2) return hash_equal(hash1, hash2, Qtrue); } + +rb_hash_hash_i(key, value, hp) + VALUE key, value; + long *hp; +{ + long h = *hp; + VALUE n; + + h = (h << 1) | (h<0 ? 1 : 0); + n = rb_hash(key); + h ^= NUM2LONG(n); + h = (h << 1) | (h<0 ? 1 : 0); + n = rb_hash(value); + h ^= NUM2LONG(n); + + *hp = h; + return ST_CONTINUE; +} + +/* + * call-seq: + * hash.hash -> fixnum + * + * Compute a hash-code for this hash. Two hashes with the same content + * will have the same hash code (and will compare using <code>eql?</code>). + */ + +static VALUE +rb_hash_hash(hash) + VALUE hash; +{ + long h; + VALUE n; + + h = RHASH(hash)->tbl->num_entries; + rb_hash_foreach(hash, rb_hash_hash_i, (VALUE)&h); + h = (h << 1) | (h<0 ? 1 : 0); + n = rb_hash(RHASH(hash)->ifnone); + h ^= NUM2LONG(n); + + return LONG2FIX(h); +} + static int rb_hash_invert_i(key, value, hash) VALUE key, value; @@ -2454,6 +2497,7 @@ Init_Hash() rb_define_method(rb_cHash,"==", rb_hash_equal, 1); rb_define_method(rb_cHash,"eql?", rb_hash_eql, 1); + rb_define_method(rb_cHash,"hash", rb_hash_hash, 0); rb_define_method(rb_cHash,"[]", rb_hash_aref, 1); rb_define_method(rb_cHash,"fetch", rb_hash_fetch, -1); rb_define_method(rb_cHash,"[]=", rb_hash_aset, 2); |