* hash.c (rb_hash_update_by): new API for Hash#update.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@30078 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,7 @@
+Sat Dec  4 11:21:50 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* hash.c (rb_hash_update_by): new API for Hash#update.
+
 Sat Dec  4 11:18:10 2010  Tanaka Akira  <akr@fsij.org>
 
 	* class.c: parenthesize macro arguments.

hash.c

@@ -1785,6 +1785,43 @@ rb_hash_update(VALUE hash1, VALUE hash2)
     return hash1;
 }
 
+struct update_arg {
+    VALUE hash;
+    rb_hash_update_func *func;
+};
+
+static int
+rb_hash_update_func_i(VALUE key, VALUE value, VALUE arg0)
+{
+    struct update_arg *arg = (struct update_arg *)arg0;
+    VALUE hash = arg->hash;
+
+    if (key == Qundef) return ST_CONTINUE;
+    if (rb_hash_has_key(hash, key)) {
+	value = (*arg->func)(key, rb_hash_aref(hash, key), value);
+    }
+    hash_update(hash, key);
+    st_insert(RHASH(hash)->ntbl, key, value);
+    return ST_CONTINUE;
+}
+
+VALUE
+rb_hash_update_by(VALUE hash1, VALUE hash2, rb_hash_update_func *func)
+{
+    rb_hash_modify(hash1);
+    hash2 = to_hash(hash2);
+    if (func) {
+	struct update_arg arg;
+	arg.hash = hash1;
+	arg.func = func;
+	rb_hash_foreach(hash2, rb_hash_update_func_i, (VALUE)&arg);
+    }
+    else {
+	rb_hash_foreach(hash2, rb_hash_update_i, hash1);
+    }
+    return hash1;
+}
+
 /*
  *  call-seq:
  *     hsh.merge(other_hash)                              -> new_hash

include/ruby/intern.h

@@ -436,6 +436,8 @@ VALUE rb_hash_fetch(VALUE, VALUE);
 VALUE rb_hash_aset(VALUE, VALUE, VALUE);
 VALUE rb_hash_delete_if(VALUE);
 VALUE rb_hash_delete(VALUE,VALUE);
+typedef VALUE rb_hash_update_func(VALUE newkey, VALUE oldkey, VALUE value);
+VALUE rb_hash_update_by(VALUE hash1, VALUE hash2, rb_hash_update_func *func);
 struct st_table *rb_hash_tbl(VALUE);
 int rb_path_check(const char*);
 int rb_env_path_tainted(void);