gistfile1.diff

diff --git a/hash.c b/hash.c
index ef8b9a8..bd60d5a 100644
--- a/hash.c
+++ b/hash.c
@@ -33,8 +33,7 @@ rb_hash_freeze(VALUE hash)
 VALUE rb_cHash;
 
 static VALUE envtbl;
-static ID id_hash, id_yield, id_default;
-
+static ID id_hash, id_yield, id_default, id_cmp;
 static int
 rb_any_cmp(VALUE a, VALUE b)
 {
@@ -99,6 +98,14 @@ rb_any_hash(VALUE a)
     return (st_index_t)RSHIFT(hnum, 1);
 }
 
+static int
+rb_uniform_cmp(VALUE a, VALUE b)
+{
+       if (rb_respond_to(a, id_cmp) && rb_respond_to(b, id_cmp))
+    return FIX2INT(rb_funcall(a, id_cmp, 1, b));
+       rb_raise(rb_eRuntimeError, "object expected to implement a Comparable interface");
+}
+
 static const struct st_hash_type objhash = {
     rb_any_cmp,
     rb_any_hash,
@@ -109,6 +116,11 @@ static const struct st_hash_type identhash = {
     st_numhash,
 };
 
+static const struct st_hash_type uniformhash = {
+    rb_uniform_cmp,
+    rb_any_hash,
+};
+
 typedef int st_foreach_func(st_data_t, st_data_t, st_data_t);
 
 struct foreach_safe_arg {
@@ -1852,6 +1864,26 @@ rb_hash_compare_by_id_p(VALUE hash)
     return Qfalse;
 }
 
+static VALUE
+rb_hash_uniform(VALUE hash)
+{
+    rb_hash_modify(hash);
+    RHASH(hash)->ntbl->type = &uniformhash;
+    rb_hash_rehash(hash);
+    return hash;
+}
+
+static VALUE
 
     rb_cHash = rb_define_class("Hash", rb_cObject);
 
@@ -2716,6 +2749,9 @@ Init_Hash(void)
     rb_define_method(rb_cHash,"compare_by_identity", rb_hash_compare_by_id, 0);
     rb_define_method(rb_cHash,"compare_by_identity?", rb_hash_compare_by_id_p, 0);
 
+    rb_define_method(rb_cHash,"uniform", rb_hash_uniform, 0);
+    rb_define_method(rb_cHash,"uniform?", rb_hash_uniform_p, 0);
+
     origenviron = environ;
     envtbl = rb_obj_alloc(rb_cObject);
     rb_extend_object(envtbl, rb_mEnumerable);
diff --git a/test/ruby/test_hash.rb b/test/ruby/test_hash.rb
index c860b25..5ad86a4 100644
--- a/test/ruby/test_hash.rb
+++ b/test/ruby/test_hash.rb
@@ -861,6 +861,31 @@ class TestHash < Test::Unit::TestCase
     assert_equal({o1=>1,o2=>2}.hash, {o2=>2,o1=>1}.hash)
   end
 
+  class MemorySlot
+    attr_reader :size
+    def initialize(size)
+      @size = size
+    end
+    
+    def <=>(other)
+      size <=> other.size
+    end
+    alias hash size
+  end
+
+  def test_uniform
+    s = MemorySlot.new(256)
+    s1 = MemorySlot.new(512)    
+    assert(!{}.uniform?)
+    h = { s => %w(obj1 obj2 ob3) }
+    h.uniform 
+    assert(h.uniform?)
+    assert_equal %w(obj1 obj2 ob3), h[s]
+    h[s1] = %w(obj4)
+    h[MemorySlot.new(256)] = %w(obj1)
+    assert_equal %w(obj1), h[s]
+  end
+
   def test_hash_bignum_hash
     x = 2<<(32-3)-1
     assert_equal({x=>1}.hash, {x=>1}.hash)