[pypy-commit] lang-smalltalk default: (cfbolz, lwassermann): implemented unwrap_uint using polymorphism to get rid of loop and extensive branches

[lwassermann]

Author: Lars Wassermann <lars.wassermann at gmail.com>
Branch: 
Changeset: r255:8f0af90c962e
Date: 2013-04-11 15:04 +0200
http://bitbucket.org/pypy/lang-smalltalk/changeset/8f0af90c962e/

Log:	(cfbolz, lwassermann): implemented unwrap_uint using polymorphism to
	get rid of loop and extensive branches

diff --git a/spyvm/model.py b/spyvm/model.py
--- a/spyvm/model.py
+++ b/spyvm/model.py
@@ -127,6 +127,9 @@
     def rshift(self, space, shift):
         raise error.PrimitiveFailedError()
 
+    def unwrap_uint(self, space):
+        raise error.UnwrappingError("Got unexpected class in unwrap_uint")
+
 class W_SmallInteger(W_Object):
     """Boxed integer value"""
     # TODO can we tell pypy that its never larger then 31-bit?
@@ -165,6 +168,14 @@
     def rshift(self, space, shift):
         return space.wrap_int(self.value >> shift)
 
+    def unwrap_uint(self, space):
+        from rpython.rlib.rarithmetic import r_uint
+        val = self.value
+        if val < 0:
+            raise error.UnwrappingError("got negative integer")
+        return r_uint(val)
+
+
     @jit.elidable
     def as_repr_string(self):
         return "W_SmallInteger(%d)" % self.value
@@ -262,6 +273,10 @@
         # and only in this case we do need such a mask
         return space.wrap_int((self.value >> shift) & mask)
 
+    def unwrap_uint(self, space):
+        from rpython.rlib.rarithmetic import r_uint
+        return r_uint(self.value)
+
     def clone(self, space):
         return W_LargePositiveInteger1Word(self.value)
 
@@ -651,6 +666,16 @@
         w_result.bytes = list(self.bytes)
         return w_result
 
+    def unwrap_uint(self, space):
+        # TODO: Completely untested! This failed translation bigtime...
+        # XXX Probably we want to allow all subclasses
+        if not self.getclass(space).is_same_object(space.w_LargePositiveInteger):
+            raise error.UnwrappingError("Failed to convert bytes to word")
+        word = 0 
+        for i in range(self.size()):
+            word += r_uint(ord(self.getchar(i))) << 8*i
+        return word
+
 class W_WordsObject(W_AbstractObjectWithClassReference):
     _attrs_ = ['words']
 
diff --git a/spyvm/objspace.py b/spyvm/objspace.py
--- a/spyvm/objspace.py
+++ b/spyvm/objspace.py
@@ -251,24 +251,7 @@
         raise UnwrappingError("expected a W_SmallInteger or W_LargePositiveInteger1Word, got %s" % (w_value,))
 
     def unwrap_uint(self, w_value):
-        if isinstance(w_value, model.W_SmallInteger):
-            val = w_value.value
-            if val < 0:
-                raise UnwrappingError("got negative integer")
-            return r_uint(w_value.value)
-        elif isinstance(w_value, model.W_LargePositiveInteger1Word):
-            return r_uint(w_value.value)
-        elif isinstance(w_value, model.W_BytesObject):
-            # TODO: Completely untested! This failed translation bigtime...
-            # XXX Probably we want to allow all subclasses
-            if not w_value.getclass(self).is_same_object(self.w_LargePositiveInteger):
-                raise UnwrappingError("Failed to convert bytes to word")
-            word = 0 
-            for i in range(w_value.size()):
-                word += r_uint(ord(w_value.getchar(i))) << 8*i
-            return word
-        else:
-            raise UnwrappingError("Got unexpected class in unwrap_uint")
+        return w_value.unwrap_uint(self)
 
     def unwrap_positive_32bit_int(self, w_value):
         if isinstance(w_value, model.W_SmallInteger):