[pypy-svn] r78167 - pypy/trunk/pypy/module/array

[arigo at codespeak.net]

Author: arigo
Date: Thu Oct 21 13:49:16 2010
New Revision: 78167

Modified:
   pypy/trunk/pypy/module/array/interp_array.py
Log:
Reorder a bit the code in item_w().  It should help the JIT
generate less operations, because it doesn't need to compare
the item with the lower and upper bounds explicitly.  It only
needs to do the casting (which requires masking) and then
comparing the result with the original value.


Modified: pypy/trunk/pypy/module/array/interp_array.py
==============================================================================
--- pypy/trunk/pypy/module/array/interp_array.py	(original)
+++ pypy/trunk/pypy/module/array/interp_array.py	Thu Oct 21 13:49:16 2010
@@ -192,32 +192,30 @@
                           mytype.bytes
                     raise OperationError(space.w_OverflowError,
                                          space.wrap(msg))
-            elif mytype.unwrap == 'str_w' or mytype.unwrap == 'unicode_w':
+                return rffi.cast(mytype.itemtype, item)
+            if mytype.unwrap == 'str_w' or mytype.unwrap == 'unicode_w':
                 if len(item) != 1:
                     msg = 'array item must be char'
                     raise OperationError(space.w_TypeError, space.wrap(msg))
                 item = item[0]
-
+                return rffi.cast(mytype.itemtype, item)
+            #
+            # "regular" case: it fits in an rpython integer (lltype.Signed)
+            result = rffi.cast(mytype.itemtype, item)
             if mytype.canoverflow:
-                msg = None
-                if mytype.signed:
-                    if item < -1 << (mytype.bytes * 8 - 1):
+                if rffi.cast(lltype.Signed, result) != item:
+                    # overflow.  build the correct message
+                    if item < 0:
                         msg = ('signed %d-byte integer is less than minimum' %
                                mytype.bytes)
-                    elif item > (1 << (mytype.bytes * 8 - 1)) - 1:
+                    else:
                         msg = ('signed %d-byte integer is greater than maximum'
                                % mytype.bytes)
-                else:
-                    if item < 0:
-                        msg = ('unsigned %d-byte integer is less than minimum'
-                               % mytype.bytes)
-                    elif item > (1 << (mytype.bytes * 8)) - 1:
-                        msg = ('unsigned %d-byte integer is greater'
-                               ' than maximum' % mytype.bytes)
-                if msg is not None:
+                    if not mytype.signed:
+                        msg = 'un' + msg      # 'signed' => 'unsigned'
                     raise OperationError(space.w_OverflowError,
                                          space.wrap(msg))
-            return rffi.cast(mytype.itemtype, item)
+            return result
 
         def __del__(self):
             self.setlen(0)