[pypy-commit] pypy PyBuffer: Optimise the common case of slicing a SimpleBuffer (fixes #2516?)

[rlamy]

Author: Ronan Lamy <ronan.lamy at gmail.com>
Branch: PyBuffer
Changeset: r91108:dce1ad161087
Date: 2017-04-21 04:11 +0100
http://bitbucket.org/pypy/pypy/changeset/dce1ad161087/

Log:	Optimise the common case of slicing a SimpleBuffer (fixes #2516?)

diff --git a/pypy/objspace/std/memoryobject.py b/pypy/objspace/std/memoryobject.py
--- a/pypy/objspace/std/memoryobject.py
+++ b/pypy/objspace/std/memoryobject.py
@@ -5,7 +5,7 @@
 
 from rpython.rlib.objectmodel import compute_hash
 from pypy.interpreter.baseobjspace import W_Root
-from pypy.interpreter.buffer import PyBuffer, SubBuffer
+from pypy.interpreter.buffer import PyBuffer, SimpleBuffer, SubBuffer
 from pypy.interpreter.error import OperationError, oefmt
 from pypy.interpreter.gateway import interp2app
 from pypy.interpreter.typedef import TypeDef, GetSetProperty,  make_weakref_descr
@@ -166,7 +166,10 @@
             raise TypeError("memoryview: invalid slice key")
 
     def new_slice(self, start, stop, step, slicelength, dim):
-        sliced = BufferSlice(self.buf, start, step, slicelength)
+        if step == 1 and isinstance(self.buf, SimpleBuffer):
+            sliced = SimpleBuffer(SubBuffer(self.buf.data, start, slicelength))
+        else:
+            sliced = BufferSlice(self.buf, start, step, slicelength)
         return W_MemoryView(sliced)
 
     def init_len(self):