[pypy-commit] pypy default: Turns out we can more or less write ctypes' from_buffer() method

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: 
Changeset: r75550:48b86a2aba0e
Date: 2015-01-27 19:45 +0100
http://bitbucket.org/pypy/pypy/changeset/48b86a2aba0e/

Log:	Turns out we can more or less write ctypes' from_buffer() method
	with the existing RPython-provided logic.

diff --git a/lib-python/2.7/ctypes/test/test_frombuffer.py b/lib-python/2.7/ctypes/test/test_frombuffer.py
--- a/lib-python/2.7/ctypes/test/test_frombuffer.py
+++ b/lib-python/2.7/ctypes/test/test_frombuffer.py
@@ -11,7 +11,6 @@
         self._init_called = True
 
 class Test(unittest.TestCase):
-    @xfail
     def test_fom_buffer(self):
         a = array.array("i", range(16))
         x = (c_int * 16).from_buffer(a)
@@ -34,7 +33,7 @@
         del a; gc.collect(); gc.collect(); gc.collect()
         self.assertEqual(x[:], expected)
 
-        self.assertRaises(TypeError,
+        self.assertRaises((TypeError, ValueError),
                           (c_char * 16).from_buffer, "a" * 16)
 
     @xfail
diff --git a/lib_pypy/_ctypes/basics.py b/lib_pypy/_ctypes/basics.py
--- a/lib_pypy/_ctypes/basics.py
+++ b/lib_pypy/_ctypes/basics.py
@@ -83,6 +83,13 @@
     def in_dll(self, dll, name):
         return self.from_address(dll._handle.getaddressindll(name))
 
+    def from_buffer(self, obj, offset=0):
+        # XXX missing size checks
+        raw_addr = buffer(obj, offset)._pypy_raw_address()
+        result = self.from_address(raw_addr)
+        result._ensure_objects()['ffffffff'] = obj
+        return result
+
 class CArgObject(object):
     """ simple wrapper around buffer, just for the case of freeing
     it afterwards
diff --git a/lib_pypy/_ctypes/structure.py b/lib_pypy/_ctypes/structure.py
--- a/lib_pypy/_ctypes/structure.py
+++ b/lib_pypy/_ctypes/structure.py
@@ -1,3 +1,4 @@
+import sys
 import _rawffi
 from _ctypes.basics import _CData, _CDataMeta, keepalive_key,\
      store_reference, ensure_objects, CArgObject
@@ -178,6 +179,8 @@
         instance = StructOrUnion.__new__(self)
         if isinstance(address, _rawffi.StructureInstance):
             address = address.buffer
+        # fix the address: turn it into as unsigned, in case it is negative
+        address = address & (sys.maxint * 2 + 1)
         instance.__dict__['_buffer'] = self._ffistruct.fromaddress(address)
         return instance